Endemic mycoses in AIDS: a clinical review

Central nervous system involvement as a relapse of disseminated histoplasmosis in an Italian AIDS patient

A case of an Italian AIDS patient who developed both meningitis and cerebral mass lesion as a final relapse of disseminated histoplasmosis is reported. Central nervous system (CNS) involvement occurred while the patient was receiving both amphotericin B and itraconazole as maintenance therapy, thus indicating the difficulty of eradicating histoplasmosis in patients with AIDS.

Antifungal prophylaxis during neutropenia and immunodeficiency

Fungal infections represent a major source of morbidity and mortality in patients with almost all types of immunodeficiencies. These infections may be nosocomial (aspergillosis) or community acquired (cryptococcosis), or both (candidiasis). Endemic mycoses such as histoplasmosis, coccidioidomycosis, and penicilliosis may infect many immunocompromised hosts in some geographic areas and thereby create major public health problems. With the wide availability of oral azoles, antifungal prophylactic strategies have been extensively developed. However, only a few well-designed studies involving strict criteria have been performed, mostly in patients with hematological malignancies or AIDS. In these situations, the best dose and duration of administration of the antifungal drug often remain to be determined. In high-risk neutropenic or bone marrow transplant patients, fluconazole is effective for the prevention of superficial and/or systemic candidal infections but is not always able to prolong overall survival and potentially selects less susceptible or resistant Candida spp. Primary prophylaxis against aspergillosis remains investigative. At present, no standard general recommendation for primary antifungal prophylaxis can be proposed for AIDS patients or transplant recipients. However, for persistently immunocompromised patients who previously experienced a noncandidal systemic fungal infection, prolonged suppressive antifungal therapy is often indicated to prevent a relapse. Better strategies for controlling immune deficiencies should also help to avoid some potentially life-threatening deep mycoses. When prescribing antifungal prophylaxis, physicians should be aware of the potential emergence of resistant strains, drug-drug interactions, and the cost. Well-designed, randomized, multicenter clinical trials in high-risk immunocompromised hosts are urgently needed to better define how to prevent severe invasive mycoses.

Fungal infections in patients with acquired immunodeficiency syndrome

The incidence and severity of fungal infections appear to increase with progression of HIV disease. Because of the significant morbidity and mortality associated with the mycoses discussed, knowledge of the clinical syndromes, early diagnosis, and prompt institution of therapy are crucial for a favorable outcome. For disseminated or invasive fungal infections, suppressive therapy must be continued to prevent relapse.

[Histoplasmosis in immunodepressed patients: study of 18 cases seen in Uberlândia, MG]

The diagnosis of histoplasmosis was made by isolation of Histoplasma capsulatum from cerebrospinal fluid (CSF), blood and bone marrow or by histopathologic (biopsy or post mortem) examination. The mean age of the patients was 35.8 years; 13 patients were male (72.2%). The disease was disseminated, with the following distribution:skin (38.8%), bone marrow (27.7%), nasopharyngeal mucosa (22.2%), lungs (22.2%), colon (11.1%), central nervous system (5.5%) and esophagus (5.5%). Adenomegaly (50%), hepatomegaly (77.7%) and splenomegaly (61.1%) were frequently seen. The most common hematologic abnormality was pancytopenia (33.3%) of the patients. Eleven patients were treated, 9 with amphotericin B and 2 with itraconazole. Eight had good clinical improvement and all of them were given amphotericin B or a triazolic as maintenance therapy. This study emphasize the importance of this mycosis in immunodepressed patients, specially AIDS patients, in whom the infection tends to invade the macrophagic-lymphoid system and preferentially the cutaneous tegument.

Recombinant Coccidioides immitis complement-fixing antigen: detection of an epitope shared by C. immitis, Histoplasma capsulatum, and Blastomyces dermatitidis

We undertook an investigation to assess the utility of a recombinant Coccidioides immitis complement-fixing (CF) antigen for detecting CF antibody in sera from patients with coccidioidomycosis. Enzyme-linked immunosorbent assays established that recombinant CF antigen and, for comparison, a commercially available coccidioidin were reactive with 19 of 19 sera from patients with active coccidioidomycosis. The recombinant antigen was significantly more sensitive than coccidioidin. The median titer obtained when patients' sera were assayed against recombinant CF antigen was 1:51,200 compared to 1:25,600 with coccidioidin (P < 0.027). The recombinant antigen was also more effective in distinguishing the antibody levels in sera from patients with pulmonary coccidioidomycosis than in sera from those with disseminated disease. Whereas patients with pulmonary disease showed a median antibody titer of 1:25,600, those with multifocal disease showed a median titer of 1:102,400 (P < 0.028). The recombinant CF antigen was found, however, to express an epitope(s) that reacted with sera from 6 of 12 patients with histoplasmosis and 2 of 12 patients with blastomycosis.