Loss of ATRIP is associated with an immune deficiency, characterized by CD4 ⁺ T cell lymphopenia and reduced B and CD16 ⁺ /CD56 ^dim NK lymphocytes. (a) Total numbers (No) of CD4⁺ T, CD8⁺ T, NK, and B cells in the peripheral blood from the ATRIP patient (F1Pt) over time. Shading indicates the age-based reference range. (b) FCM immunophenotyping of F1Pt, family members, and age-matched HCs. Percentages of CD4⁺ T, CD8⁺ T, NK, and B cells in PBMCs from F1Pt, sister (F1Si), mother (F1Mo), and father (F1Fa). Data represent one experiment, with each data point representing one biological replicate. Mean and SEM are shown. (c) IgG2 concentration (Conc.) in the peripheral blood from F1Pt over time. Shading indicates the age-based reference range. Immunoglobulin substation therapy around age 4 is indicated. (d) Total numbers (No) of neutrophils in the peripheral blood from F1Pt, demonstrating intermittent neutropenia. Shading indicates the age-based reference range. (e) Hemoglobulin concentration (Conc.) in the peripheral blood from F1Pt over time. Shading indicates an age-based reference range. Corticosteroid and anti-CD20 mAb treatment (aCD20) is indicated. (f) UMAP plot depicting cluster annotation of 25 unique T and NK subsets (left). Analysis was performed using concatenated 25-parameter FCM data of PBMCs obtained from HCs (n = 6) and F1Pt. Contour plots of HCs (middle, top) and F1Pt (middle, bottom). Bar graph showing the relative proportion of HCs and F1Pt within each T and NK subset cluster (right). (g) UMAP plot demonstrating cluster annotation of 18 unique B and innate subsets (left). Analysis was performed using concatenated 25-parameter FCM data of PBMCs obtained from HCs (n = 6) and F1Pt. Contour plots of HCs (middle, top) and F1Pt (middle, bottom). Bar graph depicting the relative contribution of HCs and F1Pt within each B and innate subset cluster (right). Data are representative of one experiment (f and g).