Abstract: Objective To evaluate the relationship between infection and innate immune status in senile patients were on chronic obstructive pulmonary disease during exacerbations(ECOPD).Methods Totally 75 patients with ECOPD were randomly divided into 2 groups: senile group(n=45),non-senile group(n=30),all patients with general treatment.Another 20 healthy individuals served as the healthy control.Levels of CD14,NK,CD158b,HLA-DR in peripheral blood were measured with flow cytometry at baseline(D1) and then again at(D15),in the meanwhile observed clinical picture to evaluate patients'conditions.Results 70 patients completed the trial correctly(40 in senile group and 30 in non-senile group).WBC count and N of senile group were lower than non-senile group(P<0.05).The positive rate of sputum bacteriological examination and CRP were statistically homogeneous,but the pathogenic strains was significantly different in both groups(P<0.05).The percentage of CD14,NK,CD158b,HLA-DR in the senile groups was decreased(P<0.05) compare with non-senile groups and healthy controls,at the D1.In the D15,above mentioned the immunologic parameter of the senile group was lower(P<0.05).Clinical picture,the faster improvement in the patients in the non-senile group compared with senile group.Conclusion The results of this study suggest that respiratory tract infections are the most frequent factors contributing to acute exacerbations both,it was linked to disorder of the innate immunity in the senile patients with COPD.These deficiency in immunity increased the duration of the stay in hospital and healthy care expense.

Key words: senile, COPD, excerbation, infection, innate immunity