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Background: Erythema multiforme is a polymorphous self-limited, often recurrent eruption that can follow herpes simplex virus (HSV) infection, hereby designated HAEM. Studies of relatively large groups of patients during one recurrent episode indicated that HAEM pathogenesis is associated with HSV gene expression, Vβ2 T cell infiltration of lesional skin and altered T cell receptor (TCR) repertoire usage by HSV-stimulated peripheral blood mononuclear cells (PBMC). However, HAEM recurrences are not always preceded by overt HSV eruptions and virus cannot be isolated from HAEM lesional skin. Therefore, it is unknown whether all HAEM recurrences experienced by a given patient are HSV related. Objective: The studies described in this report were designed to examine whether all HAEM recurrences experienced by a given patient are HSV related. Methods: We describe one patient who was studied longitudinally during 6 HAEM recurrences and in the intervening lesion-free periods. Lesional skin from all HAEM episodes was studied for HSV gene expression and infiltration by Vβ2 and Vβ3 T cells. PBMC obtained at these times were assayed for TCR repertoire usage upon HSV stimulation. Results: Lesional skin from all HAEM episodes was positive for HSV gene expression (RNA and protein) as well as Vβ2 T cell infiltration. HSV-stimulated PBMC obtained at these times had an altered TCR repertoire characterized by a predominance of Vβ2 cells. The duration of viral gene expression, Vβ2 cell infiltration and altered TCR repertoire usage correlated with the duration of clinical symptoms. Conclusion: The data suggest that HSV and a virus-specific immunopathology component are involved in the causation of all HAEM episodes experienced by the patient.

SUMMARYThe primary body site of acquisition of group A streptococci was examined prospectively in a population with endemic streptococcal pyoderma. Weekly cultures were obtained during the skin infection season from apparently normal upper respiratory and cutaneous sites (and from skin lesions when present) in 44 children and adults living on the Red Lake Indian Reservation.During the 9-week period of the study 705 of a total of 2305 cultures were positive for group A streptococci. The percentage of positive cultures from the various sites were: throat (20 %); nose (24 %); wrist (32 %); ankle (35 %); back (22 %); and skin lesions (81 %). Group A streptococci were also isolated from fingernail dirt, clothing and bedding as well as from a few household pets and insects.Analysis of serial cultures obtained from the same individuals at weekly intervals suggested that the strains isolated from skin lesions first appeared on normal skin in the 2 weeks preceding the lesion. Spread to the nose and throat followed skin acquisition and/or skin lesions.The high prevalence of group A streptococci on normal skin in the absence as well as the presence of pyoderma, and their appearance on normal skin before recovery from either skin lesions or the upper respiratory tract are consistent with the view that skin acquisition was a primary predisposing factor to pyoderma. Since the literature indicates that group A streptococci are rarely part of the normal skin flora, these findings raise the possibility of unique biological properties of these and perhaps other pyoderma strains, as distinct from other group A streptococci.

Molluscum contagiosum virus (MCV) infects preadolescent children and sexually active adults, frequently causing a disfiguring cutaneous disease in immunosuppressed HIV-infected individuals. The development of an efficacious treatment regime has been hampered by the failure to replicate the virus in the laboratory. Here we report the first demonstration of MCV replication in an experimental system. In human foreskin grafts to athymic mice, MCV induced morphological changes which were indistinguishable from patient biopsies and included the development and migration of molluscum bodies containing mature virions to the epidermal surface.