BACKGROUND: Nonspecific interstitial pneumonitis (NSIP) is most likely to be confused with usual interstitial pneumonitis (UIP). Unlike patients with UIP, the majority of patients with NSIP have a good prognosis, with most patients improving after treatment with corticosteroids. Therefore it is clinically important to differentiate NSIP from UIP. UP to now, the only means of differentiating these two diseases was by means of surgical lung biopsy. American Thoracic Society (ATS) proposed a clinical diagnostic criterial for UIP to provide assistance to clinicians in its diagnosis without surgical lung biopsy. This study is aimed to investigate whether there were clinical and radiological differences between NSIP and UIP, and the usefulness of ATS clinical diagnostic criteria for UIP in Korea. METHODS: we studied 60 patients with UIP and NSIP confirmed by surgical lung biopsy. Clinical manifestations, pulmonary function test, arterial blood gas analysis, bronchoalveolar lavage (BAL), and high resolution computed tomography (HRCT) were evaluated and analyzed by Chi-square test or t-test. The clinical criteria for UIP proposed by ATS were applied to all patients with idiopathic interstitial pneumonia. RESULTS: Forty-two patients with UIP and 18 with NSIP were pathologically identified. Among the 18 patients with NSIP (M : F = 1 : 17), the mean age was 55.2± 8.4 (44~73)yr. Among the 42 patients with UIP (M : F = 33 : 9), the mean age was 59.5±7.1 (45~74) yr (p=0.0460. Fever was more frequent in NSIP (39%) (p=0.034), but clubbing was frequently observed in UIP (33%) (p=0.023). BAL lymphocytosis was more frequent (23%) (p=0.0001) and CD4/CD8 ratio was lower in NSIP (p=0.045). On HRCT, UIP frequently showed honeycomb appearance (36 of 42 patients) through not in NSIP (p=0.0001). Six of 42 UIP patients (14.3%) met the ATS clinical criteria for IPF, and 3 of 16 NSIP patients (18.8%) met the diagnostic criteria. CONCLUSION: Being a relatively young female and having short duration of illness, fever, BAL lymphocytosis, low CD4/CD8 ratio with the absence of clubbing and honeycomb appearance in HRCT increase the likelihood of the illness being NSIP. The usefulness of ATS clinical diagnostic criteria for UIP may be low in Korea.
Adrenal Cortex Hormones ; Biopsy ; Blood Gas Analysis ; Bronchoalveolar Lavage ; Diagnosis ; Diagnosis, Differential* ; Female ; Fever ; Humans ; Idiopathic Interstitial Pneumonias ; Idiopathic Pulmonary Fibrosis* ; Korea ; Lung ; Lung Diseases, Interstitial* ; Lymphocytosis ; Prognosis ; Pulmonary Fibrosis ; Respiratory Function Tests

Although autoantibodies are routinely screened in patients with idiopathic interstitial pneumonia, there are no reliable data on their clinical usefulness. The aim of this study was to investigate the prognostic value of autoantibodies for predicting the development of new connective tissue disease in these patients and also mortality. We conducted retrospective analysis of the baseline, and follow-up data for 688 patients with idiopathic interstitial pneumonia (526 with idiopathic pulmonary fibrosis, 85 with nonspecific interstitial pneumonia, and 77 with cryptogenic organizing pneumonia) at one single tertiary referral center. The median follow-up period was 33.6 months. Antinuclear antibody was positive in 34.5% of all subjects, rheumatoid factor in 13.2%, and other specific autoantibodies were positive between 0.7%-6.8% of the cases. No significant difference in patient survival was found between the autoantibody-positive and -negative groups. However, the presence of autoantibodies, especially antinuclear antibody with a titer higher than 1:320, was a significant predictor for the future development of new connective tissue diseases (relative risk, 6.4), although the incidence was low (3.8% of all subjects during follow-up). In conclusion, autoantibodies are significant predictors for new connective tissue disease development, although they have no prognostic value.
Aged ; Antibodies, Antinuclear/blood ; Autoantibodies/*blood ; Cohort Studies ; Connective Tissue Diseases/pathology ; Female ; Follow-Up Studies ; Humans ; Idiopathic Interstitial Pneumonias/*blood/diagnosis ; Male ; Middle Aged ; Prognosis ; Retrospective Studies ; Rheumatoid Factor/blood ; Risk Factors ; Tertiary Care Centers ; Tomography, X-Ray Computed