Severity of tubulointerstitial inflammation and prognosis in immunoglobulin A nephropathy

Many risk factors for progression in immunoglobulin A nephropathy (IgAN) have been found. We focused on renal leukocyte infiltrations and cytokines in IgAN. The subjects were 204 IgAN patients. Renal histopathological changes were semiquantitatively graded. Expression of tubulointerstitial Leukocyte common antigen (LCA), CD3, CD68, interleukin (IL)-1β, and IL-10 was evaluated by immunohistochemistry. These parameters were correlated with progression of IgAN. The significance of these correlations was tested by a multivariate analysis. Glomerulosclerosis, tubular atrophy, interstitial inflammation, and hyaline arteriolosclerosis correlated with progression in all patients and also in patients with initially normal serum creatinine. Tubulointerstitial LCA, CD3, CD68, and IL-1β expression correlated with progression. CD3 had the strongest correlation. In the multivariate analysis, tubulointerstitial CD3, hypertriglyceridemia, elevated serum creatinine concentration, and interstitial fibrosis were independently associated with progressive disease in all patients, and tubulointerstitial CD3 expression and hyaline arteriolosclerosis in patients with initially normal serum creatinine. We found parameters reflecting tubulointerstitial inflammation to predict deterioration of renal function in IgAN. This was also seen in patients whose serum creatinine was normal at the time of renal biopsy. Our findings show that, an immunohistochemical evaluation of tubulointerstitial inflammation seems to be a useful tool in determining the prognosis in IgAN