Smeeth [25] reported that the risk for DVT was increased by 1.91 folds within 2 weeks to 6 months after acute infection. In two large case-control studies [26, 27], results also demonstrate that acute infection increases the risk for VTE by 2~3 folds after adjustment of other risk factors of VTE. We found DVTs in multiple organs including pulmonary arteries, kidney, liver and pancreas during autopsy of SARS patient [28], indicating that the genesis of VTE was related to virus infection.

In acute PE [29], the decreased CD ₃ and CD ₈ levels, and the increased CD ₄/CD ₈ ratio, were similar to those in CTEPH [30]. We have reported that the functions of CD ₃,CD ₈, CD ₁₆CD ₅₆ and CD ₁₉ were compromised or disordered in more than 95% acute symptomatic VTE [31].

T cells are key parts of immune cells, as they regulate the cellular and humoral immunity, and phagocyte functions in innate immunity through Th1, Th2 and Th17.The immune functions decrease when T cell functions decline. The process of immune balance is a complicated process. Different immune functioning status, including normal, decreased and disturbed immune functioning status, decides different body status. The collapse of the balancing functions of immune cells indicates that immune cells in the innate and adaptive systems have a state of no function or dysfunction.We observed significantly decreased T cell functions through cytology, and decreased whole immune cell functions through genomics, indicating the collapse of the balancing functions of immune cells in VTE patients.