Phagocytic dysfunctions: a proposal for classification.

The classification presented here is designed to help clinicians make therapeutic and diagnostic decisions. It is based on the modern view of the phagocytosis process as events involving ligand-receptor interaction, transmission of signal through second messenger systems and activation of effector mechanisms leading to specific cell behaviour. According to the classification proposed here, phagocytic disorders can be divided into extracellular disorders which are caused by abnormalities affecting ligands and cellular disorders caused by a pathological disturbance affecting the phagocytic cell. These cellular disorders are subdivided into defects of membrane receptors, defects of enzymatic equipment and defects of subcellular structures. Laboratory investigations of phagocytic cells make it possible to classify inborn, acquired, permanent and transient disorders into these groups. Examples of disorders in each of these groups are presented.