Children born to renal transplant recipients: immunologic assessment, placental antibody transfer and response to vaccination

Abstract

Despite the fact that children born to women who have undergone renal transplantation are usually born without symptoms, they have been exposed to immunosuppressive drugs during all the embryonic and fetal period. Little is known about placental antibody transfer in these mother-infant pairs. Also, not much is known on the immune system from those children at birth neither from their response to vaccination during the first year of life. In this project, 20 children born to women previously submitted to renal transplantation will be studied. They will be assessed at birth and at 8 months of age and will compared with 30 healthy children born at term and to 20 preterm children paired by gestational age to preterm children born to renal transplant recipients. Placental transfer of total IgG and of antibodies to measles, varicella, tetanus, Haemophilus influenzae type b and Streptococcus pneumoniae will be evaluated by nephelometry and enzyme immunoassays in maternal peripheral blood and on cord blood.Those children will also have their immune system assessed on cord blood samples, at birth, and on peripheral blood, at 8 months of age, in respect to the number of CD3+ T, CD4+ T and CD8+ T cells, B cells, Natural Killer cells, gd cells, regulatory T cells, NKT cells and monocytes. Cell maturation will be assessed through CD45RA and CCR7 expression on CD4+ T and CD8+ T cells and through CD27 and IgD expression on B cells. Cell activation will be studied through the expression of CD38 and HLA-DR. Expression of TLR2 and TLR4 will also be investigated on monocytes. T and B cell function will be assessed after in vitro stimulation by the expression of CD154 (CD40 ligand) in T and CD40 in B cells. Plasmacytoid and myeloid dendritic cells will be analyzed from the functional point of view after in vitro stimulation using of HLA-DR expression and interferon-alfa and TNF-alfa production.Response to tetanus, Haemophilus influenzae type b e Streptococcus pneumoniae vaccines will be assessed by specific antibodies detected by ELISA after vaccine doses administered in the first year of life.Results from this study will provide a better understanding of the immune system of children born to renal transplant recipients immediately after gestational exposure to immunosuppressive drugs and after 8 months without the influence of those drugs. (AU)