The changes in subgroup of helper T lymphocyte and calcitonin and their correlation in patients with severe hospital acquired pneumonia

Abstract

To observe the changes in subgroups of helper T cells and serum calcitonin (PCT) levels in patients with hospital acquired pneumonia (HAP) and their correlation. Eighty-nine patients with diagnosis of HAP (severe in 59 patients, mild in 30 cases) were included, with 20 healthy adults as control. Percentage of CD4(+), Th1 and Th2 cells, and Th1/Th2 ratio were determined, and sandwich immune luminescence was used to detect the level of serum PCT. The percentage of Th1 cells [(8.40 ± 3.01)%] was significantly lower in patients with severe HAP compared with that of mild pneumonia group [(13.90 ± 2.37)%, P < 0.05] and healthy controls [(17.40 ± 4.20)%, P < 0.01]. Percentage of Th2 cells was obviously higher in patients with severe HAP [(17.30 ± 5.74)%] than mild pneumonia group [(7.70 ± 2.35)%, P < 0.05] and healthy controls [(7.90 ± 1.92)%, P < 0.01]. Th1/Th2 ratio was also obviously lower in severe pneumonia group (0.57 ± 0.15) than that of mild pneumonia group (2.80 ± 0.46, P < 0.01) and healthy controls (3.11 ± 0.87, P < 0.01). Compared with healthy controls, Th1 cells in mild pneumonia patients were reduced significantly (P < 0.05), but there was no significant difference in Th2 cells and Th1/Th2 ratio (both P > 0.05). There was no difference in CD4(+) among severe, mild pneumonia and healthy controls [(30.20 ± 10.83)%, (34.70 ± 13.57)%, (28.80 ± 9.61)%, respectively, all P >0.05]. The level of PCT (μg/L) was significantly elevated in mild and severe pneumonia patients compared with that of healthy controls (1.73 ± 0.88, 3.51 ± 2.66 vs. 0.30 ± 0.10, both P < 0.01), and the level of PCT in severe pneumonia was significantly higher than that of mild pneumonia (P < 0.05). Regression analysis of Th1/Th2 and PCT revealed a significant negative correlation, with regression equation Y = -0.937x (F=236.23,P = 0.0000). Patients with severe HAP had obvious imbalance of Th1/Th2. The suppression of cellular immune function, reduction in Th2 cells and exacerbation of anti-inflammatory reaction intensify the infection leading to multiple organ dysfunction syndrome. There is obvious negative correlation between Th1/Th2 and PCT. PCT could be used as an indicator of immune response in reflecting cellular and humoral immunity of the patient.