Association between immunoglobulin isotypes and cytogenetic risk groups in multiple myeloma.

person Ramya Muddasani NYU Winthrop University Hospital, Mineola, NY info_outline Ramya Muddasani, Angela Ramdhanny, Gabriel Lutz, Meredith Akerman, Albert Ho, Jaime Andres Suarez, Marc Justin Braunstein

Authors person Ramya Muddasani NYU Winthrop University Hospital, Mineola, NY info_outline Ramya Muddasani, Angela Ramdhanny, Gabriel Lutz, Meredith Akerman, Albert Ho, Jaime Andres Suarez, Marc Justin Braunstein Organizations NYU Winthrop University Hospital, Mineola, NY, Pathline-Emerge, Ramsey, NJ, Montefiore Hosp, New York City, NY, NYU Langone Med Ctr, Great Neck, NY Abstract Disclosures Research Funding Other Foundation Background: Cytogenetic abnormalities (CA) carry prognostic significance in MM. Immunoglobulin isotypes also predict disease behavior, with non-IgG subtypes historically being associated with poorer outcomes. We hypothesized that MM non-IgG isotype and higher risk CA are associated with greater degree of marrow infiltration (BM%) and presence of end organ damage at presentation. Methods: 552 MM patients were retrospectively analyzed using a multi-institution repository of BM%, isotype, and CA risk groups stratified by mSMART criteria. A subset of 110 patients were used to assess clinical comparisons and associations between CA, isotype, and end organ damage using the chi-square or Fisher’s exact test for categorical variables and the Mann-Whitney test to compare between groups for continuous variables. Results: There was a higher BM% seen in the intermediate risk group compared to standard risk group (50% vs 20%, p < 0.04). A lower BM% was seen in the IgG subtype compared to other isotypes (27% vs 45%, p < 0.02). CA including del(13q), del(16q), dup(1p), dup(1q), t(4;14), t(11;14), and trisomy 11 were associated with a higher BM%. When comparing isotypes to CA risk groups, IgA isotype was associated with greater risk, including del(13q) and del(16q). IgG isotype was associated with trisomy 11, while light chain MM correlated with higher risk CA including del(17p), and dup(1q). Lytic lesions on presentation were more frequent in patients with trisomy 11 and less frequently in IgA MM. Anemia presented more in IgA MM, and renal failure in patients with t(14;16). Conclusions: Lower BM% was found in IgG isotype MM, which correlated with standard risk CA, whereas light chain MM was associated with higher risk CA; this risk group being more likely to present with renal failure. Unexpectedly, lytic lesions on presentation correlated with non-IgA isotype and better risk CA. Further studies are needed to confirm these findings prospectively to determine if they can predict end organ damage in patients with specific isotypes or CA groups.