Objective: To identify the balance of Th1/Th2 cytokine expression in the kidney and evaluate the difference in cytokine balance between patients with lupus nephritis WHO classes IV and V.
Methods: The expression of the CD40 molecule on cultured human mesangial cells was assessed by flow cytometry after stimulation with interferon gamma (IFN-gamma) or other cytokines. Frozen sections of kidney tissue from 10 patients with lupus nephritis and two non-SLE patients (with minimal-change disease) were stained with monoclonal antibodies for interleukin (IL)-4, IL-10, IL-12, IFN-gamma, CD4, CD8, CD40, CD68 and CD40L.
Results: CD40 expression of cultured mesangial cells was up-regulated by IFN-gamma, but was not down-regulated in the presence of the Th2 cytokines IL-4 and IL-10. In the glomeruli, CD40 expression and the ratios of IFN-gamma-/IL-10-, IL-12-/IL-4- and (IFN-gamma+IL-12)/(IL-4+IL-10)-positive cells were significantly higher in class IV than in class V lupus nephritis (P < 0.05). Also CD40, IFN-gamma and the activity index derived from the renal biopsy were closely correlated.
Conclusion: IFN-gamma may contribute to the pathogenesis of proliferative glomerulonephritis by the up-regulation of CD40 and the activation of the cellular immune response in human lupus.