Expression of Th2 Cytokines Decreases the Development of and Improves Behçet's Disease–Like Symptoms Induced by Herpes Simplex Virus in Mice

In the etiology of Behçet's disease (BD), viral infection has long been postulated as a contributing factor, and viral involvement has been demonstrated. However, viral infection alone is not sufficient to explain the pathogenesis of BD, and some evidence suggests that immunologic abnormalities are also important. To study the possible role of immune regulation in the development of BD-like symptoms induced by herpes simplex virus inoculation in ICR mice, macrophages were deleted by use of liposome-encapsulated clodronate (lip-Cl(2)MDP). Treatment with lip-Cl(2)MDP suppressed the development of BD-like symptoms, and this suppression was correlated with the induction of interleukin-4 expression in mouse spleens. When the Th2 adjuvant ovalbumin (OVA)-alum was injected into mice with BD-like symptoms, their cutaneous symptoms improved. Adoptive transfer with splenocytes from OVA-alum-injected mice also resulted in improvement. These findings suggest that up-regulated Th2 cytokine expression can attenuate the development of and improve some BD-like symptoms.