Maternally acquired IgG immunity in neonates born to renal transplanted women

• This is the first study on placental antibody transfer in renal transplanted women.
• Neonates from transplanted mothers are born with low median tetanus antibodies.
• Mothers with up-to-date vaccination had neonates with higher tetanus antibodies.
• Maternal antibodies were associated with neonatal antibodies for all antigens.
• Low gestational age, preeclampsia and hypertension may reduce neonatal antibodies.

Neonates born to renal transplanted women are exposed in utero to immunosuppressors and to antenatal conditions that may predispose the neonate to a high risk of prematurity and intrauterine growth retardation. These factors might interfere with the transfer of maternal IgG immunity. Total IgG levels and specific antibodies to measles, varicella, tetanus, Haemophilus influenzae type b (Hib) and Streptococcus pneumoniae (serotypes 4,6B,9V,14,18C,19F and 23F) were evaluated on maternal and cord blood samples of 23 sets of renal transplanted women and their newborns and 32 sets of healthy women-newborns at term. Total IgG levels were measured by nephelometry and specific antibodies, by ELISA. Renal transplanted mothers had lower median tetanus antibodies (0.67 IU/mL) than controls (1.53 IU/mL; p = 0.017). Neonates from renal transplanted mothers had lower median tetanus antibodies (0.95 IU/mL) than controls (1.97 IU/mL, p = 0.008). Antibodies to measles, varicella, Hib and the 7 serotypes of S. pneumoniae were similar between groups. Maternal antibodies were associated with an increase in neonatal antibodies for all antigens; gestational age was associated with an increase in Hib neonatal antibodies. Preeclampsia was associated with a decrease in neonatal total IgG and serotype 4 S. pneumoniae antibodies; chronic hypertension was associated with a decrease in neonatal serotype 6B S. pneumoniae antibodies. As neonates from transplanted women may be born with lower tetanus antibodies than controls, efforts should be made to keep maternal vaccines up-to-date. Clinical antenatal care with control of preeclampsia, chronic hypertension and prevention of premature delivery might also contribute to neonatal antibody levels to specific antigens at birth.