Mast cells, TGF-beta1 and myofibroblasts expression in lupus nephritis outcome.

Renal biopsies of 69 patients with lupus nephritis were studied according to the WHO classification. The aim of the present study was to correlate the interstitial tryptase-positive mast cells with the interstitial TGF-beta1 and alpha-SM actin expression and clinical outcome of lupus nephritis, and identify the pathological role of the interstitial tryptase-positive mast cells in lupus nephritis. The mean follow-up time was 70.7 +/- 54.4 months. Eight patients were grouped as WHO class II lupus nephritis, 15 patients as class III, 28 patients as class IV and 18 patients as class V. Interstitial tryptase-positive mast cells were not correlated with clinical outcome and interstitial TGF-beta1 expression in lupus nephritis. Interstitial tryptase-positive mast cells were correlated with tubulo-interstitial alpha-SM actin expression for WHO class V lupus nephritis, but not to the other classes. In conclusion, in spite of interstitial tryptase-positive mast cells being related to renal interstitial fibrosis process, their expression according to the clinical outcome of lupus nephritis was not significant.