Histopathology of deep-seated fungal infections and detailed examination of granulomatous response against cryptococci in patients with acquired immunodeficiency syndrome.

This understood without starting paper describes general histopathological features of deep-seated mycoses in patients with acquired immunodeficiency syndrome (AIDS) detailed histological examination on cryptococcal lesions with a consideration of morphological modification caused by treatment with highly active antiretroviral therapy (HAART). In a histopathological review of 164 patients with total human immunodeficiency virus (HIV) infection, the microscopical appearance of esophageal candidiasis which was common in those with single organ involvement revealed necrotic debris containing proliferating hyphae at the site of mucosal erosions without fungal invasion of underlying tissue. The incidence of oral and esophageal candidiasis was followed by that of pulmonary aspergillosis and Candida pneumonia. Nineteen patients including one treated with HAART had generalized cryptococcosis, representing the most common generalized fungal disease. The essential histologic features of the disease were yeast cell proliferation with a histiocytic response, but only minor lymphocytic and neutrophilic components. This was different from those induced by both Candida and Aspergillus infections. Three histologic patterns were recognized in the pulmonary cryptococcal lesions, two of which could be graded with respect to the degree and type of inflammatory reaction. The first was a mild one consisting of small scattered foci of intra-alveolar cryptococcal proliferation with a histiocytic response. The second pattern involved massive cryptococcal infection, which might have been simply more extensive than that in the former. Capillary involvement of alveolar septa was an important common finding in the eighteen patients who had not been treated with HAART. The absence of T cells and decreasing function of antigen-presenting activity in histiocytes were confirmed by immunohistological examination. These findings suggest that the lungs of AIDS patients without HAART offer little resistance to bloodstream dissemination by Cryptococci. The third pattern demonstrated in the patient treated with HAART was characterized by the presence of CD4+ cells, greater response of histiocytes and multinucleated giant cell formation, and lack of massive capillary involvement.