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Günaydin NC, Chou J, Karaca NE, Aksu G, Massaad MJ, Azarsiz E, Ertan Y, Geha RS, Kütükçüler N. A novel disease-causing CD40L mutation reduces expression of CD40 ligand, but preserves CD40 binding capacity. Clin Immunol 2014; 153:288-91. [PMID: 24845792 DOI: 10.1016/j.clim.2014.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 05/03/2014] [Indexed: 10/25/2022]
Abstract
Mutations in CD40 ligand (CD40L) that permit residual CD40L expression typically impair binding of CD40. We report a male patient who presented with recurrent bacterial respiratory tract infections, normal IgM, decreased IgG, absent IgA levels, and CD40L expression at ~50% of the level observed in the normal control. He subsequently developed autoimmunity, inflammatory bowel disease, severe opportunistic infections suggestive of a combined immunodeficiency, and a cervical spine schwannoma. Whole exome sequencing of the patient's genomic DNA revealed a novel missense mutation (p.H47Y) in CD40L. Although this mutation was predicted to be benign in silico, flow cytometry at 13 years of age demonstrated markedly decreased CD40L expression (~32% of normal control) that retained the capacity to bind soluble CD40-Ig, suggesting that the mutation impairs CD40L surface expression without affecting its affinity for CD40. This case highlights the variability in the clinical evolution and phenotype of CD40L deficiency.
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Affiliation(s)
- Nurşen C Günaydin
- Department of Pediatric Immunology, Ege University, Faculty of Medicine, Erzene Mh., 35040 Izmir, Turkey
| | - Janet Chou
- Division of Immunology, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, USA
| | - Neslihan E Karaca
- Department of Pediatric Immunology, Ege University, Faculty of Medicine, Erzene Mh., 35040 Izmir, Turkey
| | - Güzide Aksu
- Department of Pediatric Immunology, Ege University, Faculty of Medicine, Erzene Mh., 35040 Izmir, Turkey
| | - Michel J Massaad
- Division of Immunology, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, USA
| | - Elif Azarsiz
- Department of Pediatric Immunology, Ege University, Faculty of Medicine, Erzene Mh., 35040 Izmir, Turkey
| | - Yesim Ertan
- Ege University, Faculty of Medicine, Department of Pathology, Izmir, Turkey
| | - Raif S Geha
- Division of Immunology, Boston Children's Hospital and Department of Pediatrics, Harvard Medical School, Boston, USA.
| | - Necil Kütükçüler
- Department of Pediatric Immunology, Ege University, Faculty of Medicine, Erzene Mh., 35040 Izmir, Turkey.
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