RESUMEN
OBJECTIVE: To explore the serum cytokine profile associated with disease activity during pregnancy and postpartum in MS, and to assess any potential biomarkers predicting the occurrence of relapses during this period. METHODS: We included 53 MS pregnant women recruited between 2007 and 2018. Interferon-gamma, Tumor necrosis factor-alpha, interleukin-17, granulocyte/macrophage-colony stimulating factor, Activin-A, interleukin-10, and programmed-death-ligand-1 (PD-L1) were measured quarterly in serum by ELISA. RESULTS: Seventeen patients (32%) experienced relapses during pregnancy or puerperium and 37(68%) did not. We did not found differences in clinical characteristics or treatment status between the two groups. However, relapsing patients showed at the first trimester of pregnancy considerably lower levels of serum Activin-A (336.4 pg/dl [289.6-491.7], median [IQR] vs. 760.0 pg/dl [493.2-1108.0],p = .003), which correlated positively with serum PD-L1 (r = 0.53,p = .0005) and IL-10 (r = 0.43,p = .004) values. Activin-A levels lower than 515 pg/ml at the first trimester identified patients with high probability of relapsing during pregnancy and postpartum (OR = 13.75, CI: 2.5-76.8, p = .001). CONCLUSIONS: MS patients with no relapses during pregnancy and puerperium showed an early triggering of a tolerogenic innate immune response evidenced by high serum Activin-A concentrations during the first trimester of pregnancy. Thus, serum Activin-A can be a useful biomarker to predict clinical activity during this period.