The effect of systemic corticosteroid therapy on the expression of toll-like receptor 2 and toll-like receptor 4 in the cutaneous lesions of leprosy Type 1 reactions.

Background: Leprosy is complicated by immunological reactions which can occur before, during and after successful completion of multidrug therapy. Genetic studies have suggested that polymorphisms in toll-like receptors (TLRs) may affect the susceptibility of an individual with leprosy to developing Type 1 reactions.

Objectives: To examine the gene and protein expression of TLRs in the cutaneous lesions of leprosy Type 1 reactions at the onset of reaction and during systemic corticosteroid therapy.

Methods: Patients who were being treated for leprosy type 1 reactions with corticosteroids as part of a randomized controlled trial of corticosteroid treatment had skin biopsies performed before, during and at the end of treatment. The gene and protein expression of TLR2 and TLR4 were measured.

Results: We have demonstrated that the gene hARP-P0 is a suitable control gene for TLR gene expression studies in this population. The gene and protein expression of TLR2 and TLR4 were both reduced significantly during corticosteroid treatment.

Conclusions: This is the first study to examine the expression of TLR2 and TLR4 in vivo in individuals experiencing leprosy Type 1 reactions. The data support the possibility of an important role for TLR2 and TLR4 in the pathogenesis of this important complication of leprosy.