[T-lymphocytes disorders in pulmonary sarcoidosis]

Sarcoidosis is a granulomatous disorder of unknown aetiology accompanied by variable immunological changes which concern both the monocyte and lymphocyte cell line. During the course of this disease anomalies of distribution (with accumulation in the disease tissue contrasting with a peripheral lymphopenia) and also of T cell functions (a predominance of CD4 T lymphocytes within the lesions and spontaneous expression of activation criteria) have been described. Recent works show some disturbances of T cell function and evoke the possibility of the initial pathology being related to this cell. Some current hypotheses place the T cell receptor for the antigen and the interleukin 2 receptor whose dysfunction will lead to an anomaly of the transduction of the activating signal of the T lymphocyte. The intrinsic origin (genetically determined) or extrinsically (retroviral) of these disturbances remains however to be determined.