Autoimmune thrombocytopenia in Waldenstrom's macroglobulinemia

Autoimmune phenomena are well-recognised complications of Waldenstrom's mac roglobulinemia (WM) and IgM monoclonal gammopathy. Peripheral neuropathy an d cold agglutinin hemolytic anemia are the most common reported and occur i n 5-10% of patients. Autoimmune thrombocytopenia has been rarely reported i n WM and its incidence is not known. In this study we report the case of a 67-year old man who presented with autoimmune thrombocytopenia who was subs equently found to have WM. Laboratory investigation demonstrated that plate let-associated IgM (PAIgM) but not PAIgG was clearly elevated compared to n ormal controls. In addition the patient's serum reacted strongly with a pan el of donor platelets analysed with an indirect platelet immunofluorescence assay utilising an anti-IgM secondary antibody. Glycoprotein specificity c ould not however be demonstrated by ELISA techniques for platelet glycoprot eins IIbIIIa, IaIIa, IbIXa, and IV. We also reviewed the case records of 10 4 additional cases of WM diagnosed at our institution between 5/93 and 5/99 , Three further cases with clinically significant autoimmune thrombocytopen ia were identified. The overall incidence of autoimmune thrombocytopenia (4 /105, 3.8%) in this cohort of patients was similar to the incidence of peri pheral neuropathy (7/105, 6.7%) and cold agglutinins (3/105, 2.9%). (C) 200 1 Wiley-Liss, Inc.