T Cell Responses In Symptomatic Moderate Patients With Pandemic 2009 H1n1 Influenza A Virus Infection

The response of the host immune system should be appropriate to fight against pandemic 2009 H1N1 (pH1N1) influenza A virus without causing damage to its self. T cells play an indispensable role in the fight against the virus, but have the potential to cause host immunopathological changes. A better understanding of the immunoregulation that occurs during pH1N1 infection is necessary for preventing severity of the disease. In this study, we found that a significantly higher percentage of V delta 1(+) T cells and increased expression of activation markers in total T cells in patients with moderate pH1N1 infection could lead to its efficient fight against the virus. On the other hand, the percentages of total and CD4(+) T cells were decreased along with an increased expression of exhaustion marker-Tim-3 on T cells that might suppress excessive T cell responses in the host. This tuning of T cell responses might be necessary in efficient combat against pH1N1 virus, without aggravating T cell mediated immunopathology in patients with moderate pH1N1-infection.