Immunohistochemical localization of IL-8 and TGF-beta in streptococcal glomerulonephritis.

Abstract

Acute poststreptococcal glomerulonephritis (APSGN) is characterized by diffuse glomerular hypercellularity, primarily as a result of accumulation of neutrophils (exudative glomerulonephritis), increase in intrinsic glomerular cells, and transient pathological mesangial matrix expansion. Cytokines and growth factors are supposed to play an important role as mediators of inflammation and as progression factors in various renal disorders. Interleukin-8 is a recently described cytokine, defined as a selective activator and chemoattractant of polymorphonuclear leukocytes (PMNL) and transforming growth factor (TGF)-beta plays a central role in the accumulation of pathological extracellular matrix in glomerulonephritis. This study analyzed the biopsies of ten patients with APSGN, using immunohistochemistry (avidin-biotin complex/horseradish peroxidase method) using monoclonal antibodies anti-IL-8, anti-TGF-beta 1, beta 2, beta 3. Controls consisted of non-immune mouse serum, or anti-TGF-beta preabsorbed with human recombinant TGF-beta. Compared with normal renal tissue, and minimal change disease, an increased glomerular IL-8 and TGF-beta staining was observed in all of the biopsies. Furthermore, in one patient, we observed a weak deposit of TGF-beta in tubulointerstitium. Immunoreactive IL-8 and TGF-beta in glomeruli was correlated with light microscopic and clinical features. There was a significant association (P < 0.05), between IL-8 glomerular immunoreactivity and neutrophil infiltration and between TGF-beta glomerular staining and mesangial matrix expansion. Otherwise, there was no correlation with the mesangial cellularity. It was concluded that increased protein expression of IL-8 and TGF-beta are observed in APSGN and may play a role in the acute glomerular inflammation.