Celocentesis for early prenatal diagnosis of hemoglobinopathy

OBJECTIVE

Celocentesis is an invasive technique that can provide prenatal diagnosis of single-gene disorders, from as early as 7 weeks' gestation. The objective of this study was to examine the safety of celocentesis.

METHODS

In this prospective study, celocentesis was performed for prenatal diagnosis of hemoglobinopathy in 402 singleton pregnancies in which both parents were carriers of β-thalassemia or sickle cell disease trait. We assessed procedure-related maternal discomfort or pain, success of sampling and obtaining results, pregnancy outcome and postnatal follow-up.

RESULTS

First, celocentesis was carried out at a median gestational age of 8.6 (range, 6.9-9.9) weeks and celomic fluid was successfully aspirated in 99.8% of cases. Second, 67% of women had no or only mild discomfort, 18% had moderate discomfort, 12% had mild-to-moderate pain and 3% had severe pain. Third, prenatal diagnosis from analysis of the celomic fluid was successful in 93.8% cases, and in the last 121 cases, it was always successful. Fourth, in all cases of successful sampling and analysis of celomic fluid, the diagnosis was concordant with results obtained from additional prenatal or postnatal testing. Fifth, in addition to diagnosis of hemoglobinopathy, quantitative fluorescence polymerase chain reaction analysis, which was performed to evaluate maternal contamination using several markers for chromosomes X, Y, 21, 18 and 13, led to the accurate diagnosis of chromosomal aneuploidy. Sixth, in all cases of an affected fetus diagnosed by celocentesis in which the parents chose termination of pregnancy, this was carried out < 10 weeks' gestation. Seventh, in 97.1% (298/307) of the continuing pregnancies there was live birth, in seven (2.3%) there was miscarriage and in two (0.7%) there was loss to follow-up. Eighth, fetal abnormalities were diagnosed in three (1%) cases, including unilateral transverse amputation of the forearm, unilateral moderate hydronephrosis and small-bowel duplication. All neonates were examined by a pediatrician and were found to be phenotypically normal, except for the three cases with a prenatally diagnosed defect.

CONCLUSIONS

Celocentesis can be used for early prenatal diagnosis of genetic abnormalities, and the procedure-related risk of pregnancy complications appears to be low. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.

Incidence of haemoglobinopathies in Sicily: the impact of screening and prenatal diagnosis

BACKGROUND

Haemoglobinopathies are a major public health problem in Sicily: it was estimated a frequency of 1/245 couples are at risk of haemoglobinopathies. This paper reviews legislative actions, prevention activities, carrier screening, genetic counselling, foetal sampling and laboratory methodology analysis evolution reporting the results of 30 years of prevention actions to assess the efficiency of our preventative programme in the control of haemoglobinopathies in Sicily.

METHODS

This programme consisted principally of five phases: legislative actions, public awareness campaign, carrier screening, genetic counselling and prenatal diagnosis.

RESULTS

These programmes have been very effective, which we can see from a greater public awareness of thalassaemia and its prevention in the target population furthermore by a marked decline in the incidence of thalassaemia major and sickle cell anaemia from 1 in 245 live births in the absence of prevention to 1 in 2000, with a reduction in about 85%. The residual cases were because of a conscious choice by expecting parents in relation to improved life expectancy as well as improved quality of life of the affected patients.

CONCLUSION

The study suggests that public health authorities should act and invest in a similar programme for prevention of thalassaemia, as well as in relation to the increased survival of patients and the consequent organ complications.

Evidence of alloreactive T lymphocytes in fetal liver: implications for fetal hematopoietic stem cell transplantation

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.

Evidence of induced non-tolerance in HLA-identical twins with hemoglobinopathy after in utero fetal transplantation

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.

The risks of early cordocentesis (12-21 weeks): analysis of 500 procedures

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.

First trimester fetal blood sampling

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.