We showed that the recent thymus output function, reflected by the expression of CD31 of CD4+ T cells and that of CD8+ T cells, was decreased from patients with CHB, those with HBV-LC to those with HBV-PLC, and was significantly decreased in patients with HBV-PLC compared with those with CHB and those with HBV-LC. The gene discussed is CD4; the disease is laryngotracheoesophageal cleft.