Early diagnosis of severe primary immunodeficiencies, TREC/KREC assay

Overview

Severe combined immunodeficiency (SCID) represents the most serious form of primary immunodeficiencies. SCID is associated with a profound impairment of immune functions caused by T cell or combined T and B cell defects.

In this short summary article, we present the possibility to use a relatively simple and straightforward test for the presence of naive T and/or B lymphocytes, which can be performed from a dry blood spots. Variants of this test, called TREC (T cell receptor excision circles) for T lymphocytes and KREC (kappa-deleting recombination excision circles) for B lymphocytes, are used worldwide for screening programs for early detection and subsequent early treatment of severe immune disorders indicated for stem cell transplants or gene therapy. SCID neonatal screening is being progressively implemented in the US and in some European countries such as Norway and Switzerland. Pilot studies are underway in other countries such as the Netherlands and Sweden, France, Italy, Spain and the UK. Screening was recently fully implemented in Israel. In the Czech Republic, the test is currently available at two academic reference sites for Bohemian and Moravian regions for selective investigation in the indicated patients. Application for a pilot study is considered in a near future.

In this short article, we provide practical information on the current implementation and availability of these tests in the Czech Republic. The information targets mainly pediatricians, but the test is available also to GPs for children and adolescents, possibly to other physicians, and to parents of children, mainly in families with a positive family history of suspected primary immunodeficiency.

Keywords:

mass screening – SCID (severe combined immunodeficiency) – early diagnosis – test TREC (T cell receptor excision circles) for T lymphocytes – test KREC (kappa-deleting recombination excision circles) for B lymphocytes