Circulating levels of cytokines in poststreptococcal glomerulonephritis

Cellular immune mechanisms are important in the pathogenesis of acute glomerulonephritis, as underlined by recent demonstrations of cytokine activity in the urine and in the renal tissue of some of these patients. Therefore, we decided to study circulating levels of IL-6, TNF alpha and PDGF measured by ELISA in 12 patients with acute poststreptococcal glomerulonephritis (PSGN) on admission, at the time of discharge from the hospital, 45 days and 3 months later. We also studied 9 patients with acute streptococcal pharyngitis without nephritis, during acute infection, 8 and 21 days later and 20 normal children (control group). On admission, patients with PSGN had increased IL-6 levels (12.4 +/- 4 pg/ml vs control = 2.57 +/- 0.34 pg/ml, p < 0.05) which returned to normal at the time of discharge from the hospital, 8 to 17 days later. TNF alpha was also elevated in the acute phase (8.11 +/- 1.19 pg/ml vs 3.74 +/- 1.4 pg/ml in controls, p < 0.005) but significant individual variation was detected in serial determinations. Levels of PDGF were always normal. In acute streptococcal tonsillitis without nephritis, IL-6 and TNF alpha were increased at the time of active infection, but levels of IL-6 fell to the normal range after 1 week while the increase observed in association with PSGN develops 2 to 3 weeks after infection and followed the clinical course of the disease.