Normal total lymphocytes counts.Low percentages of CD4+ (16%; RV: 28.4-44.4***) and CD19 (3%; RV: 4-33*).IgA deficiency (<7 mg/dL; RV: 45-236**) with normal IgG and IgM**.Moderately reduced proliferation assays.Poor weight gain, mitral stenosis, pulmonary hypertension, mild motor and speech delay, recurrent infections, hearing loss, lymphadenopathies, dysmorphic features. Here, CD19 is linked to pulmonary arterial hypertension.