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PubMed1994

The role of cytokines in the formation of the schistosome egg granuloma.

Schistosomiasis mansoni is a helminth-induced disease infecting over 120 million people in the tropics. Morbidity and mortality are caused by parasite eggs that evoke in the liver and intestines of infected persons, T cell-mediated granulomatous inflammation and irreversible fibrosis. In the murine model granulomatous inflammation is induced by CD4+ T helper lymphocytes. This short review summarizes recent observations that implicate a variety of lymphokines and cytokines as mediators of the granulomatous inflammatory response. Mediator production was examined in splenocyte as well as granuloma cell cultures of infected or egg granuloma-bearing mice. In the synchronous pulmonary granuloma model generated around i.v. injected eggs in naive mice IL-1 mRNA expression and IL-1 production were detectable within the first 4 days of granuloma growth. After 4-6 days TNF-alpha mRNA message appeared and cytokine production was observed. With the aging of the granuloma, production of both cytokines diminished. Thus, these cytokines are considered to be the primary recruiters of cellular aggregation in granuloma growth. The role of TNF-alpha in granuloma formation was also confirmed in infected mice. Whereas treatment of animals with anti-TNF-alpha antiserum diminished hepatic granuloma size, repeated injection of murine rTNF-alpha into chronically-infected mice enhanced the downmodulated granuloma response. With the administration of specific anti-lymphokine mAbs and recombinant murine lymphokines, as well as serial assays of lymphokine production by splenic, granuloma lymphocytes of infected mice, the role of INF-gamma, IL-2 and IL-4 was delineated. Interferon-gamma was found to be produced very early at the inception of the liver granulomatous response. By the time granulomas reached maximal size (8 wks post infection) production declined. Concurrently IL-2, IL-4 production peaked with maximal granuloma growth and declined with the onset of the immune modulation of the inflammation. Whereas these latter lymphokines appear to play a proinflammatory role, IFN-gamma when administered in large doses diminished granulomatous inflammation, plays a regulatory role in the maintenance of the granulomatous response. The T helper cell population of the granulomas may also influence the lymphokine profile of the developing granuloma. So far precursor type TH0, and TH2 subset of helper cells have been cloned from liver granulomas. The former secreted both IL-2, IL-4 and IFN-gamma lymphokines and adoptively transferred the granulomatous response.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Cytokine profiles of filarial granulomas in jirds infected with Brugia pahangi.

BACKGROUND: A granulomatous inflammatory response develops in jirds infected subcutaneously or intraperitoneally with filarial nematodes namely Brugia pahangi and B. malayi. Previous studies by light and electron microscopy have shown cellular inflammatory responses in and around these granulomas. Furthermore, the cellular inflammatory responses of granulomas found in the lymphatics and peritoneal cavity appear to be similar. The purpose of this study was to determine the cytokine profiles of granulomas in the peritoneal cavity of B. pahangi-infected jirds and to determine whether the granulomas release any proinflammatory cytokines ex vivo. METHODS: A semiautomated quantitative polymerase chain reaction (Q-PCR) was performed on cDNA prepared from the granulomas of infected jirds to study the species-specific mRNA expression of IL-2, IL-4, IFN-gamma, IL-5, and IL-10. Genomic DNA was extracted from the granulomas, and parasite DNA was detected by Q-PCR by amplifying the HhaI repeat sequence. The levels of the inflammation-causing cytokines IL-6 and TNFalpha that were secreted by the granulomas were measured by cell-based assays. RESULTS: Florid granulomas showed higher levels of IFN-gamma than other cytokines, linking this Th1 cytokine to the granulomatous inflammation that develops in jirds and humans. IL-4 expression was much lower than that of IFN-gamma but higher than that of IL-10. A low level of IL-5 mRNA expression was detectable in all granulomas as was the level of IL-2 expression. The levels of the inflammatory cytokines IL-6 and TNFalpha, secreted by intact granulomas, spontaneously increased by 48 h after culture. Parasite antigen stimulation and subsequent release of IL-6 and TNFalpha by the granulomas indicated a moderate increase in the levels of these two cytokines. The amplification of the Brugia HhaI repeat DNA and Wolbachia 16S rDNA indicated worm components and bacterial components in the granulomatous tissue. CONCLUSION: Granuloma development in filarial infections is a complex process involving cellular reactions responding to parasite/bacteria and their components. The interactions between worm-derived granulomas and their hosts are dynamic and multifaceted. The data collected thus far suggest that the expression profiles of many of the measured cytokines in the lymphoid tissues of Brugia-infected jirds are different from those of the cytokines in granulomas. Moreover, granulomas have the ability to secrete the inflammatory cytokines IL-6 and TNFalpha.

Journal Article↗
PubMed2005

Pyogenic granulomas after silicone punctal plugs: a clinical and histopathologic study.

PURPOSE: To describe clinical findings, histopathologic changes, and risk factors for pyogenic granuloma formation complicating silicone punctal plug therapy. DESIGN: Retrospective observational case series. METHODS: Between November 2000 and April 2004, 903 silicone punctal plugs of the same brand were inserted in 404 subjects. Cases associated with pyogenic granuloma formation were identified and reviewed. Granulation tissue was obtained from 10 patients for histopathologic examination. Multiple risk regression analyses identified factors related to pyogenic granuloma development and factors associated with histologic patterns. RESULTS: Pyogenic granuloma development led to the extrusion of 4.2% of all plugs placed in a median time period of 141 days. All patients presented with varying degrees of plug extrusion. Similar distributions of partial and complete plug extrusions, as well as bilateral and unilateral plug extrusions, were seen. Findings at presentation ranged from a subclinical pyogenic granuloma causing partial plug extrusion to a pyogenic granuloma in the punctum with a ring of fibrovascular tissue retaining a completely extruded plug. Histopathologic examination revealed two patterns, representing either acute pyogenic granuloma or involuting pyogenic granuloma. Pyogenic granulomas resolved after 3.1 +/- 1.3 weeks in all patients after plug removal. Multiple regression analysis revealed that large plug size was associated with increased pyogenic granuloma formation (P < .0001). Partial or complete plug extrusion was associated with active or involuting pyogenic granuloma, respectively (P = .023). CONCLUSION: Pyogenic granuloma-related spontaneous plug extrusions may be more common than previously thought and can present with a range of clinical findings. The degree of plug extrusion correlates with the histopathologic pattern. Larger plug size and sharp edges in plug geometry may be responsible for pyogenic granuloma formation.

Adult↗
PubMed2001

Mycobacterium bovis BCG-induced granuloma formation depends on gamma interferon and CD40 ligand but does not require CD28.

Progressive granuloma formation is a hallmark of chronic mycobacterial infection. Granulomas are localized, protective inflammatory reactions initiated by CD4+ T cells, which contribute to control of bacterial growth and blockade of bacterial dissemination. In order to understand the costimulatory requirements that allow CD4+ T cells to directly or indirectly induce granulomas, we studied granuloma formation after 6 weeks in Mycobacterium bovis BCG-infected CD28- and CD40 ligand (CD40L)-deficient mice and compared it to granuloma formation in infected wild-type inbred mice and infected cytokine-deficient mice. We characterized granulomas morphologically in liver sections, analyzed granuloma infiltrating cells by flow cytometry, and measured cytokine production by cultured granuloma cells. CD28-deficient mice have no defect at the local inflammatory site, inasmuch as they form protective granulomas and control bacterial growth. However, there are fewer activated T cells in the spleen compared to infected wild-type animals, and quantitative differences in the cellular composition of the granuloma are observed by flow cytometry. In CD40L-deficient mice, the granuloma phenotype is very similar to the phenotype in gamma interferon (IFN-gamma)-deficient mice. Both IFN-gamma-deficient and CD40L-deficient mice form granulomas which prevent bacterial dissemination, but control of bacterial growth is significantly impaired. The relative proportion of CD4+ T cells in granulomas from both CD28(-/-) and CD40L(-/-) mice is significantly decreased compared with wild-type animals. Both models demonstrate that the phenotype and activation stage of systemic T cells do not always correlate with the phenotype and activation stage of the localized granulomatous response.

Animals↗
PubMed2005

Frequency and significance of granulomas in a cohort of incident cases of Crohn's disease.

BACKGROUND AND AIMS: Epithelioid granulomas is one of the best histological criterion for distinguishing Crohn's disease (CD) from other inflammatory bowel diseases. Few data are available on the time of occurrence of epithelioid granulomas, and the value of epithelioid granulomas in predicting outcome has been determined only in cohorts of prevalent CD cases. Our objective was to evaluate epithelioid granuloma occurrence in incident CD cases and to examine the associations between epithelioid granulomas and outcome. PATIENTS AND METHODS: We reviewed the histological reports of endoscopic and surgical specimens in a cohort of 188 consecutive incident CD cases seen in 1994 and 1995, and recorded the occurrence of epithelioid granulomas, isolated giant cells, and microgranulomas. Kaplan-Meier curves were plotted for time from CD diagnosis to immunosuppressive treatment or surgery, and associations between epithelioid granulomas and outcome were evaluated in a multivariate analysis. Follow up was at least five years. RESULTS: Granulomas were found in 69 (37%) patients, including 46 (25%) at presentation. Median time from CD diagnosis to epithelioid granuloma detection was 0.16 (0-63) months overall, and 9.59 (0.1-63) months in 23 patients who became epithelioid granuloma positive during follow up. Isolated giant cells were found in 6% of patients and microgranulomas in 12%. Epithelioid granuloma detection increased with the number of endoscopic sampling procedures; sampling site had no influence. By multivariate analysis, epithelioid granulomas were associated with surgical resection but not immunosuppressive therapy. CONCLUSIONS: Epithelioid granulomas may separate CD into two pathological subsets and may indicate aggressive disease.

Adolescent↗
PubMedDate not supplied

A new morphological concept and classification of granulomatous inflammation: the polar granulomas.

An historical analysis of granulomas and a new morphological concept and classification of granulomatous inflammation, the polar-granulomas, are presented. The historical analysis of the concept of granulomas reveals that the still proclaimed confusion concerning the process was due more to Virchow's comparison of granulomas to ordinary granulation tissue than to tumors and to objections of pathologists to Metchnikoff's theory of phagocytosis. And it is strange to verify that differences between granulomas and granulation tissue, although already established in the end of the 19th Century, were overlooked by the majority of pathologists. In this Century , the knowledge of granulomatous inflammation was greatly improved by Aschoff 's concept of reticulum endothelial system, Mitsuda test for types of leprosy, Jadassohn- Lewandowsky law, South American classification of leprosy into polar forms, and Forbus contribution to histogenesis and morphological classification of granulomas. The best model for the study of granulomatous inflammation is leprosy, because this disease is characterized by two different clinical polar forms, each one having particular types of phagocytosis (complete or incomplete) and of granulomas (tuberculoid or non tuberculoid). Based on the phenomenon of phagocytosis, polar forms of leprosy, Jadassohn- Lewandowsky law, metamorphosis of macrophages and nature of the etiologic agent, granulomas can be defined as a reactional hyperplasia of macrophages towards inanimate agents and towards animate agents of low virulence. Also based in the same data, a morphological classification of granulomas into polar types, tuberculoid and non tuberculoid, is proposed. The polar tuberculoid type follows the Jadassohn- Lewandowsky law, its etiologic agent is absent or scarce (complete phagocytosis) - and comprise two sub-types: tubercle-like and sarcoid-like. The polar non tuberculoid type does not follow the Jadassohn- Lewandowsky law, its etiologic agent is always present or copious (incomplete phagocytosis) and comprises two sub-types: giant cell and persistent macrophage. In the latter case, macrophages behave as a culture medium cell or as a storage cell. When both polar tuberculoid and non tuberculoid structures are found together in the same disease, granuloma can be called interpolar . If both types occur simultaneously in the same disease, granuloma would be bipolar. It seems that the proposed definition of granulomas combines morphology with functional activity of macrophages, easily observed in routine histopathological examination by optical microscopy. This morphological classification into polar granulomas (ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Differential↗
PubMed1991

Substance P does not alter interleukin-1 expression by splenic or granuloma macrophages in murine schistosomiasis.

Substance P (SP) is an undecapeptide with neurotransmitter and immunoregulatory properties. In murine schistosomiasis, ova naturally induce liver and intestinal granulomas. These granulomas contain macrophages, and eosinophils that produce SP. A report showed that human blood monocytes isolated by adherence release interleukin-1 (IL-1) in response to SP (Lotz et al. (1989) Science 241, 1218). IL-1 is important for initiation of hypersensitivity granulomas. Therefore, it was determined whether SP modulates granuloma macrophage IL-1 production in murine schistosomiasis. Macrophages were obtained from lung and liver granulomas, and from spleens of infected mice. A thymocyte proliferation assay measured IL-1 activity in culture supernatants. Total RNA, extracted from macrophages, was assayed for IL-1 alpha and beta mRNA by Northern blotting using cDNA probes. In response to lipopolysaccharide (LPS), splenic macrophages and macrophages from young lung granulomas released appreciable IL-1. Macrophages from liver granulomas, that were lesions older than the lung granulomas, were unresponsive to LPS with regard to IL-1 secretion. Yet, granuloma macrophages spontaneously expressed IL-1 alpha and beta mRNA. LPS enhanced IL-1 mRNA expression in both splenic and granuloma macrophages. Exposure of macrophages from all sources to SP did not alter IL-1 secretion or gene expression. Similarly, the responsiveness of macrophages to LPS was not affected by concomitant exposure to SP. It is concluded that, in the murine system, SP does not directly influence splenic or granuloma macrophage IL-1 secretion or gene expression. Also, it appears that macrophage secretion of IL-1 is rapidly down-regulated following granuloma elicitation.

Animals↗
PubMed1984

Schistosoma mansoni egg granuloma size reduction in challenged baboons after vaccination with irradiated cryopreserved schistosomula.

Young male baboons born in captivity were immunized with an attenuated, cryopreserved schistosomular vaccine derived from gamma-irradiated (50 krad) cercariae of the Puerto Rican strain of Schistosoma mansoni. Protection against a heterologous Kenyan strain of S. mansoni, after percutaneous infection, was assessed. Partial protection (33-53% reduction in worm burden) was obtained in three of six vaccinated-challenged baboons, an unremarkable result. Of greater interest was the fact that all six unvaccinated-challenged control baboons, but only one of the six vaccinated-challenged baboons, had macroscopic egg granulomas on their liver surfaces. This difference in granuloma size was substantiated by measuring hepatic and colonic granulomas. The mean (+/- SEM) hepatic and colonic granuloma diameters for the six unvaccinated baboons were 406 +/- 38 micron and 313 +/- 27 micron, respectively, and for the five "typical" vaccinated-challenged baboons the mean diameters were 283 +/- 27 micron and 202 +/- 23 micron, respectively. Both hepatic and colonic granulomas were significantly smaller in the five typical vaccinated-challenged baboons. Not only did the exceptional vaccinated-challenged baboon have very large hepatic and colonic granulomas, but also it was the only one of its group whose mesenteric lymph node cells were not suppressed in their in vitro proliferative response to a schistosome antigen. These results strongly suggest that granuloma size reduction in the majority of the vaccinated baboons was the result of immunoregulation--i.e., the small postvaccination granulomas were "modulated." Despite their small size, hepatic granulomas in the typical vaccinated baboons were apparently as effective in sequestering egg toxins and preventing hepatocyte damage as the larger granulomas of the control baboons. Smaller, less obstructive granulomas are thought to be more beneficial to the host than large, vigorous granulomas, with respect to lessening chronic disease. The present results give encouragement that a vaccine to ameliorate disease in human schistosomiasis is possible. This effect should add to the attractiveness of partial protection against challenge infections conferred by attenuated larval vaccines, as reported by others, to yield a dually beneficial vaccine for human use.

Animals↗
PubMed1999

A management strategy for vocal process granulomas.

OBJECTIVES/HYPOTHESIS: Review the roles of aggressive gastroesophageal reflux management and speech therapy in the treatment of patients with vocal process granulomas. Describe and assess our investigation and management protocol. STUDY DESIGN: Retrospective review of 55 patients with 61 vocal granulomas treated according to a standard protocol at the Sydney Voice Clinic. Comparison with previous published series and review of the relevant literature pertaining to granulomas and to reflux. Description of laryngopharyngeal reflux grading, investigative modalities, and treatment regimen. METHODS: Case notes were reviewed and tabulated for age, sex, diagnosis, predisposing factors for granuloma formation, grade of laryngopharyngeal reflux, investigations, treatment, resolution, and recurrence. All patients were followed up for at least 12 months after resolution. RESULTS: Fourteen of the 61 granulomas occurred after intubation. Ten patients were professional voice users. Our assessment of the 55 granuloma patients revealed an incidence of 76% of gastroesophageal reflux disease in patients with and without known vocal fold trauma. There was a 50% recurrence rate following surgical excision. However, aggressive antireflux therapy, lifestyle modifications, and adjuvant speech therapy were successful in achieving resolution of most of the granulomas and preventing recurrence. In four patients, antireflux surgery was required and total resolution of the granulomas followed. CONCLUSIONS: Vocal process granulomas have perplexed laryngologists with their indeterminate pathogenesis and tendency to recur. Multiple surgical excisions and a variety of combined medical regimens have been used to treat granulomas with variable success. Recurrence after excision commonly occurs as the underlying causative factors have not been appropriately managed and may re-establish the chronic inflammatory process. We found acid reflux to be a common factor in the majority of our patients with granulomas. Therefore treatment should focus on managing both reflux and any functional voice disease or disorder. The only indications for laryngeal surgery are to resolve diagnostic doubt or to treat acute airway compromise. Based on results, we suggest an algorithm for the investigation and management of vocal process granulomas founded on appropriate antireflux and speech therapy.

Adult↗
PubMed2002

Eosinophilic granuloma of the cervical spine.

STUDY DESIGN: A meta-analysis was performed based on 53 cases of cervical eosinophilic granuloma reported in the literature and 1 in an adult treated by the authors. OBJECTIVE: To stress the clinical and radiologic differences between cervical and thoracolumbar spinal eosinophilic granuloma and to point out differences between adults and children with cervical eosinophilic granuloma to avoid false diagnosis. SUMMARY OF BACKGROUND DATA: Until now, cervical eosinophilic granuloma has been reported in 43 children and 9 adults. In 1 case the age is unknown. In previous studies, differences between adults and children with cervical eosinophilic granuloma have not been analyzed, nor has cervical eosinophilic granuloma been compared with thoracolumbar eosinophilic granuloma. METHODS: All reported cases of cervical eosinophilic granuloma were analyzed concerning age and sex distribution, clinical and radiologic presentation, therapy, and outcome. The authors' case in a 46-year-old patient is discussed. RESULTS: The presenting symptoms of cervical eosinophilic granuloma are usually pain and restricted range of motion. In contrast to eosinophilic granuloma of the thoracic spine and lumbar spine, the neurologic symptoms are less frequent, and the first radiographic sign is an osteolytic lesion. Vertebra plana is a rare sign in cervical eosinophilic granuloma. In children, the middle cervical spine is most often affected, whereas in adults it is the second vertebra. The outcome of the patients has been good in most cases, independently of treatment. CONCLUSION: In most cases of cervical eosinophilic granuloma, immobilization is an adequate therapy. If the process continuous to progress, radiotherapy is recommended. Surgical treatment should be reserved for cases with instability or neurologic defects.

Adolescent↗
PubMed1987

Variation of hepatic fibrosis and granuloma size among mouse strains infected with Schistosoma mansoni.

To investigate the relation between the size of circumoval granulomas and hepatic fibrosis, a variety of mouse strains infected with Schistosoma mansoni were examined and the number of eggs in the tissues, the fibrotic responses to the eggs, and the volume of the granulomas were determined. Marked differences in granuloma volume and in hepatic fibrosis were found between mouse strains, and those strains with the largest granulomas also showed the most hepatic fibrosis. On the other hand no significant correlation between granuloma size and hepatic fibrosis was found in the progeny of the F2 generation and backcrosses between F1 mice and the parental strains when crosses were made between Nmri mice (high granuloma volume and high fibrosis) and C57BL/6 mice (low granuloma volume and low fibrosis). Hepatic fibrosis per egg decreased with increasing infection intensity while granuloma volume was unaffected, indicating that fibrosis and granuloma size are at least in part modulated by different factors. The number of eggs found in the tissues per worm pair and the proportion of eggs in the liver also decreased as infection intensity increased. Some influence of the major histocompatibility complex on both granuloma size and fibrosis was found. Congenic mice on the C57BL/10 and C3H/HeSn backgrounds showed larger granulomas in H-2b than in H-2k mice, but no such correlation was found in comparing C57BL/6 mice with B6.H-2k mice. Less hepatic fibrosis was found in B10.M (H-2f), B10.SM (H-2v), and B10.RIII (H-2r) animals than in C57BL/10 mice. The regulation of granuloma size and of hepatic fibrosis is clearly complex and involves genes both outside of and within the major histocompatibility complex.

Animals↗
PubMed1994

[The 69th annual meeting symposium. II: Mechanism of necrotizing granuloma formation and its function].

Histological features of tuberculosis are caseation necrosis and epithelioid cell granuloma formation. Both phenomena are interpreted as expression of cellular immunity. Caseation necrosis is thought to be immunopathology and epithelioid cell granuloma formation is considered to be expression of protective immunity. Recently roles of cytokines for granuloma formation are gradually elucidated. In this symposium, mechanisms and functions of necrosis and granuloma formation Dr. Akagawa reported differentiation of two types of phenotypically different macrophages from human monocytes by GM (granulocyte-macrophage)-CSF or M (macrophage)-CSF. Interestingly such a basic differentiation induced by CSF was affected by IL-4 (interleukin-4). Langerhans-like dendritic cells were generated by cooperation of GM-CSF and IL-4, and multinucleated cells were generated by cooperation of IL-4 and M-CSF. Dr. Fukuda reported human Langerhans cell granulomatosis (LCG) from the pathological and immunohistochemical standpoints. In situ proliferation of LCs in the LCG was demonstrated by immunohistochemistry using antibody to PCNA (proliferating cell nuclear antigen) which is used to detect proliferating cells. In the course of granuloma formation, damage and disruption of lung structure such as alveolar basement membrane and elastic tissue framework, and reactive intraluminar fibrosis was observed. Mechanism of cystic dilation was also reported. Cytokines might play important roles in these events. Dr. Ina demonstrated experimental epithelioid cell granuloma formation. Extract (granuloma inducing factor, GIF) from Schistosoma mansoni Egg-induced granuloma, TNF -alpha, or IL-1 beta were coated, individually on the surface of beads, then these beads were inoculated to rat's skins or cultured with rat's monocytes. Four weeks later, epithelioid cell granuloma was demonstrated histologically and electronmicroscopically around beads in vitro and in vivo. GIF-induced granuloma was more organized than cytokine-induced ones. In vitro using human monocytes, activated macrophages accumulated around beads of which cytokines or GIF were coated. It was suspected that many cytokines or other factors are needed to make epithelioid cell granuloma. Dr. Sakamoto showed the presence of acid fast bacilli and various inflammatory cells including lymphocytes and macrophages in the tuberculous caseous necrosis after exudative reaction (E-necrosis) by immunohistochemistry. But no acid fast bacilli or inflammatory cells were found in the caseous necrosis after productive reaction (P-necrosis). TNF-alpha (tumor necrosis factor-alpha) and IL-4 were stained in the E-necrosis and IL-4 and ICAM-1 (intercellular adhesion molecule-1) were positively stained in the cytoplasm of epithelioid cells by immunohistochemistry. It was suspected that many cells and cytokines were involved in epithelioid cell granuloma formation and caseous necrosis formation.(ABSTRACT TRUNCATED AT 400 WORDS)

Granuloma↗
PubMed1996

Local suppression of IFN-gamma in hepatic granulomas correlates with tissue-specific replication of Leishmania chagasi.

BALB/c mice are susceptible to infection with the visceralizing species of Leishmania, Leishmania chagasi. The parasite load initially rises in the liver and spontaneously subsides, whereas parasite multiplication begins later and remains lower in the spleen. To investigate whether this organ-specific multiplication of L. chagasi correlates with localized immune responses, we compared cytokine production by splenic vs hepatic immune cells. Livers from infected mice contained granulomas harboring intracellular L. chagasi amastigotes, whereas few amastigotes were present in the spleen. FACS analysis granuloma cells showed granuloma lymphocytes expressed a memory/effector phenotype. Granuloma cells cultured in vitro produced IL-10 and IL-6 but no detectable IFN-gamma, IL-4 or IL-5. In contrast, splenocytes from the same animals secreted IFN-gamma, IL-4, IL-6, and IL-10. T cells were depleted from granuloma cells by immune lysis, and the results indicated that IL-10 and IL-6 were derived at least in part from a non-T cell compartment. Paradoxically, FACS-purified Thy-1+ granuloma lymphocytes were able to produce IFN-gamma in the absence of other granuloma cells, suggesting IFN-gamma production might usually be inhibited by a granuloma-associated non-T cell element. Coculture of splenocytes with either granuloma cells or supernatants from granuloma cultures inhibited the usual splenocyte production of IFN-gamma and IL-4 but not IL-10. Thus, there may be a unique granuloma-associated suppressive factor accounting for the absence of IFN-gamma in hepatic granuloma cultures. It may be the absence of IFN-gamma in the liver and presence in the spleen that allows or inhibits parasite survival, respectively, in these different locations.

Animals↗
PubMed1998

The schistosome granuloma: characterization of lymphocyte migration, activation, and cytokine production.

Granuloma formation and its regulation are dependent on lymphocytes. Therefore, we compared the characteristics of lymphocytes derived from the spleens and granulomas of Schistosoma mansoni-infected mice during the course of their disease. We examined lymphocyte cell cycle kinetics, migration, expression of activation Ags (CD69 and IL-2R), cytokine production (IL-2, IL-4, IFN-gamma), and apoptosis. Lymphocytes in the G2/M phase of the cell cycle and high levels of lymphocyte intracellular IL-2 were found in the spleen but not in the granuloma. Cell trafficking experiments showed Ag-specific recruitment of schistosomal egg Ag (SEA)-reactive lymphoblasts into granulomas in vivo, as well as recruitment to, residence within, and egress from granulomas in vitro. Granuloma-derived lymphocytes were more highly activated than splenic lymphocytes based on higher levels of CD69 and IL-2R expression. While the granuloma microenvironment was rich in Th2 cytokines, during peak granuloma formation, the lymphocytes per se from the spleen and granuloma did not exhibit a dominant Th1 or Th2 cytokine profile, producing low but similar levels of IL-4 and IFN-gamma. The discrepancy between high IL-2R expression and low levels of IL-2 protein production by granuloma lymphocytes was associated with increased apoptosis in the granuloma compared with the spleen. These findings support the hypothesis that granulomas may play a role in the regulation of systemic pathology in schistosomiasis by adversely affecting the survival of SEA-reactive, immunopathogenic T lymphocytes.

Animals↗
PubMed1987

Induction of granuloma-dependent angiotensin-converting enzyme and eosinophil chemotactic factor in the skin of athymic nude mice.

Activities of angiotensin-converting enzyme (ACE), other proteinases, and eosinophil chemotactic factor (ECF-G) are known to be elevated in hepatic hypersensitivity granulomas of thymus intact (nu/+) mice after Schistosoma mansoni infection. The enzyme activities also increase, but to a lesser degree in hepatic granulomas of athymic nude (nu/nu) mice, and ECF-G is not detectable. In this study isolated hepatic granulomas from nu/+ mice were grafted into the skin of uninfected nu/nu mice, and changes in those cellular functions were determined to examine whether the newly formed granulomas by recipient nu/nu cells acquire the functional activities as well as the histological appearance of nu/+ granulomas. ACE and ECF-G rapidly disappeared from grafted sites during the first 5 days, corresponding to loss of nu/+ cells from the graft. Reduction in activities of arylsulfatases, lysozyme, and acid phosphatase also occurred, but to a lesser extent. Recovery of ACE and ECF-G activities to the levels seen in nu/+ hepatic granulomas was observed by 14 days after grafting when nu/nu cells had accumulated in the grafts and formed new granulomas. Other enzymes increased to approximately half the levels seen in grafted donor granulomas. Circulating eosinophilia also increased. The findings indicate that nu/nu cells that accumulated in the skin grafts not only morphologically mimicked nu/+ type granulomas but also demonstrated nu/+ levels of cellular function. Analysis of skin granulomas developing in nu/+ mice after grafting of nu/+ hepatic granulomas showed the similar histology and enzymatic changes, whereas the skin sites inoculated with purified schistosome eggs alone caused neither significant histological changes nor elevation of ACE activity.

Acid Phosphatase↗
PubMed2003

Impaired hepatic granuloma formation in mice deficient in C-C chemokine receptor 2.

Granulomas are characterized histologically by a nodular collection of macrophages with occasional admixture of epithelioid cells, multinucleate giant cells, and other immunocompetent cells. Chemokines are considered to play an important role in the recruitment of these constituent cells of granulomas. The present study has examined the effect of a deficiency of C-C chemokine receptor-2 (CCR2) on hepatic granuloma formation induced by a single injection of Zymosan A. In CCR2+/+ mice, the number and the size of granulomas gradually increased until they reached peak values at 10 days after the injection. In contrast, both the number and the size of granulomas were smaller in CCR2-/- mice than in CCR2+/+ mice from days 5 to 21. They showed low peaks at day 5, after which the number and the size of the granulomas gradually decreased. Immunohistochemical analysis of the constituent granuloma cells using cell type-specific monoclonal antibodies revealed rapid accumulation of blood monocytes, with subsequent differentiation to macrophages, in CCR2+/+ mice during days 2-10. This process was greatly impaired in CCR2-/- mice and granulomas remained small. At all time points, the percentage of polymorphonuclear cells in granulomas was higher in CCR2-/- mice than in CCR2+/+ mice. Interestingly, multinucleate giant cells were frequently observed in granulomas in CCR2-/- mice, whereas they rarely appeared in CCR2+/+ mice. Profiles of liver cytokine RNA levels as well as serum cytokine levels revealed reduced expression of the Th1 cytokine IFN-gamma in CCR2-/- mice. These data clearly indicate that signalling through CCR2 has many effects on the normal growth and development of hepatic granulomas.

Animals↗
PubMed1982

Comparison of mycobacterial granulomas in guinea-pig lymph nodes.

A study was made of mycobacterial-induced granulomas in guinea-pig lymph nodes. Live BCG (Pasteur) induced a granuloma containing epithelioid cells while Cobalt irradiated Mycobacterium leprae induced a granuloma comprised of phagocytic macrophages. The granulomas were quantitated by measurement of lymph node weight and the areas of infiltration in histological sections. The time course of granuloma formation induced by Co-irradiated M. leprae was veary different from the time course of the granuloma formation induced by BCG. Collagen synthesis assessed by incorporation of 14C-proline into collagenase sensitive protein was greater in lymph nodes draining the site of injection of Co-irradiated BCG than those draining the site of injection of Co-irradiated M. leprae during the first 10 weeks. Collagen synthesis was delayed in the nodes from animals injected with live BCG for at least 10 weeks. Single cell suspensions of draining lymph nodes containing granulomas consisted of lymphocytes and large cells (epithelioid cells and macrophages). A high proportion of the large cells were found to be non-adherent in the live BCG-induced epithelioid cell granuloma. In contrast, M. leprae-induced granulomas contained a high percentage of adherent large cells. In both the granulomas, the majority of large cells were esterase positive and showed the presence of fibronectin. Most of the large cells in the granulomas did not carry receptors for the Fc component of IgG or the C3 component of complement and did not exhibit peroxidase activity.

Animals↗
PubMed1998

IL-6-deficient mice form granulomas in murine schistosomiasis that exhibit an altered B cell response.

IL-6 can play an important role in various biological activities. Using IL-6-deficient, 129 x C57BL/6 mice and normal littermate controls, we studied the role of IL-6 in granulomas of mice infected with schistosomiasis mansoni. Granulomas from IL-6(+/+) mice produced large quantities of IL-6, derived from T, B, and myeloid cells. Yet, IL-6 mutant mice generated normal-appearing granulomas of appropriate size. Multiple-parameter flow cytometric analysis of dispersed granuloma cells revealed no substantial differences. Granuloma cells and splenocytes were cultured in vitro to measure cytokine and immunoglobulin production. Compared to control cells, IL-6(-/-) granuloma cells secreted more IL-4, IL-5, and IL-10. However, splenocytes secreted cytokines comparably. In the IL-6(-/-) state, the granuloma cells released less IgE and substantially more IgM, although IgG1, IgG2a, and IgA secretion remained normal. ELISPOT assay showed that dispersed granuloma cells from IL-6-deficient animals had substantially more IgM-secreting B cells. Thus, schistosome granulomas make IL-6 that is not essential for most aspects of granuloma development. However, IL-6 deficiency results in some disturbance of granuloma cytokine and immunoglobulin expression.

Animals↗