Thymic Hormone Therapy for Histiocytosis X?

Abstract
To the Editor: The cause of histiocytosis X is unknown, and although the disorder has certain features of neoplasia, the high incidence of spontaneous remission and the histology are against this. Osband et al. suggested that the disease was due to a primary immunodeficiency, and demonstrated a deficiency of H2 receptors on circulating lymphocytes that correlated with defective functional suppressor activity.1 Incubation of lymphocytes with a crude calf thymic extract largely corrected these abnormalities. Patients treated with this extract had a remission rate of over 50 per cent, a figure similar to that achieved with steroids and cytotoxic agents.We . . .