Usual interstitial pneumonia (UIP) is a progressive fibrous lung disease with occasional fatal outcomes. However, the extent and rate of progression varies markedly from one patient to another. As a result, it is difficult to determine the time of the initial treatment and assess the disease activity and course. Fibroblast foci (FF) is well known to synthesize collagen actively by their myofibroblasts component. However, the prognostic value of the FF have not been evaluated in patients with UIP. Therefore this study was undertaken to determine how the number of fibroblastic foci can reflect the disease activity and progression.

Twenty patients with UIP(M:F=13:7), who were diagnosed by a surgical lung biopsy. The number of fibroblastic foci was analyzed in terms of its correlation with the clinical manifestations. pulmonary function test, arterial blood gas analysis, and a bronchoalveolar lavage(BAL).

The number of fibroblastic foci did not correlate with the various lung function tests and the other clinical parameters. Intersetingly, the percentage of neutrophils in the bronchoalveolar lavage fluid did correlate with the quantity of the normalized Vv of FF(r=0.60, p<0.05). The patients were divided into 2 groups, group I and II, arbitratily, according to the value of the normalized Vv. The clinical parameters and the PFT results were not different between the two groups. In particular, the survival rate between the two groups according to the Kaplan-Meier analysis were not different.

A large number of FF does not imply a bad prognosis in patients wit UIP.