Analysis of superantigenic toxin Vbeta T-cell signatures produced during cases of staphylococcal toxic shock syndrome and septic shock.

Most clinical isolates of Staphylococcus aureus harbour genes encoding superantigenic toxins that bind the Vbeta domain of T-cells, but little information is available concerning superantigenic toxin production during staphylococcal toxic shock syndrome (TSS) and septic shock. This prospective study investigated 14 patients with staphylococcal TSS or septic shock; the toxin gene profile of each isolate was determined and flow-cytometry was used to identify the discriminant Vbeta signature (DVbetaS) of each superantigenic toxin in vitro. Attempts were also made to identify in-vivo production of superantigenic toxin DVbetaS in patients' blood. The DVbetaS identified in vitro were: toxic shock syndrome toxin (TSST)-1, Vbeta 2; staphylococcal enterotoxin (SE), Vbeta 9, Vbeta 22; SEB, Vbeta 3, Vbeta 14, Vbeta 17; SED, Vbeta 1, Vbeta 8; egc, Vbeta 5.3, Vbeta 7.1, Vbeta 9, Vbeta 23; and SElK, Vbeta 5.1. The DVbetaS of TSST-1 and SEB were detected in patients with menstrual and non-menstrual TSS, respectively, whereas no Vbeta signature was detected during septic shock. All patients with septic shock (but only one patient with TSS) had lymphopenia and/or impaired cellular immunity. Detection of a superantigenic toxin DVbetaS may help to show which toxin is produced during staphylococcal TSS, thus confirming the diagnosis and hastening the administration of anti-toxin therapy. In contrast, this approach failed to demonstrate superantigenic toxin involvement in cases of septic shock. In this latter condition, a superantigenic toxin may not be produced by S. aureus, or its production may occur without expansion of targeted T-cells because of T-cell apoptosis and/or anergy.