Abstract 60

Background: Burns or scalds may be associated with transient rashes, fever, and rarely toxic shock syndrome (TSS), a condition resulting from Staphylococcal superantigenic activation of the Vβ2+ subset of T cells.

Subjects and Measurements: T cell phenotypes were measured in venous samples using standard flow cytometric techniques in 6 children admitted to a paediatric unit following burns. None of these cases showed hypotension; 4 developed fever and diarrhoea, 2 had an erythematous rash. Staphylococci were grown from the burn in all children. All cases were discharged within 10 days without serious sequelae. Control samples were analyzed from age-matched children sampled prior to routine surgery.

Results: Four cases showed significant changes in the repertoire of their circulating T lymphocytes, equivalent to that described in patients with toxic shock syndrome. Decreased total lymphocyte counts were observed in all 4 (median 0.6, range 0.3-1.1×109/dl), and raised proportions of Vβ2+ T cells were observed (median 15% of CD3+ cells, range 12-26%, control median 8% range 5-9%, p<0.02). All Vβ2+ cells identified expressed the activation antigen CD45R0 (seen in <20% of control cells). These changes in burns cases resolved within days, and were not present at discharge.

Conclusions: Superantigens activating Vβ2+ cells are involved in burn pathologies more frequently than is recognised, and that this does not always lead to TSS. The T cell repertoire was distorted in those patients with fever, diarrhoea and low lymphocyte counts: these may be proxy measures of bacterial superantigen activity.