Serum protein electrophoresis in a 61-year-old woman with psoriasis and psoriatic arthritis showed a monoclonal spike that was identified as IgM-k monoclonal immunoglobulinemia by immunodiffusion and immunoelectrophoresis. There was no clinical evidence of myeloma, Waldenström macroglobulinemia, or lymphoma, and the M component has not changed over a three-year observation period. This unusual occurrence may represent another disease entity that may be associated with nonmyelomatous monoclonal immunoglobulinemia.
(JAMA 231:171-173, 1975)
Lergier JE, Gowans JDC. Monoclonal IgM Immunoglobulinemia in Psoriatic Arthritis. JAMA. 1975;231(2):171-173. doi:10.1001/jama.1975.03240140031020