1
|
Tahiat A, Belbouab R, Yagoubi A, Hakem S, Fernini F, Keddari M, Belhadj H, Touri S, Aggoune S, Stoddard J, Niemela J, Zerifi F, Melzi S, Aboura R, Saad-Djaballah A, Ferhani Y, Ketfi A, Messaoudi H, Bencharif Madani T, Benhacine Z, Dehimi A, Okka K, Amroune F, Fellahi M, Bendahmane C, Khoulani R, Oukil A, Soufane A, Bourelaf I, Boubidi C, Boukhenfouf N, Amine Ifri M, Khelafi N, Boudiaf H, Khelifi Touhami T, Meçabih F, Boucelma M, Zelaci A, Gacem O, Ladj MS, Mekki A, Bensaadi N, Benhalima M, Zeroual Z, Bioud B, Benameur M, Bouhdjila R, Bouzerar Z, Ibsaine O, Maouche H, Kedji L, Smati L, Boukari R, Lambert C, Rosenzweig SD, Notarangelo LD, Djenouhat K. Flow cytometry-based diagnostic approach for inborn errors of immunity: experience from Algeria. Front Immunol 2024; 15:1402038. [PMID: 39072316 PMCID: PMC11273131 DOI: 10.3389/fimmu.2024.1402038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 06/27/2024] [Indexed: 07/30/2024] Open
Abstract
Purpose In this study, we retrospectively reviewed the use of flow cytometry (FCM) in the diagnosis of inborn errors of immunity (IEIs) at a single center in Algeria. Sharing insights into our practical experience, we present FCM based diagnostic approaches adapted to different clinical scenarios. Methods Between May 2017 and February 2024, pediatric and adult patients presenting with clinical features suggestive of immunodeficiency were subjected to FCM evaluation, including lymphocyte subset analysis, detection of specific surface or intracellular proteins, and functional analysis of immune cells. Results Over a nearly seven-year period, our laboratory diagnosed a total of 670 patients (372 (55.5%) males and 298 (44.5%) females), distributed into 70 different IEIs belonging to 9 different categories of the International Union of Immunological Societies classification. FCM was used to diagnose and categorize IEI in 514 patients (76.7%). It provided direct diagnostic insights for IEIs such as severe combined immunodeficiency, Omenn syndrome, MHC class II deficiency, familial hemophagocytic lymphohistiocytosis, and CD55 deficiency. For certain IEIs, including hyper-IgE syndrome, STAT1-gain of function, autoimmune lymphoproliferative syndrome, and activated PI3K delta syndrome, FCM offered suggestive evidence, necessitating subsequent genetic testing for confirmation. Protein expression and functional assays played a crucial role in establishing definitive diagnoses for various disorders. To setup such diagnostic assays at high and reproducible quality, high level of expertise is required; in house reference values need to be determined and the parallel testing of healthy controls is highly recommended. Conclusion Flow cytometry has emerged as a highly valuable and cost-effective tool for diagnosing and studying most IEIs, particularly in low-income countries where access to genetic testing can be limited. FCM analysis could provide direct diagnostic insights for most common IEIs, offer clues to the underlying genetic defects, and/or aid in narrowing the list of putative genes to be analyzed.
Collapse
Affiliation(s)
- Azzeddine Tahiat
- Department of Medical Biology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Reda Belbouab
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Abdelghani Yagoubi
- Pediatric Gastroenterology, Centre Algérois de Pédiatrie, Algiers, Algeria
| | - Saliha Hakem
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Faiza Fernini
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Malika Keddari
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Hayet Belhadj
- Department of Pediatrics, Central Hospital of the Army, Algiers, Algeria
| | - Souad Touri
- Department of Pediatrics, Blida University Hospital, University of Blida, Blida, Algeria
| | - Samira Aggoune
- Department of Pediatrics, El-Harrach Hospital, University of Algiers 1, Algiers, Algeria
| | - Jennifer Stoddard
- Immunology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Julie Niemela
- Immunology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Farida Zerifi
- Department of Pediatrics, Ain Taya Hospital, University of Algiers 1, Algiers, Algeria
| | - Souhila Melzi
- Department of Pediatrics, Bab El-Oued University Hospital, University of Algiers 1, Algiers, Algeria
| | - Rawda Aboura
- Department of Pediatrics, Bab El-Oued University Hospital, University of Algiers 1, Algiers, Algeria
| | - Amina Saad-Djaballah
- Department of Pediatrics, Bologhine Hospital, University of Algiers 1, Algiers, Algeria
| | - Yacine Ferhani
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Abdalbasset Ketfi
- Department of Pneumology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Hassen Messaoudi
- Department of Internal Medicine, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Tahar Bencharif Madani
- Department of Pediatrics, Mansourah Hospital, University of Constantine, Constantine, Algeria
| | - Zouleikha Benhacine
- Department of Pediatrics, Constantine University Hospital, University of Constantine, Constantine, Algeria
| | - Abdelhak Dehimi
- Department of Pediatrics, Setif University Hospital, University of Setif, Setif, Algeria
| | - Kamelia Okka
- Department of Pediatrics, Setif University Hospital, University of Setif, Setif, Algeria
| | - Fairouz Amroune
- Department of Pediatrics, Setif University Hospital, University of Setif, Setif, Algeria
| | - Meriem Fellahi
- Department of Pediatrics, Setif University Hospital, University of Setif, Setif, Algeria
| | | | - Radia Khoulani
- Department of Pediatrics, Meftah Hospital, Blida, Algeria
| | - Asma Oukil
- Department of Medical Biology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Asma Soufane
- Department of Medical Biology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Imene Bourelaf
- Department of Medical Biology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Chahynez Boubidi
- Department of Pediatrics A, Hussein Dey University Hospital, University of Algiers 1, Algiers, Algeria
| | | | | | | | - Houda Boudiaf
- Department of Pediatric Oncology, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | | | - Fethi Meçabih
- Department of Immunology, Institut Pasteur d’Algérie, University of Algiers 1, Algiers, Algeria
| | - Malika Boucelma
- Department of Internal Medicine, Kouba Hospital, University of Algiers 1, Algiers, Algeria
| | - Amara Zelaci
- Department of Pediatrics, El Oued Hospital, El Oued, Algeria
| | - Ourida Gacem
- Department of Pediatrics, Birtraria Hospital El Biar, University of Algiers 1, Algiers, Algeria
| | - Mohamed Samir Ladj
- Department of Pediatrics, Birtraria Hospital El Biar, University of Algiers 1, Algiers, Algeria
| | - Azzedine Mekki
- Department of Pediatrics B, Hussein Dey University Hospital, University of Algiers 1, Algiers, Algeria
| | - Nadia Bensaadi
- Department of Pediatrics, Tizi Ouzou University Hospital, University of Tizi Ouzou, Tizi Ouzou, Algeria
| | - Malika Benhalima
- Algiers Faculty of Pharmacy, University of Algiers 1, Algiers, Algeria
| | - Zoulikha Zeroual
- Department of Pediatrics A, Hussein Dey University Hospital, University of Algiers 1, Algiers, Algeria
| | - Belkacem Bioud
- Department of Pediatrics, Setif University Hospital, University of Setif, Setif, Algeria
| | - Mustapha Benameur
- Department of Internal Medicine, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| | - Rachid Bouhdjila
- Department of Pediatrics, Constantine University Hospital, University of Constantine, Constantine, Algeria
| | - Zahir Bouzerar
- Department of Pediatrics, Bab El-Oued University Hospital, University of Algiers 1, Algiers, Algeria
| | - Ouardia Ibsaine
- Department of Pediatrics, Ain Taya Hospital, University of Algiers 1, Algiers, Algeria
| | - Hachemi Maouche
- Department of Pediatrics, El-Harrach Hospital, University of Algiers 1, Algiers, Algeria
| | - Leila Kedji
- Department of Pediatrics, Blida University Hospital, University of Blida, Blida, Algeria
| | - Leila Smati
- Department of Pediatrics, Bologhine Hospital, University of Algiers 1, Algiers, Algeria
| | - Rachida Boukari
- Department of Pediatrics, Mustapha University Hospital, University of Algiers 1, Algiers, Algeria
| | - Claude Lambert
- Cytometry Unit, Immunology Laboratory, Saint-Etienne University Hospital, Saint-Étienne, Lyon, France
| | - Sergio D. Rosenzweig
- Immunology Service, Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Luigi D. Notarangelo
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Kamel Djenouhat
- Department of Medical Biology, Rouiba Hospital, University of Algiers 1, Algiers, Algeria
| |
Collapse
|
2
|
Peng XP, Al-Ddafari MS, Caballero-Oteyza A, El Mezouar C, Mrovecova P, Dib SE, Massen Z, Smahi MCE, Faiza A, Hassaïne RT, Lefranc G, Aribi M, Grimbacher B. Next generation sequencing (NGS)-based approach to diagnosing Algerian patients with suspected inborn errors of immunity (IEIs). Clin Immunol 2023; 256:109758. [PMID: 37678716 DOI: 10.1016/j.clim.2023.109758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/23/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
The advent of next-generation sequencing (NGS) technologies has greatly expanded our understanding of both the clinical spectra and genetic landscape of inborn errors of immunity (IEIs). Endogamous populations may be enriched for unique, ancestry-specific disease-causing variants, a consideration that significantly impacts molecular testing and analysis strategies. Herein, we report on the application of a 2-step NGS-based testing approach beginning with targeted gene panels (TGPs) tailored to specific IEI subtypes and reflexing to whole exome sequencing (WES) if negative for Northwest Algerian patients with suspected IEIs. Our overall diagnostic yield of 57% is comparable to others broadly applying short-read NGS to IEI detection, but data from our localized cohort show some similarities and differences from NGS studies performed on larger regional IEI cohorts. This suggests the importance of tailoring diagnostic strategies to local demographics and needs, but also highlights ongoing concerns inherent to the application of genomics for clinical IEI diagnostics.
Collapse
Affiliation(s)
- Xiao P Peng
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America.
| | - Moudjahed Saleh Al-Ddafari
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, Algeria; Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany
| | - Andres Caballero-Oteyza
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany; RESIST - Cluster of Excellence 2155 to Hanover Medical School, Satellite Center Freiburg, Germany
| | - Chahrazed El Mezouar
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, Algeria; Pediatric Department, Medical Center University of Tlemcen, Faculty of Medicine, University of Tlemcen, Algeria
| | - Pavla Mrovecova
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany
| | - Saad Eddin Dib
- Pediatric Department, Medical Center University of Tlemcen, Faculty of Medicine, University of Tlemcen, Algeria
| | - Zoheir Massen
- Pediatric Department, Medical Center University of Tlemcen, Faculty of Medicine, University of Tlemcen, Algeria
| | - Mohammed Chems-Eddine Smahi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, Algeria; Specialized Mother-Child Hospital of Tlemcen, Department of Neonatology, Faculty of Medicine, University of Tlemcen, Algeria
| | - Alddafari Faiza
- Department of Internal Medicine, Medical Center University of Tlemcen, Faculty of Medicine, University of Tlemcen, Tlemcen, Algeria
| | | | - Gérard Lefranc
- Institute of Human Genetics, UMR 9002 CNRS-University of Montpellier, France
| | - Mourad Aribi
- Laboratory of Applied Molecular Biology and Immunology, W0414100, University of Tlemcen, Algeria.
| | - Bodo Grimbacher
- Institute for Immunodeficiency, Center for Chronic Immunodeficiency, Medical Center, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany; DZIF - German Center for Infection Research, Satellite Center Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, Albert-Ludwigs University, Freiburg, Germany; RESIST - Cluster of Excellence 2155 to Hanover Medical School, Satellite Center Freiburg, Germany.
| |
Collapse
|
3
|
Mousavi Khorshidi MS, Seeleuthner Y, Chavoshzadeh Z, Behfar M, Hamidieh AA, Alimadadi H, Sherkat R, Momen T, Behniafard N, Eskandarzadeh S, Mansouri M, Behnam M, Mahdavi M, Heydarazad Zadeh M, Shokri M, Alizadeh F, Movahedi M, Momenilandi M, Keramatipour M, Casanova JL, Cobat A, Abel L, Shahrooei M, Parvaneh N. Clinical, Immunological, and Genetic Findings in Iranian Patients with MHC-II Deficiency: Confirmation of c.162delG RFXANK Founder Mutation in the Iranian Population. J Clin Immunol 2023; 43:1941-1952. [PMID: 37584719 DOI: 10.1007/s10875-023-01562-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 07/30/2023] [Indexed: 08/17/2023]
Abstract
PURPOSE Major histocompatibility complex class II (MHC-II) deficiency is a rare inborn error of immunity (IEI). Impaired antigen presentation to CD4 + T cells results in combined immunodeficiency (CID). Patients typically present with severe respiratory and gastrointestinal tract infections at early ages. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy. METHODS We describe the clinical, immunologic, and genetic features of eighteen unrelated Iranian patients with MHC-II deficiency. RESULTS Consanguinity was present in all affected families. The median age at the initial presentation was 5.5 months (range 7 days to 18 years). The main symptoms included failure to thrive, persistent diarrhea, and pneumonia. Autoimmune and neurologic features were also documented in about one-third of the patients, respectively. Thirteen patients carried RFXANK gene mutations, two carried RFX5 gene mutations, and three carried a RFXAP gene mutation. Six patients shared the same RFXANK founder mutation (c.162delG); limited to the Iranian population and dated to approximately 1296 years ago. Four of the patients underwent HSCT; three of them are alive. On the other hand, nine of the fourteen patients who did not undergo HSCT had a poor prognosis and died. CONCLUSION MHC-II deficiency is not rare in Iran, with a high rate of consanguinity. It should be considered in the differential diagnosis of CID at any age. With the limited access to HSCT and its variable results in MHC-II deficiency, implementing genetic counseling and family planning for the affected families are mandatory. We are better determined to study the c.162delG RFXANK heterozygous mutation frequency in the Iranian population.
Collapse
Affiliation(s)
- Mohadese Sadat Mousavi Khorshidi
- Division of Allergy and Clinical Immunology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Yoann Seeleuthner
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de La Santé Et de La Recherche Médicale (INSERM) U1163, Necker Hospital for Sick Children, Paris, France
- Imagine Institute, University Paris Cité, Paris, France
| | - Zahra Chavoshzadeh
- Allergy and Immunology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Maryam Behfar
- Pediatric Cell and Gene Therapy Research Center, Gene, Cell & Tissue Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- Children's Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Ali Hamidieh
- Pediatric Cell and Gene Therapy Research Center, Gene, Cell & Tissue Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- Children's Medical Center, Pediatric Center of Excellence, Tehran University of Medical Sciences, Tehran, Iran
| | - Hosein Alimadadi
- Division of Gastroenterology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Roya Sherkat
- Immunodeficiency Diseases Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Tooba Momen
- Department of Allergy and Clinical Immunology, Child Growth and Development Research Center, Research Institute for Primordial Prevention of Noncommunicable Disease, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Nasrin Behniafard
- Children Growth Disorder Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
- Department of Allergy and Clinical Immunology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Shabnam Eskandarzadeh
- Allergy and Clinical Immunology Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mahboubeh Mansouri
- Allergy and Immunology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahdiyeh Behnam
- Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
- Dr. Shahrooei Lab, 22 Bahman St., Ashrafi Esfahani Blvd, Tehran, Iran
| | - Mohadese Mahdavi
- Division of Allergy and Clinical Immunology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Heydarazad Zadeh
- Allergy and Immunology Department, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Shokri
- Department of Pediatrics, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Fatemeh Alizadeh
- Division of Allergy and Clinical Immunology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahshid Movahedi
- Division of Allergy and Clinical Immunology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mana Momenilandi
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de La Santé Et de La Recherche Médicale (INSERM) U1163, Necker Hospital for Sick Children, Paris, France
- Imagine Institute, University Paris Cité, Paris, France
| | - Mohammad Keramatipour
- Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Jean-Laurent Casanova
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de La Santé Et de La Recherche Médicale (INSERM) U1163, Necker Hospital for Sick Children, Paris, France
- Imagine Institute, University Paris Cité, Paris, France
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, Rockefeller University, New York, NY, USA
| | - Aurélie Cobat
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de La Santé Et de La Recherche Médicale (INSERM) U1163, Necker Hospital for Sick Children, Paris, France
- Imagine Institute, University Paris Cité, Paris, France
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, Rockefeller University, New York, NY, USA
| | - Laurent Abel
- Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Institut National de La Santé Et de La Recherche Médicale (INSERM) U1163, Necker Hospital for Sick Children, Paris, France
- Imagine Institute, University Paris Cité, Paris, France
- St. Giles Laboratory of Human Genetics of Infectious Diseases, Rockefeller Branch, Rockefeller University, New York, NY, USA
| | - Mohammad Shahrooei
- Dr. Shahrooei Lab, 22 Bahman St., Ashrafi Esfahani Blvd, Tehran, Iran
- Clinical and Diagnostic Immunology, Department of Microbiology, Immunology, and Transplantation, KU Leuven, Louvain, Belgium
| | - Nima Parvaneh
- Division of Allergy and Clinical Immunology, Department of Pediatrics, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
- Children's Medical Centre, No 62 Gharib St, Tehran, 1419733152, Iran.
| |
Collapse
|
4
|
Al-Mousa H, Barbouche MR. Genetics of Inborn Errors of Immunity in highly consanguineous Middle Eastern and North African populations. Semin Immunol 2023; 67:101763. [PMID: 37075586 DOI: 10.1016/j.smim.2023.101763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
Consanguineous marriages in Middle Eastern and North African (MENA) countries are deeply-rooted tradition and highly prevalent resulting into increased prevalence of autosomal recessive diseases including Inborn Errors of Immunity (IEIs). Molecular genetic testing is an important diagnostic tool for IEIs since it provides a definite diagnosis, genotype-phenotype correlation, and guide therapy. In this review, we will discuss the current state and challenges of genomic and variome studies in MENA region populations, as well as the importance of funding advanced genome projects. In addition, we will review the MENA underlying molecular genetic defects of over 2457 patients published with the common IEIs, where autosomal recessive mode of inheritance accounts for 76% of cases with increased prevalence of combined immunodeficiency diseases (50%). The efforts made in the last three decades in terms of international collaboration and of in situ capacity building in MENA region countries led to the discovery of more than 150 novel genes involved in IEIs. Expanding sequencing studies within the MENA will undoubtedly be a unique asset for the IEI genetics which can advance research, and support precise genomic diagnostics and therapeutics.
Collapse
Affiliation(s)
- Hamoud Al-Mousa
- Section of Allergy and Immunology, Department of Pediatrics, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia; College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
| | - Mohamed-Ridha Barbouche
- Department of Microbiology, Immunology and Infectious Diseases, College of Medicine and Medical Sciences, Arabian Gulf University, Manama, Bahrain.
| |
Collapse
|
5
|
Moundir A, Ouair H, Benhsaien I, Jeddane L, Rada N, Amenzoui N, Jouhadi Z, Adnane F, Hafidi NE, Kili A, Bourhanbour Drissi A, Babakhouya A, Benmiloud S, Hbibi M, Benajiba N, Hida M, Bouskraoui M, Mahraoui C, Admou B, Bakkouri JE, Ailal F, Bousfiha AA. Genetic Diagnosis of Inborn Errors of Immunity in an Emerging Country: a Retrospective Study of 216 Moroccan Patients. J Clin Immunol 2023; 43:485-494. [PMID: 36367635 DOI: 10.1007/s10875-022-01398-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/27/2022] [Indexed: 11/13/2022]
Abstract
PURPOSE Genetic testing provides great support to validate the clinical diagnosis of inborn errors of immunity (IEI). However, the high cost and advanced technology make these tests inaccessible to a large proportion of patients in low-income countries. In the present study, we aim to evaluate the Moroccan experience in genetic testing and to report the main molecular features and difficulties encountered in genetic diagnosis. METHODS We performed a multi-center retrospective analysis of all patients with a molecular diagnosis and registered in the national registry between 2010 and 2022. To estimate the impact of the newly identified mutations, we calculated the Combined Annotation Dependent Depletion (CADD) score and the mutation significance cutoff (MSC) for each variant. RESULTS A total of 216 (29%) patients received a genetic diagnosis out of 742 patients with IEI included in the registry. All genetic tests were performed in the context of thesis projects (40%) or international collaborations (60%). A set of 55 genetic defects were identified, including 7 newly reported: SNORA31, TBX21, SPPL2A, TYK2, RLTPR, ZNF341, and STAT2 GOF. Genetic diagnoses were more frequent in the defects of innate and intrinsic immunity with a percentage of 78%, while antibody deficiencies had a lower frequency with a percentage of 17.5%. Only one genetic diagnosis has been made in the complement deficiency group. The most commonly used molecular techniques were Sanger sequencing (37%) followed by targeted gene sequencing (31%). CONCLUSION The thesis projects and collaborations were beneficial as they allowed us to provide a definitive genetic diagnosis to 29% of the patients and to contribute to the identification of new genetic defects and mutations. These results offer insight into the progress made in genetic diagnoses of IEI in Morocco, which would provide a baseline for improving the clinical management of patients with IEI.
Collapse
Affiliation(s)
- Abderrahmane Moundir
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
| | - Hind Ouair
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
| | - Ibtihal Benhsaien
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Leila Jeddane
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
- Laboratoire National de Référence, Mohamed VI University of Health Sciences, Casablanca, Morocco
| | - Nouredine Rada
- Department of Pediatric Infectious Diseases, Mohammed VI University Hospital, Marrakech, Morocco
| | - Naïma Amenzoui
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Zineb Jouhadi
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Fatima Adnane
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Naïma El Hafidi
- Department of Pediatric Infectious Diseases, Ibn Sina University Hospital, Rabat, Morocco
| | - Amina Kili
- Department of Pediatric Hemato-Oncology, Ibn Sina University Hospital, Rabat, Morocco
| | - Asmaa Bourhanbour Drissi
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
- Immunology Laboratory, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Abdeladim Babakhouya
- Department of Pediatric Infectious Diseases, Hassan II University Hospital, Fes, Morocco
| | - Sarra Benmiloud
- Department of Pediatric Infectious Diseases, Hassan II University Hospital, Fes, Morocco
| | - Mohamed Hbibi
- Department of Pediatric Infectious Diseases, Hassan II University Hospital, Fes, Morocco
| | - Noufissa Benajiba
- Department of Pediatrics, Mohammed VI University Hospital, Oujda, Morocco
| | - Mustapha Hida
- Department of Pediatric Infectious Diseases, Hassan II University Hospital, Fes, Morocco
| | - Mohamed Bouskraoui
- Department of Pediatric Infectious Diseases, Mohammed VI University Hospital, Marrakech, Morocco
| | - Chafiq Mahraoui
- Pneumo-Allergology Unit, Rabat Children Hospital, Faculty of Medicine, Mohammed V University, Rabat, Morocco
| | - Brahim Admou
- Immunology Laboratory, Mohammed VI University Hospital, Marrakech, Morocco
| | - Jalila El Bakkouri
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
- Immunology Laboratory, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Fatima Ailal
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco
| | - Ahmed Aziz Bousfiha
- Clinical Immunology, Inflammation and Allergy Laboratory (LICIA), Faculty of Medicine and Pharmacy, Hassan II University, Casablanca, Morocco.
- Department of Pediatric Infectious Diseases and Clinical Immunology, A. Harouchi Children Hospital, Ibn Rochd University Hospital, Casablanca, Morocco.
| |
Collapse
|
6
|
Cai YQ, Zhang H, Wang XZ, Xu C, Chao YQ, Shu Y, Tang LF. A Novel RFXANK Mutation in a Chinese Child With MHC II Deficiency: Case Report and Literature Review. Open Forum Infect Dis 2020; 7:ofaa314. [PMID: 32875002 PMCID: PMC7452370 DOI: 10.1093/ofid/ofaa314] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/17/2020] [Indexed: 12/04/2022] Open
Abstract
Major histocompatibility complex (MHC) II deficiency is a rare primary immunodeficiency disorder that is characterized by the deficiency of MHC class II molecules. The disease is caused by transcription factor mutations including class II transactivator (CIITA), regulatory factor X-5 (RFX5), RFX-associated protein (RFXAP), and RFXAP-containing ankyrin repeat (RFXANK), respectively. Mutations in the RFXANK gene account for >70% of all known patients worldwide. Herein, we reported a 10-month-old boy with MHC II deficiency caused by a novel mutation in the RFXANK gene (c.337 + 1G>C). The boy was admitted to the hospital due to pneumonia and diarrhea at 4 months of age. Genetic analysis revealed a novel homozygous mutation in the RFXANK gene, which derived from the c.337 + 1G>C heterozygous mutations in the RFXANK gene of his parents. The boy died 3 months after diagnosis. More than 200 cases have been reported, and a review of the literature revealed different mutation rates of 4 transcription factors in different countries or regions. This is the first case report of MHC II deficiency from East Asia. We also describe all gene mutations that cause MHC II deficiency and the epidemiology of MHC II deficiency with gene mutations in this paper.
Collapse
Affiliation(s)
- Yu Qing Cai
- Department of Pulmonology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - HangHu Zhang
- Department of Pulmonology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China.,Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, Shaoxing, China
| | - Xiang Zhi Wang
- Department of Pulmonology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - ChengYun Xu
- Department of Pulmonology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yun Qi Chao
- Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - YingYing Shu
- Department of Endocrinology, Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lan Fang Tang
- Department of Pulmonology, Children's Hospital of Zhejiang University School of Medicine & National Clinical Research Center, Hangzhou, China
| |
Collapse
|
7
|
Romdhane L, Mezzi N, Hamdi Y, El-Kamah G, Barakat A, Abdelhak S. Consanguinity and Inbreeding in Health and Disease in North African Populations. Annu Rev Genomics Hum Genet 2019; 20:155-179. [PMID: 31039041 DOI: 10.1146/annurev-genom-083118-014954] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
North Africa is defined as the geographical region separated from the rest of the continent by the Sahara and from Europe by the Mediterranean Sea. The main demographic features of North African populations are their familial structure and high rates of familial and geographic endogamy, which have a proven impact on health, particularly the occurrence of genetic diseases, with a greater effect on the frequency and spectrum of the rarest forms of autosomal recessive genetic diseases. More than 500 different genetic diseases have been reported in this region, most of which are autosomal recessive. During the last few decades, there has been great interest in the molecular investigation of large consanguineous North African families. The development of local capacities has brought a substantial improvement in the molecular characterization of these diseases, but the genetic bases of half of them remain unknown. Diseases of known molecular etiology are characterized by their genetic and mutational heterogeneity, although some founder mutations are encountered relatively frequently. Some founder mutations are specific to a single country or a specific ethnic or geographic group, and others are shared by all North African countries or worldwide. The impact of consanguinity on common multifactorial diseases is less evident.
Collapse
Affiliation(s)
- Lilia Romdhane
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, 1002 Tunis Belvédère, Tunisia; .,Department of Biology, Faculty of Sciences of Bizerte, Université Tunis Carthage, 7021 Jarzouna, Tunisia
| | - Nessrine Mezzi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, 1002 Tunis Belvédère, Tunisia;
| | - Yosr Hamdi
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, 1002 Tunis Belvédère, Tunisia;
| | - Ghada El-Kamah
- Department of Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo 12622, Egypt
| | - Abdelhamid Barakat
- Laboratoire de Génétique Humaine et Biologie Moléculaire, Département de Recherche Scientifique, Institut Pasteur du Maroc, 20100 Casablanca, Morocco
| | - Sonia Abdelhak
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, 1002 Tunis Belvédère, Tunisia;
| |
Collapse
|
8
|
El Hawary RE, Mauracher AA, Meshaal SS, Eldash A, Abd Elaziz DS, Alkady R, Lotfy S, Opitz L, Galal NM, Boutros JA, Pachlopnik Schmid J, Elmarsafy AM. MHC-II Deficiency Among Egyptians: Novel Mutations and Unique Phenotypes. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2019; 7:856-863. [DOI: 10.1016/j.jaip.2018.07.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/14/2018] [Accepted: 07/20/2018] [Indexed: 11/15/2022]
|
9
|
Farrokhi S, Shabani M, Aryan Z, Zoghi S, Krolo A, Boztug K, Rezaei N. MHC class II deficiency: Report of a novel mutation and special review. Allergol Immunopathol (Madr) 2018; 46:263-275. [PMID: 28676232 DOI: 10.1016/j.aller.2017.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 04/08/2017] [Accepted: 04/20/2017] [Indexed: 11/29/2022]
Abstract
The MHC II deficiency is a rare autosomal recessive primary immunodeficiency syndrome with increased susceptibility to respiratory and gastrointestinal infections, failure to thrive and early mortality. This syndrome is caused by mutations in transcription regulators of the MHC II gene and results in development of blind lymphocytes due to the lack of indicatory MHC II molecules. Despite homogeneity of clinical manifestations of patients with MHC II deficiency, the genetic defects underlying this disease are heterogeneous. Herein, we report an Iranian patient with MHC II deficiency harbouring a novel mutation in RFXANK and novel misleading clinical features. He had ataxic gait and dysarthria from 30 months of age. Epidemiology, clinical and immunological features, therapeutic options and prognosis of patients with MHC II are reviewed in this paper.
Collapse
Affiliation(s)
- S Farrokhi
- Department of Immunology, Asthma and Allergy, The Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran
| | - M Shabani
- Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Primary Immunodeficiency Diseases Network (PIDNet), Universal Scientific Education and Research Network (USERN), Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Boston, MA, USA
| | - Z Aryan
- Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Pediatric Respiratory Diseases Education and Research Network (PRDERN), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - S Zoghi
- Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Primary Immunodeficiency Diseases Network (PIDNet), Universal Scientific Education and Research Network (USERN), Tehran, Iran
| | - A Krolo
- CeMM Research Center of Molecular Medicine, Austrian Academy of Sciences, and Division of Neonatal Medicine and Intensive Care, Department of Pediatrics and Adolescent Medicine, Medical University Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria; Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria; St Anna Kinderspital and Children's Cancer Research Institute, Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - K Boztug
- CeMM Research Center of Molecular Medicine, Austrian Academy of Sciences, and Division of Neonatal Medicine and Intensive Care, Department of Pediatrics and Adolescent Medicine, Medical University Vienna, Vienna, Austria; Ludwig Boltzmann Institute for Rare and Undiagnosed Diseases, Vienna, Austria; Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria; St Anna Kinderspital and Children's Cancer Research Institute, Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | - N Rezaei
- Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Network of Immunity in Infection, Malignancy and Autoimmunity (NIIMA), Universal Scientific Education and Research Network (USERN), Boston, MA, USA.
| |
Collapse
|
10
|
Barbouche MR, Mekki N, Ben-Ali M, Ben-Mustapha I. Lessons from Genetic Studies of Primary Immunodeficiencies in a Highly Consanguineous Population. Front Immunol 2017; 8:737. [PMID: 28702026 PMCID: PMC5485821 DOI: 10.3389/fimmu.2017.00737] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/12/2017] [Indexed: 11/29/2022] Open
Abstract
During the last decades, the study of primary immunodeficiencies (PIDs) has contributed tremendously to unravel novel pathways involved in a variety of immune responses. Many of these PIDs have an autosomal recessive (AR) mode of inheritance. Thus, the investigation of the molecular basis of PIDs is particularly relevant in consanguineous populations from Middle East and North Africa (MENA). Although significant efforts have been made in recent years to develop genetic testing across the MENA region, few comprehensive studies reporting molecular basis of PIDs in these settings are available. Herein, we review genetic characteristics of PIDs identified in 168 patients from an inbred Tunisian population. A spectrum of 25 genes involved was analyzed. We show that AR forms compared to X-linked or autosomal dominant forms are clearly the most frequent. Furthermore, the study of informative consanguineous families did allow the identification of a novel hyper-IgE syndrome linked to phosphoglucomutase 3 mutations. We did also report a novel form of autoimmune lymphoproliferative syndrome caused by homozygous FAS mutations with normal or residual protein expression as well as a novel AR transcription factor 3 deficiency. Finally, we identified several founder effects for specific AR mutations. This did facilitate the implementation of preventive approaches through genetic counseling in affected consanguineous families. All together, these findings highlight the specific nature of highly consanguineous populations and confirm the importance of unraveling the molecular basis of genetic diseases in this context. Besides providing a better fundamental knowledge of novel pathways, their study is improving diagnosis strategies and appropriate care.
Collapse
Affiliation(s)
- Mohamed-Ridha Barbouche
- Laboratory of Transmission, Control and Immunobiology of Infection (LR11IPT02), Institut Pasteur de Tunis, Tunis, Tunisia.,Faculty of Medicine, Université de Tunis El Manar, Tunis, Tunisia
| | - Najla Mekki
- Laboratory of Transmission, Control and Immunobiology of Infection (LR11IPT02), Institut Pasteur de Tunis, Tunis, Tunisia.,Faculty of Medicine, Université de Tunis El Manar, Tunis, Tunisia
| | - Meriem Ben-Ali
- Laboratory of Transmission, Control and Immunobiology of Infection (LR11IPT02), Institut Pasteur de Tunis, Tunis, Tunisia
| | - Imen Ben-Mustapha
- Laboratory of Transmission, Control and Immunobiology of Infection (LR11IPT02), Institut Pasteur de Tunis, Tunis, Tunisia.,Faculty of Medicine, Université de Tunis El Manar, Tunis, Tunisia
| |
Collapse
|
11
|
Ben-Mustapha I, Ben-Farhat K, Guirat-Dhouib N, Dhemaied E, Larguèche B, Ben-Ali M, Chemli J, Bouguila J, Ben-Mansour L, Mellouli F, Khemiri M, Béjaoui M, Barbouche MR. Clinical, Immunological and Genetic Findings of a Large Tunisian Series of Major Histocompatibility Complex Class II Deficiency Patients. J Clin Immunol 2013; 33:865-70. [DOI: 10.1007/s10875-013-9863-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 01/02/2013] [Indexed: 11/29/2022]
|
12
|
Romdhane L, Kefi R, Azaiez H, Ben Halim N, Dellagi K, Abdelhak S. Founder mutations in Tunisia: implications for diagnosis in North Africa and Middle East. Orphanet J Rare Dis 2012; 7:52. [PMID: 22908982 PMCID: PMC3495028 DOI: 10.1186/1750-1172-7-52] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 08/02/2012] [Indexed: 01/17/2023] Open
Abstract
Background Tunisia is a North African country of 10 million inhabitants. The native background population is Berber. However, throughout its history, Tunisia has been the site of invasions and migratory waves of allogenic populations and ethnic groups such as Phoenicians, Romans, Vandals, Arabs, Ottomans and French. Like neighbouring and Middle Eastern countries, the Tunisian population shows a relatively high rate of consanguinity and endogamy that favor expression of recessive genetic disorders at relatively high rates. Many factors could contribute to the recurrence of monogenic morbid trait expression. Among them, founder mutations that arise in one ancestral individual and diffuse through generations in isolated communities. Method We report here on founder mutations in the Tunisian population by a systematic review of all available data from PubMed, other sources of the scientific literature as well as unpublished data from our research laboratory. Results We identified two different classes of founder mutations. The first includes founder mutations so far reported only among Tunisians that are responsible for 30 genetic diseases. The second group represents founder haplotypes described in 51 inherited conditions that occur among Tunisians and are also shared with other North African and Middle Eastern countries. Several heavily disabilitating diseases are caused by recessive founder mutations. They include, among others, neuromuscular diseases such as congenital muscular dystrophy and spastic paraglegia and also severe genodermatoses such as dystrophic epidermolysis bullosa and xeroderma pigmentosa. Conclusion This report provides informations on founder mutations for 73 genetic diseases either specific to Tunisians or shared by other populations. Taking into account the relatively high number and frequency of genetic diseases in the region and the limited resources, screening for these founder mutations should provide a rapid and cost effective tool for molecular diagnosis. Indeed, our report should help designing appropriate measures for carrier screening, better evaluation of diseases burden and setting up of preventive measures at the regional level.
Collapse
Affiliation(s)
- Lilia Romdhane
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, BP 74, 13 Place Pasteur, Tunis 1002, Tunisia
| | | | | | | | | | | |
Collapse
|
13
|
Djidjik R, Messaoudani N, Tahiat A, Meddour Y, Chaib S, Atek A, Khiari ME, Benhalla NK, Smati L, Bensenouci A, Baghriche M, Ghaffor M. Clinical, immunological and genetic features in eleven Algerian patients with major histocompatibility complex class II expression deficiency. ALLERGY, ASTHMA, AND CLINICAL IMMUNOLOGY : OFFICIAL JOURNAL OF THE CANADIAN SOCIETY OF ALLERGY AND CLINICAL IMMUNOLOGY 2012; 8:14. [PMID: 22863278 PMCID: PMC3511802 DOI: 10.1186/1710-1492-8-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 07/24/2012] [Indexed: 11/10/2022]
Abstract
Presenting processed antigens to CD4+ lymphocytes during the immune response involves major histocompatibility complex class II molecules. MHC class II genes transcription is regulated by four transcription factors: CIITA, RFXANK, RFX5 and RFXAP. Defects in these factors result in major histocompatibility complex class II expression deficiency, a primary combined immunodeficiency frequent in North Africa. Autosomal recessive mutations in the RFXANK gene have been reported as being the principal defect found in North African patients with this disorder. In this paper, we describe clinical, immunological and genetic features of 11 unrelated Algerian patients whose monocytes display a total absence of MHC class II molecules. They shared mainly the same clinical picture which included protracted diarrhoea and respiratory tract recurrent infections. Genetic analysis revealed that 9 of the 11 patients had the same RFXANK founder mutation, a 26 bp deletion (named I5E6-25_I5E6+1, also known as 752delG26). Immunological and genetic findings in our series may facilitate genetic counselling implementation for Algerian consanguineous families. Further studies need to be conducted to determine 752delG26 heterozygous mutation frequency in Algerian population.
Collapse
Affiliation(s)
- Réda Djidjik
- Immunology Department, Beni Messous Teaching Hospital, Algiers, Algeria
| | | | - Azzedine Tahiat
- Immunology Department, Beni Messous Teaching Hospital, Algiers, Algeria
| | - Yanis Meddour
- Immunology Department, Central Hospital of the Army, Algiers, Algeria
| | - Samia Chaib
- Immunology Department, Central Hospital of the Army, Algiers, Algeria
| | - Aziz Atek
- Pediatrics Department A, Beni Messous Teaching Hospital, Algiers, Algeria
| | | | | | - Leila Smati
- Pediatrics Department, Bologhine Hospital, Algiers, Algeria
| | | | | | - Mohammed Ghaffor
- Immunology Department, Beni Messous Teaching Hospital, Algiers, Algeria
| |
Collapse
|
14
|
Guirat-Dhouib N, Baccar Y, Mustapha IB, Ouederni M, Chouaibi S, El Fekih N, Barbouche MR, Fezaa B, Kouki R, Hmida S, Mellouli F, Bejaoui M. Oral HPV infection and MHC class II deficiency (A study of two cases with atypical outcome). Clin Mol Allergy 2012; 10:6. [PMID: 22524894 PMCID: PMC3349517 DOI: 10.1186/1476-7961-10-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 04/23/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Major histocompatibility complex class II deficiency, also referred to as bare lymphocyte syndrome is a rare primary Immunodeficiency disorder characterized by a profondly deficient human leukocyte antigen class II expression and a lack of cellular and humoral immune responses to foreign antigens. Clinical manifestations include extreme susceptibility to viral, bacterial, and fungal infections. The infections begin in the first year of life and involve usually the respiratory system and the gastrointestinal tract. Severe malabsorption with failure to thrive ensues, often leading to death in early childhood. Bone marrow transplantation is the curative treatment. CASE REPORTS Here we report two cases with a late outcome MHC class II deficiency. They had a long term history of recurrent bronchopulmonary and gastrointestinal infections. Bone marrow transplantation could not be performed because no compatible donor had been identified. At the age of 12 years, they developed oral papillomatous lesions related to HPV (human papillomavirus). The diagnosis of HPV infection was done by histological examination. HPV typing performed on the tissue obtained at biopsy showed HPV type 6. The lesions were partially removed after two months of laser treatment. CONCLUSIONS Viral infections are common in patients with MHC class II and remain the main cause of death. Besides warts caused by HPV infection do not exhibit a propensity for malignant transformation; they can cause great psychosocial morbidity.
Collapse
Affiliation(s)
- Naouel Guirat-Dhouib
- Centre National de Greffe de Moelle Osseuse, Service d'immuno-Hématologie Pédiatrique, Faculté de Médecine de Tunis 2, Rue Djebel Lakhdhar, 1006 Tunis, Tunisia.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
15
|
Barbouche MR, Galal N, Ben-Mustapha I, Jeddane L, Mellouli F, Ailal F, Bejaoui M, Boutros J, Marsafy A, Bousfiha AA. Primary immunodeficiencies in highly consanguineous North African populations. Ann N Y Acad Sci 2012; 1238:42-52. [PMID: 22129052 DOI: 10.1111/j.1749-6632.2011.06260.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The study of inbred populations has contributed remarkably to the description of new autosomal recessive primary immunodeficiencies (PIDs). Here, we examine the pattern of PIDs in North African populations and assess the impact of highly prevalent consanguinity. This review reports on the current status of pediatricians' awareness of PIDs in Egypt, Morocco, and Tunisia, where awareness of PIDs is relatively recent. The phenotypic distribution of PIDs is reported and compared among the three countries and with other populations. Data analysis reveals a prevalence of autosomal recessive forms and a peculiar distribution of major PID categories, particularly more combined immunodeficiencies than antibody disorders. In these endogamous communities, molecular diagnosis is critical to developing a genetic-based preventive approach. The organization of diagnosis and care services in these resource-limited settings faces many obstacles. Autosomal recessive PIDs are overrepresented; thus, it is critical to continue investigation of these diseases in order to better understand the underlying mechanisms and to improve patient care.
Collapse
|
16
|
Major histocompatibility complex class II expression deficiency caused by a RFXANK founder mutation: a survey of 35 patients. Blood 2011; 118:5108-18. [DOI: 10.1182/blood-2011-05-352716] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AbstractInherited deficiency of major histocompatibility complex (MHC) class II molecules impairs antigen presentation to CD4+ T cells and results in combined immunodeficiency (CID). Autosomal-recessive mutations in the RFXANK gene account for two-thirds of all cases of MHC class II deficiency. We describe here the genetic, clinical, and immunologic features of 35 patients from 30 unrelated kindreds from North Africa sharing the same RFXANK founder mutation, a 26-bp deletion called I5E6-25_I5E6 + 1), and date the founder event responsible for this mutation in this population to approximately 2250 years ago (95% confidence interval [CI]: 1750-3025 years). Ten of the 23 patients who underwent hematopoietic stem cell transplantation (HSCT) were cured, with the recovery of almost normal immune functions. Five of the patients from this cohort who did not undergo HSCT had a poor prognosis and eventually died (at ages of 1-17 years). However, 7 patients who did not undergo HSCT (at ages of 6-32 years) are still alive on Ig treatment and antibiotic prophylaxis. RFXANK deficiency is a severe, often fatal CID for which HSCT is the only curative treatment. However, some patients may survive for relatively long periods if multiple prophylactic measures are implemented.
Collapse
|
17
|
Shrestha D, Szöllosi J, Jenei A. Bare lymphocyte syndrome: an opportunity to discover our immune system. Immunol Lett 2011; 141:147-57. [PMID: 22027563 DOI: 10.1016/j.imlet.2011.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/30/2011] [Accepted: 10/11/2011] [Indexed: 11/27/2022]
Abstract
Bare lymphocyte syndrome (BLS) is a rare immunodeficiency disorder manifested by the partial or complete disappearance of major histocompatibility complex (MHC) proteins from the surface of the cells. Based on this specific feature, it is categorized into three different types depending on which type of MHC protein is affected. These proteins are mainly involved in generating the effective immune responses by differentiating 'self' from 'non-self' antigens through a process referred to as antigen presentation. Investigations on BLS have immensely contributed to our understanding of the transcriptional regulation of these molecules and have led to the discovery of several important proteins of the antigen presentation pathway. Reviews on this subject consistently project type II BLS, MHC II deficiency as BLS syndrome, although literatures' document cases of other types of BLS too. Therefore, in this article, we have assembled information on the BLS syndrome to produce a systematic narration while emphasizing the importance of BLS system in studying various aspects of immune biology.
Collapse
Affiliation(s)
- Dilip Shrestha
- Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, Nagyerdei krt 98, Debrecen 4032, Hungary
| | | | | |
Collapse
|
18
|
|
19
|
Picard C, Fischer A. Hematopoietic stem cell transplantation and other management strategies for MHC class II deficiency. Immunol Allergy Clin North Am 2010; 30:173-8. [PMID: 20493394 DOI: 10.1016/j.iac.2010.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Major histocompatibility complex (MHC) class II expression deficiency is a rare condition with autosomal recessive transmission. The defect of MHC class II leads to combined immunodeficiency with defective CD4(+) T-cell development and a lack of T helper cell-dependent antibody production by B cells. The clinical course of disease is characterized by the recurrence of bacterial, viral, fungal, and protozoan infections. The optimal symptomatic care that is available involves the prophylactic use of antibiotics and the administration of immunoglobulin with adequate nutritional support. Hematopoietic stem cell transplantation is the only known treatment available to cure MHC class II expression deficiency.
Collapse
Affiliation(s)
- Capucine Picard
- Study Center of Primary Immunodeficiencies, Necker Hospital, Assistance Publique-Hôpitaux de Paris, 149 rue de Sèvres, Paris 75015, France.
| | | |
Collapse
|
20
|
The 752delG26 mutation in the RFXANK gene associated with major histocompatibility complex class II deficiency: evidence for a founder effect in the Moroccan population. Eur J Pediatr 2010; 169:1069-74. [PMID: 20414676 DOI: 10.1007/s00431-010-1179-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 02/23/2010] [Indexed: 10/19/2022]
Abstract
Major histocompatibility complex class II plays a key role in the immune response, by presenting processed antigens to CD4+ lymphocytes. Major histocompatibility complex class II expression is controlled at the transcriptional level by at least four trans-acting genes: CIITA, RFXANK, RFX5 and RFXAP. Defects in these regulatory genes cause MHC class II immunodeficiency, which is frequent in North Africa. The aim of this study was to describe the immunological and molecular characteristics of ten unrelated Moroccan patients with MHC class II deficiency. Immunological examinations revealed a lack of expression of MHC class II molecules at the surface of peripheral blood mononuclear cells, low CD4+ T lymphocyte counts and variable serum immunoglobulin (IgG, IgM and IgA) levels. In addition, no MHC class II (HLA DR) expression was observed on lymphoblasts. The molecular analysis identified the same homozygous 752delG26 mutation in the RFXANK genes of all patients. This finding confirms the association between the high frequency of the combined immunodeficiency and the defect in MHC class II expression and provides strong evidence for a founder effect of the 752delG26 mutation in the North African population. These findings should facilitate the establishment of molecular diagnosis and improve genetic counselling for affected Moroccan families.
Collapse
|
21
|
Renella R, Picard C, Neven B, Ouachée-Chardin M, Casanova JL, Le Deist F, Cavazzana-Calvo M, Blanche S, Fischer A. Human leucocyte antigen-identical haematopoietic stem cell transplantation in major histocompatiblity complex class II immunodeficiency: reduced survival correlates with an increased incidence of acute graft-versus-host disease and pre-existing viral infections. Br J Haematol 2006; 134:510-6. [PMID: 16848795 DOI: 10.1111/j.1365-2141.2006.06213.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Major histocompatibility complex class II deficiency, a rare autosomal recessive primary immunodeficiency, is caused by the defective expression of human leucocyte antigen (HLA) class II molecules due to mutated trans-acting elements of any one of four regulatory genes (CIITA, RFXANK, RFX5, RFXAP). The impaired CD4 T-cell differentiation and antigen presentation in the periphery results in a severe defect of cellular and humoral response consistent with severe recurrent infections, leading to a poor prognosis. Currently, allogeneic haematopoietic stem cell transplantation (HSCT) is the only curative approach, but the overall cure rate is lower than in other immunodeficiencies. We report a single centre experience of 17 HSCTs with 15 HLA-identical donors between 1981 and 2004. Eight patients survived, while the occurrence of acute graft-versus-host disease (GVHD) was 50%. This study aimed to identify potential risk factors for GVHD and outcome within pre-HSCT complications related to the immunodeficiency. Five of seven patients with pre-existing viral infections developed acute GVHD > or = grade II, of whom four died. Two of seven patients without detectable pre-existing viral infection developed GVHD > or = grade II, and one died. The difference was significant (P < 0.05). A plausible link with other factors potentially associated with the development of GVHD could not be found. We suggest that the reduced survival after HLA-identical HSCT may be caused by the high incidence of pre-existing viral infections and associated with the onset of severe acute GVHD.
Collapse
Affiliation(s)
- Raffaele Renella
- Unité d'Immunologie et Hématologie Pédiatrique, Faculté de Médecine Université Réné Descartes, Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
Knowledge of the genetic mutations of primary immune deficiency syndromes has grown significantly over the last 30 years. In this article the authors present an overview of the clinical aspects, laboratory evaluation, and genetic defects of primary immunodeficiencies, with an emphasis on the pathophysiology of the known molecular defects. This article is designed to give the primary pediatrician a general knowledge of this rapidly expanding field.
Collapse
Affiliation(s)
- James W Verbsky
- Division of Rheumatology, Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | | |
Collapse
|
23
|
Krawczyk M, Masternak K, Zufferey M, Barras E, Reith W. New functions of the major histocompatibility complex class II-specific transcription factor RFXANK revealed by a high-resolution mutagenesis study. Mol Cell Biol 2005; 25:8607-18. [PMID: 16166641 PMCID: PMC1265745 DOI: 10.1128/mcb.25.19.8607-8618.2005] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transcription factors RFX and CIITA are major players in regulation of the expression of all classical and nonclassical major histocompatibility complex class II (MHC-II) genes. RFX nucleates the formation of a multiprotein complex, called the MHC-II enhanceosome, on MHC-II promoters. Assembly of this enhanceosome is an obligatory step for recruitment of the coactivator CIITA and thus for activation of MHC-II gene transcription. We have analyzed the function of the ankyrin repeat-containing protein RFXANK, which forms the heterotrimeric RFX complex together with RFX5 and RFXAP. We discovered that ANKRA2, the closest paralogue of RFXANK, can substitute for RFXANK in the activation of MHC-II genes and that this ability is mediated by its ankyrin repeat domain (ARD). This finding provided the basis for a high-resolution structure-function analysis of the ARD of RFXANK, which allowed us to map the RFX5 interaction domain and residues critical for assembly of the RFX complex. We also found that mutations in the fourth ankyrin repeat of RFXANK abolish assembly of the enhanceosome on MHC-II promoters in vivo but not in vitro, suggesting a new role of RFXANK in facilitating promoter occupation in the context of chromatin.
Collapse
Affiliation(s)
- Michal Krawczyk
- Department of Pathology and Immunology, University of Geneva Medical School, CMU, 1 rue Michel-Servet, CH-1211 Geneva, Switzerland
| | | | | | | | | |
Collapse
|
24
|
Prod'homme T, Dekel B, Barbieri G, Lisowska-Grospierre B, Katz R, Charron D, Alcaide-Loridan C, Pollack S. Splicing defect in RFXANK results in a moderate combined immunodeficiency and long-duration clinical course. Immunogenetics 2003; 55:530-9. [PMID: 14574520 DOI: 10.1007/s00251-003-0609-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2003] [Revised: 08/25/2003] [Indexed: 10/26/2022]
Abstract
MHC class II deficiency provokes a severe immunodeficiency characterized by a lack of antigen-specific immune response. In the absence of bone marrow transplantation (the only curative treatment), patients affected by this genetic recessive disease die in early childhood. However, others and we have recently described cases of mild or asymptomatic immunodeficiencies with defects in either CIITA (class II transactivator) or RFX5, both proteins required for the transcription of HLA-D genes. We describe in this report the first case of moderate immunodeficiency resulting from a defect in RFXANK, another transcription factor essential for HLA-D expression. The patient did not display any detectable expression of MHC class II molecules on B lymphocytes, monocytes or activated T lymphocytes. Accordingly HLA-D transcription was altered in the corresponding B-lymphoblastoid cell line. The defect in RFXANK was observed both at the transcript and protein level. Indeed a homozygous IVS4+5G>A mutation was evidenced in RFXANK, and shown to hamper the splicing of intron 4. However, we had shown previously that a defect in intron 4 can lead to the skipping of exon 4, and that the resulting truncated protein retains the capacity to activate HLA-DR expression. Therefore, like the two cases of moderate immunodeficiencies described previously, we demonstrate that the RFXANK defect presented here is coherent with a residual activity of the mutant protein. We thus propose that the common feature displayed by mildly immunodeficient patients is the leakiness of the mutations, which might allow a local or temporal expression of MHC class II molecules.
Collapse
Affiliation(s)
- Thomas Prod'homme
- INSERM U396, Centre de Recherches Biomedicales des Cordeliers, 15 rue de l'Ecole de Medecine, 75006 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Wiszniewski W, Fondaneche MC, Louise-Plence P, Prochnicka-Chalufour A, Selz F, Picard C, Le Deist F, Eliaou JF, Fischer A, Lisowska-Grospierre B. Novel mutations in the RFXANK gene: RFX complex containing in-vitro-generated RFXANK mutant binds the promoter without transactivating MHC II. Immunogenetics 2003; 54:747-55. [PMID: 12618906 DOI: 10.1007/s00251-002-0521-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2002] [Revised: 10/24/2002] [Indexed: 10/25/2022]
Abstract
MHC class II deficiency is a combined immunodeficiency caused by defects in the four regulatory factors, CIITA, RFXANK, RFX5 and RFXAP, that control MHC II expression at the transcriptional level. The RFXANK gene encodes one subunit of the heterotrimeric RFX complex that is involved in the assembly of several transcription factors on MHC II promoters. Seven different RFXANK mutations have previously been reported in 26 unrelated patients. The most frequent mutation, a 26-bp deletion (752delG-25), has been identified in 21 patients. The other mutations are all nonsense or splice-site mutations, leading to proteins lacking all or part of the RFXANK ankyrin repeat region. We report two novel missense mutations, D121V and R212X, resulting in loss of function of the gene. We investigated the in vivo effects of these mutations and of three other point mutations on the expression of the RFXANK RNA and protein. The number of RFXANK transcripts was severely reduced in all patients except one. The RFXANK protein was barely detected in two cases. In addition, guided by a structural model of RFXANK, we investigated experimental mutants of the C-terminal tyrosine 224. Substitution Y224A, but not Y224F, led to the loss of function of RFXANK. Two null mutants, D121V and Y224A, were tested in protein interaction and DNA binding assays. The D121V mutant was unable to form the RFX complex, indicating that D121 is required for RFXAP binding. The Y224A mutant formed an RFX complex that bound normally to the MHC II promoter, but did not lead to MHC class II expression, whereas Y224F RFXANK retained the wild-type function. This indicates that an aromatic ring, but not the phenyl chain of tyrosine, is necessary at position 224 for normal RFXANK function. Studies on the Y224A mutant suggest that, in addition to the RFX subunits and CIITA, another protein is essential for MHC class II expression. This protein appears to interact with the fourth ankyrin repeat of RFXANK.
Collapse
|
26
|
Villard J, Masternak K, Lisowska-Grospierre B, Fischer A, Reith W. MHC class II deficiency: a disease of gene regulation. Medicine (Baltimore) 2001; 80:405-18. [PMID: 11704716 DOI: 10.1097/00005792-200111000-00006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- J Villard
- Immunology and Transplant Unit, Division of Immunology and Allergology, Geneva University Hospital, Geneva, Switzerland.
| | | | | | | | | |
Collapse
|
27
|
Abstract
The bare lymphocyte syndrome (BLS) is a hereditary immunodeficiency resulting from the absence of major histocompatibility complex class II (MHCII) expression. Considering the central role of MHCII molecules in the development and activation of CD4(+) T cells, it is not surprising that the immune system of the patients is severely impaired. BLS is the prototype of a "disease of gene regulation." The affected genes encode RFXANK, RFX5, RFXAP, and CIITA, four regulatory factors that are highly specific and essential for MHCII genes. The first three are subunits of RFX, a trimeric complex that binds to all MHCII promoters. CIITA is a non-DNA-binding coactivator that functions as the master control factor for MHCII expression. The study of RFX and CIITA has made major contributions to our comprehension of the molecular mechanisms controlling MHCII genes and has made this system into a textbook model for the regulation of gene expression.
Collapse
Affiliation(s)
- W Reith
- Jeantet Laboratory of Molecular Genetics, Department of Genetics and Microbiology, University of Geneva Medical School, 1 rue Michel-Servet, Geneva 4, 1211 Switzerland.
| | | |
Collapse
|
28
|
Lennon-Duménil AM, Barbouche MR, Vedrenne J, Prod'Homme T, Béjaoui M, Ghariani S, Charron D, Fellous M, Dellagi K, Alcaïde-Loridan C. Uncoordinated HLA-D gene expression in a RFXANK-defective patient with MHC class II deficiency. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 166:5681-7. [PMID: 11313409 DOI: 10.4049/jimmunol.166.9.5681] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe the analysis of a patient, JER, presenting classical immunological features of MHC class II deficiency. Unexpectedly, some HLA transcripts (HLA-DRA, HLA-DQA, and HLA-DMA) were found to be expressed in the JER cell line at nearly wild-type levels, while HLA-DPA and the HLA-D beta-chain transcripts were not detected. Gene reporter experiments confirmed the differential transcriptional activities driven by the HLA-D promoters in the JER cells. A defect in RFXANK was first suggested by genetic complementation analyses, then assessed with the demonstration of a homozygous mutation affecting a splice donor site downstream exon 4 of RFXANK. Because the severe deletion of the resulting protein cannot account for the expression of certain HLA-D genes, minor alternative transcripts of the RFXANK gene were analyzed. We thereby showed the existence of a transcript lacking exon 4, encoding a 28-aa-deleted protein that retains a transcriptional activity. Altogether, we characterize a new type of mutation in the RFXANK gene in a MHC class II-defective patient leading to an uncoordinated expression of the HLA-D genes, and propose that this phenotype is ensured by severely limited amounts of an active, although truncated RFXANK protein.
Collapse
Affiliation(s)
- A M Lennon-Duménil
- Institut National de la Santé et de la Recherche Médicale Unité 276, Institut Pasteur, Paris, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|