IL6R and systemic lupus erythematosus: sIL-6R/sgp 130 ratio was 2.93-folds higher in SLE group (p < 0.01), respectively 4.06 folds in LN group (p < 0.01), when compared with control group, respectively 1.38 folds in LN compared with SLE group (p < 0.05) and 1.43 folds when compared with IgA nephropathy group (p < 0.05).