DEFENSES PULMONAIRES LOCALES ET D'AMPLIFICATION

The pulmonary defences are remarkably efficacious in the protection against infections and against other respiratory diseases caused by noxious substances or gases in the inhaled air, if we consider the degree of the daily explosion and the rarity of respiratory diseases in the normal man, in the majority of cases. On the whole, the elements of the defence system work easily and without becoming fatigued. Nevertheless, more and more examples are found of isolated immunitary deficiencies associated with repeated pulmonary affections. Deficiencies of factors of complement (C₅), an anomaly of ciliary function (Kartagener's syndrome), the absence of immunoglobulins (IgA), abnormal leucocytes, all these predispose to infections of the lungs. However, a single deficiency by itself cannot cause a predisposition to major pulmonary infections. The fact that compensatory mechanisms may intervene bears witness to the suppleness of the defence apparatus. Whereas the selective deficiencies are extremely useful for evaluating the importance of the different elements of the pulmonary defence, their absence also brings into relief the faculties of adaptation of the pulmonary defences.