Mononuclear cell activation and decreased renal function in IgA nephropathy with crescents.

Our previous immunohistologic studies with monoclonal antibodies (mAb) showed that glomerular and interstitial accumulations of mononuclear cells (MNC) were common features of many types of proliferative glomerulonephritis, especially crescentic glomerulonephritis. The current study examined a series of patients with crescentic IgA disease, since IgA disease in general has a highly variable course and the presence of crescents is one indicator of likely progression to end-stage renal failure. We compared the intraglomerular and interstitial infiltrates within biopsies from patients with crescentic IgA nephropathy (N = 5) versus those with noncrescentic IgA (N = 18), or normal controls (N = 10). Few leucocytes were found within glomeruli of normal (2.4 +/- 0.7 cells/glomerular cross section) (mean +/- SEM) or noncrescentic IgA disease biopsies (3.8 +/- 0.7), and no activated MNC bearing receptors for interleukin-2 (IL-2R) were detected. By contrast, in crescentic IgA disease, glomerular leucocytes were increased (5.1 +/- 0.6, P less than 0.01), due to increased monocyte (3.1 +/- 0.9, P less than 0.01) and T cell (1.4 +/- 0.4, P less than 0.01) infiltration, and IL-2R + MNC were then observed (1.2 +/- 0.5, P less than 0.05). Studies of interstitial cells showed small numbers of leucocytes within normal kidneys (101 +/- 16/mm2). Biopsies from noncrescentic IgA disease showed a fivefold increase in interstitial MNC infiltration (total leucocytes 565 +/- 105/mm2, P less than 0.01), due to an influx of T cells (283 +/- 59/mm2, P less than 0.01) and monocytes (120 +/- 32/mm2, P less than 0.01), and including a mean of 20% IL-2R+ MNC (114 +/- 29/mm2, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)