Intact T cell responses in ataxia telangiectasia

Ataxia tetangiectasia (A-T) is an autosomat recessive multisystem disorder associated with a variable immune deficiency. The mechanism for this remains unclear. Qualitative and quantitative defects of cellular immunity have been previously reported. However, despite laboratory evidence of significant immune abnormalities, opportunistic infections are uncommon. To address this discrepancy, we analyzed cytokine production by quantitative real-time PCR and Tcell function at the single cell level by flow cytometry in four A-T patients. CD4 and CD8 Tcell subsets from these patients displayed intact signaling in response to anti-CD3 stimulation, similar to controls. Stimulated Tcells from A-T patients also produced normal to increased levels of Th1 (IL-2, IFN-gamma) and Th2 (IL-10, IL-4) cytokines, relative to control values. Our results suggest that Tcells from A-T patients may be more functionally intact than previously observed. This helps to explain the paucity of opportunistic infections encountered, unlike that encountered in other primary immunodeficiencies. (c) 2006 Elsevier Inc. All rights reserved.