Pregnancy History Influences the Level of Autophagy in Peripheral Blood Mononuclear Cells From Pregnant Women

Objective: Maternal immune responses are altered during pregnancy and differ between nulliparous and multiparous women. The influence of a prior gestation on autophagy in peripheral blood mononuclear cells (PBMCs) from pregnant women has not been determined and is the subject of this investigation. Methods: Peripheral blood mononuclear cells were isolated from 212 pregnant women and immediately lysed in the presence of protease inhibitors, and the extent of autophagy was determined by quantitation of the concentration of p62 (sequestosome-1) in the lysates by enzyme-linked immunosorbent assay (ELISA). In PBMCs, the p62 level is inversely related to the extent of autophagy. The level of the stress-inducible 70-kDa heat shock protein (hsp70), an inhibitor of autophagy, was also measured in the lysates by ELISA. Data were analyzed by the Spearman rank correlation, Mann-Whitney U test, or Kruskal-Wallis test, as appropriate. Results: The p62 concentration in PBMCs increased (autophagy decreased) with the number of previous live (P = .0322), preterm (P = .0143), or term (P = .0418) deliveries. The p62 level was lower (autophagy higher) in women with a prior spontaneous pregnancy loss but no deliveries as compared to women with their first conception (P = .0087). The intracellular hsp70 concentration correlated with the p62 level (P < .0001). Conclusion: Multiparity is associated with a reduced level of autophagy in PBMCs. Dysregulated autophagy might be one mechanism leading to spontaneous abortion in nulliparous women.