Newborn screening was initiated in the early sixties and was initially limited to a few metabolic diseases using dried blood spots (DBS) collected on filter paper (Guthrie cards). During the 1990-ties, attempts were made to use these cards to screen for severe combined immunodeficiency (SCID) in newborns and in 2005, Jennifer Puck published a landmark paper where she and her co-workers described a PCR method for estimating the number of recently formed T cells (TREC – T cell receptor excision circles) using dried blood spots. This method detects a number of different forms of primary immunodeficiency involving T cells (T cell lymphopenia) but is primarily aimed at detecting children with SCID. This method has received world-wide recognition and is currently used routinely in several countries.
In 2011, Nakagawa and co-workers described a similar assay whereby B cells could also be enumerated using dried blood spots (KREC – kappa receptor excision circles), allowing estimation of both T and B cell lymphopenia in the same sample, which coupled with a marker for all cells (actin), laid the foundation for an extended screening for immunodeficiency. This test, which is currently being used in pilot experiments in several countries, is currently included in the national newborn screening programs in Sweden and Germany.
NGS tests such as WES and WGS are also currently being explored for use on disease affected and, lately, even healthy newborns and the future development in this field, including multi-omic analyses on Guthrie card extracts, will be discussed at the meeting.