The concentrations of sMer were also found to correlate to decreasing levels of C1q and the presence of anti-DNA antibodies but not to the presence of rheumatoid factor of IgG, IgM, or IgA class and patients with rheumatoid factor had the same mean sMer and sTyro levels as those without rheumatoid factor. Here, CD40LG is linked to rheumatoid factor measurement.