Transplantation of a fetus with paternal Thy-1(+)CD34(+) cells for chronicgranulomatous disease

A fetus diagnosed with X-linked chronic granulomatous disease was transplan ted with Thy-1(+)CD34(+) cells of paternal origin, The transplant was perfo rmed at 14 weeks gestation by ultrasound guided injection into the peritone al cavity, The fetus was delivered at 38 weeks gestation after an otherwise uneventful pregnancy, Umbilical. cord blood was collected and used to dete rmine the level of peripheral blood chimerism as well as levels of function al engrafted cells. Flow cytometry was used to detect donor leukocytes iden tified as HLA-A2(-)B7(+) cells, whereas recipient cells were identified as HLA-A2(+)B7(-) cells. No evidence of donor cell engraftment above a level o f 0.01% was found. PCR was used to detect HLA-DRB1*15(+) donor cells among the recipient's HLA-DRB1*15(-) cells, but no engraftment was seen with a se nsitivity of 1:1000. The presence of functional, donor-derived neutrophils was assessed by flow cytometry using two different fluorescent dyes that me asure reactive oxygen species generated by the phagocyte NADPH oxidase, No evidence of paternal-derived functional neutrophils above a level of 0.15% was observed. Peripheral blood and bone marrow samples were collected at 6 months of age. Neither sample showed engraftment by HLA typing using both f low cytometry and PCR, Functional phagocytes were also not observed. Furthe rmore, no indication of inmunological tolerance specific for the donor cell s was indicated by a mixed lymphocyte reaction assay performed at 6 months of age. While there appears to be no engraftment of the donor stem cells, t he transplant caused no harm to the fetus and the child was healthy at 6 mo nths of age, Analyses of fetal tissues, obtained from elective abortions, r evealed that CD3(+) T cells and CD56(+)CD3(-) NK cells are present in the l iver at 8 weeks gestation and in the blood by 9 weeks gestation. The presen ce of these lymphocytes may contribute to the lack of donor cell engraftmen t in the human fetus.