Effect of pregnancy on serum cytokines in SLE patients

Introduction: The aim of this study was to evaluate an extensive panel of cytokines involved in immune regulation during pregnancy in patients with systemic lupus erythematosus (SLE) and in healthy women.Methods: A total of 47 consecutive successful pregnancies in 46 SLE patients and 56 pregnancies in 56 matched healthy subjects, as controls, were prospectively studied. Serum interleukin (IL)-1-α, IL-1-β, IL-2, IL-6, IL-8, IL-10, IL-12p70, interferon (INF)-γ and tumor necrosis factor (TNF)-α were detected in sera obtained at the first and third trimester of pregnancy by a highly sensitive, multiplexed sandwich ELISA.Results: Medians (pg/ml) of serum levels of most helper T (Th)1-type cytokines were significantly lower in the third trimester compared with those observed in the first trimester of pregnancy in healthy women: INF-γ 2.0 vs 3.4, TNF-α 10.2 vs 11.5, IL-1-α 0.9 vs 1.1, IL-1-β 0.6 vs 1.0, IL-2 3.0 vs 3.5, and IL-12p70 4.9 vs 5.6 (P-values < 0.02 for all). By contrast, only the IL-1-α serum levels were lower in the third trimester compared with the first trimester in SLE patients (P = 0.006). IFN-γ/IL-6 and IFN-γ/IL-10 ratios were higher in controls than in SLE (P = 0.002, and P = 0.001, respectively); moreover, they were significantly reduced in the third compared to the first trimester of pregnancy in healthy women, but not in SLE.Conclusions: In SLE patients, Th1/Th2 cytokine serum level ratio does not decrease during pregnancy progression as much as in healthy pregnant women. This could account for the observation of a low frequency of disease flares in the third trimester of gestation.