Anti‐platelet and Anti‐DNA IgM in waldenström macroglobulinemia and ITP

Abstract

We describe a monoclonal IgM that was purified from the serum of a patient with Waldenström macroglobulinemia and thrombocytopenia. The binding and idiotypic characteristics of the patient's macroglobulin were similar to those of a human monoclonal IgM secreted by a hybridoma established from peripheral blood lymphocytes of a patient with systemic lupus erythematosus and immune thrombocytopenia. In the absence of other causes for thrombocytopenia in this patient, our results suggest an autoimmune mechanism for destruction of platelets by the monoclonal IgM. This is the first report of a Waldenström macroglobulinemia with anti-platelet activity of monoclonal IgM. Although the study involves a single patient, the results suggest that there may be a common origin for autoantibodies in autoimmune diseases and monoclonal immunoglobulins having autoantibody activity in monoclonal gammopathies.

Autoimmune thrombocytopenia in Waldenstr�m's macroglobulinemia

“…This mechanism may also be the cause of the autoimmune thrombocytopenia reported in this case although it is of course not possible to exclude passive binding of the paraprotein as the cause of the elevated PAIgM. Binding of monoclonal IgM to autologous platelets has also been demonstrated in previous reports [6][7][8]. IgM monoclonal proteins with anti-platelet activity have also been implicated in EDTA-dependent pseudothrombocytopenia and acquired platelet function defects [12][13][14].…”

“…Symptomatic autoimmune thrombocytopenia has been reported in four individual case reports, but the incidence has not been formally studied [6][7][8][9]. Review of the case records of a further 104 cases diagnosed at our institution identified 3 additional patients.…”

“…Autoimmune thrombocytopenia has been reported rarely in WM [6][7][8][9] but the incidence has not been systematically evaluated. In this study we report the case of a 67-year-old man who presented with symptomatic autoimmune thrombocytopenia who was subsequently found to have WM.…”

IgG-associated immune thrombocytopenia in Waldenström macroglobulinemia

“…A few reports have referred to the mechanism of immune thrombocytopenia associated with WM, and both platelet-associated IgM (PA-IgM) and IgG (PA-IgG) have been shown to be a possible etiology [13,[15][16][17][18]. In this report, we show a case of immune thrombocytopenia in WM with IgM and IgG paraproteins, which improved after chemotherapy against WM.…”

“…Increased PA-IgM has been detected in some patients with immune thrombocytopenia related to WM [13,16,17]. Varticovski et al [15] revealed antiplatelet activity of monoclonal IgM in a WM case. Two groups reported patients with WM-associated immune thrombocytopenia who showed elevated PA-IgM levels in contrast to normal PA-IgG levels [13,16].…”