RELATIONSHIP BETWEEN HYDROCARBON EXPOSURE AND NEPHROPATHOLOGY IN PRIMARY GLOMERULONEPHRITIS

It has been proposed that renal tubular damage and chronic hydrocarbon exposure are causally related to progression of renal failure in prim ary glomerulonephritis. We examined the relationship between hydrocarb on exposure and morphological parameters of tubulointerstitial damage in 59 patients with biopsy-proven primary glomerulonephritis (prolifer ative, n = 52; membranous, n = 7). From a mean follow-up period of 6 y ears patients were divided into two groups (GP) according to the prese nce or absence of progressive renal failure (GP 1, n = 24 with progres sive renal failure) and (GP 2, n = 35 without progressive renal failur e). The two groups were comparable in age, sex, duration of diagnosis (since the time of biopsy) and blood-pressure control. Patients were b lindly assessed for chronic hydrocarbon exposure by a validated questi onnaire. Biopsy cylinders were blindly assessed retrospectively for re lative interstitial volume of the renal cortex by the point-counting m ethod. In addition an assessment was made of the degree of fibrosis an d chronic inflammatory cellular infiltrate. Hydrocarbon exposure score derived from the questionnaire until the time of renal biopsy correla ted both with interstitial volume (r = 0.55; P < 0.001) and serum crea tinine (r = 0.46; P < 0.001). Moreover, interstitial volume also corre lated with serum creatinine (r = 0.63; P < 0.001). Chronic hydrocarbon exposure scores and relative interstitial volume in the renal cortex at the time of renal biopsy was significantly higher in GP 1 than GP 2 (P < 0.001). The degree of interstitial fibrosis and chronic inflamma tory cellular infiltrate was also significantly higher in GP 1 than GP 2 (P < 0.01). At the time of renal biopsy patients from GP 1 had a si gnificantly higher mean serum creatinine than in GP 2 but the degree o f proteinuria and proportion of patients with hypertension were simila r. The result of this study suggests that chronic hydrocarbon exposure and tubulointerstitial damage are causally interrelated and may be im portant risk factors in the progression of renal failure in patients w ith primary glomerulonephritis.