Immunoglobulin class and subclass concentrations after treatment of childhood leukemia

With greatly increased survival rates after childhood leukemia during the l ast 3 decades, the long-term effects of the treatment have became more evid ent. The disease and its treatment impair the immune system, but the durati on of this impairment is unknown. The authors studied the serum concentrati ons of immunoglobulins and IgG subclasses in 20 Icelandic children cured of leukemia on. average 8 years and 3 months after their treatment ended. Alt hough no mal ked deviations were found in the concentrations of the main im munoglobulin Glasses IgA, IgM, IgG, and IgE, the IgG subclass levels were b elow reference values. The patients had on average 0.9 of age standardized reference values of IgG1, 0.5 of IgG2, 0.8 of IgG3, and 0.7 of IgG4. Howeve r, none had any autoimmune diseases or a markedly increased tendency for in fections. The results indicate that although the immunoglobulin classes reg ain their normal values within a few years after cessation of treatment, re covery of the IgG subclasses, especially IgG2, is impaired.