Circulating lymphocyte number was significantly decreased in patients with sepsis. However, it remains unknown which severity phase (sepsis, severe sepsis, and septic shock) does it develop and what happen on each subpopulation. Eight patients with differing severities of sepsis (31 sepses, 33 severe sepses, and 16 septic shocks) were enrolled. Quantitative real-time polymerase chain reaction (RT-PCR) of Th1, Th2, and Th17; regulatory T (Treg) cell-specific transcription factor T-bet; GATA-3; RORgammat (RORγt); forkhead box P3 (FOXP3); and IL-17 mRNA were performed, and the enzyme-linked immunosorbent assay (ELISA) was used to detect serum interferon (IFN)-γ, IL-4, and IL-10. In this study, the Th1, Th2, Treg transcription factors, and related cytokines IFN-γ, IL-4, and IL-10 levels of sepsis and severe sepsis patients in peripheral blood were significantly higher than those of the normal controls. Except for IL-17, the T-bet, GATA-3, and IFN-γ levels of septic shock patients were lower than those of sepsis patients. We also observed that the proportions of Th17/Treg in the sepsis and septic shock groups were inversed. From the above, the inflammatory response especially the adaptive immune response is still activated in sepsis and severe sepsis, but significant immunosuppression was developed in septic shock. In addition, the proportion of Th17/Treg inversed may be associated with the illness aggravation of patients with sepsis.