Lysozyme activity in bronchial and broncho-alveolar fluids

Patients affected by different diseases were submitted to bronchial and bronchoalveolar lavage, performed by fiberoptic bronchoscopy under xylocaine anesthesia. Bronchial lavage levels of lysozyme are very high and depend on the secretory rate of the mucosa, although further amounts can be derived from bronchial washings during inflammatory processes by neutrophils. Broncho-alveolar levels are mainly a function of macrophage secretion and dosages may provide an insight to the dynamic behaviour of macrophages in their response to foreign stimuli. Alveoli and blood levels reach an equilibrium, as assessed by mixed venous and arterial blood samples. Administration of exogenous lysozyme is able to increase bronchial IgA and sIGA. Serum immunoglobulins are higher as well, because of the polyclonal stimulation of the lymphocytes. Antiinflammatory properties and modulation of PMN arrival to inflammatory sites play a role in diminishing the enzymatic load to the lung and bronchi.