To identify proteins associated with DL, we first compared analyte prevalence between patients with DL and patients with SLE without cutaneous involvement (as measured through SLEDAI and LAI) using the same set of analytes assessed for identification of LN signatures (94 IgG, IgA, and IgM antibodies and 105 additional SLE-associated proteins/analytes; Supplemental Table 2). This evidence concerns the gene CD40LG and systemic lupus erythematosus.