Abstract: Objective To investigate the value of lymphocyte count in assessing cellular immune function in patients with
community-acquired pneumonia. Methods Ninety-three patients with community-acquired pneumonia (including 53
non-severe and 40 severe cases) and 52 healthy adults were examined for routine blood test and T lymphocyte count. Blood
lymphocyte counts and absolute T lymphocyte counts were compared among the 3 groups and their correlation was analyzed.
Results Compared with the healthy control subjects, patients with community-acquired pneumonia showed significantly
lower blood lymphocyte counts and CD3 + , CD4 + , and CD8 + levels (P<0.05). CD3 + , CD4 + , and CD8 + levels were positively
correlated with blood lymphocyte counts. With blood lymphocyte count as the independent variable (L), and the regression
equations for CD3+, CD4+, and CD8+ levels were CD3+=485.45L+313.48 (F=59.68, P<0.01), CD4+=192.57L+290.11 (F=24.62, P<0.01),
and CD8+=275.14L+18.04 (F=23.46, P<0.01) in the control group; CD3+=564.15L+25.04 (F=96.56, P<0.01), CD4+=381.91L-37.45 (F=
68.60, P<0.01), and CD8+=165.61L+61.83 (F=55.47, P<0.01) in non-severe pneumonia group; and CD3+=565.44L+49.09 (F=31.87, P<
0.01), CD4+=332.34L-17.37 (F=43.64, P<0.01), and CD8+=223.46L+54.39 (F=13.90, P<0.01) in severe pneumonia group. Conclusion
Patients with community-acquired pneumonia have decreased cellular immune function. Absolute T lymphocyte count can be
estimated by blood lymphocyte count to save the cost of laboratory tests.