Vβ profile in toxic shock syndrome: A possible diagnostic test
Introduction
Toxic Shock Syndrome (TSS), which is caused by superantigens (SAg) from Staphylococcus aureus and Streptococcus pyogenes, was first described in 1978 [1]. SAg bypass the normal antigen presentation via MHC class II molecules and directly bind the lateral aspect of the T cell receptor (TCR) at the TCR Vβ region. Due to this method of binding, the signature feature of SAg activity is the expansion of T lymphocyte populations bearing the particular Vβ chain(s) that the SAg binds to [2].
The diagnosis of TSS is difficult in its early phases and there is currently no diagnostic test. An accurate diagnostic test may facilitate better treatments for toxic shock such as intravenous immunoglobulin [3]. We sought to determine the Vβ profile of circulating T cells from a cohort of patients with TSS.
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Methods
Following institutional Ethics committee approval, 1.1 ml of whole blood was sampled serially from 7 patients with TSS and 11 non-septic ICU adult controls (negative controls). The samples were stained with a panel of monoclonal antibodies directed against 24 Vβ segments (IO Test Beta Mark, Immunotech, Mareille, France) in addition to CD4 (Becton Dickinson, San Jose, CA, USA) and CD8 (Immunotech, Mareille, France) [4]. Following staining, the samples were analysed by flow cytometry to determine
Results
Seven patients with TSS aged from 3 to 35 years of age were sampled. Three patients had a single sample, two were bled twice, one had four samples while another had nine samples over a 4-month period. Eleven single samples were taken from 11 negative controls. All patients with TSS showed a skewed Vβ profile. As an example in Fig. 2, data from a 12-year-old girl on day 5 post onset of TSS shows an expansion of Vβ segments 3, 12, 14 and 17 which have known affinity for Staphylococcal Enterotoxin
Conclusions
In patients with TSS skewing of the T cell Vβ repertoire can be detected rapidly and reliably. This could form the basis of a diagnostic test that may allow application of more targeted therapies, such as immunoglobulin in patients with TSS.
References (5)
Toxic-shock syndrome associated with phage-group-I Staphylococci
Lancet
(1978)Rapid analysis of the Vbeta repertoire of CD4 and CD8 T lymphocytes in whole blood
J. Immunol. Methods
(2003)