Genay O Pilarowski1, Tareian Cazares2, Li Zhang3, Joel S Benjamin1, Ke Liu4, Sajjeev Jagannathan2, Nadeem Mousa2, Jennifer Kasten5, Artem Barski6, Andrew W Lindsley7, Hans T Bjornsson8. 1. Predoctoral Program in Human Genetics, Johns Hopkins School of Medicine, Baltimore, Md; McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Md. 2. Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. 3. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Md. 4. Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. 5. Division of Pathology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio. 6. Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio. 7. Division of Allergy and Immunology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio. Electronic address: andrew.lindsley@cchmc.org. 8. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University, Baltimore, Md; Department of Pediatrics, Johns Hopkins School of Medicine, Baltimore, Md; Faculty of Medicine, University of Iceland, Reykjavik, Iceland; Department of Genetics and Molecular Biology, Landspitali University Hospital, Reykjavik, Iceland.
Abstract
BACKGROUND: Kabuki syndrome (KS) is commonly caused by mutations in the histone-modifying enzyme lysine methyltransferase 2D (KMT2D). Immune dysfunction is frequently observed in individuals with KS, but the role of KMT2D in immune system function has not been identified. OBJECTIVE: We sought to understand the mechanisms driving KS-associated immune deficiency (hypogammaglobulinemia [low IgA], splenomegaly, and diminished immunization responses). METHODS: We performed a comprehensive evaluation of humoral immunity and secondary lymphoid tissues in an established KS (Kmt2d+/βGeo) mouse model and validated select findings in a patient with KS. RESULTS: Compared with wild-type littermates, Kmt2d+/βGeo mice demonstrated deficiencies in multiple B-cell lineages and reduced serum IgA and elevated IgM levels across multiple ages. The bone marrow, spleen, and intestine of Kmt2d+/βGeo mice contained diminished numbers of IgA-secreting cells, while elevated germinal center B cells were found in the mesenteric lymph node and Peyer patches. Kmt2d+/βGeo mice have decreased size and numbers of Peyer patches, a finding confirmed in human samples. We identified deficiency of Itgb7 RNA and protein expression, a gene encoding an adhesion protein that mediates intestinal homing, and we demonstrated KMT2D-dependent control of ITGB7 expression in a human cell line. CONCLUSIONS: Kmt2d haploinsufficiency has broad deleterious effects on B-cell differentiation, specifically hampering gut lymphocyte homing and IgA+ plasma cell differentiation. Intestinal lymphoid defects caused by ITGB7 deficiency have not previously been recognized in KS, and these results provide new mechanistic insights into the pathogenesis of KS-associated immune deficiency.
BACKGROUND:Kabuki syndrome (KS) is commonly caused by mutations in the histone-modifying enzyme lysine methyltransferase 2D (KMT2D). Immune dysfunction is frequently observed in individuals with KS, but the role of KMT2D in immune system function has not been identified. OBJECTIVE: We sought to understand the mechanisms driving KS-associated immune deficiency (hypogammaglobulinemia [low IgA], splenomegaly, and diminished immunization responses). METHODS: We performed a comprehensive evaluation of humoral immunity and secondary lymphoid tissues in an established KS (Kmt2d+/βGeo) mouse model and validated select findings in a patient with KS. RESULTS: Compared with wild-type littermates, Kmt2d+/βGeo mice demonstrated deficiencies in multiple B-cell lineages and reduced serum IgA and elevated IgM levels across multiple ages. The bone marrow, spleen, and intestine of Kmt2d+/βGeo mice contained diminished numbers of IgA-secreting cells, while elevated germinal center B cells were found in the mesenteric lymph node and Peyer patches. Kmt2d+/βGeo mice have decreased size and numbers of Peyer patches, a finding confirmed in human samples. We identified deficiency of Itgb7 RNA and protein expression, a gene encoding an adhesion protein that mediates intestinal homing, and we demonstrated KMT2D-dependent control of ITGB7 expression in a human cell line. CONCLUSIONS:Kmt2dhaploinsufficiency has broad deleterious effects on B-cell differentiation, specifically hampering gut lymphocyte homing and IgA+ plasma cell differentiation. Intestinal lymphoid defects caused by ITGB7 deficiency have not previously been recognized in KS, and these results provide new mechanistic insights into the pathogenesis of KS-associated immune deficiency.
Authors: Sietse M Aukema; Selina Glaser; Mari F C M van den Hout; Sonja Dahlum; Marinus J Blok; Morten Hillmer; Julia Kolarova; Raf Sciot; Dina A Schott; Reiner Siebert; Constance T R M Stumpel Journal: Fam Cancer Date: 2022-07-19 Impact factor: 2.446
Authors: Jens Wittner; Sebastian R Schulz; Tobit D Steinmetz; Johannes Berges; Manuela Hauke; William M Channell; Adam F Cunningham; Anja E Hauser; Andreas Hutloff; Dirk Mielenz; Hans-Martin Jäck; Wolfgang Schuh Journal: Mucosal Immunol Date: 2022-03-28 Impact factor: 8.701