[Clinical usefulness of serum IFN-gamma level in patients with chronic obstructive pulmonary disease]

The objective of this study was to gain a clear idea of rule of change in serum IFN-gamma level in patients with chronic obstructive pulmonary disease and to evaluate the clinical usefulness of IFN-gamma as a marker of immune condition. The serum IFN-gamma levels of 15 patients with chronic bronchitis, 15 patients with cor pulmonale, 15 patients with acute bronchitis, and 15 normal subjects were measured by radio-immuno-assay. Differences between the four groups were tested, and in the chronic bronchitis group, the serum IFN-gamma levels, before and after treatment were compared. The results showed that compared with the normal group (0.8 +/- 0.17 IU/ml), the serum level changed little in the cor pulmonale group (0.93 +/- 0.25 IU/ml); it was not higher in the chronic bronchitis group (1.23 +/- 0.39 IU/ml, P > 0.05), but it went up significantly after treatment for 7 days (1.84 +/- 0.51 IU/ml, P < 0.05). The highest level of IFN-gamma was noted in the acute bronchitis group (2.24 +/- 0.71 IU/ml, P < 0.01). There was a significant difference compared with other groups (P < 0.01). These results suggest that relative deficiency of serum IFN-gamma may be a factor inducing repeated respiratory infection, and the serum level of IFN-gamma can be used as an index to assess the immune condition of patients with chronic obstructive pulmonary disease.