The samples were incubated in the dark at room temperature for 10?min. the excised signal ends) is then accomplished by proteins of the non-homologous end-joining pathway. Accordingly, null mutations in or affect the development of T and B lymphocytes, causing T? ?B? SCID. However, hypomorphic mutations in the same genes may cause milder phenotypes [5], [6]. This study presents the clinical, immunologic and molecular characteristics of 21 consecutive patients from Kuwait who presented with or gene defects between the years 2004 and 2016. 2.?Methods 2.1. Patients data The patients’ data were retrieved from the Kuwait National Primary Immunodeficiency Disorders Registry (KNPIDR), which prospectively recruited patients since 2004. The project was approved by the Research and Ethics Committee of the Ministry of Health, Kuwait. 2.2. Genetic Tacrolimus monohydrate testing Genomic DNA was extracted from whole Tacrolimus monohydrate blood. Sanger DNA sequencing was performed according to standard protocols. Targeted next-generation sequencing was performed using the PID v2 panel and Ion Torrent S5 sequencer (ThermoFisher), with an average coverage of 253?. Variant calling was performed using Ion Reporter software (ThermoFisher). For whole exome sequencing, exome capture was performed using the SureSelect Human All Exon v4?+?UTR kit (Agilent Technologies). A HiSeq 2000 system (Illumina) was used to generate 100 base-pair paired-end reads, with an average on-target coverage of 80?. Reads were aligned to the GRCh37 HIF3A reference assembly human genome using BWA [7] Single nucleotide variants and indels were detected with GATK using standard hard filtering parameters [8]. Variants with a read coverage ?2? and a Phred-scaled SNP quality of ?20 were eliminated. Whole genome sequencing, read mapping, local de novo assembly, and variant calling and annotation were performed by Complete Genomics, Inc. 2.3. Lymphocyte markers Peripheral venous blood was drawn using tubes made up of EDTA. Blood samples were processed within two hours of collection. Test tubes were prepared with 100?l of blood, and 10?l of the CYTO-STAT tetra CHROME CD45-FITC/CD4-RD1/CD8-ECD/CD3-PC5, CYTO-STST tetra CHROME CD45-FITC/CD56-RD1/CD19-ECD/CD3-PC5 murine monoclonal antibody mixture, anti-CD4/CD45RA or CD4/CD45RO (Beckman Coulter, USA) was added. These antibody mixtures allow for the simultaneous identification and quantification of total CD3+, CD3+ ?CD4+, CD3+ ?CD8+, CD19+ and CD3?/CD56+ lymphocyte subpopulations, and the expression of CD45RA or CD45RO on CD4+ T cells. The samples were incubated in the dark at room temperature for 10?min. After incubation, stabilization and fixation of the stained cells were performed by adding Immunoprep kit reagents (Beckman Coulter, USA). The analysis of the lymphocyte subsets was performed with an EPICS XL-MCL flow cytometer (15?mW) (Beckman Coulter Electronics, FL) equipped with an argon ion laser that Tacrolimus monohydrate was tuned to a wavelength of 488?nm. The values of the lymphocyte subpopulations were determined as a percentage of mononuclear cells. Absolute values of the lymphocyte subsets (counts per l) were decided via the addition of flow count fluorospheres (Beckman Coulter, USA). We performed a fluorescence gating strategy, using CD45+ vs. Tacrolimus monohydrate side scatter. Internal quality assurance was performed using optical alignment beads, which are compensation reagents that are used to eliminate bleed through fluorescence, and Immunotrol control cells. Data analysis was performed with the Coulter tetraONE SYSTEM software and System II software. 2.4. T-lymphocyte proliferative responses Peripheral blood was obtained from the subjects by venipuncture, and PBMC were separated by Ficoll-paque (Pharmacia Biotech, Sweden) density gradient centrifugation. The PBMC were suspended in RPMI medium (GIBCO, USA) made up of 10% fetal calf serum (GIBCO, USA). The PBMC were aliquoted into 96 well tissue culture plates at a density of 105 cells per well and stimulated with one of the following brokers: phytohemagglutinin (PHA) (5?g/ml, Sigma-Aldrich, USA), anti-CD3 antibody (OKT3, 10?g/ml, Bender MedSystems), candida antigen (2?g/ml, Greer Laboratories, USA) or purified protein derivative (PPD, 10?g/ml, CSL Limited, Australia). Cultures were pulsed at 96?h with [3H]thymidine (1?Ci per well) to assess mitogen/antigen-induced proliferation, and the thymidine uptake into DNA was determined 18?h later. 2.5. Serum immunoglobulin and antibodies levels The quantitation of immunoglobulins (IgM, IgG, IgA) in serum was performed by rate nephelometry using the Beckman specific protein analyzer (Beckman Devices Inc., CA). Serum levels of IgG antibodies against tetanus toxoid (TT),.