Pure red cell aplasia associated with B cell lymphoma: Demonstration of bone marrow colony inhibition by serum immunoglobulin

A 58-year old male with follicular small cleaved B cell lymphoma developed pure red cell aplasia (PRCA) during chemotherapy. To understand the etiology of the PRCA, we studied the effects of patient sera on the progenitor cell colony formation of normal human bone marrow cells in vitro. We demonstrated a marked inhibition of normal bone marrow progenitor cell colony formation by patient sera, but not pooled normal human sera. Immunoglobulin was then precipitated from patient sera for similar studies. The majority of the precipitated immunoglobulin was of the IgG type. The immunoglobulin fraction markedly inhibited normal bone marrow progenitor cell colony formation, whereas the non-immunoglobulin fraction was not inhibitory. The presence of inhibitory serum immunoglobulin correlated with the hematologic status of the patient. We conclude that the development of PRCA in patients with B cell lymphoma may be due to a serum IgG inhibitor of bone marrow progenitor cell growth.