Preservation of allergic contact dermatitis to poison ivy (Urushiol) in late HIV disease - The implications and relevance to immunotherapy with contact allergens

Background: Delayed hypersensitivity reactions (DTH) are lost with progression of HIV disease, This loss of DTH commonly occurs before the onset of opportunistic infections and is an independent predictor of disease progression, Objective: We wanted to determine whether patients in late HIV disease with a history of allergic contact dermatitis (ACD) to poison ivy continue to react to poison ivy, Methods: Twelve HIV+ patients with a past history of ACD to poison ivy were tested with an extract prepared from poison ivy leaves, All but 1 patient had CD4+ T cell counts <200/mu l, and 5 patients had had an opportunistic infection. Results: All 12 patients showed positive reactions ranging from mild erythema and infiltration to marked erythema with bulla formation, Conclusions: ACD is considered a variant of DTH, and as DTH results in a T helper 1 cytokine pattern. However, the antigen-specific effector cells in ACD may be more diverse than in DTH. This diversity could explain the continued reaction to some contact allergens in late disease and may be important in the use of contact allergens for immunotherapy.