Semaphorin 3A, a potential immune regulator in familial Mediterranean fever

Abstract

Objective. Semaphorin 3A (sema3A) plays a regulatory role in immune responses with effects on both T and B regulatory cells. Familial Mediterranean fever (FMF) is an autoinflammatory disease, yet a possible role for regulatory T and B cells has been described. Methods. 17 FMF patients during attack and then in remission, 8 FMF patients with smoldering disease and 12 healthy controls were enrolled. Sema3A in serum and its expression on regulatory T and B cells was evaluated. Clinical parameters of FMF patients were assessed. Results. Semaphorin 3A serum level was lower in FMF patients during attack, smoldering disease or remission than healthy controls, (242.3 ± 9.8 ng/ml vs. 258.9 ± 11.5 ng/ml vs. 232.5 ± 22.7 ng/ml vs. 323.3 ± 160.2 ng/ml, respectively p < 0.05). This decrease was specifically noted on regulatory B and T cells in FMF patients during attack and in smoldering disease and normalised in remission. Conclusion. Sema3A expression on T and B regulatory lymphocytes is low in FMF patients during attack and in smoldering disease compared to the expression in remission and healthy controls. These results are in line with previous descriptions suggesting a possible role of regulatory T cells in termination of FMF attacks. Further studies are needed to verify these preliminary findings.