Langerhans cell histiocytosis. Clinical study and long-term evolution in 21 patients

BACKGROUND: Clinical data of patients with Langerhans cell histiocytosis ar e well established, although new diagnostic methods and specially long term evolution of the disease with lung involvement are not well-known. METHODS: In all cases, patients were diagnosed by means of pathologic study of the lung samples, either by transbronchial biopsy in 7 patients, or by surgical lung biopsy in 8 patients. Six patients were diagnosed by bone bio psy. Other patients were diagnosed by bronchoalveolar lavage (BAL). In 4 pa tients, who underwent BAL, the study of antibodies CD1 (CD1a) was positive (> 5%). Lymphocytopenia was detected in 28% of patients, whereas no decreas e in delayed cutaneous hypersensitivity tests was detected in any of them. After a follow-up study of 12.8 years (range: 4-22 years), 7 patients had d ead, 6 patients showed severe lung involvement and other 5 patients did not have lung affection. CONCLUSIONS: The diagnosis of Langerhans cell histiocytosis has improved by detection of immunologic and histochemical markers recently introduced. Th e study of the delayed cutaneous hypersensitivity tests dis not show anergy or hipoergy. Long term evolution of patients with lung involvement is poor .