Among the 56 patients with VTE, 25 (44.6%) had decreased CD3 + T cells, 25 had reduced CD8 + T cells and 23 (41%) had increased CD4 + /CD8 + ratio. These findings indicated the ability of T cells to recognize antigen and transmit activation signals was significantly compromised, and the capability of T cells to kill the pathogen infected cells decreased. The compromised T cell immune function is often identified in patients with malignancy, use of immunosuppressant, viral infection or malnutrition (15, 16) . In the present study, none of patients had malignancies or were treated with immunosuppressants. Therefore, the pathogenesis of VTE might be closely related to viral infection or malnutrition. In our report, the syn-thesis and release of virus-like micro-organisms were noted in the lymphocytes under an electron microscope in a young pulmonary hypertension patient with increased D-Dimer (10) .