Intraglomerular monocyte infiltration and immune deposits in diffuse lupus glomerulonephritis

Previous studies have suggested that separately, glomerular monocyte (MO) infiltration and persistent glomerular immune deposits have opposite prognostic implications in lupus nephritis (LN). To see whether these pathological variables are inversely related, 37 renal biopsy specimens from 37 patients with diffuse proliferative LN were assessed histologically for activity index, chronicity index, and mean glomerular deposit score per biopsy (deposit index [DI]); the latter was determined semiquantitatively on a scale of 0 to 4.0. Frozen sections were double immunolabeled for immunoglobulin G (IgG) and CD68, a marker for MOs. For each glomerulus in each biopsy specimen, the number of CD68+ cells was counted and the amount of IgG scored semiquantitatively on a scale of 0 to 4.0. For each biopsy specimen, the mean number of MOs per glomerular cross-section (MO index [MOI]) was calculated. Linear regression analysis showed a moderately strong inverse correlation between individual glomerular IgG deposit score and individual glomerular MO count (r = -0.447; P < 0.0001), a weaker but significant inverse correlation between DI and MOI (r = -0.350; P = 0.0389), and a positive correlation between the DI determined histologically in each case and the corresponding DI scored on the immunolabeled sections (r = 0.534; P = 0.0105). The results indicate that the amount of glomerular deposit and the extent of glomerular MO infiltration are inversely related in LN.