In vivo and in vitro detection of a superantigenic toxin Vbeta signature in two forms of streptococcal toxic shock syndrome

The aim of this study was to examine the production of superantigenic toxins in vivo and in vitro in two patients with streptococcal toxic shock syndrome (TSS). In the first patient, a woman with puerperal fever and Streptococcus pyogenes peritonitis, flow cytometry of blood cells and in vitro studies of the isolate showed massive expansion of Vbeta 2-positive T cells corresponding to SpeC production. In the second case, involving a patient with streptococcal TSS and purpura fulminans following non-steroidal anti-inflammatory drug (NSAID) therapy, no Vbeta expansion of T cells was observed in vivo, but the SpeC Vbeta signature was also detected in vitro. In this latter patient, NSAID administration and/or severe disseminated infection might partly explain the absence of Vbeta T cell expansion in vivo. Combined in vivo and in vitro detection of a superantigenic toxin Vbeta signature may be useful to determine which superantigenic toxin is involved in individual cases of streptococcal TSS.