Th9/IL-9 may participate in the pathogenesis of multiple myeloma.

Introduction: This research is aimed to evaluate the correlation between Th9-associated cytokine levels in MM patients, clinical features, and therapy.
Methods: Peripheral blood samples were taken in 52 MM patients and 20 healthy volunteers matched by sex and age. The patients with MM were separated into two groups: the untreated group (27) and the remission group (25). An enzyme-linked immunosorbent assay (ELISA) was used to measure the IL-9 plasma levels. The levels of Th9-associated cytokines' mRNA expression (IL-9, PU.1, and IRF4) were measured in RT-qPCR. We also analyzed the correlations between the IL-9 plasma levels and the clinical parameters of newly diagnosed MM patients.
Results: The IL-9 plasma levels and the Th9-associated cytokines (IL-9, PU.1, and IRF4) mRNA levels in newly diagnosed MM patients were significantly elevated than those in healthy volunteers and significantly decreased after achieving remission. Moreover, PU.1 and IRF4 had a positive correlation with the IL-9 mRNA expression. Then, we found that the upregulation of IL-9 plasma levels correlates with the severity of anemia and decreased albumin Levels.
Conclusion: The results demonstrate that Th9/IL-9 may be involved in the pathogenesis of MM and is correlated with worse patient conditions such as lower hemoglobin and serum albumin. More work is necessary to confirm whether they might serve as a useful therapeutic target and prognostic marker for MM.
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