The clinical relevance of IgG subclasses in acute leukemias: low serum IgG as a risk factor for early death due to infection in acute myelogenous leukemia.

In order to investigate the clinical significance of IgG subclass levels in adult patients treated for acute lymphocytic (ALL) or myelogenous leukemias (AML), patients were tested before and in regular intervals during and after chemotherapy. Ten patients treated for acute lymphocytic leukemia had normal total IgG and IgG subclass levels that decreased under chemotherapy. This decrease was not associated with septic complications. In contrast, total IgG and subclass levels increased in most patients with acute myelogenous leukemia during chemotherapy and bone marrow aplasia. Those patients with newly diagnosed AML and low total serum IgG before treatment with intensive remission induction chemotherapy had, however, an increased risk of early death due to septic complications.