Activated T Lymphocytes, Interferon, and Retrovirus-like Particles in Psoriatic Lesions

To the Editor.—  Increasing evidence points to the importance of immune mechanisms in the pathogenesis of psoriasis. The role of humoral v cellular immune reactions in the development of psoriatic skin lesions seems still to be open for discussion. In the September Archives (1982;118:652-657), Jablonska et al claimed that the polymorphonuclear leukocytes play an important role in the earliest stages of development of psoriatic lesions. Recently, we have obtained data indicating that lymphocytes and macrophages are involved in the pathogenesis of psoriasis.Macrophages and T cells are regularly found in early psoriatic lesions. There is great variation in the relative proportions of these cells, depending on the clinical activity of the disease.¹ When monoclonal antibodies against T-cell surface antigens are used, both helper-inducer and suppressor-cytotoxic T cells can be demonstrated.² To determine the functional state of T cells in the psoriatic plaque, we have studied the presence of