This study is based upon 48 patients with angio-immunoblastic lymphadenopathy and 36 patients whose lymph nodes revealed, in addition to angio-immunoblastic lymphadenopathy (AILD) , histologic features interpreted as malignant lymphoma of the immunoblastic type in the diagnostic biopsy.Progression into immunoblastic lymphoma (IL) w a s observed in 35%, or eight, of the 23 patients with AILD in whom follow-up biopsies or autopsy were performed. Multiple clusters or islands of compactly arranged large lymphoid cells constituted the initial histologic evidence of IL. Subsequent tissue examination revealed progression of the disease in the form of diffuse replacement of lymph nodes by the neoplastic cellular proliferation. No significant differences in the past history, clinical or laboratory findings were observed between the patients with AILD and those whose lymph node biopsies were interpreted as AILD + IL. These two groups differed greatly, however, with respect to rate of complete remission following; either prednisone o r chemotherapy, or both (63% for AILD vs. 26% for AILD + IL.; p = 0.01); median survival (35 months for AILD vs. six months for AILD + IL; p = 0.0004); incidence of malignant lymphoma at autopsy (20% for AILD vs. 82% for ALLD + IL; p < 0.005); and the finding of extranodal malignant lymphoma at autopsy (10% in AILD vs.64% in AILD + IL; p < 0.025). In the AILD group, median survival of patients who had complete remission after prednisone was significantly longer than that of patients who had partial or no remissions ( p = 0.02) and the same was true for patients who were given chemotherapy (p < 0.003). In the AILD + IL group, a similar difference in the median survival was observed in patients treated with chemotherapy ( p < 0.007), but not in those treated with prednisone (p = 0.31).C a n~~r 41578-606, 1978.NGIO-IMMUNOBLASTIC LYMPHADENOPATHY maglobulinemia and Coombs' positive hemolytic A (AILD)'s~'4 or immunoblastic lymphade-anemia are frequently present. The lymph nodes nopathy" is a systemic disease clinically charac-in AILD reveal a polymorphic picture consisting terized by fever, generalized lymphadenopathy of a proliferation of small vessels, immunoand hepatosplenomegaly. Polyclonal hypergam-blasts* and plasma cells. Similar clinical and From the