CD40LG and systemic lupus erythematosus: No differences in the plasma concentrations (mg/dl) of IgG, IgA, and IgM were observed between HD and SLE patients (IgG: 1083 ± 34.74 for HD vs. 1348 ± 125 for SLE; IgA: 262.2 ± 42.85 for HD vs. 319 ± 34.39 for SLE; IgM: 129.9 ± 16.55 for HD vs. 149.6 ± 20.76 for SLE).