Cystic fibrosis (CF) is a severe chronic monogenic disorder. Immune system in CF patients is fully functional at birth, without any immunodeficiency. All pathological findings are secondary as a result of chronic immune system stimulation by pathogens during life. Dominant finding is hypergammaglobulinemia which is increasing with age. In the most cases there is no need for immunotherapy in CF patients with the exception of transient hypogammaglobulinemia in the first months of live and status after lung transplantation. Although chronic infection is one of the causal factors of the disease and immune system of CF patients must be involved in this, it is obvious that immune function failure is secondary. This article summarizes current knowledge about immune system in cystic fibrosis patients.

        Key words: cystic fibrosis, immune system, lymphocytes, antibodies, cytokines, inflammation, chronic infection