INCREASED GLOMERULAR AND INTERSTITIAL LFA-1 EXPRESSION IN PROTEINURICIMMUNOGLOBULIN-A NEPHROPATHY

The cell populations infiltrating the kidneys and the LFA-1 expression were studied in renal biopsy specimens from patients with proteinuric (n = 15, group 1) and nonproteinuric (n = 12, group 2) immunoglobulin A nephropathy. Both groups were matched for age and renal function at the time of biopsy. Proliferative glomerular changes were more common ly seen in group 1. Both groups had similar numbers of intraglomerular and interstitial total leukocytes, monocytes/macrophages, and T cells (P = NS). However, glomerular LFA-1 alpha- and -beta-positive cells w ere significantly higher in group 1 (2.3 +/- 0.2 and 3.3 +/- 0.1 per g lomerulus) than in group 2 (0.2 +/- 0.08 and 0.5 +/- 0.05 per glomerul us) (P < 0.005 and P < 0.01, respectively). Group 1 had much higher in terstitial LFA-1 alpha- (109 +/- 20/mm(2)) and -beta-positive cells (1 57 +/- 40/mm(2)) in comparison with group 2 (29 +/- 12/mm(2) and 42 +/ - 17/mm(2)) (P < 0.005 and P < 0.01, respectively). No association bet ween glomerular and interstitial LFA-l-positive cells was seen. In add ition, tubular HLA-DR expression was higher in group 1 (29 +/- 6/mm(2) ) than in group 2 (9 +/- 2/mm(2)) (P < 0.005), but the interstitial HL A-DR-positive cells were similar in both groups. There was a significa nt association between interstitial LFA-1 alpha- and -beta-positive ce lls and tubular HLA-DR expression in group 1 (P < 0.01 and P < 0.005, respectively) but not in group 2. Interestingly, the extent of interst itial but not glomerular LFA-1 alpha and -beta expression was highly r elated to the degree of proteinuria in group 1 (P < 0.01 and P < 0.002 , respectively). In conclusion, proteinuria in immunoglobulin A nephro pathy is associated with increased LFA-1 expression by glomerular and interstitial infiltrating cells. However, interstitial but not glomeru lar LFA-l-positive cells are strongly related with the degree of urina ry protein excretion. The exact link between LFA-1 expression and prot einuria needs further investigation. (C) 1996 by the National Kidney F oundation, Inc.