Some immunological aspects of the long-term remission in acute lymphoblastic leukemia in children

Nineteen children aged from 3 to 16 years with first long-term hematologic remission were studied. Cell-mediated immunity was assayed by the reaction to dinitrochlorobenzene (DNCB), nitroblue tetrazolium reduction test (NBT) and lysozyme activity. Humoral immunity was determined by immunoglobulin (IgG, IgA, IgM) levels in serum. The DNCB-reaction was positive in 50% of children treated from 12 to 36 months. Percentage and absolute counts of NBT-positive granulocytes and lysozyme/granulocyte ratio systematically increased with time of therapy. In all studied children IgG was normal, IgA and IgM were depressed to 40% and 76% of normal value (with the exception of 2 children after cessation of therapy, in which IgA was normal). It seemed that continuous control of the immunologic status during long-term cytostatic therapy is essential in clinical practice.