Zuzana Rennerová, Miloš Jeseňák, Peter Bánovčin
Phagocytes (neutrophils, monocytes, macrophages) play a key role in the early non-specific immune response against bacterial and fungal pathogens. Phagocytosis is a multistage process that starts with transendothelial migration of neutrophils. Migration of circulating neutrophils to the sites of infection and inflammation is induced by chemotactic substances. The pathogens are absorbed and phagosom and phagolysosom are created. Then the pathogens are killed by activated phagocytes with help of oxygen-dependent mechanisms (NADPH synthase and NO-synthase) and also independent mechanisms (different substances stored in cytoplasmatic granules). Primary immunodeficiency disorders (PIDs) of phagocytosis can result from a reduced number of phagocytes (severe congenital neutropenia, cyclic neutropenia) or their defective function (chronic granulomatous disease, myeloperoxidase deficit, leukocyte adhesion deficiency 1 and 2). These represent 12.5 % from all PIDs. Patients suffer from recurrent and severe bacterial infections (especially Staphyloccocus aureus) and fungal infections (Candida and Aspergillus species). Disorders of phagocytosis usually manifest early after birth with omphalitis or reaction to the BCG vaccination. Respiratory tract and cutaneous infections predominate, recurrent oral infections are present in most cases (periodontitis, stomatitis). Lymphadenitis, deep-seeded abscesses are also common. Monocytes and macrophages disorders increase risk of mycobacterial infections. Therapy requires regular antibiotic and antifungal prophylaxis in the cases of severe PIDs. Recombinant growth colony stimulating factor (G-CSF in congenital neutropenia) and INFγ (CGD, defects in immunity against mycobacterium) are helpful in some disorders. Quickly and sufficient antibiotic treatment is important in the case of infection. Hematopoietic stem cell transplantation is curative treatment in majority disorders, but it is used only in severe PIDs because of risk of rejection. Gene therapy has been attempted in a few patients with CGD only with partial success. BCG vaccination is prohibited in all patients with phagocytes disorders.