High-resolution computed tomography patterns and immunopathogenetic findings in drug-induced pneumonitis

We tried to determine whether high-resolution computed tomography (HRCT) patterns correlate with the immunopathogenetic findings and whether they could provide helpful information for predicting the outcomes in non-neoplastic drug-induced pneumonitis. The HRCT images were classified as most suggestive of pneumonitis, diffuse alveolar damage (DAD), non-specific interstitial pneumonia, organizing pneumonia (OP), hypersensitivity pneumonitis, and acute eosinophilic pneumonia (AEP) in 34 patients with non-neoplastic drug-induced pneumonitis. The patients were analyzed for the bronchoalveolar lavage (BAL) cell findings and for the circulating levels of interferon-inducible protein 10 (IP-10) and macrophage-derived chemokine (MDC), which were measured by an enzyme-linked immunosorbent assay. The cumulative dose of corticosteroids received by the patients and the day when they required supplemental oxygen were calculated as outcome markers. There were no differences in the circulating chemokine levels and the BAL cell profiles except for the eosinophil percentages among the HRCT patterns. Most of the cases with pulmonary eosinophilia belonged to the OP and AEP groups, and the circulating MDC levels correlated with BAL eosinophil percentages. We could not find any relationship between the BAL cell profiles or the chemokine levels and the outcome markers. In contrast, the HRCT patterns rather predicted the outcomes because larger cumulative dose of steroids and longer oxygen supply were required for the patients in the DAD and OP groups. In contrast, all patients with AEP recovered without steroid administration. The present study suggests that HRCT does not predict cellular pathophysiology but it may predict the corticosteroid use in non-neoplastic drug-induced pneumonitis.