Maternal CD4+ microchimerism in HIV-exposed newborns after spontaneous vaginal delivery or caesarean section.

Background: Maternal CD4+ cell microchimerism may be greater after caesarean section compared to spontaneous vaginal delivery and could cause mother-to-child transmission (MTCT) in HIV-exposed newborns.

Aims: To evaluate maternal CD4+ cell microchimerism in HIV-exposed newborns after spontaneous vaginal delivery or caesarean section.

Study Design And Subjects: In this prospective single-centre study, neonates whose mothers were infected with HIV and had normal MTCT risk according to the German Austrian Guidelines were considered for study enrolment. Maternal CD4+ cell microchimerism in the newborns' umbilical cord blood was measured and compared by mode of delivery.

Results: Thirty-seven HIV-infected mothers and their 39 newborns were included in the study. None of the 17 (0.0%) newborns delivered vaginally had quantifiable maternal CD4+ cells (95% confidence interval (CI): 0.00-0.00) in their circulation at birth compared with four of 16 (25.0%) newborns delivered via planned caesarean section, who showed 0.01-0.66% maternal cells (95% CI: -0.06-0.16; P=0.02) in their circulation. The intention to treat analysis, which included six additional newborns delivered by unplanned caesarean section, showed quantifiable maternal CD4+ cells in one (0.05%; 95% CI: -0.02-0.04) of 23 (4.3%) newborn at birth compared to four of 16 (25.0%) born via planned caesarean section (95% CI: -0.06-0.16; P=0.04). There was no MTCT in any of the newborns.

Conclusion: In this small cohort, spontaneous vaginal delivery in HIV-infected women with normal MTCT risk was associated with lower maternal CD4+ cell transfer to newborns compared to planned caesarean section.