Expression of T helper 17 cells and interleukin 17 in lupus nephritis patients

Background

Modern data suggest that interleukin 17 (Il-17) and Il-17 producing cells play an important role in the pathogenesis of lupus nephritis (LN). It was reported that T helper 17 migrate to the kidney and contribute to inflammatory processes.

Aim of the work

To measure the frequencies of peripheral blood T helper-17 (Th17) cells and IL-17 concentration in urine in systemic lupus erythematosus (SLE) patients and to study their association with disease activity and renal involvement.

Patients and methods

This work included 45 patients; 36 females and 9 males with 20 matching controls. Patients were subjected to clinical and laboratory assessments with emphasis on renal affection. The SLE disease activity index was also calculated. Expression of Th-17 cells in peripheral blood was measured by flow cytometry via the combined expression of CD3, IL-23R, intracellular IL-22, IL-17 and urinary IL-17 was measured by ELISA.

Results

The patients’ mean age was 26.5 ± 7.6 years and disease duration was 6.03 ± 4.3 years. Th17 expression and urinary IL-17 were significantly higher in patients than controls (p = 0.04 and p < 0.001 respectively). Th17 cell frequencies and IL-17 levels significantly correlated with renal biopsy classification for LN (p = 0.02 and p = 0.04 respectively). Th17 cell expression and IL-17 levels were comparable in SLE patients with and without LN. Th17 cell frequencies significantly correlated with serum creatinine, SLEDAI and inversely with C3 (p = 0.003), while IL-17 significantly correlated with CD3 cells, proteinuria and erythrocyte sedimentation rate.

Conclusion

Peripheral blood Th17 cell frequencies and IL-17 in urine are highly linked to LN in SLE and are promising markers of disease activity in LN. Both are valuable targets for future therapeutic applications.