CD52 and systemic lupus erythematosus: Additionally, plasma CD52 positively correlated with IgM titers (n = 40; r = 0.41, p = 0.0086) and weakly correlated with IgG titers (n = 40; r = 0.30, p = 0.059), which were found to be significantly elevated in SLE patients (n = 20) compared to healthy controls (n = 18) (Figures 2D, E and Figure S3C).