ABSTRACT
Paecilomyces variotii is a commonly occurring species in air and food, and it is also associated with many types of human infections. Tissue forms of the fungus Paecilomyces variotii or their cytoskeletons were revealed in the cytoplasm of erythrocytes in patients with allergy and bronchial asthma in paecilomycosis. Our study was aimed at investigating the role of red blood cells in the mechanisms of the nonspecific protection of the host in conditions of chronic persistent infection of the blood with the fungus of the genus Paecilomyces. We examined a total of eighty-four 16-to-72-year-old patients (39 men and 45 women) presenting with activation of paecilomyces infection in blood. We used laboratory, biochemical, allergic-and-immunological and microbiological methods of study. Fungal cultures were identified phenotypically and by means of phylogenetic analysis.Our findings are suggestive of a new type of the oxygen-dependent mechanism of cytotoxicity of erythrocytes, which is caused by permanent formation of reactive oxygen species as a result of non-enzymatic oxidation of haemoglobin to methaemoglobin. The resulting superoxide anion radical (O2-), hydrogen peroxide (H2O2), and hydroxyl radical (OH-) exhibit a powerful bactericidal action which is, probably, activated when the fungal cells are captured and immersed in the erythrocyte cytoplasm or in a closed cavity formed by RBCs around large fungal cells. In conditions of chronic blood infection with tissue forms of fungi of the genus Paecilomyces oxygen-dependent cytotoxicity of erythrocytes is the main mechanism of readjustment of blood from the infectious agent of Paecilomycosis.
