Infections in hairy cell leukemia (leukemic reticuloendotheliosis).

Of 22 patients with hairy cell leukemia, 18 developed life-threatening infections. Susceptibility to infection appeared to be increased nonspecifically, in that a wide range of infecting organisms were noted. Pseudomonas aeruginosa was the organism isolated most frequently. Four patients had disseminated Mycobacterium kansasii, and one had bacillus Calmette-Guerin lymphadenitis. Two patients developed serious fungal infections (Candida albicans in one and Allescheria boydii in the other). One patient had disseminated cytomegalovirus infection and two had toxoplasmosis. Splenectomy did not appear to decrease the infection rate. The infection rate initially increased following chemotherapy (P less than 0.001), then returned to pretreatment levels by two months following treatment. Infections were most frequent during granulocytopenia (P less than 0.01), but granulocytopenia was not a prerequisite for either life-threatening or fatal infections. Monocytopenia may be a more important factor than granulocytopenia in risk of infection in hairy cell leukemia patients.