COUGH RECEPTOR SENSITIVITY TO CAPSAICIN AND TARTARIC ACID IN PATIENTSWITH MYCOPLASMA-PNEUMONIA

There has been no detailed study of cough sensitivity during acute low er respiratory infection. The aim of this study was to clarify cough s ensitivity in Mycoplasma pneumonia, which is a well known acute lower respiratory infection with persistent nonproductive cough. We examined cough sensitivity to inhaled capsaicin and tartaric acid in both the acute and the convalescent phases of Mycoplasma pneumonia, cell differ entials in bronchoalveolar lavage fluid, and pathologic findings of tr ansbronchoscopic bronchial biopsy specimens. Although dry cough was ob served in all patients during Mycoplasma pneumonia, cough sensitivity in the acute phase [capsaicin: 19.8 (GSEM, 0.214) mu M, tartaric acid: 0.26 (GSEM, 0.356) M] were not enhanced compared with those in both c ontrol subjects [capsaicin: 27.9 (GSEM, 1.24) mu M, tartaric acid: 0.3 16 (GSEM, 0.079) M] and patients in the convalescent phase [capsaicin: 15.7 (GSEM, 0.219) mu M, tartaric acid: 0.50 (GSEM, 0.326) M] when al l symptoms including cough had disappeared. The percentage of lymphocy tes and neutrophils in bronchoalveolar lavage fluid BALF was significa ntly greater than in the control subjects, and lymphocyte-dominant bro nchitis was observed in biopsied specimens. We conclude that cough thr eshold to inhaled capsaicin or tartaric acid was not enhanced during a cute Mycoplasma pneumonia with lymphocyte-predominant bronchitis. This is the first report examining cough sensitivity in patients with acut e lower respiratory infection with pneumonia.