Conversely, the HGB level was lower in the SLE-ILD group than in the SLE group, and there were no statistical differences between the two groups concerning serum levels of WBC, PLT, Cr, Urea, IgG, IgA, IgM, C3, C4 and IgE (Table 1). This evidence concerns the gene C4A and systemic lupus erythematosus.