phenotype affects entity CD4-positive, alpha-beta T cell abnormal T cell physiology abnormal CD4-positive, alpha-beta T cell physiology abnormal single positive T cell physiology CD4+ T cell dysfunction any functional anomaly of the subset of T lymphocytes that carry the CD4 marker, recognize intravesicular peptides bound to MHC class-II molecules, and turn on antibody production abnormal CD4+ T cell physiology MPheno.ontology MP:0005463 abnormal CD4-positive T cell physiology abnormal CD4+ T cell function CD4-positive, alpha-beta T cell physiology phenotype