Anti-Pseudomonas heat-stable opsonins in acute lymphoblastic leukemia of childhood.

Heat-stable opsonic activity against Pseudomonas aeruginosa and Staphylococcus epidermidis was measured in sera of 33 children with acute lymphoblastic leukemia at selected times during treatment of their disease. Compared to adults, opsonization of P. aeruginosa was normal in children tested at the time of diagnosis and before chemotherapy. Immediately after achievement of remission, opsonic activity against Pseudomonas was significantly decreased (P smaller than 0.05) compared with pretreatment activity. Activity usually returned to normal and remained so during long-term remission maintenance therapy. In children studied just prior to death from unremitting leukemia, however, anti-Pseudomonas opsonic activity was significantly decreased when compared with that of a group of children before any leukemic treatment (p smaller than 0.005). Anti-S. EPIDERMIDIS OPSONIC ACTIVITY SHOWED NO CHANGES DURING THE PATIENT'S COURSE. Decreased serum opsonic activity may significantly contribute to the increased incidence of severe Pseudomonas infections in patients with acute lymphoblastic leukemia.