HLA typing used with cultured amniotic and chorionic villus cells for early prenatal diagnosis or parentage testing without one parent's availability

Prenatal HLA typing of uncultured amniocytes prior to the collection of related allogeneic cord blood

DNA samples isolated from corresponding uncultured amniotic fluid, cord blood and maternal blood (n=5) were subjected to low resolution typing of the HLA-A, -B and -DRB loci by the polymerase chain reaction using sequence-specific primers (PCR-SSP). Furthermore, the effect of ethylene diamine tetraacetate disodium salt (EDTA) on the quality of genomic DNA isolated from amniotic fluid samples after long-term storage was evaluated. Unambiguous results of HLA typing could be achieved from all amniotic fluid samples stabilized with EDTA. PCR-SSP typing failed in DNA samples from amniotic fluid without the addition of EDTA. In all cases the fetal HLA type could be confirmed by the result from the corresponding cord blood typing. Contamination with maternal DNA led to additional weak PCR-SSP bands in one case, but data interpretation was still unambiguous. Reliable fetal HLA typing can be achieved directly from amniotic fluid and culturing of amniocytes is not required.

Characterization of T-cell receptor V beta repertoire in ovarian tumour-reacting CD3+ CD8+ CD4- CTL lines

T cells from tumour infiltrating lymphocytes (TIL) cultured in media containing IL-2 were shown to mediate in vitro and in vivo antitumor responses. To characterize the T-cell antigen receptor (TCR) V beta expression in autologous cytotoxic effectors we isolated CD3+ CD8+ CD4- cells from cultures of TIL and tumour-associated lymphocytes (TAL) and analysed the TCR V beta repertoire of CD3+ CD8+ CD4- lines of known HLA-A, -B and -C phenotype, using polymerase chain reaction (PCR). These lines showed preferential lysis of autologous tumours and lysed, to a much lesser extent, NK and LAK cell-sensitive targets. Tumour lysis was inhibited by antibodies to CD3 and MHC class I antigens indicating that they are cytotoxic T lymphocytes (CTL). These CD8+ CTL lines expressed a broad distribution of TCR V beta repertoire which was dominated by particular groups of V beta families in each CTL line. However, no predominant expression of one or the same V beta segment in all CTL lines was observed although statistical correlations between V beta family usage and magnitude of the antitumour cytolytic response were found. These results suggest that certain TCR V beta families may be selected by antigen in ovarian tumour-reactive T cells and this selection may be affected by Ag expression, and/or host factors. To our knowledge, this is the first documentation of TCR V beta repertoire of human ovarian tumour-reactive CD3+ CD8+ CD4- CTL from different individuals of known HLA types.

Prenatal diagnosis and treatment of 21-hydroxylase deficiency

Prenatal diagnosis of 21-hydroxylase deficiency, the most common cause of congenital adrenal hyperplasia (CAH), has benefited from the advances in endocrinologic and molecular genetic studies. In 1976, prenatal diagnosis of the disease was first attempted by measuring 17-hydroxyprogesterone in the amniotic fluid in the second trimester of pregnancy. Discovery of a close linkage between HLA and the disease gave a second approach for prenatal diagnosis, the latter being made by linkage study of the haplotypes of the index case in a given family. Diagnosis was later made directly by molecular biology. Currently, the studies of the C4-CYP21B gene locus by Southern blotting and the CYP21B gene mutations by PCR methods simplify the diagnostic procedure of an early and accurate prenatal diagnosis in the first trimester. In these conditions all families are now informative. Moreover, using a direct genetic analysis associated with the possibility of detecting the heterozygotes in a non-related CAH population, a prenatal diagnosis can be done in a family without a previously CAH affected child. From our results in a series of 274 pregnancies at risk for CAH in whom prenatal diagnosis has been made by these different approaches, it can be concluded that steroid analysis in the amniotic fluid is an accurate method but provides only a late (second trimester) diagnosis, while an early and accurate diagnosis now relies on adequate molecular genetic studies on chorion villus biopsies. In the aim to prevent the virilization of the external genitalia in CAH female fetuses, prenatal treatment was instituted in our group in 1979 by giving dexamethasone to the mother. This prenatal treatment appears safe for the fetus and the child and is effective in preventing virilization of CAH affected females. Although the degree of prevention is not always complete in all cases, the advantages of prenatal treatment are prevailing over the complications observed in a few mothers.

DNA amplification for DQ typing as an adjunct to serological prenatal HLA typing for the identification of potential donors for umbilical cord blood transplantation

It has recently been demonstrated that umbilical cord blood from genotypically human leukocyte antigen (HLA)-matched donors can provide sufficient numbers of progenitor cells for hematopoietic reconstitution. This technique has been successfully applied in the treatment of two children affected with Fanconi anemia (FA). Fetal cells from the potential sibling donors were first tested to determine that the fetus was not affected with FA. Unaffected fetal cells were then tested for HLA type. Cord blood from compatible donors can be harvested at birth and used immediately or frozen for subsequent use in hematopoietic reconstitution. We now show that fetal cell DNA amplification and hybridization for DQ typing can be an important adjunct procedure to verify serologically determined HLA class II types and/or to establish class II haplotype identity with the affected sibling.

Newborn screening, prenatal diagnosis, and prenatal treatment of congenital adrenal hyperplasia due to 21-hydroxylase deficiency

Congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency can be detected by newborn screening. Benefits of screening for affected newborns include the prevention of severe adrenal crisis, its sequelae, and progressive signs of androgen excess. First-trimester prenatal diagnosis is possible by HLA typing and/or DNA analysis of genes within the HLA complex of chorionic villus cells; for second-trimester diagnosis, hormonal measurement o f amniotic fluid and HLA typing or DNA analysis of amniotic cells are used. Results of prenatal treatment of CAH have varied, and the efficacy of prenatal treatment by maternal glucocorticoid therapy requires further investigation.

Human umbilical cord blood: a clinically useful source of transplantable hematopoietic stem/progenitor cells

This is a review and discussion of studies leading to the first use of human umbilical cord blood, material usually discarded, for the provision of stem/progenitor cells for clinical hematopoietic reconstitution. This prospect arose as a result of extensive studies of the harvesting and cryopreservation of cord blood and of its numerical content of progenitor cells demonstrable in vitro. A male patient with Fanconi anemia (FA) was conditioned with a modified regimen of cyclophosphamide and irradiation that accommodates the abnormally high sensitivity to these agents that is characteristic of FA. Cryopreserved cord blood had been retrieved at birth from a female sibling known from prenatal testing to be unaffected by FA and to be human leukocyte antigen (HLA)-compatible with the prospective sibling recipient. After conditioning and therapeutic infusion of thawed cord blood, successful hematopoietic reconstitution was indicated by the general health of the patient, who had previously required supportive transfusions, by satisfactory hematological criteria and by counts of hematopoietic progenitor cells of various types in the bone marrow. Complete engraftment of the myeloid system with donor cells was evident from cytogenetics, ABO typing, study of DNA polymorphisms, and normal cellular resistance to cytotoxic agents that reveal the fragility of FA cells; the blood contained a residuum of host lymphocytes exhibiting chromosomal damage, but the trend has been towards eliminating these damaged cells. This implies that cord blood from a single individual should provide sufficient reconstituting cells for effective hematopoietic repopulation of an autologous or an HLA-compatible allogeneic recipient.

Personal identification by HLA typing of cultured fibroblasts derived from cadaveric tissues

A method for HLA typing of cultured fibroblasts derived from abdominal skin was developed and applied for personal identification of a cadaver. Successful results were obtained using the conventional NIH HLA typing method for lymphocytes after a slight modification.

Gamma interferon induces detectable serological and functional expression of DR and DP but not DQ antigens on cultured amniotic fluid cells

Cultured amniotic fluid cells, which are used for HLA typing studies for the prenatal diagnosis of HLA linked diseases and for prenatal determination of paternity, usually contain mixtures of fibroblastic and epithelioid cells. Cells of both types lack constitutive expression of HLA class II antigens, but these can be induced by pretreatment with gamma interferon. Both serological and functional studies indicate that detectable levels of DR and DP but not DQ antigens can be thereby induced. DR and DP cannot, however, be induced on chorionic villus cells.

HLA-A,B,C,DR typing and 17-OHP determination for second trimester prenatal diagnosis of 21-hydroxylase deficient CAH

In 18 families at risk for the HLA-linked, 21-hydroxylase deficient form of autosomal recessive congenital adrenal hyperplasia (CAH), prenatal diagnosis (PD) was performed using two methods: (1) HLA-A,B,C typing and in the latter 11 cases also DR typing of cultured amniotic fluid cells (AFC) using the standard microcytotoxicity assay, and (2) measurement of second trimester amniotic fluid 17-hydroxyprogesterone (17-OHP) concentration using gel chromatography and radioimmunoassay. The accuracy of the prenatal predictions was confirmed by postnatal HLA typing of umbilical cord blood lymphocytes and by clinical evaluation. In 16/18 families, both HLA typing of AFC and 17-OHP measurements proved informative for PD. The predictions of both methods were concordant in 14/16 families (88 per cent). In ten of these families, a normal fetus was predicted, and in four, an affected fetus; all pregnancies were carried to term and all predictions were confirmed postnatally. In 2/16 cases (12 per cent), however, the predictions were discordant: the prenatal HLA typing indicated an affected fetus, whereas the 17-OHP values predicted a normal fetus. Both pregnancies were continued and two healthy boys were delivered. The discordance proved to be due to a 'missed' HLA antigen in one case and to serologically cross-reactive HLA antigens in the second. Finally, in 2/18 cases, prenatal assessment of fetal genotype had to rely on HLA typing alone as 17-OHP measurement was not performed in one family and in the second family the 17-OHP values obtained were not informative due to inadvertent continuation of hormone therapy to the date of amniocentesis. In both cases, the HLA typing data accurately predicted a normal fetus. In conclusion, a combination of HLA typing of cultured AFC and 17-OHP measurements of amniotic fluid permits accurate prenatal diagnosis of CAH in most cases (88 per cent). In addition, the supplementary use of HLA-DR typing of AFC as presented here for the first time proved helpful in families with HLA-A,B homozygosity due to parental sharing of antigens and can be informative for identifying HLA-B/21-OH recombinant haplotypes.