Comparison of bronchoalveolar lavage cell findings in complete-resolution pneumonia and delayed-resolution pneumonia

In some patients with bacterial pneumonia, the resolution of chest radiograph shadows are delayed. There have been many clinical and pathological studies on delayed-resolution pneumonia (DR). However, there are no reports concerning inflammatory cell findings of bronchoalveolar lavage (BAL) fluid in patients with DR. We compared the BAL fluid cell findings in patients with DR with those in patients with complete-resolution pneumonia (CR).

The subjects included six patients whose chest radiograph shadows were completely resolved within 2 weeks after an appropriate antibiotic administration (CR), and nine patients whose chest radiograph shadows were unresolved more than 2 weeks after the treatment (DR). BAL was done 2-3 weeks after the antibiotic treatment in both groups. We compared differential counts and lymphocyte subsets in BAL fluid among patients with CR, patients with DR, and asymptomatic subjects.

There were no significant differences in BAL fluid cell findings between CR groups and asymptomatic groups. On the other hand, the percentages of lymphocytes, neutrophils and eosinophils in DR group were significantly increased compared with those in CR and normal groups. There was no significant difference in the CD4+/CD8+ ratio of BAL lymphocytes among the three groups.

It is suggested that infiltration of inflammatory cells in the lung exists in DR, despite the disappearance of inflammatory reaction in the peripheral blood.