Israel Medical Association Journal

Inborn errors of immunity (IEI), formerly known as primary immunodeficiencies (PID), comprise a diverse group of genetic disorders characterized by increased susceptibility to infections, autoimmunity, autoinflammatory conditions, allergies, and malignancies. These disorders exhibit a broad spectrum of clinical manifestations, including extra-hematopoietic manifestations, which may also present later in life. IEI diagnosis has significantly advanced, in line with the common use of next-generation sequencing-based genetic platforms, such as whole-exome and whole-genome sequencing. Treatment approaches have evolved beyond infection management to include curative therapies such as hematopoietic stem cell transplantation, gene therapy, and targeted pharmacologic treatments. In this review, we explore recent advancements in the understanding, diagnosis, and treatment of IEI, emphasizing the rapid progress in this expanding field.

Objective: To assess the ability of TREC and KREC counts to identify patients with combined T and B cell immunodeficiency in a pilot study in Israel.

Methods: We studied seven children born in Israel during the years 2010–2011 and later diagnosed with SCID, and an additional patient with pure B cell immunodeficiency. TREC and KREC in peripheral blood upon diagnosis and in their neonatal Guthrie cards were analyzed using real-time quantitative polymerase chain reaction, as were Guthrie cards with dried blood spots from healthy newborns and from normal and SCID-like controls.

Results: The first features suggestive of SCID presented at age 3.1 ± 2.4 months in all patients. Yet, the diagnosis was made 4.1 ± 2.9 months later. Their TREC were undetectable or significantly low at their clinical diagnosis and in their originally stored Guthrie cards, irrespective of the amount of their circulating T cells. KREC were undetectable in six SCID patients who displayed B cell lymphopenia in addition to T cell lymphopenia. KREC were also undetectable in one patient with pure B cell immunodeficiency.

Conclusions: TREC and KREC quantification are useful screening tests for severe T and B cell immunodeficiency. Implementation of these tests is highly important especially in countries such as Israel where a high frequency of consanguinity is known to exist.