Transbronchial biopsy in sarcoidosis: the role of immunohistochemical analysis for granuloma detection.

In this study 27 transbronchial biopsy specimens obtained from patients with clinical and/or laboratory features suggestive for sarcoidosis were analysed with conventional morphology and immunohistochemistry comparing the sensitivity and reproducibility of the two methods. A limited panel of monoclonal antibodies recognizing epitopes resistant to conventional fixation and embedment procedures were used (CD45R0, CD68, anti-cheratin, anti-collagen IV). All specimens were independently observed by two different pathologists. On the basis of the recognition of bona-fide noncaseating granulomas, 9 cases were uniformly judged as positive, 10 cases as negative, but 8 cases were considered doubtful. Immunohistochemical analysis reliably demonstrated the presence of epithelioid cells in 3 of these cases and absence in 5. These data suggest that the use of a limited immunohistochemical analysis can significantly improve histological diagnosis of sarcoidosis on small transbronchial biopsies using conventional routine material.