CD8+ T-Cell Responses Identify β-Cell Autoimmunity in Human Type 1 Diabetes

  1. Roberto Mallone12,
  2. Emanuela Martinuzzi12,
  3. Philippe Blancou34,
  4. Giulia Novelli5,
  5. Georgia Afonso12,
  6. Manuel Dolz,
  7. Graziella Bruno5,
  8. Lucy Chaillous,
  9. Lucienne Chatenoud12,
  10. Jean-Marie Bach34 and
  11. Peter van Endert12
  1. 1INSERM, U580, Paris, France
  2. 2Université Paris Descartes, Faculté de Médecine René Descartes, Paris, France
  3. 3INRA, Immuno-Endocrinology Unit, ENVN, Nantes, France; the Université de Nantes, Nantes, France
  4. 4Università di Torino, Department of Internal Medicine, Torino, Italy
  5. 5CHU de Nantes, Hôpital Hôtel-Dieu, Clinique d’Endocrinologie, Nantes, France
  1. Address correspondence and reprint requests to Roberto Mallone or Peter van Endert, INSERM U580, Hôpital Necker, 161 rue de Sèvres, 75743 Paris Cedex 15, France. E-mail: mallone{at}necker.fr or vanendert{at}necker.fr

Abstract

Despite the understanding that type 1 diabetes pathogenesis is mediated by T-cells, detection of these rare lymphocytes remains largely elusive. Suitable T-cell assays are highly needed, since they could offer preclinical diagnoses and immune surrogate end points for clinical trials. Although CD4+ T-cell assays have met with limited success, CD8+ T-cells are increasingly recognized as key actors in the diabetes of the NOD mouse. CD8+ T-cells are likely to play a role also in humans and may provide new markers of β-cell autoimmunity. Taking advantage of a panel of HLA-A2–restricted β-cell epitopes derived from preproinsulin, GAD, and islet glucose-6-phosphatase catalytic subunit-related protein (IGRP), we have implemented an islet-specific CD8+ T-cell interferon-γ enzyme-linked immunospot (ISL8Spot) assay. The ISL8Spot assay is capable of detecting and quantifying β-cell–reactive CD8+ T-cells directly ex vivo, without any preliminary expansion, using either fresh or frozen samples. Positive ISL8Spot responses separate new-onset diabetic and healthy samples with high accuracy (86% sensitivity, 91% specificity), using as few as five immunodominant epitopes. Moreover, sensitivity reaches 100% when the ISL8Spot assay is complemented by antibody determinations. Combination of CD8+ T-cell measurements with immune intervention strategies may open new avenues toward type 1 diabetes prediction and prevention.

Footnotes

  • The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

    • Accepted November 27, 2006.
    • Received October 6, 2006.
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