Analysis of superantigenic toxin Vβ 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 V beta 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 V beta signature (DV beta S) of each superantigenic toxin in vitro. Attempts were also made to identify in-vivo production of superantigenic toxin DV beta S in patients' blood. The DV beta S identified in vitro were: toxic shock syndrome toxin (TSST)-1, V beta 2; staphylococcal enterotoxin (SE), V beta 9, V beta 22; SEB, V beta 3, V beta 14, V beta 17; SED, V beta 1, V beta 8; egc, V beta 5.3, V beta 7.1, V beta 9, V beta 23; and SElK, V beta 5.1. The DV beta S of TSST-1 and SEB were detected in patients with menstrual and non-menstrual TSS, respectively, whereas no V beta 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 DV beta S 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.