クリプトコックス症の臨床研究

Abstract

Cryptococcosis is the third most common deep mycosis in Japan. Cryptococcus neoformans is known to grow in pyres of pigeon feces. Chicken feces in Thailand were tested for whether C. neoformans could be isolated, because there is considerable prevalence of cryptococcal meningitis in patients with HIV in that country. We isolated C. neoformans from chicken feces in as many as at 70 % of the villages tested. Chicken as well as pigeon feces were believed to be an origin of infection. We have studied the relation between in vitro virulence and thickness of polysaccharide capsules. Strains with thicker capsules such as YC-11 or YC-5 showed more resistance to macrophage phagocytosis than strains with thinner capsules like YC-27 or YC-13. This finding was consistent with the cytokine dynamic state in mice cryptococcosis. Th1 was dominant in infections with thinner capsule strains, although Th2 was relatively dominant in those with thick capsules. The clinical features of 104 cases with pulmonary cryptococcosis were summarized. Radiological findings of pulmonary cryptococcosis varied depending on the time course of the disease and on immunological status. There were no specific symptoms and signs except for positive glucronoxylomannan. Those in azole class were the most commonly prescribed antifungals. New generation antifungals voriconazole and intravenous itraconazole showed potent clinical efficacy in pulmonary cryptococcosis.