Impaired IL10 signaling characterizes a subgroup of IBD patients, whereas the majority of children with severe IBD including EO forms normally produces and responds to IL10. Defective IL22 signaling may additionally impair intestinal epithelial clearance. Our data point out the complexity of IBD, which represent a group of distinct diseases with several pathogenetic abnormalities.

Identification in humans of a bona fide marginal zone B cell population, which differentiates from a splenic marginal zone precursor through a NOTCH2 signaling pathway.

BackgroundAnderson's disease (AD) or chylomicron retention disease (CMRD) is a very rare hereditary lipid malabsorption syndrome. In order to discover novel mutations in the SAR1B gene and to evaluate the expression, as compared to healthy subjects, of the Sar1 gene and protein paralogues in the intestine, we investigated three previously undescribed individuals with the disease.MethodsThe SAR1B, SAR1A and PCSK9 genes were sequenced. The expression of the SAR1B and SAR1A genes in intestinal biopsies of both normal individuals and patients was measured by RTqPCR. Immunohistochemistry using antibodies to recombinant Sar1 protein was used to evaluate the expression and localization of the Sar1 paralogues in the duodenal biopsies.ResultsTwo patients had a novel SAR1B mutation (p.Asp48ThrfsX17). The third patient, who had a previously described SAR1B mutation (p.Leu28ArgfsX7), also had a p.Leu21dup variant of the PCSK9 gene. The expression of the SAR1B gene in duodenal biopsies from an AD/CMRD patient was significantly decreased whereas the expression of the SAR1A gene was significantly increased, as compared to healthy individuals. The Sar1 proteins were present in decreased amounts in enterocytes in duodenal biopsies from the patients as compared to those from healthy subjects.ConclusionsAlthough the proteins encoded by the SAR1A and SAR1B genes are 90% identical, the increased expression of the SAR1A gene in AD/CMRD does not appear to compensate for the lack of the SAR1B protein. The PCSK9 variant, although reported to be associated with low levels of cholesterol, does not appear to exert any additional effect in this patient. The results provide further insight into the tissue-specific nature of AD/CMRD.

The online version of this article has a Supplementary Appendix. BackgroundPatients with the Shwachman-Diamond syndrome often develop hematologic complications. No risk factors for these complications have so far been identified. The aim of this study was to classify the hematologic complications occurring in patients with Shwachman-Diamond syndrome and to investigate the risk factors for these complications. Design and MethodsOne hundred and two patients with Shwachman-Diamond syndrome, with a median followup of 11.6 years, were studied. Major hematologic complications were considered in the case of definitive severe cytopenia (i.e. anemia <7 g/dL or thrombocytopenia <20×10 9 /L), classified as malignant (myelodysplasia/leukemia) according to the 2008 World Health Organization classification or as non-malignant. ResultsSevere cytopenia was observed in 21 patients and classified as malignant severe cytopenia (n=9), non-malignant severe cytopenia (n=9) and malignant severe cytopenia preceded by nonmalignant severe cytopenia (n=3). The 20-year cumulative risk of severe cytopenia was 24.3% (95% confidence interval: 15.3%-38.5%). Young age at first symptoms (<3 months) and low hematologic parameters both at diagnosis of the disease and during the follow-up were associated with severe hematologic complications (P<0.001). Fifteen novel SBDS mutations were identified. Genotype analysis showed no discernible prognostic value. ConclusionsPatients with Shwachman-Diamond syndrome with very early symptoms or cytopenia at diagnosis (even mild anemia or thrombocytopenia) should be considered at a high risk of severe hematologic complications, malignant or non-malignant. Transient severe cytopenia or an indolent cytogenetic clone had no deleterious value.Key words: Shwachman-Diamond syndrome, genotype, aplastic anemia, secondary leukemia, cytopenia, myelodysplasia, monosomy 7.Citation: Donadieu J, Fenneteau O, Beaupain B, Beaufils S, Bellanger F, Mahlaoui N, Lambilliotte A, Aladjidi N, Bertrand Y, Mialou V, Perot C, Michel G, Fouyssac F, Paillard C, Gandemer V, Boutard P, Schmitz J, Morali A, Leblanc T, Bellanné-Chantelot C, and Classification of and risk factors for hematologic complications in a French national cohort of 102 patients with Shwachman-Diamond syndrome