Renal interstitial mast cell counts differ across classes of proliferative lupus nephritis

Abstract

Systemic lupus erythematosus frequently involves the kidneys leading to significant morbidity and mortality. It is classified according to glomerular involvement pattern but tubulointerstitial lesions are also important for progression and prognosis, as seen in other kidney glomerular diseases. One of the cell types which participate in this process are mast cells. The aim of the study was to analyze the counts of tryptase-positive and chymase-positive mast cells in lupus nephritis classes II, III and IV. Material consisted of 42 renal biopsies from patients with lupus nephritis; 11 class II, 9 class III and 22 class IV. Chymase-and tryptase-containing cells were stained by immunohistochemistry and counted microscopically. Mean count of chymase-positive mast cells was 9.8/10 high power fields (hpf) for the whole group, 4.66 for class II, 11.89 for class III, and 11.51 for class IV. The mean count of tryptase-positive cells was 18.6/10 hpf for the whole group, 7.65 for class II, 25.57 for class III, and 21.23 for class IV. The differences between lupus nephritis classes were significant both for chymase-and tryptase-positive cells. Tryptase-but not chymase-positive cell counts showed a correlation with the creatinine level (R = 0.35). These results suggest that mast cells are involved to a different degree in the pathogenesis of lupus nephritis depending on the class of the disease.

Original paper Renal interstitial mast cell count is significantly higher in membranoproliferative glomerulonephritis than in class IV lupus nephritis

“…In our study, more mast cells were seen in MPGN than in LN. In our present and previous studies [26], we have found the same positive correlation with RIV and creatinine level. Hiromura et al examined the number of interstitial mast cells in both MPGN and LN.…”

“…They found a correlation between mast cell count, interstitial fibrosis, creatinine level and leukocyte infiltration, but not with urinary protein excretion; the same results were obtained in our study. In our previous study, we found that mast cell counts differ across classes of SLE, which suggests that these cells play a role in the pathogenesis of LN [26].…”

Mast cells in systemic and cutaneous lupus erythematosus

“…Moreover, we confirmed that mast cells contribute to renal tubulointerstitial fibrosis, while the number of mast cells correlates with the renal interstitial volume (RIV) [23,24].…”

Changes of memory B- and T-cell subsets in lupus nephritis patients

“…Lupus nephritis (LN) develops in ~50% SLE patients, representing the main cause of morbidity and mortality [1,2]. The significance of self-reacting B-cells in the pathogenesis of LN is supported by a strong causal link between autoantibodies against double stranded DNA (dsDNA) and renal involvement [3,4].…”