Expression of NKG2D and CD107 in CD8+ effector memory lymphocytes in Churg-Strauss syndrome
M. Boita, G. Rolla, R. Mallone, E. Martinuzzi, E. Heffler, P. Circosta, A.R. Elia, A. Cignetti, S. Caillat-Zucman, M. De Menthon, G. Guida
2012 Vol.30, N°1 ,Suppl.70
PI 0057, PF 0061
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PMID: 22640649 [PubMed]
Accepted : 28/02/2012
In Press: 14/05/2012
Churg-Strauss syndrome (CSS) is a necrotising vasculitis of small vessels in which oligoclonally expanded TCR Vβ CD8+ effector memory T cells populations (TEM) may be involved in vasculitic damage. The aim of this study was to assess the functional role of CD8+ T cells in CSS patients by flow cytometry analysis of membrane expression of cytotoxic markers NKG2D and CD107a.
Immunostaining of peripheral T cells and effector memory lymphocytes (TEM) from CSS patients and controls was performed by gating CD28 and CD45RA in the CD8+NKG2D+ and CD4+NKG2D+ populations. CD107a expression was evaluated in both whole CD8+ and CD4+ and the TEM cells by gating CD62 and CD45RA following polyclonal stimulation.
NKG2D expression was shifted toward the CD8+CD28- fraction of T cells in CSS patients compared to healthy controls (56.1±25.8% versus 17.2±7.3%, respectively, p=0.002). CD8+Vβ+ expanded T cells showed a significantly increased expression of NKG2D compared to the whole CD8+ T cell population (91.4±1.9% versus 79.7±3.8%, respectively, p=0.015). Moreover the CD8+ population from CSS upregulates CD107a on its surface upon polyclonal stimulation in a significantly higher proportion than healthy subjects (26.2±10.8% versus 8.2±2.9%, p=0.0031) and the majority CD8+ CD107+ cells from CSS patients showed a TEM phenotype compared to controls (64.8±4.9% vs. 19.8±2.9, respectively, p<0.001).
In CSS, CD8+ TEM lymphocytes show markers of cytotoxic activity, which suggests a role for these cells in vasculitic damage.