Treatment of intractable ulcerating enterocolitis of infancy by allogeneic bone marrow transplantation

Very early onset inflammatory bowel disease associated with aberrant trafficking of IL-10R1 and cure by T cell replete haploidentical bone marrow transplantation

PURPOSE

Loss-of-function mutations in IL10 and IL10R cause very early onset inflammatory bowel disease (VEO-IBD). Here, we investigated the molecular pathomechanism of a novel intronic IL10RA mutation and describe a new therapeutic approach of T cell replete haploidentical hematopoietic stem cell transplantation (HSCT).

METHODS

Clinical data were collected by chart review. Genotypes of IL10 and IL10R genes were determined by Sanger sequencing. Expression and function of mutated IL-10R1 were assessed by quantitative PCR, Western blot analysis, enzyme-linked immunosorbent assays, confocal microscopy, and flow cytometry.

RESULTS

We identified a novel homozygous point mutation in intron 3 of the IL10RA (c.368-10C > G) in three related children with VEO-IBD. Bioinformatical analysis predicted an additional 3' splice site created by the mutation. Quantitative PCR analysis showed normal mRNA expression of mutated IL10RA. Sequencing of the patient's cDNA revealed an insertion of the last nine nucleotides of intron 3 as a result of aberrant splicing. Structure-based modeling suggested misfolding of mutated IL-10R1. Western blot analysis demonstrated a different N-linked glycosylation pattern of mutated protein. Immunofluorescence and FACS analysis revealed impaired expression of mutated IL-10R1 at the plasma membrane. In the absence of HLA-identical donors, T cell replete haploidentical HSCT was successfully performed in two patients.

CONCLUSIONS

Our findings expand the spectrum of IL10R mutations in VEO-IBD and emphasize the need for genetic diagnosis of mutations in conserved non-coding sequences of candidate genes. Transplantation of haploidentical stem cells represents a curative therapy in IL-10R-deficient patients, but may be complicated by non-engraftment.

Phenotypic characterization of very early-onset IBD due to mutations in the IL10, IL10 receptor alpha or beta gene: a survey of the Genius Working Group

OBJECTIVE

Early-onset inflammatory bowel disease starting within the first months of life could be due to a particular genetic defect. We set up the GENetically determined ImmUne-mediated enteropathieS (GENIUS) network and collected infants with a proven defect of the IL10 axis for accurate phenotyping of disease presentation and evolution.

DESIGN

Ten patients with early-onset inflammatory bowel disease with confirmed mutations in IL10, IL10RA, or IL10RB genes were characterized on clinical, endoscopic-histological, immunobiological, and radiological findings. Functional assays to confirm defective responses to IL10 were performed on peripheral blood mononuclear cells.

RESULTS

A functional defect in IL10 signaling was confirmed in all IL10R patients tested. Disease started with severe diarrhea within the first 12 weeks in all patients. All infants showed Crohn's disease-like ulcerations limited to the colon with marked perianal inflammation (fissures, abscess, and fistula); disease progression to the small bowel occurred in only 1 patient. Four of the 10 patients had granulomata on histology, and all patients showed Crohn's disease-like mesenteric infiltration on imaging. Disease pattern was indistinguishable between IL10R alpha or beta chain or IL10 defects; autoimmunity was not observed. Mutations in IL10 were more frequently associated with bacterial and viral infections. Patients responded partially to treatment with steroids or anti-tumor necrosis factor drugs, whereas hematopoietic stem cell transplantation proved efficacious.

CONCLUSION

The importance of the IL10 pathway within the colonic mucosa is highlighted by the development of severe colitis within a few weeks in infants with mutations in IL10, IL10RA, or IL10RB. Immunosuppression failed to correct the defect in this pathway, which seems to be a key to controlling inflammation in the colon.

Loss of interleukin-10 signaling and infantile inflammatory bowel disease: implications for diagnosis and therapy

BACKGROUND & AIMS

Homozygous loss of function mutations in interleukin-10 (IL10) and interleukin-10 receptors (IL10R) cause severe infantile (very early onset) inflammatory bowel disease (IBD). Allogeneic hematopoietic stem cell transplantation (HSCT) was reported to induce sustained remission in 1 patient with IL-10R deficiency. We investigated heterogeneity among patients with very early onset IBD, its mechanisms, and the use of allogeneic HSCT to treat this disorder.

METHODS

We analyzed 66 patients with early onset IBD (younger than 5 years of age) for mutations in the genes encoding IL-10, IL-10R1, and IL-10R2. IL-10R deficiency was confirmed by functional assays on patients' peripheral blood mononuclear cells (immunoblot and enzyme-linked immunosorbent assay analyses). We assessed the therapeutic effects of standardized allogeneic HSCT.

RESULTS

Using a candidate gene sequencing approach, we identified 16 patients with IL-10 or IL-10R deficiency: 3 patients had mutations in IL-10, 5 had mutations in IL-10R1, and 8 had mutations in IL-10R2. Refractory colitis became manifest in all patients within the first 3 months of life and was associated with perianal disease (16 of 16 patients). Extraintestinal symptoms included folliculitis (11 of 16) and arthritis (4 of 16). Allogeneic HSCT was performed in 5 patients and induced sustained clinical remission with a median follow-up time of 2 years. In vitro experiments confirmed reconstitution of IL-10R-mediated signaling in all patients who received the transplant.

CONCLUSIONS

We identified loss of function mutations in IL-10 and IL-10R in patients with very early onset IBD. These findings indicate that infantile IBD patients with perianal disease should be screened for IL-10 and IL-10R deficiency and that allogeneic HSCT can induce remission in those with IL-10R deficiency.