Decreased production of interleukin-12 and interferon-γ is associated with renal involvement in systemic lupus erythematosus

Objective. To analyze the type 1/type 2 cytokine balance in patients with systemic lupus erythematosus (SLE) according to the presence of renal disorder and activity status. Methods. We measured the serum levels of type 1 (IFN-γ, IL-12) and type 2 cytokines (IL-4, IL-10) as well as spontaneous and stimulated cytokine production from peripheral blood mononuclear cells (PBMC) in 40 patients with SLE. Results. Patients with lupus nephritis (LN) showed significantly lower levels of serum IL-12 and IFN-γ than those without LN. Production of IL-12 and IFN-γ by stimulated PBMC were also decreased in patients with LN. The circulating IL-12 correlated positively with IFN-γ, but inversely with IL-10. The SLEDAI scores correlated well with the ratio of IL-4/IFN-γ levels. Conclusion. The reduced production of IL-12 and IFN-γ and the resultant shift towards the type 2 cytokine phenotype may be associated with LN.