CD4 and systemic lupus erythematosus: IL-13 expression in CD8+ T cells was greater than that in CD4+ T cells on a per cell basis as determined by the mean fluorescence intensity (MFI) (HC: 396.67 ± 26.54, 165.64 ± 6.10, p<0.0001; SLE: 470.42 ± 27.39, 158 ± 8.65, p<0.0001).