Recovery of blood B-lymphocytes and serum immunoglobulins after chemotherapy for childhood acute lymphoblastic leukemia.

Recovery of humoral immunity after cessation of chemotherapy for childhood acute lymphoblastic leukemia (ALL) was investigated by determining blood leukocyte, lymphocyte and B-lymphocyte, and serum immunoglobulin (Ig) levels and IgG subclasses at 0, 1, 3, 6, 9, and 12 months after cessation of chemotherapy for ALL in 14 patients. Blood B-lymphocytes were analyzed with the use of flow cytometry and monoclonal CD20 antibody. At cessation of chemotherapy, the amount of blood B-lymphocytes was subnormal in most patients but increased to normal levels in 1 month after therapy was discontinued. The recovery of serum Ig, which reflect B-cell function, was slower, but occurred by 6 months after therapy was discontinued in most patients. The authors conclude that by 6 months after cessation of chemotherapy for ALL, a sufficiently functioning immune system by these parameters is established and that prophylactic antibiotics can be withdrawn and immunizations started.