Clinical Diversity and Treatment Outcomes in IgM Monoclonal Gammopathy Associated with Cold Agglutinin Disease and Cryoglobulinemia: A Single Center Study

Background: Cold agglutinin disease (CAD) and cryoglobulinemia are rare immune-mediated complications of IgM monoclonal gammopathies, such as Waldenström macroglobulinemia (WM) and monoclonal gammopathy of undetermined significance (MGUS). Methods:We retrospectively analyzed 11 patients with CAD and/or cryoglobulinemia out of 159 cases of IgM monoclonal gammopathy diagnosed at Fundeni Clinical Institute between 2018 and 2024. Results: Median age was 66 years; 54.5% were female. All patients had IgM kappa monoclonal proteins. CAD was present in 63.6%, cryoglobulinemia in 36.4%, with renal involvement in all cryoglobulinemia cases. Common symptoms included anemia (median hemoglobin 8.5 g/dL), Raynaud’s syndrome (45.5%), and neuropathy (27.3%). The majority of patients received rituximab-based regimens as part of their treatment. A hemoglobin increase ≥2 g/dL without transfusions was observed in 63.6% of patients after 2 cycles. Overall response rate ≥VGPR was 18.2%. Mortality was 63.6%, mainly due to infections and cardiovascular disease. Conclusions:Patients with CAD and cryoglobulinemia associated with IgM monoclonal gammopathy show heterogeneous clinical features and poor outcomes. Despite partial hematologic improvement, high mortality highlights the need for early intervention and optimized therapies.