Role of immune-related conditions in smoldering myeloma and MGUS.

8104 Background: Recent guidelines emphasize tailored follow-up and the need for clinical trials for high-risk smoldering myeloma (SMM). Emerging evidence from epidemiological studies suggests that immune-related conditions play a role in the causation of myeloma precursor disease (SMM and monoclonal gammopathy of undetermined significance; MGUS) and are of clinical importance for the risk of developing multiple myeloma. The aim of our study is to assess whether there is an altered biology in SMM/MGUS patients with preceding immune-related conditions. Methods: From our ongoing prospective SMM/MGUS natural history study, we evaluated 56 SMM and 60 MGUS patients. Information on autoimmunity was identified at baseline. All patients underwent extensive clinical and molecular characterization. At baseline, all patients underwent bone marrow biopsy evaluation using immunohistochemistry and multi-color flow cytometry of plasma cells. We assessed expression patterns of adverse plasma cell markers (CD56 and CD117)...