“…It has recently been shown that lympho cytes from individuals with asthma, atopic eczema or rhinoconjunctivitis have a de creased responsiveness to stimulation by phytohaemagglutinin (PHA), concanavalin A (Con A) and purified protein derivative (PPD) [Andersen and Hjorth, 1975;Grove et al, 1975;Hovmark, 1975;Strannegârd et al 1975Strannegârd et al , 1976. These findings are con cordant with the earlier demonstration of decreased cell-mediated immunity, mea sured as delayed hypersensitivity, in patients with atopic disease [Palacios et al, 1966;Lobitz et al, 1972], In addition to the de creased mitogenic responsiveness of lym phocytes from atopic individuals, a signifi cant decrease in relative and absolute num bers of circulating thymus-dcrivcd (T) cells has been observed in such individuals [Luckasen et al, 1974;Gottlieb and Hanifin, 1974;McGeady and Buckley, 1974;Strannegârd et al, 1976;Carapeto et al, 1976].…”