In utero fetal liver hematopoietic stem cell transplantation: is there a role for alloreactive T lymphocytes.
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Publications and source records attributed to C Jakil.
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The use of hematopoietic stem cells for in utero transplantation to create permanent hematochimerism represents a new concept in fetal therapy, although this approach has provided heterogeneous results. In this paper we have undertaken molecular, phenotypic and functional studies aimed at identifying the presence of fully competent T lymphocytes in samples of fetal livers and cord blood. We found mature VDJ TCR beta chain transcripts in fetal liver cells taken from 7 to 16 weeks of gestation and a similar pattern was detected in cord blood cells sampled from 13.5 to 20.5 weeks of gestation. A Vbeta8 gene sequence comparable to that detected in adult PBMC was found in fetal liver samples at 9 or 17 weeks gestation. PreTalpha message was detected in all samples and its expression decreased in fetal blood samples with increasing gestational age while Calpha message appeared at 9.4 weeks and its expression increased during gestational age. T cell clones obtained from fetal liver cells showed a mature TCR alphabeta+, CD8+ phenotype and displayed strong alloreactivity against allo-MHC class I molecules. The presence of alloreactive T lymphocytes may explain the failure to engraft in fetuses older than 13 to 16 weeks and may provide insights into fetal liver transplantation. Bone Marrow Transplantation (2000) 25, 135-141.
Fetus-to-fetus transplantation has been suggested for the treatment of hemoglobinopathies in utero. However, dissimilar results have to date been obtained by different groups. We describe a case in which fetus-to-fetus transplantation in HLA-identical twins was performed at the 19th week of gestation by infusion of 0.8 ml of fetal blood from normal to beta-thalassemia affected fetus with the main aim of inducing tolerance. No evidence of engraftment, determined by KM19 polymorphism, was present after 2 years of the procedure. Moreover, an alloreactive cytotoxic T lymphocyte precursor (CTLp) study of affected fetus vs donor and other different stimulators showed that immunization vs tolerance was the real effect of the procedure.
Five hundred cordocenteses were performed between 12 and 21 weeks. The indications were thalassaemia (386), rapid karyotyping (97), feto-maternal allo-immunization (10), rubella (6), and toxoplasmosis (1). One hundred and ten pregnancies underwent termination on the basis of the result, while 20 of the 370 pregnancies intended to continue were lost to follow-up. Amongst these were 16 fetal losses (4.3 per cent) and 22 premature deliveries (5.9 per cent); no other complications were reported. Four adverse prognostic factors were identified: (a) cord bleeding; (b) fetal bradycardia; (c) prolonged procedure time; and (d) anterior insertion of the placenta. There was no 'obvious' difference in fetal loss rate with advancing gestation until 19-21 weeks, when the risk of fetal loss decreased to 2.5 per cent.
The authors report 8 diagnostic cordocentesis performed at the end of the first trimester. The indication was thalassemia (5 cases) and karyotyping (3 cases). The technique requires that the operator holds both the probe and the needle (25 G X 90 mm); the fetal blood sample ranged between 0.25 and 0.35 cc, sufficient in all cases for the diagnosis. 1 pregnancy was terminated on the basis of the diagnostic result; no complications reported at a 3-weeks follow-up in the remaining 7 patients. The first trimester cordocentesis offers several advantages if compared to CVS, especially for thalassemia prenatal diagnosis; furthermore it opens new perspectives for intrauterine transplantations. More experience is required to assess the safety of the procedure.
The authors report their experience on 140 diagnostic cordocenteses performed in the early trimester of pregnancy (technique, indications and complications). Furthermore the Authors report preliminary data concerning various fetal blood biochemical parameters (22) obtained by cordocentesis at 18-19 weeks of pregnancy (42 cases). Fetal and maternal values are compared.