Chemotaxis of DOCK8-deficient T cells migrating toward CXCL12 in collagen gel matrices. (A–D) Velocity toward chemokine (A), chemokine directionality (B), track speed (C), and directionality (D). Each symbol represents the means of these values for individually tracked cells from each sample. The horizontal line designates the average of these means. T cells from four patients and eight controls were evaluated from four experiments. In two separate experiments, normal T cells were transfected with DOCK8 siRNA or nonspecific (NS) siRNA. (E) Cartoon showing measurements of chemotaxis, based upon the actual route that a cell took as indicated by the gray dotted line. (F) Representative flow cytometric measurement of CXCR4 (receptor for CXCL12) expression on cells used in the chemotaxis assays. Unpaired two-tailed Student’s t tests were performed. All statistical comparisons were nonsignificant.