Assessment of cellular immune parameters in paediatric toxic shock syndrome: a report of five cases.

Toxic shock syndrome (TSS) and septic shock (SS) share many clinical signs of an exacerbated inflammatory response. In this report, we investigated whether TSS presents similar features of delayed immunosuppression as described in SS. Five children with TSS from paediatric intensive care units in a university hospital were monitored. TSS cases were defined by the association of standardized clinical signs of TSS and confirmed by measurement of specific Vbeta expansions corresponding to toxin gene profile of the isolated strains. As in SS, an increased percentage of circulating regulatory T cells (Treg) was observed in patients with TSS. However, in contrast to SS, neither lymphopenia nor decreased HLA-DR expression on monocytes was measured. In conclusion, whereas SS and TSS exhibited similar clinical presentation, the present observation suggests that respective pathophysiological mechanisms induce different immune alterations. Future studies must isolate and better characterize the phenotypic and functional properties of Treg subsets during TSS to understand the mechanisms sustaining their increase, especially the putative role of superantigens.