[Usefulness of CD1 expression on surfaces of cells in bronchoalveolar fluid for diagnosis of histiocytosis X--our experience].

Histiocytosis X (HX), also referred as Langerhans cell granulomatosis is a disorder characterized by the presence of destructive granulomas containing Langerhans cells, lymphocytes, eosinophils and fibroblastes in the involved organs. Three presentations are commonly observed: 1) nonproductive cough or effort dyspnea, 2) spontaneous pneumothorax 3) incidental pulmonary infiltrates on chest X-ray in asymptomatic patients. HRCT may be helpful in the initial diagnosis of pulmonary HX. HRCT scans show nodules, cysts and estimate the extent of disease. But the final diagnosis of histiocytosis X requires the histologic demonstration of specific histiocytosis X cell in biopsy specimens of the lung. The aim of this study was to define the importance of the detection of Langerhans cells in bronchoalveolar lavage fluid (BALF) for the diagnosis of HX. The searched cells express a specific CD1 antigen, recognized by the monoclonal antibody OKT-6. In our study the demonstration of more than 5% of CD1 positive cells was defined to confirm HX. We have studied the BALF in 21 patients with suspected histiocytosis X. In BALF of 4 patients more than 5% of CD1 positive cells were found. In 1 of them HX was confirmed with open lung biopsy. Two patients displayed 5% of CD1 positive cells. The final diagnosis of the first patient was hypersensitivity pneumonitis and of the second one was bronchitis chronica. In 5 patients out of 15 patients in whom less than 5% of CD1 positive cells were found histiocytosis X was histologically proven. In other 10 patients the following disorders were histologically recognised: pulmonary emphysema 3 cases, pneumoconiosis-3, LMA-BOOP-1, sarcoidosis-1 and pleuritis eosinophilica-1. The estimation of Langerhans cells in BALF can be a useful method among the diagnostic procedures for histiocytosis X. It is necessary to remember that demonstration of less than 5% of CD1 positive cells do not exclude histiocytosis X.