Prevalence and clinical characteristics of immune thrombocytopenic purpura in a cohort of monoclonal gammopathy of uncertain significance.

Monoclonal gammopathy of uncertain significance (MGUS) may become symptomatic for autoimmune manifestations. We report on the prevalence and clinical course of immune thrombocytopenic purpura (ITP) observed in a consecutive series of 228 MGUS patients. At MGUS diagnosis, ITP was determined in 6/228 cases, accounting for a prevalence of 2630/100 000 [95% confidence interval (CI): 1210-5620]. One incidental ITP case occurred after 21 months of follow-up. After a follow-up of 681.3 patient-years, the crude incidence of ITP in MGUS was 146.8 per 100 000 patient-year (95% CI: 3.7-817.8). Overall, these observations point to an association between MGUS and ITP.