Lymphoproliferative diseases in disorders of the immune system

Severe immunodeficiency diseases are complicated by the development of malignancies of the immune system itself, mainly non-Hodgkin's lymphoma (NHLs). These occur in immunosuppressed organ allograft recipients; in cancer chemotherapy patients; in patients with primary immunodeficiency diseases; in chronic dialysis patients; in victims of the Acquired Immunodeficiency Syndrome (AIDS); and in persons with various autoimmune diseases either untreated or given immunosuppressive therapy. Most of these NHLs are reticulum cell sarcomas or immunoblastic sarcomas. Immunologically, most are of B-cell origin. Most tumors are extranodal in distribution. They show a remarkable predilection for the brain. Possible causes of the NHLs include oncogenic viruses; disturbed immune surveillance; chronic antigenic stimulation; impaired immunoregulation; carcinogenic effects of immunosuppressive, cytotoxic or other drugs; and genetic susceptibility to lymphomagenesis.