Further investigations revealed the following findings: echocardiography demonstrated pulmonary arterial hypertension (PAH); cranial CT showed multiple bilateral basal ganglia calcifications; bone marrow biopsy detected EBV-DNA positivity (6.5 × 103 copies/ml); renal tissue immunohistochemistry showed CD8+ cells (scattered, −50/HPF) and CD4+ cells (focal, −40/HPF), with negative LMP-1 but scattered EBER+ signals (−25/HPF). Here, CD4 is linked to pulmonary arterial hypertension.