Monoclonal antibody identification of infiltrating mononuclear leukocytes in lupus nephritis

Monoclonal antibody identification of infiltrating mononuclear leukocytes in lupus nephritis (LN). Populations of mononuclear inflammatory cells infiltrating the renal interstitium in LN were studied by means of an avidin–biotin immunoperoxidase technique applied to cryostat sections of 26 renal biopsies (3 WHO class IIb; 4 class III; 8 class IV; 4 class V; 4 class III and V; and 3 class IV and V). The majority of interstitial leukocytes were T cells (mean 65.7 ± 14.1). The number of cells reactive with OKT 8 (47.3 ± 11.0) exceeded the number of OKT 4 positive cells (32.5 ± 11.3) in 22 of 26 biopsies. Cells reactive with antimonocyte antibodies OKM 1 and OKM 5 (6.7 ± 5.9 and 7.9 ± 5.9, respectively) and B lymphocytes (OKB 2 3.9 ± 3.5) were a minor component of the interstitial infiltrates. Monocytes were the predominant cell type among stained cells in glomerular tufts and crescents. Tissue T 4 /T 8 ratios varied widely (range 0.31 to 1.81), and were less than 1 in 22 of 26 patients. There was no correlation between tissue T 4 /T 8 ratios and simultaneous peripheral blood T 4 /T 8 ratios. Using stepwise multivariate linear regression, tissue T 4 /T 8 ratio was found to correlate highly with renal histologic activity (P 4 /T 8 ratio in LN was significantly lower than that of other glomerular and interstitial diseases studied (P