IMMUNE RECOVERY IN CHILDREN WITH MALIGNANCY AFTER CESSATION OF CHEMOTHERAPY

Purpose: To study longitudinally the extent and recovery of cellular a nd humoral immune alterations in children with cancer after completion of their therapy. Patients and Methods: Using standard immune assays, cellular and humoral immunity was measured in 43 infants and children with cancer at completion of therapy and every 3 months thereafter fo r 1 year. There were 17 patients with acute lymphoblastic leukemia, 9 with Hodgkin disease, and 17 with solid nonhematopoietic tumors. All c hildren had received standard childhood immunizations before diagnosis of cancer. Immune assays performed included circulating lymphocyte su bpopulations, in vitro antigen-induced responses, and total concentrat ions of serum immunoglobulin G (IgG), IgM, IgA, and IgG subclasses, an d specific antibodies against diphtheria, tetanus, pertussis, and poli ovirus types I, II, and III. Results: At completion of therapy, the ma jority of patients had low circulating lymphocyte subpopulations and a ntigen-induced responses. Serum antibody concentrations were low in up to 89% of patients regardless of the underlying malignancy. Although improvement occurred during the year of follow-up, 35 of 43 (81%) pati ents continued to exhibit one or more immune abnormalities 9 to 12 mon ths after cessation of chemotherapy. Younger patients had more persist ent alterations. Other risk factors studied (including gender, duratio n of therapy, and underlying malignancy) did not correlate with the se verity of the immune defects. With the exception of poliovirus antibod ies, specific antibody titers against common childhood vaccine antigen s were deficient at completion of therapy and 9 to 12 months later in a substantial proportion of patients. Conclusion: Children with malign ancy have persistent specific and nonspecific immune alterations 9 to 12 months after cessation of chemotherapy. The clinical implications o f these in vitro observations are unclear and require further evaluati on.