Serum cytokine patterns in immunoglobulin m monoclonal gammopathy‐associated polyneuropathy

ABSTRACT Introduction: Polyneuropathy with immunoglobulin M monoclonal gammopathy (IgM‐PNP) is associated with the presence of IgM antibodies against nerve constituents such as myelin associated glycoprotein (MAG) and gangliosides. Methods: To test whether B‐cell‐stimulating cytokines are increased in IgM‐PNP, we measured serum concentrations of 11 cytokines in 81 patients with IgM‐PNP and 113 controls. Results: Median interleukin (IL)‐6 concentrations were higher in patients with IgM‐PNP, and median IL‐10 concentrations were higher in the subgroup with anti‐MAG IgM antibodies. These serum concentrations were not increased in 110 patients with multifocal motor neuropathy. Discussion: Median IL‐6 and IL‐10 serum concentrations differ between patients with anti‐MAG neuropathy and other patients with IgM‐PNP compared with healthy and neuropathy controls. These differences may indicate differences in immune‐mediated disease mechanisms. Muscle Nerve 59:694–698, 2019