Multiple myeloma (MM) patients are immunodeficient. Complement C1q is an important cofactor of both nonspecific and humoral immunity, and it participates in the immunomodulation of multiple tumors. Thus, this study aimed to determine the risk factors and clinical significance of C1q expression in MM patients. In total, 193 MM patients were examined. The mean value of C1q in the patient group (130.46 ± 36.17 mg/L), was lower than that in the control group (anemia and nonmalignant hematologic disease). C1q dynamically changed with different MM stages and was recovered to normal levels when the disease was in remission; however, it decreased again after disease progression. The risk factors of C1q reduction included Durie-Salmon stage and the immunoglobulin type of the disease. In conclusion, C1q appears to be a useful biomarker of tumor burden and a prognostic factor of disease relapse. C1q is a potential marker of the immunodeficiency status in MM patients.
Keywords: Multiple myeloma; complement C1q; immunodeficiency.