Objective. To clarify the incidence of monogenic IBD-like diseases and the features of clinical course and response to therapy of major types of inflammatory bowel diseases (IBD) among children under the age of 6 with manifestation of the disease. Patients and methods. The study included 135 children under the age of 6 with manifestation of IBD; in the comparison group, there were 128 children after the age of 6 with manifestation of IBD (97 children with ulcerative colitis (UC) and 31 children with Crohn’s disease (CD)) who were observed for at least 1 year. All children underwent a standard examination, including calprotectin and antineutrophil antibodies testing, determination of activity by the Pediatric Ulcerative Colitis Activity Index (PUCAI) or the Pediatric Crohn’s Disease Activity Index (PCDAI), depending on the nosology. Children with the onset of IBD under 6 years of age underwent a genetic testing using Primary Immunodeficiency Panel by next-generation sequencing. All children were analyzed for efficacy of therapy during catamnestic observation. Results. It was revealed that in the study group the incidence of monogenic IBD-like diseases was 6.7%, of UC – 71.1%, of CD – 22.2%. Major types of IBD with very early onset differed little in their clinical, endoscopic and laboratory features from the forms with manifestation at an older age. In most cases, both CD (57%) and UC (71%) were characterized by low activity. Very earlyonset CD was characterized by isolated localization of the colon (53%, p = 0.037) and a non-stenotic and non-penetrating behaviour of the disease (60% of cases). The leading clinical symptoms were diarrhea (67%) and blood in the stool (63%, p = 0.04). Very early-onset UC was characterized by total lesion of the colon (84%, p = 0.001) and the development of anemia (48%, p = 0.01). Among children with very early-onset UC, the percentage of glucocorticosteroid-dependence and glucocorticosteroid-resistance was high, but anti-TNFα therapy was prescribed late. Conclusion. It is advisable to observe children with very early-onset IBD in federal multidisciplinary clinics, where there is experience in managing patients with this pathology. Key words: inflammatory bowel disease, very early onset, Crohn’s disease, ulcerative colitis, primary immunodeficiency, treatment, children
Revisiting Crohn's disease as a primary immunodeficiency of macrophages