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


METHODS
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.


RESULTS
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).


CONCLUSIONS
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.
Infection Diseases Department, Beijing Jishuitan Hospital, Beijing 100035, China. sunchd2000@163.com
Cheng-dong
CD
Sun
Si
S
Liu
Zhen
Z
Li
Yan
Y
Wen
D002116:Calcitonin / Q000097:blood*; D016022:Case-Control Studies; D003428:Cross Infection / Q000097:blood / Q000276:immunology*; D006801:Humans; D011014:Pneumonia / Q000097:blood / Q000276:immunology*; D012189:Retrospective Studies; D006377:T-Lymphocytes, Helper-Inducer / Q000166:cytology*; D018417:Th1 Cells; D018418:Th2 Cells
D002116:Calcitonin