Immunological abnormalities associated with hereditary haemorrhagic telangiectasia

Authors

  • A. Guilhem,

    Corresponding author
    1. CHU de Montpellier, Service de Médecine Interne A, Hôpital Saint Eloi, Montpellier, France
    • Correspondence: Alexandre Guilhem, MD, Service de Médecine Interne A, Hôpital Saint Eloi 80, avenue Augustin Fliche 34295, Montpellier cedex 5, France.

      (fax: +33 4 67 33 72 91; e-mail: alexandre.guilhem@gmail.com).

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  • C. Malcus,

    1. Hospices Civils de Lyon, Laboratoire d'immunologie, Hôpital E Herriot, Lyon, France
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  • B. Clarivet,

    1. CHU de Montpellier, Unité de Recherche Clinique et Epidémiologique, Hôpital La Colombiere, Montpellier, France
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  • H. Plauchu,

    1. Hospices Civils de Lyon, Centre National de Référence pour la Maladie de Rendu-Osler, Service de Génétique, Hôpital Louis Pradel, Bron, France
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  • S. Dupuis-Girod

    1. Hospices Civils de Lyon, Centre National de Référence pour la Maladie de Rendu-Osler, Service de Génétique, Hôpital Louis Pradel, Bron, France
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Abstract

Objective

Hereditary haemorrhagic telangiectasia (HHT) is a genetic disorder related to mutations in one of the coreceptors to the transforming growth factor-β superfamily (ALK1 or endoglin). Besides the obvious vascular symptoms (epistaxis and arteriovenous malformations), patients have an unexplained high risk of severe bacterial infections. The aim of the study was to assess the main immunological functions of patients with HHT using the standard biological tests for primary immunodeficiencies.

Design, setting and subjects

A prospective single-centre study of 42 consecutive adult patients with an established diagnosis of HHT was conducted at the National French HHT Reference Center (Lyon). Lymphocyte subpopulations and proliferation capacity, immunoglobulin levels and neutrophil and monocyte phagocytosis, oxidative burst and chemotaxis were assessed.

Results

Innate immunity was not altered in patients with HHT. With regard to adaptive immunity, significant changes were seen in immunological parameters: primarily, a lymphopenia in patients with HHT compared with healthy control subjects affecting mean CD4 (642 cells μL−1 vs. 832 cells μL−1, < 0.001), CD8 (295 cells μL−1 vs. 501 cells μL−1, < 0.0001) and natural killer (NK) cells (169 cells μL−1 vs. 221 cells μL−1, < 0.01), associated with increased levels of immunoglobulins G and A. This lymphopenia mainly concerned naïve T cells. Proliferation capacities of lymphocytes were normal. Lymphopenic patients had a higher frequency of iron supplementation but no increase in infection rate. Lower levels of immunoglobulin M and a higher rate of pulmonary arteriovenous malformations were found amongst patients with a history of severe infection.

Conclusions

Patients with HHT exhibit immunological abnormalities including T CD4, T CD8 and NK cell lymphopenia and increased levels of immunoglobulins G and A. The observed low level of immunoglobulin M requires further investigation to determine whether it is a specific risk factor for infection in HHT.

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