Pattern of serum immunoglobulins and free light chain levels among patients diagnosed with multiple myeloma in Southeast Nigeria

Abstract

Background: Abnormal plasma cells in multiple myeloma produce excessive amounts of immunoglobulins and free light chains, of which certain patterns predict patient survival. Objective: To determine the pattern of elevated and suppressed serum immunoglobulins and free light chain levels among patients diagnosed with multiple myeloma in southeast Nigeria. Materials and Methods: This was a 5-year retrospective study of laboratory results of newly diagnosed symptomatic multiple myeloma patients at three tertiary hospitals in southeast Nigeria. Serum immunoglobulin gamma (IgG), immunoglobulin alpha (IgA), and immunoglobulin mu (IgM) results that were obtained at the time of diagnosis of multiple myeloma were included. Medical records obtained were as follows: age, sex, serum protein, and free light chain concentrations. Data analysis was performed with IBM SPSS 20.0, and P value < 0.05 was considered to be statistically significant. Results: Serum immunoglobulin results of 147 patients comprising 79 (54%) males and 68 (46%) females were included, with mean ± standard deviation age of 60 ± 11.1 years. The most frequently elevated immunoglobulin was IgG (114 [77.6%]) followed by IgA (17 [12%]), then IgM (13 [9%]). Serum IgA was the most frequently suppressed immunoglobulin (71 [48.3%]). Suppression of uninvolved immunoglobulins was commonest with IgG myeloma as 72 (49%) patients had either suppressed IgA < 70 mg/dL, IgM < 40 mg/dL, or both. With values more than 100 mg/L, kappa was the more frequently involved light chain. Conclusion: Elevated IgG was the commonest immunoglobulin, with kappa being the commonly involved free light chain, whereas IgA was the most suppressed immunoglobulin. It is important to determine the patterns of monoclonal proteins in patients with multiple myeloma to predict treatment response and patient survival.