Evaluation of lymphoid defects in specific inborn errors of immunity using a single-tube multicolor flow cytometry assay.

The present study aimed to evaluate lymphoid defects in patients with specific IEIs (n = 28) using a 12-antibody 9-color single-tube flow cytometry assay. The lymphoid defects (lymphocyte counts below the reference range) were significantly higher in XLA patients (p-0.0002), CVID patients (p-0.00022), WAS patients (p- < 0.001), HIES patients (p- < 0.001), CHS patients (p < 0.001), and CGD patients (p < 0.0002) than age-matched controls. The lymphoid defects (lymphocyte counts above the reference range) were significantly higher in LAD-1 than age-matched controls (p < 0.001). In patients with XLA, the NK cells were reduced in 50% and naïve Tc cells in 33.3% of patients. The patients with CVID showed reduced CD4 + T cell subset in 75% and increased memory Tc cells in 50% of patients. In WAS, absolute B cell, naïve B cell, switched memory B cell, CD4 + T cell, and naïve Th cell counts were decreased in 100% of patients. In HIES, the CD4 + T cell and memory Th cell count was reduced in 100% of patients. In CGD, reduced absolute count of T cells, CD4 + T cells, CD8 + T cells, naïve Th cells, memory Th cells, naïve Tc cells and γδ T cells and increased B-cell counts were noted in 67% of cases. Both B- and T-cell defects were identified in HIGM, MHC-II deficiency, LAD-1, CHS, CARD-11, and STXBP2 defects. No significant difference was observed between routine and single-tube panel results by paired T-test.