The monograph examines one of the urgent problems of modern clinical medicine - the treatment of patients with atypically occurring infectious and inflammatory diseases that occur in immunocompromised patients, which include "often and long-term ill" children and adults suffering from various persistently recurring diseases of a viral, bacterial or viral-bacterial etiology. The analysis of the existing treatment and rehabilitation methods is conducted. Own data are presented, obtained by studying the state of the interferon system and the characteristics of the functioning of the immune system in this category of patients. Defects in the interferon system and various immune system damages are described. The approaches and principles of interferon and immunotherapy in patients with interferon and immunodeficiency are determined. The characteristic of immune and interferon therapy is given. Interferon and immunotherapy programs developed by the authors for children and adults suffering from repeated respiratory and recurrent herpes virus infections are presented. The monograph is of interest to doctors of various specialties: allergists, immunologists, pediatricians, general practitioners, ENT doctors, infectious disease specialists, as well as for clinical residents, graduate students and researchers.