Diagnosis of toxic shock syndrome by two different systems; clinical criteria and monitoring of TSST-1-reactive T cells

Mild forms of toxic shock syndrome toxin-1-mediated exanthematous disease related to Staphylococcus aureus infection

The present report describes three patients with toxic shock syndrome toxin (TSST)-1-associated exanthematous disease. In all patients, fever and systemic erythema without hemodynamic disturbance occurred following cellulitis of the lower limbs. At the site of infection, TSST-1 producing Methicillin-susceptible Staphylococcus aureus was detected. They defervesced and erythema resolved in response to administration of an antimicrobial drug, thereby avoiding severe illness. These patients did not meet the criteria for a clinical diagnosis of toxic shock syndrome. Measurement of T-cell receptor Vβ2-positive T cells in the peripheral blood early after onset of symptoms was useful for diagnosis.

Lesson of the month 2: toxic shock syndrome

Toxic shock syndrome (TSS) represents a fascinating example of immune activation caused by infection resulting in a dramatic and challenging clinical syndrome. TSS is commonly associated with tampon use and still causes significant morbidity and mortality in young healthy women. A misconception is that TSS presents with a skin rash and only occurs in women and children; however, it can occur in males and can present without skin changes. TSS presents initially as a febrile illness and within a few hours can progress to severe hypotension and multiple organ failure (MOF). Staphylococcus aureus and group A beta haemolytic streptococcus (GABHS) can secrete toxins from a small or hidden focus of infection and hence blood culture and sensitivity (C+S) tests can be negative, thereby making diagnosing this condition challenging. Clindamycin is superior to penicillin in the treatment of this condition and significantly decreases the mortality rate in TSS. However, there is also an important role for intravenous immunoglobulins (IVIG). Early intensive care unit (ICU) as well as surgical team involvement (in selected cases) is required to avoid mortality which may approach 70%.

High affinity of interaction between superantigen and T cell receptor Vbeta molecules induces a high level and prolonged expansion of superantigen-reactive CD4+ T cells

In mice implanted with an osmotic pump filled with the superantigen (SAG) staphylococcal enterotoxin A (SEA), the Vβ3(+)CD4(+) T cells exhibited a high level of expansion whereas the Vβ11(+)CD4(+) T cells exhibited a mild level of expansion. In contrast, in mice implanted with an osmotic pump filled with SE-like type P (SElP, 78.1% homologous with SEA), the Vβ11(+)CD4(+) T cells exhibited a high level of expansion while the Vβ3(+)CD4(+) T cells exhibited a low level of expansion, suggesting that the level of the SAG-induced response is determined by the affinities between the TCR Vβ molecules and SAG. Analyses using several hybrids of SEA and SElP showed that residue 206 of SEA determines the response levels of Vβ3(+)CD4(+) and Vβ11(+)CD4(+) T cells both in vitro and in vivo. Analyses using the above-mentioned hybrids showed that the binding affinities between SEA and the Vβ3/Vβ11 β chains and between SEA-MHC class II-molecule complex and Vβ3(+)/Vβ11(+) CD4(+) T cells determines the response levels of the SAG-reactive T cells both in vitro and in vivo.