Fetal thymus size is inversely correlated to frequency of regulatory T-cells in a prospective birth cohort: Results from the PRINCE study

Objective: Recently, a dramatic rise in the incidence of autoimmune disease in children has been observed. It has been proposed that prenatal stress will influence the development of fetal immune organs and incidence of autoimmune disease in postnatal life.

Methods: The prospective PRINCE cohort (Prenatal Determinants of Children's Health) investigates the relationship between maternal stress with the fetal immune system and postnatal health. 200 pregnant women representative of the normal population received ultrasound examinations at gestational week 24, 30 and 36. Maternal stress factors, nutrition and pregnancy complications were assessed by standardized interview. Chord blood was analyzed by flow-cytometry.

Results: Thymus transversal diameter was positively correlated with gestational age, fetal weight and fetal size corresponding to a normal growth pattern. The frequency of regulatory T-cells in chord blood showed normal distribution and was not related to gestational week, birth weight or pregnancy complications. However, there was a significant inverse correlation between thymus size and frequency of chord blood regulatory T-cells.

Fig. 1: Regulatory T-cells and thymus transversal diameter

Conclusion: Previous studies have shown that chord blood regulatory T-cells and fetal thymus growth are sensitive markers of fetal immune challenges. For the first time we could show a significant correlation between both markers in a normal birth cohort.