Renal bcl-2/bax expression in childhood Henoch-Schönlein nephritis: prognostic importance?

Authors: KENAN BEK, AYŞEGÜL OKSAL, GÜLAY DEMİRCİN, MEHMET BÜLBÜL, ÖZLEM AYDOĞ, ALİ DELİBAŞ, AYŞE ÖNER

Abstract: To investigate the renal expression of apoptosis regulatory proteins b-cell lymphoma 2 (bcl-2) and bcl-2 associated X (bax) in children with Henoch–Schönlein nephritis (HSN) Materials and methods: Renal expression of antiapoptotic bcl-2 and proapoptotic bax proteins were studied immunohistochemically in 22 children with HSN. The kidneys of 5 children who died due to nonrenal reasons were used as the control. The patients were compared according to their renal histopathology and prognosis. Results: Nephrotic or nephrotic-nephritic renal involvement was the most common presentation. Histopathological findings were Class I in 1, Class II in 5, Class III in 10, Class IV in 4, and Class V in 2 patients. IgA staining was shown in all biopsies. Bcl-2 and bax proteins mainly showed tubular and crescentic expression. This was significantly different for bcl-2 in tubules and bax in distal tubules compared to the controls (P < 0.05). No significant difference between bax and bcl-2 expression was observed among patients. However the mean values of the bcl-2/bax ratio, that is, the balance between survival and apoptosis, were significantly higher in crescents of the severe histopathologic group and in distal tubules of the poor prognosis group (P < 0.05). Conclusion: A higher bcl-2/bax ratio, that is relative to the predominance of cell survival in distal tubules and crescents in HSN, seems to be a poor prognostic factor in children.

Keywords: Apoptosis, bax, bcl-2, children, Henoch-Schönlein nephritis, prognosis

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