When studying the correlation between RF-IgM and the 25 proteins in data obtained for the controls, excluding data from SLE patients, five of these proteins were found not to correlate (rs < 0.2) to RF-IgM, i.e., keratin, type II cytoskeletal 7 (KRT7 or sarcolectin), glutamic-oxaloacetic transaminase 1 (GOT1 or aspartate aminotransferase, cysteine aminotransferase), ethanolamine phosphate phospholyase (ETNPPL or alanine--glyoxylate aminotransferase 2-like 1, AGXT2L1), renin (REN), and dimethylaniline monooxygenase 1 (FMO1). This evidence concerns the gene KRT7 and systemic lupus erythematosus.