Defective T cell chemotaxis to sphingosine 1-phosphate and chemokine CCL21 in idiopathic T lymphocytopenia.

T cell chemotaxis to sphingosine 1-phosphate (S1P) and the chemokines CCL21 and CCL5 was studied in ten adults with T lymphocytopenia, other immunological abnormalities (nine of ten), and frequent bacterial infections (seven of ten). Mean chemotactic responses to S1P of CD4 T cells from CD4 T lymphocytopenic patients and of CD8 T cells from CD8 T lymphocytopenic patients were significantly lower than those of healthy matched controls. Chemotaxis to CCL21 was lower than that of controls for CD4 T cells of three CD4 T lymphocytopenic patients and for CD8 T cells of three CD8 T lymphocytopenic patients, but none of the T cells of patients had diminished chemotaxis to CCL5. Defective T cell chemotactic responses to S1P and some chemokines may lead to subset-selective abnormal T cell trafficking and chronic T cell lymphocytopenia.