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Effects of stimulation and suppression of cell-mediated immunity on experimental cryptococcosis.

A model of cryptococcosis was developed using intraperitoneal infections of guinea pigs. This model shared characteristics with cryptococcosis in humans and was used to study the effects of immunosuppression and immunostimulation on cryptococcosis. Female guniea pigs survived longer than males; perphaps this was related to a greater capacity of their monocytes to kill cryptococci. A brief course of cortisone shortened survival of females and resulted in depressed immune and inflammatory responses, which persisted long after cortisone was stopped. Stimulation of the immune response by treatment with cryptococci in Freund complete adjuvant improved survival in males. Preliminary studies indicated the usefulness of this model for the study of other potential immunostimulants, including immune lymphocytes, transfer factor prepared from immune lymphocytes, and levamisole. Overall, long-term survivors appeared to clear disseminated cryptococci from extraperitoneal sites including brain, rather than prevent dissemination of cryptococci from the peritoneal cavity. The quantity of the inflammatory response in infectious foci, rather than the ability of individual leukocytes to kill crytococci, may have determined the outcome of most infections.

Animals↗

Genetic resistance to murine cryptococcosis: increased susceptibility in the CBA/N XID mutant strain of mice.

In a survey of 301 normocomplementemic inbred mice (belonging to nine different strains: BALB/cN nu/nu and nu/+, CBA/N, C57BL/KsJ, C57BR/cdJ, CBA/CaJ, BRVR, DW/+, and C57BL/6J) for natural resistance to Cryptococcus neoformans, cumulative survival values were found to range from 12 to 22 days. When the average organ weights of infected animals were compared with reference values obtained in uninfected mice of the same age and genetic lineage, the following changes were documented. In the CBA/N strain, the mean spleen and brain weights increased 313 and 13.5%, respectively, whereas the mean liver weight remained unchanged. In the CBA/Ca strain, cerebral cryptococcosis was the dominant clinical feature, and a 54% increase in mean brain weight was recorded at the time of death. The averaged liver weight was drastically lower, whereas spleen weight values evinced a biphasic pattern of transient splenomegaly followed by involution. At the median time of death, CBA/N mice had significantly more cryptococci in the liver and spleen than corresponding CBA/Ca mice. In the (CBA/N X CBA/Ca)F1 mice, susceptibility to C. neoformans segregated according to the sex-linked inheritance of the X-linked immunodeficiency (xid) gene. It is concluded that (i) susceptibility to cryptococcosis is under multigenic control, (ii) the xid locus on the X chromosome influences susceptibility to cryptococcosis, and (iii) xid mice behave differently than CBA/Ca mice in their organ response during the course of the infection.

Animals↗

Genetic resistance to murine cryptococcosis: the beige mutation (Chédiak-Higashi syndrome) in mice.

The influence of the bgJ and bg2J mutations on the susceptibility of mice to experimental cryptococcosis was studied in inbred mice of the C57BL/6J and C3H/HeJ strains. Although infected animals with the bg/bg genotype had a significantly shorter lifespan than bg/+ or +/+ animals, C3H/He beige-2J mice were less susceptible than C57BL/6 beige-J mice when compared with nonbeige mice of similar background. On days 18 and 19 after infection, quantitation of cryptococci in the brain, liver, and spleen revealed that the overall burden of organisms in infected C57BL/6 beige-J mice was in excess of one log unit above that found in the brain, liver, and spleen of infected C57BL/6 +/+ mice. At that time, C57BL/6 beige-J mice showed a 53% increase in mean brain weight, a 67.8% decrease in mean liver weight, and a 58.6% decrease in mean spleen weight, when compared with uninfected animals of the same age and genetical lineage. The corresponding figures for C57BL/6 +/+ mice were a 32% increase in mean brain weight, a 41.4% decrease in mean liver weight, and a 23.4% decrease in mean spleen weight. From these data, it is concluded that the beige mutation in mice is associated with increased susceptibility to cryptococcosis, the accrued susceptibility of the beige mutant is related to more rapid changes in the weight profile of the target organs as well as to a higher rate of growth or decreased clearance of Cryptococcus neoformans or both, and other autosomal genes are likely to be involved in the genetic control of susceptibility to murine cryptococcosis.

Animals↗

A 77-kilodalton protein of Cryptococcus neoformans, a member of the heat shock protein 70 family, is a major antigen detected in the sera of mice with pulmonary cryptococcosis.

Heat shock proteins (HSPs) from several pathogenic microbes have been shown to be target molecules of humoral responses as well as cellular immune responses. However, little is known about target molecules in pulmonary cryptococcosis. Western blotting analysis revealed that experimentally induced pulmonary cryptococcosis in (BALB/c x DBA/2)F1 mice was associated with the appearance of serum antibodies to a 77-kDa protein derived from Cryptococcus neoformans as well as to 18-, 22-, 25-, 36-, and 94-kDa proteins. Since the 77-kDa band also reacted with rabbit polyclonal antibodies against 70-kDa HSP (HSP70) family members, the protein was predicted to be a member of the HSP70 family. We also purified HSP70 directly from a C. neoformans cell extract by Mono Q fast protein liquid chromatography and ATP-agarose affinity column chromatography and showed that it was positive in immunoblot analysis using either serum from C. neoformans-infected mice or rabbit anti-HSP70 antibodies. N-terminal amino acid sequencing of this purified protein confirmed that the 77-kDa protein was a member of the HSP70 protein family. A 66-kDa protein, which coincidentally purified with the HSP70 protein and was identified as a member of the HSP60 family by N-terminal amino acid sequencing, was not reactive with sera from C. neoformans-infected mice. Thus, a protein associated with the HSP70 family and derived from C. neoformans was a major target molecule of the humoral response in murine pulmonary cryptococcosis.

Amino Acid Sequence↗

Evaluation of a monoclonal antibody-based latex agglutination test for diagnosis of cryptococcosis: comparison with two tests using polyclonal antibodies.

Cryptococcal antigen detection has become a routine biological test performed for patients with AIDS. The poor prognosis of cryptococcosis explains the need for reliable tests. We evaluated the performances of a newly commercialized agglutination test that uses a monoclonal antibody specific for cryptococcal capsular polysaccharide (Pastorex Cryptococcus; Sanofi-Diagnostics Pasteur, Marnes-la-Coquette, France) and compared them with those of tests that use polyclonal immune sera (Cryptococcal Antigen Latex Agglutination System, Meridian Diagnostics, Inc., Cincinnati, Ohio; and Crypto-LA, International Biological Labs Inc., Cranbury, N.J.). The sensitivities and specificities of the tests were compared by using purified polysaccharides and yeast suspensions. Clinical specimens (131 serum samples, 41 cerebrospinal fluid samples, 34 urine samples, and 19 bronchoalveolar lavage samples) from 87 human immunodeficiency virus-positive subjects with (40 patients) and without (47 patients) culture-proven cryptococcosis were retrospectively tested during a blinded study. The effect of pronase treatment of samples was assessed for Pastorex Cryptococcus and the Cryptococcal Antigen Latex Agglutination System, and the antigen titers were compared. Our results show that (i) during the screening, concordance among the three tests was 97%; (ii) the use of pronase enhanced both the sensitivities and specificities of the Pastorex Cryptococcus test; (iii) titers agreed for 67% of the cerebrospinal fluid samples and 60% of the serum samples; and (iv) cryptococcosis was detected equally well with Pastorex Cryptococcus and with the other tests, whatever the infecting serotype (A, B, or D). The meaning of in vitro sensitivity and the relationship between titers and sensitivity are discussed. The results show that Pastorex Cryptococcus is a rapid and reliable test for the detection of cryptococcal antigen in body fluids and suggest that kits cannot be used interchangeably to monitor antigen titers in patients.

AIDS-Related Opportunistic Infections↗

Involvement of multiple Cryptococcus neoformans strains in a single episode of cryptococcosis and reinfection with novel strains in recurrent infection demonstrated by random amplification of polymorphic DNA and DNA fingerprinting.

We compared the abilities of random amplification of polymorphic DNA and DNA fingerprinting, with oligonucleotide probes, to type five pairs of Cryptococcus neoformans clinical isolates recovered from five separate human immunodeficiency virus-positive patients in London, England. The two techniques had comparable discriminatory abilities when applied to these isolates. A total of eight different isolate types were demonstrated in these patients. No isolate type was observed in more than one patient. Two of the isolate pairs recovered from single episodes of cryptococcosis within 1 day of each other were genotypically indistinguishable by both methods. The other three pairs of isolates were all distinguishable. One of these isolate pairs was obtained from a single episode of cryptococcosis, while the other two were obtained from recurrent infections. These results indicate that multiple strains of C. neoformans may be responsible for a single episode of cryptococcosis and that recurrent infection may occur as a result of reinfection with a novel strain.

Base Sequence↗

Plasma (1-->3)-beta-D-glucan and fungal antigenemia in patients with candidemia, aspergillosis, and cryptococcosis.

(1-->3)-beta-D-Glucan is one of the major structural components of fungi, and it seems that it can be detected by the fractionated (1-->3)-beta-D-glucan-sensitive component from a Limulus lysate, factor G. We evaluated the concentration of (1-->3)-beta-D-glucan by using factor G and other fungal antigens in 24 patients with clinical evidence of mycosis and 36 healthy subjects. The mean concentration of (1-->3)-beta-D-glucan in the plasma of the healthy subjects was found to be 2.7 +/- 1.9 pg/ml (range, < 6.9 pg/ml), and it was found to be substantially higher in all 11 patients with candidemia (mean, 2,207.4 pg/ml; range, 325.4 to 8,449.0 pg/ml). Eight of those 11 patients with candidemia (73%) were positive for the Cand-Tec heat-labile candida antigen and only 3 patients (27%) were positive for mannan antigen. Three patients with invasive pulmonary aspergillosis were positive for galactomannan and had, in addition, high concentrations of (1-->3)-beta-D-glucan (mean, 323.3 pg/ml; range, 27.0 to 894.0 pg/ml). All 10 patients with cryptococcosis (including 2 patients with probable cryptococcosis) were positive for cryptococcal antigen by the Eiken latex test; however, (1-->3)-beta-D-glucan levels were not elevated in these patients (mean, 7.0 pg/ml; range, < 16.5 pg/ml). Our results indicated that (1-->3)-beta-D-glucan levels are elevated in patients with candidiasis and aspergillosis but not in those with cryptococcosis.

Adult↗

Combination therapy of experimental candidiasis, cryptococcosis and aspergillosis in mice.

Combination pairs of the major systematic antimycotic drugs, amphotericin B (AmphB), 5-fluorocytosine (5-FC) and ketoconazole (Ktz) were administered to mice with experimental candidiasis, cryptococcosis and aspergillosis at a variety of combination ratios. The 3 mycoses were produced with 3 strains each of Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, respectively, which were preselected to represent 3 different degrees of 5-FC sensitivity ('normally sensitive', 'moderately resistant', and 'definitely resistant'). The life-prolonging effect of the combinations was compared with the effect of each partner administered alone at the same and at the double dosage. Using the U test of Mann and Whitney and setting limits which on the whole were more rigorous than those of the isobole methods commonly applied to the study of drug interactions, the effects of the concentrations were classified as 'synergistic', 'additive', 'indifferent' or 'antagonistic'. The combination AmphB plus 5-FC was definitely synergistic or definitely additive in all 3 candidiasis models, the most pronounced synergism occurring in the infection with the 'definitely 5-FC-resistant' C. albicans strain; in cryptococcosis produced by any of the 3 C. neoformans strains the effect was definitely additive, but only slightly additive or indifferent in the 3 aspergillosis models. The combination AmphB plus Ktz was slightly synergistic in candidiasis produced by one C. albicans strain, but definitely antagonistic in this mycosis produced by the remaining 2 strains of the same species; the combination was definitely additive or, even, slightly synergistic in the 3 cryptococcus models, but, again, antagonistic in aspergillosis produced by all 3 strains of A. fumigatus. 5-FC plus Ktz was additive or indifferent in the 3 candidiasis models, but throughout indifferent in cryptococcosis and aspergillosis.

Amphotericin B↗

Combination therapy of experimental candidiasis, cryptococcosis, aspergillosis and wangiellosis in mice.

Combination pairs of 5-fluorocytosine (5-FC) + itraconazole (Itra), 5-FC + fluconazole (Fluc), and amphotericin B (Amph B) + Itra were administered to mice with experimental candidiasis, cryptococcosis, aspergillosis and wangiellosis with a variety of combination ratios. The life-prolonging effect of the combinations was compared with the effect of each partner administered alone and with a double dosage. Using the U test of Mann and Whitney, the effects of the concentration were classified as synergistic, additive, indifferent or antagonistic; the degree of the interaction was compared with the known effect of Amph B and 5-FC combinations. The combination 5-FC + Itra was definitely synergistic or additive in candidiasis and aspergillosis. The most pronounced synergism occurred in the infection with a 5-FC-resistant strain of Candida albicans. The degree of synergism was the same as with 5-FC + Amph B. In cryptococcosis this combination was indifferent. The combination of 5-FC + Itra merits clinical investigation, especially in candidiasis and aspergillosis. Amph B + Itra was mostly indifferent and weakly antagonistic; the degree of antagonism was significantly weaker than the one observed with Amph B + ketoconazole (Keto). In candidiasis, 5-FC + Fluc was synergistic, but indifferent in cryptococcosis and aspergillosis.

Amphotericin B↗

Combination therapy with fluconazole and flucytosine for pulmonary cryptococcosis.

We investigated, in vitro, the combined effects of fluconazole (FLCZ) and flucytosine (5-FC) against different strains of Cryptococcus neoformans, and retrospectively analyzed the clinical efficacy of combination therapy of FLCZ and 5-FC in patients with pulmonary cryptococcosis. The minimum inhibitory concentrations (MICs) of antifungal agents and drug interaction were determined by the broth microdilution method and checkerboard titration. FLCZ and 5-FC showed synergistic activity against 8 (32%) of 25 strains of C. neoformans. The clinical efficacy of the 2 drugs when combined together was good in 9 (90%) patients and fair in 1 (10%) patient with pulmonary cryptococcosis. Renal dysfunction occurred in 1 patient. Our results suggest that a combination therapy using FLCZ and 5-FC is clinically useful in patients with pulmonary cryptococcosis who otherwise show a limited response to monotherapy.

Adult↗

Pulmonary cryptococcosis in the rat.

We evaluated a rat model of pulmonary cryptococcosis. Rats immunized subcutaneously with cryptococcal antigen developed peritoneal but not pulmonary macrophage migration inhibition factor (MIF) to cryptococcal cell extract antigens. They did not develop MIF to capsular polysaccharide antigens. Conversely, when rats were immunized subcutaneously with heat-killed cryptococcus neoformans, migration inhibition factor was detected in alveolar but not in peritoneal macrophages. Finally, rats given viable cryptococci subcutaneously developed both pulmonary and extrapulmonary cell-mediated immune responses. When viable C. neoformans were administered directly into bronchi of the right lung, immunologically intact rats developed hard nodular lesions in the ipsilateral lung. These contained caseous centers with numerous cryptococci seen on histologic examination. Over the course of 9 months, the lesions shrunk and disappeared. In contrast, congenitally athymic (nude) rats developed progressive cryptococcosis with widespread dissemination. The rat appears to be a useful model for study of pulmonary cryptococcosis.

Animals↗

Cryptococcosis in a llama (Lama glama).

Cryptococcosis was diagnosed in a 17-year-old male llama that had been euthanatized following an acute onset of neurologic disease. Tissues affected included the brain, spinal cord, lung, and kidney. The character of the leukocytic response varied from minimal to pyogranulomatous. Cryptococcosis has not been previously reported in a llama, although the infection has been described in 2 other species of New World camelids. The pathogenesis of cryptococcosis is briefly reviewed.

Animals↗

Cutaneous cryptococcosis mimicking basal cell carcinoma in a patient with AIDS.

BACKGROUND: Cryptococcosis is an opportunistic infection caused by the encapsulated yeast Cryptococcus neoformans. This ubiquitous organism has emerged as a frequent finding in immunosuppressed patients, especially those with underlying malignancies, organ transplants, and the acquired immune deficiency syndrome (AIDS). Cutaneous manifestations of cryptococcosis occur in 10 to 15% of patients having systemic involvement. These skin lesions may simulate a variety of different disease entities. METHODS: A case of crytococcosis mimicking a basal cell carcinoma is the subject of a case report presentation. RESULTS: A case of cutaneous cryptococcosis mimicking basal cell carcinoma occurred in a patient with AIDS, who did not appear to have dissemination, but was treated aggressively to stem possible occult systemic disease. CONCLUSION: Cutaneous crytococcosis may mimic other dermatologic disorders.

AIDS-Related Opportunistic Infections↗

Pulmonary cryptococcosis: comparison of clinical and radiographic characteristics in immunocompetent and immunocompromised patients.

STUDY OBJECTIVES: We compared the clinical characteristics and imaging findings between immunocompetent and immunocompromised patients in whom pulmonary cryptococcosis had been diagnosed to define the role of serum cryptococcal antigen (sCRAG) and radiographs during a follow-up period of up to 1 year. DESIGN: Retrospective cohort study. SETTING: University hospital. PATIENTS: The clinical records, chest radiographs, and CT scan findings of 13 immunocompetent and 16 immunocompromised patients with a diagnosis based on cerebrospinal fluid (CSF) culture, sCRAG titers, and cytologic or histologic confirmation of the presence of pulmonary cryptococcosis were reviewed during the course of the study. Two thoracic radiologists reviewed chest radiographs and CT scans for morphologic characteristics and the distribution of parenchymal abnormalities, and a final reading was reached by consensus. The correlation between serial radiographs and sCRAG titers was examined in 9 immunocompetent and 10 immunocompromised patients. MEASUREMENTS: Serum or CSF cryptococcal antigen. RESULTS: The most common clinical symptom was cough, which was present in 24 patients (82.8%). Pulmonary nodules were the most frequent radiologic abnormality. Cavitation within nodules and parenchymal consolidation were significantly less common in immunocompetent patients compared to immunocompromised patients (p = 0.02 and p = 0.05, respectively). Immunocompromised patients tended to have a larger extent of pulmonary involvement than immunocompetent patients, the changes seen on their serial radiographs were more variable, and their corresponding sCRAG titers were higher (> 1:256). In the immunocompetent patients, the radiographic characteristics of lesions usually improved with a corresponding decrease in sCRAG titers over time. CONCLUSIONS: Our study suggests that pulmonary cryptococcosis usually follows a benign clinical course in immunocompetent patients. Immunocompromised patients often undergo an evolution to cavitary lesions that represent a more aggressive disease nature. Serial radiographic changes and changes in sCRAG titers reliably reflect disease progression and the response to therapy.

Adolescent↗

Riu's stain in the diagnosis of pulmonary cryptococcosis. Introduction of a new diagnostic method.

Pulmonary cryptococcosis is thought to be a rare disease. Clinically, it presents no characteristic symptoms, signs or chest x-ray film findings. Most of the reported cases of pulmonary cryptococcosis were not diagnosed either antemortem or before surgical intervention. A simple diagnostic method, Riu's stain, can be used routinely in bronchoscopic brushing smears, or for needle aspiration cytologic studies, making pulmonary cryptococcosis easy to diagnose.

Adult↗

Pulmonary manifestations of disseminated cryptococcosis in patients with AIDS.

Forty-eight patients with disseminated cryptococcosis and AIDS were retrospectively studied to define the pulmonary manifestations. Cryptococcus neoformans (CN) was first isolated from a pulmonary site in 12 patients. Disseminated disease was subsequently documented in all these patients. Symptoms and roentgenographic manifestations (normal, nodular/circumscribed infiltrates, pleural effusions, lobar consolidation) were diverse. Interstitial infiltrates predicted the presence of another opportunistic lung infection besides cryptococcosis in five patients (three untreated and two treated patients). Infectious causes other than cryptococcosis were established by culture and clinical course in five of the ten patients who developed chest roentgenographic abnormalities during amphotericin B therapy. Endobronchial abnormalities were identified in four patients at bronchoscopy. Bronchoalveolar lavage (9/9) and pleural fluid (3/3) cultures were sensitive tests for detection of pulmonary involvement with CN.

Acquired Immunodeficiency Syndrome↗

Cryptococcosis: a review of the Brazilian experience for the disease.

Cryptococcosis is a systemic mycosis caused by Cryptococcus neoformans. The disease occurs in patients with cellular immunodeficiency. The incidence of cryptococcosis arises with aids, and mycosis is one of the opportunistic infections that defines AIDS. After the HAART era the occurrence of cryptococcosis decreased all over the world, but it still continues to be a prevalent disease in Brazil. Thus, we consider this paper to be very important as a result of our reviewing of Brazilian literature regarding some relevant aspects of that disease.

AIDS-Related Opportunistic Infections↗

Pleural cryptococcosis with idiopathic CD4 positive T-lymphocytopenia.

A 19-year-old man was admitted to our hospital because of chest pain. He was diagnosed as having pleural cryptococcosis by pleural biopsy. His CD4 positive T-lymphocyte count was low (< 300 microl) and there was no evidence of human immunodeficiency virus infection. He was successfully treated with fluconazole. However, his CD4 positive lymphocyte counts remained low after the recovery and he was diagnosed as idiopathic CD4 positive T-lymphocytopenia. Pleural cryptococcosis is rare and its predisposing condition is still controversial. To our knowledge, this is the first case of pleural cryptococcosis associated with idiopathic CD4 positive T lymphocytopenia.

Adult↗