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Immune dysfunction in the elderly: effect of thymic hormone administration on several in vivo and in vitro immune function parameters.

The effects of short-term thymic hormone administration on age-associated immune function were evaluated. Two groups of individuals greater than 65 years of age were treated for 30 days with thymic extracts (TP1) or placebo; before and after this treatment a panel of in vitro and in vivo parameters was determined according to a very rigorous experimental protocol. In most individuals, TP1 treatment was associated with an improvement in cutaneous delayed-type response to PPD. Moreover, an increase in a circulating T cell subpopulation bearing the CD45R surface antigen ("virgin" T cells), and in NK cell cytotoxic activity was also observed in some subjects. Finally, lymphocyte responsiveness to PHA tended to increase, while no effect on lymphocyte ability to produce IL-2 following mitogen stimulation was observed. These findings suggest that TP1 treatment may influence age-related alterations in immune function parameters in some subjects.

Aged

Mucosal immune dysfunction associated with alcoholic IgA nephropathy.

We investigated the hypothesis that alcohol-induced changes of the immune system result in IgA nephropathy (IAN). Wistar rats were infused with liquid diet containing alcohol: "alcoholics." Control rats received an isocaloric diet with glucose instead of alcohol. IAN was diagnosed by mesangial IgA deposition. When compared to controls, serum IgA in alcoholic rats with IAN had a fourfold increase and a twofold increase in alcoholics without IAN. The intestinal lamina propria showed overall lymphocyte depletion in alcoholic rats. The decrease was not uniform for all the lymphocyte subgroups: it resulted in a relative increase in IgA-B cells in alcoholic rats with IAN but not in alcoholic rats without IAN. No significant differences were observed between alcoholic and control rats in the percentages of spleen lymphocyte subtypes. We suggest that dysfunction of the mucosal immune system may be related to the induction of IAN in chronic alcohol consumption.

Alcoholism

Viral persistence and immune dysfunction.

Viruses can persist for years without provoking an effective host immune response or otherwise causing the cell destruction characteristic of an acute viral infection. Clinically relevant principles, generalizable to many persistent viruses, are exemplified by measles and lymphocyte choriomeningitis viruses. The LCMV model indicates that viral persistence and the anergic state are reversible.

Animals

Lack of age-associated immune dysfunction in mucosal-associated lymph nodes.

The magnitude of the immune response in old and young mice to trinitrophenylated bovine gamma-globulin was measured in various lymphatic sites at a cellular level using the plaque-forming cell assay. As we have previously shown, the number of splenic IgM, IgG, and IgA anti-TNP PFC progressively declined in aging C57BL/6J male mice. In addition, mice receiving antigen in the 4 footpads and the base of the tail exhibited similar decline in the number of PFC in the draining peripheral lymph nodes with increasing age. In contrast, mesenteric and mediastinal lymph node IgM, IgG, and IgA anti-TNP PFC response to TNP-BGG in complete Freund's adjuvant, i.p. or via gastric intubation, in old mice remained unimpaired compared with the number in younger mice. The data support the view that the mucosal-associated lymphoid system differs from the systemic system with regard to immune competence with age. Furthermore, the findings imply a site preference for a decline in immune function with aging.

Aging

Immune dysfunction following infection with chicken anemia agent and infectious bursal disease virus. II. Alterations of in vitro lymphoproliferation and in vivo immune responses.

To determine the functional impact of alterations in lymphocyte concentrations and ratios following infection with chicken anemia agent (CAA) alone or in combination with infectious bursal disease virus (IBDV) on the immune system of young chickens, in vitro lymphoproliferation assays and in vivo responses to vaccination with several common viral agents were assessed at various time intervals post-inoculation (PI). Concanavalin A (Con A), phytohemagglutinin (PHA) and pokeweed mitogen (PWM) stimulation of splenic lymphocytes (SPL) collected from control birds could not be detected until 10-14 days PI. Infection with CAA was characterized by significantly higher PWM stimulation of SPL at 17 days PI and significantly lower PWM stimulation of peripheral blood lymphocytes (PBL) at 14 days PI, compared with uninfected controls. Concanavalin A and PWM stimulation of SPL was significantly increased in birds inoculated with IBDV alone. Lymphocytes harvested from birds inoculated simultaneously with CAA and IBDV had significantly lower responses. Effects on humoral and cell-mediated immunity following CAA and/or IBDV were determined by evaluating vaccination responses to Newcastle disease virus (NDV), fowl pox virus (FPV) and infectious laryngotracheitis virus (ILTV) during the acute phase of CAA infection (2 weeks PI). Vaccination of birds 2 weeks following CAA infection at 1 day of age resulted in decreased protection against NDV (85.7%) and ILTV (7.1%) challenge compared with protection rates in control birds (100% and 53.3% respectively). Infectious bursal disease virus infection was associated with decreased protection against NDV (60%) only. Concomitant infection at 1 day of age resulted in a greater reduction in NDV challenge protection (33.3%), slightly decreased FPV protection (87.5%), increased numbers of persistent FPV vaccination lesions and increased protection against ILTV challenge (71.4%). Vaccination of birds 2 weeks following CAA infection at 2 weeks of age resulted in slightly decreased NDV humoral antibody, development of persistent FPV vaccination lesions (17%) and increased immunity to ILTV challenge compared with control birds (83.3% vs. 66.7%). Chickens inoculated with IBDV alone displayed a more severe depression in NDV antibody titers and only a slight decrease in ILTV protection. Vaccination following concomitant infection at 2 weeks of age resulted in a higher percentage of FPV persistent vaccination lesions (39%) and greatly enhanced immunity to ILTV challenge (100%).

Animals

An in vitro analogue of immune dysfunction with altered immunoglobulin production in the aged.

The consequences of aging of the immune system include impaired T-lymphocyte responsiveness and aberrant immunoglobulin production. Although T cells from elderly individuals have a well-described defect in lymphoblastic transformation in response to some polyclonal mitogens, immunoglobulin abnormalities have lacked a clear in vitro model. Peripheral blood mononuclear cells from 13 young and 13 old healthy donors were cultured with phytohemagglutinin (PHA) or pokeweed mitogen (PWM). Old-donor-cell phytohemagglutinin (PHA), but not PWM, cultures had significantly lower lymphoblastic transformation compared with young donor cultures. IgG, IgA, and IgM production tended to be lower in old- versus young-donor PWM cell cultures. By contrast, despite lower lymphoblastic transformation in old-donor PHA cell cultures, immunoglobulin production was higher for old- versus young-donor cell cultures. No significant age differences were present in initial lymphocyte counts, percent B cells, T cells or monocytes, or helper/suppressor ratios to explain this enhancement in immunoglobulin production. PHA-stimulated mononuclear cell cultures in the aged demonstrate not only a defect in proliferation but also increased immunoglobulin production. This in vitro system may be useful to characterize further the pathogenesis of altered immunoglobulin production in the elderly.

Adult

High frequency of immune dysfunctions in asbestos workers and in patients with malignant mesothelioma.

We have examined the primary immune responses, the numbers of total T (T11+) cells, T-helper (T4+) cells, T-suppressor (T8+) cells, and natural killer (NK) (Leu7+) cells, in 118 healthy control subjects and compared the data to those obtained from 20 patients with clinically diagnosed malignant mesothelioma and 375 long-term asbestos workers without neoplasia. The absolute numbers of total T (T11+) and T-helper (T4+) cells were normal in asbestos workers without neoplasia but were significantly reduced in patients with mesothelioma. T-suppressor (T8+) cells, on the other hand, remained unchanged in the patients but were significantly elevated among the asbestos workers. This resulted in a marked reduction in T-helper (Th) to T-suppressor (Ts) ratios in mesothelioma patients and in asbestos workers. Seventy percent of the mesothelioma patients (14 of 20) had significantly depressed NK-cell activity which could be augmented but not normalized by coincubation in patients' peripheral blood lymphocytes (PBL) with interferon (IFN). Among the asbestos workers three distinctive subgroups could be identified: heightened (H-NK), normal (N-NK), and low (L-NK) NK activity. The NK activity of the L-NK group could be stimulated but not normalized by coincubation with IFN, a finding closely resembling that in malignant mesothelioma patients. Phenotyping of the circulating NK cells revealed a unique Leu7+ subset in increased numbers with a brightly fluorescent property in stable mesothelioma patients with relatively stable or slowly progressive disease and in more than 30% of the asbestos workers.(ABSTRACT TRUNCATED AT 250 WORDS)

Asbestos

Immune dysfunction in children after corrective surgery for congenital heart disease.

OBJECTIVE: To study the effect of open- and closed-heart surgery on the immune status of infants and children. DESIGN: Prospective study. Data collected before anesthesia and surgery and 2 and 24 hrs after surgery. SETTING: Operating room and pediatric ICU in a children's hospital. PATIENTS: Children undergoing surgery for correction of congenital heart disease (age 3 months to 12 yrs). A total of 31 patients were studied (open-heart surgery, n = 25; closed-heart surgery, n = 6). MEASUREMENTS AND MAIN RESULTS: Increased neutrophil counts and lymphopenia were observed after both open- and closed-heart surgery. Serum levels of the complement components C3 and C4 were depressed after open-heart surgery, but not after closed procedures. The percentage of T3+ and T4+ lymphocytes, proliferative responses of the lymphocytes and serum immunoglobulin (Ig)G and IgM were decreased from preoperative levels after open-heart surgery. The percentage of T8+ lymphocytes and serum IgA levels did not change. Intraoperative variables and postoperative severity of illness (Pediatric Risk of Mortality score) did not correlate with immune suppression. CONCLUSIONS: The immune system is affected after pediatric cardiac surgery, particularly after open-heart surgery.

Cardiac Surgical Procedures

Chronic ethanol exposure before injury produces greater immune dysfunction after thermal injury in rats.

Chronic alcoholics constitute a small but significant subgroup of burned patients. The effects of chronic alcohol exposure on immune function in burned patients has not to our knowledge been studied. This study was designed to determine the effect of chronic alcohol exposure before burn injury on immune function after injury in rats. Immune function assessed by in vivo chemotaxis and responsiveness of non-adherent splenocytes to both a T-cell mitogen, concanavalin A, and a B-cell mitogen, lipopolysaccharide, was measured at 4 days after a 20% BSA full-thickness burn injury and/or gavage of 2.4 gm/kg/day of ethanol for 14 days. Chronic ethanol ingestion before burn injury produced significant suppression in chemotaxis and response to lipopolysaccharide but not in response to concanavalin A. These results suggest that chronic alcohol exposure before injury can contribute to further impaired immune function after injury, and may lead to increased susceptibility to infection and increased mortality.

Alcoholism

Humoral immune dysfunction as a result of prenatal exposure to diphenylhydantoin: correlation with the occurrence of physical defects.

The effect of prenatal exposure to diphenylhydantoin (DPH) on postnatal immune function of offspring was studied using a longitudinal experimental design and in vivo immunoassays. Maternal Balb/c mice were dosed by gavage on gestation days 9 through 18 with 0, 20, 40, or 60 mg/kg DPH. Humoral immune function was assessed by measuring the serum antibody levels to type III pneumococcal polysaccharide 5 days after immunization by radioimmunoassay. Cell-mediated immune function was assessed by measuring the delayed-type hypersensitivity response to the contact allergen oxazolone using a micrometer method. A dose-related suppression of humoral immune function was observed in male and female offspring at 25 days but not at 15 weeks of age. Cell-mediated immunity was not affected by prenatal DPH exposure at 25 days or 15 weeks of age. Offspring developed purulent eye exudates at 12 days of age; the incidence and persistence was related to DPH dose. The immunosuppressive effect of DPH on humoral immune function was significantly greater in offspring born with open eye defect than in similarly treated but physically normal offspring. The results suggest that prenatal exposure to DPH may adversely affect the normal development and expression of humoral immune function, particularly in those offspring with other manifestations of DPH's developmental toxicology.

Abnormalities, Drug-Induced

Phosphodiesterase and immune dysfunction in atopic dermatitis.

Atopic dermatitis and the other atopic conditions occur as a result of direct or indirect influences from cells of hematopoietic origin. Cellular immune abnormalities have been described, but appear to be secondary to cutaneous inflammation in atopic dermatitis. Pharmacophysiologic abnormalities are numerous and may relate to defective cyclic nucleotide metabolism in circulating and infiltrating leukocytes. A consistent leukocyte abnormality is elevated cyclic AMP-phosphodiesterase. This enzyme abnormality results in reduced intracellular cyclic AMP, creating a net permissive effect upon cell function. Phosphodiesterase inhibitors have been demonstrated to reduce abnormal histamine release and IgE production by cultured leukocytes. Studies of phosphodiesterase and associated defects in atopic leukocytes may lead to delineation of basic pathogenetic mechanisms as well as providing the potential for therapeutic targeting.

Dermatitis, Atopic

Integrative subtyping by bile acid metabolism identifies CLCA1/UGT2A3/ZG16 as markers of immune dysfunction and poor prognosis in colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is the primary driver of cancer-related death and illness across the world. Despite the full-scale shift of the treatment approach for some colorectal cancer patients due to the use of immune checkpoint inhibitors (ICIs), primary resistance still poses a huge challenge to clinicians. Bile acid metabolism is involved in the pathogenesis of CRC. However, its particular function in shaping the tumor immune microenvironment (TIME) and its effect on prognosis and immune treatment response remain unclear. METHODS: Based on the transcriptome and clinical data from The Cancer Genome Atlas-Colon Adenocarcinoma (TCGA-COAD) cohort, we performed unsupervised consensus clustering and classified patients into different molecular subtypes according to bile acid metabolism. We subsequently compared overall survival (OS), immune cell infiltration levels, and differentially expressed genes among the subtypes. In addition, protein-protein interaction (PPI) network and Cox proportional hazards regression were used to identify key hub genes. Finally, the expression of these crucial hub genes was validated in the Gene Expression Omnibus (GEO) cohort and independent clinical patients. RESULTS: The bile-low group showed a significant reduction in OS time (p = 0.0049). The infiltration levels of CD8+ T cells (p < 0.05) and M1 macrophages (p < 0.01) were significantly higher in the bile-low group than in the bile-high group. We identified three key genes-CLCA1, UGT2A3, and ZG16-and found that they all were downregulated in tumor tissues across the TCGA-COAD and GEO datasets, as well as in independent clinical samples. Survival analysis showed that high CLCA1 expression was significantly associated with favorable overall survival (p < 0.001), whereas UGT2A3 (p = 0.23) and ZG16 (p = 0.17) did not reach statistical significance. The three hub genes were negatively correlated with the (TIDE) score (CLCA1: R = - 0.24, p < 0.001; UGT2A3: R = - 0.15, p = 0.0022; ZG16: R = - 0.14, p = 0.0039). CONCLUSION: Our findings suggest that bile acid metabolism could shape the TIME via key genes CLCA1, UGT2A3, and ZG16, and subsequently modify CRC prognosis and immunotherapy responses. These genes may serve as potential prognostic indicators and mechanistic mediators linking bile acid metabolism to T-cell dysfunction, offering insights for future combination strategies targeting the metabolism-barrier-immunity axis.

CLCA1

Acquired immune dysfunction in homosexual men: immunologic profiles.

Homosexual men with Kaposi sarcoma, lymphadenopathy syndrome, opportunistic infection, and nonhomosexual traditional Kaposi sarcoma were evaluated for B cell, T cell, and complement immunity and compared to normal controls and homosexual controls. No significant immunologic abnormalities were found in the traditional Kaposi group. All homosexual groups, including the homosexual controls, had a significant decrease in the helper/suppressor cell ratio. Functional abnormalities of T-cell immunity were observed in the homosexual Kaposi sarcoma, lymphadenopathy syndrome, and opportunistic infection groups. Significant elevations of IgG, IgM, IgA, and IgE were found in the lymphadenopathy group, while only IgG and IgA were elevated in the Kaposi sarcoma group. C3, C4, and immune complexes were normal, while total hemolytic complement activity was increased in the Kaposi sarcoma and lymphadenopathy syndrome groups.

Acquired Immunodeficiency Syndrome

Immune dysfunction in the critically ill infant and child.

Factors contributing to the high prevalence of immunodeficiency in the PICU population include conditions that lead to frequent requirement of intensive care, suppression of immunity secondary to an acute insult, and iatrogenic measures. The immunodeficiency observed in the critically ill correlates well with their susceptibility to infection and explains the high prevalence of nosocomial sepsis in the PICU--a major cause of morbidity and mortality in critically ill children. Dysactivation of the immune system during an acute insult, with the subsequent release of humoral mediators from activated immune cells, leads to tissue injury and may be involved in the pathogenesis of ARDS, DIC, capillary leak syndrome, and to the development of multiple organ system failure. Suggested approaches to correct the immunodeficiency in the critically ill include reconstitutional immunotherapy, mediator-inhibiting drugs, and mediator removal by plasma exchange. Intensivists should be aware of the phenomenon of immunodeficiency in the critically ill, be accordingly aggressive in diagnosing and treating infections, and avoid, as much as possible, measures that further suppress immunity.

Acquired Immunodeficiency Syndrome