A study of the functions of polymorphonuclear neutrophil in patients with Down's syndrome.

Patients with Down's syndrome (DS) are predisposed to infectious diseases, particularly of the respiratory tract. Together with the occurrence of cardiac defects, this is one of the main determinants of their life expectancy. The aim of the present work was to study a series of immunological parameters that would allow us to evaluate the functional behaviour of the neutrophil polymorphonuclears of the patients with trisomy 21 and the possible relationship between this and the susceptibility of this kind of patient to such infections. The results obtained point a significant decrease (p less than 0.001) in the adhesiveness index and in the two indexes relating to the evaluation of random mobilities of cells ("leading front" and "lower face of filter"). Although the neutrophil chemotactic responsiveness of these patients is decreased with any of the attractants employed (casein and activated sera), the differences observed with respect to the control population are more patent upon analyzing the function on the "lower face of filter". Study of phagocytosis of Candida albicans and candidicidal activity of PMN reveals a normal behaviour in the presence of autologous (patient) and heterologous (control) serum. We propose that the alterations found in the PMN cell functions of DS patients could be due to intrinsic cellular defects and that this would help to explain why such patients tend to undergo repetitive infective processes.