Immunologic studies of peripheral blood in a child with hypogammaglobulinemia. Suggested mechanism for the development of malignant B-cell lymphoma.

A case of a 7-year-old boy with common variable hypogammaglobulinemia who developed B-cell-type non-Hodgkin's lymphoma is reported. Immunologic studies of his peripheral blood before the development of lymphoma revealed: (1) although peripheral T-cell and B-cell counts were normal, serum IgG and IgA levels were remarkably reduced; (2) DNA synthesis in response to phytohemagglutinin-P (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) stimulation were decreased; (3) DNA synthesis in response to EBV was enhanced; (4) in vitro IgG production with the patient's peripheral blood lymphocytes was significantly depressed; and (5) helper and suppressor activities of the patient's T-cells did not differ from that of normal controls. Six months after the investigation systemic involvement of malignant lymphoma appeared. The lymphoma was diagnosed as a lymphoblastic diffuse one. Lymph node cell marker analysis revealed that the lymphoblasts had surface mu and kappa chain, cytoplasmic IgM, and HLA-DR antigen. Blastogenesis of B-cell series may be suppressed by a feedback mechanism with the B-cells and antibody. In the current case, impairment of such a mechanism with defect of immunoglobulin production might finally induce malignant B-lymphoid proliferation.