To study the effects of thymosin α1 combined with anti-infective therapy on the prognosis of severe pneumonia and analyze its possible mechanism.

71 patients with severe pulmonary infection were randomly divided into treatment group (38 cases) and control group (33 cases). The control group was given routine anti-infection and symptomatic support treatment. On the basis of routine anti-infection and symptomatic support treatment, the treatment group were given thymosin α1 1.6 mg subcutaneously once a day for 7 consecutive days and then changed to twice a week. T lymphocyte subsets and NK cells in peripheral blood were measured before and after treatment with thymosin α1. Inflammatory factors tumor necrosis factor alpha and interleukin 10 were measured by enzyme-linked immunosorbent assay (ELISA). Moreover, compared the antibiotic use time, hospitalization time and mortality between groups.

There were no significant differences in gender, age, heart rate, respiratory rate, PaO₂, PaO₂/FiO₂, systolic blood pressure and positive sputum culture between the two groups (P>0.05). The mortality rate was 15.78% with 6 patients died in the treatment group, and the mortality rate of the control group was 21.21% with 7 cases died, and the difference was significantly (P<0.05). The antibiotic application time and hospitalization days in the treatment group were significantly shorter than those in the control group [12.95±1.94) vs. (15.98±2.01) d, (15.73±2.13) vs. (18.74±3.60) d, respectively] (P<0.05). Before treatment, the number of CD3, CD4, CD8, CD4/CD8 and NK cells in the two groups had no significant difference; after treatment, the number of CD3, CD4, CD8 and NK cells in the two groups increased significantly; the number of CD3, CD4, CD8 and NK cells in the treatment group [(48.57±7.21)%, (32.83±4.20)%, (24.89±3.05)%, (20.01±2.96)%] were higher than those in the control group[45.89±6.72)%, (29.04±3.16)%, (21.53±2.56)%, (16.72±2.03)%] (P<0.05). Before treatment, there was no significant difference in the levels of TNF-α and IL-10 between the two groups. After treatment, the levels of TNF-α in both groups were significantly lower, and the levels of TNF-α in the treatment group were significantly lower than those in the control group [(17.95±2.28) vs. (20.79±3.02)] (P<0.05). After treatment, the levels of IL-10 in both groups were significantly higher than those before treatment, and the levels of IL-10 in the treatment group were significantly higher than those in the control group [(12.82±1.12) vs. (9.79±1.02)] (P<0.05).

Immunocyte dysfunction exists in severe pneumonia patients. Thymosin α1 immunotherapy may well regulate the function of immune cells, alleviate inflammation in vivo, and enhance the anti-infective effect.