[Prenatal diagnosis of severe and hereditary immune deficiencies].

Antenatal diagnosis is now available for most severe inherited immune deficiencies. Several techniques are used: the development of methods for sampling fetal tissue as soon as the tenth week of gestation has made possible the antenatal diagnosis of immune deficiencies associated with detectable enzyme defects, and, in combination with recent molecular biology techniques, can be expected to allow early identification of severe combined immune deficiencies due to the absence of T lymphocyte precursors, agammaglobulinemia, and some instances of X-linked chronic granulomatous disease. A great number of immune deficiencies can be identified by direct studies of fetal lymphocytes or polymorphonuclear leukocytes in fetal blood sampled by fetoscopy at the twentieth week of gestation. Fetal blood studies combined with skin biopsy examination allows the diagnosis of immune defects associated with partial albinism such as Chediak-Higashi disease. No reliable antenatal diagnostic method is as yet available for two severe diseases: Wiskott-Aldrich syndrome, that can be expected to become detectable in utero using molecular biology techniques, and ataxia-telangiectasia. Antenatal diagnosis of a severe immune deficiency does not necessarily indicate termination of the pregnancy as in some cases, such as severe combined immune deficiencies, HLA-identical bone marrow transplantation at birth or in utero is permanently successful in over 90% of cases.