Evaluation of T helper-1/-2 balance on the basis of IgG subclasses and serum cytokines in children with glomerulonephritis

Background: To clarify the mechanism of deposition of immunoglobulin G (IgG) subclasses in glomerulonephritis in children, we investigated IgG subclasses in glomerular deposits and T helper subtype 1 (T(H)1)/T(H)2 cytokine balance in pediatric patients with glomerulonephritis. Methods: We enrolled 95 children in whom glomerulonephritis had been diagnosed in our hospital between 1993 and 2000. Patients were divided into 5 groups according to histological diagnosis: 31 patients with lupus nephritis (LN), 22 patients with membranoproliferative glomerulonephritis (MPGN), 7 patients with membranous glomerulonephritis (MGN), 20 patients with Henoch-Schonlein purpura nephritis, and 20 patients with IgA nephropathy. We compared serum IgG subclass values, serum cytokine (interleukin-2 [IL-2] receptor [IL-2R], IL-2, IL-4) values, and immunofluorescence, evidence of glomerular IgG subclasses in the kidney among groups. Results: (1) High serum IgG1 and IgG2 values and glomerular IgG1 and IgG2 deposits were found frequently in the LN group. (2) High serum IgG3 values and glomerular IgG3 deposits were found frequently in the MPGN group. (3) High serum IgG4 values and glomerular IgG4 deposits were found frequently in the MGN group. (4) Conversely, cytokine measurements showed high serum IL-2 and IL-2R values in the LN and MPGN groups, and serum IL-4 values were high in the MGN group. Conclusion: These findings suggest that the pathogenetic mechanism of LN may involve both the T(H)1 and T(H)2 pattern, the pathogenetic mechanism of MPGN may involve the T(H)1 pattern, and the pathogenetic mechanism of MGN may involve the T(H)2 pattern.