Unraveling the paradoxes of HIV-associated psoriasis: a review of T-cell subsets and cytokine profiles.

HIV-associated psoriasis appears paradoxical, being a T-cell mediated disease in the face of decreasing T-cell counts. Furthermore, psoriasis is generally mediated by type-1 cytokines, whereas in HIV, type-2 cytokines tend to predominate. How can one have psoriasis in the essentially Th2 environment of HIV? The details and pertinent research regarding T cell subsets and cytokine profiles in psoriasis, HIV, and HIV-associated psoriasis were reviewed. It appears that both in the presence and absence of HIV infection, psoriasis is largely mediated by memory CD8 T cells, and that IFN-gamma secreted by these cells and others is of key importance. Studying psoriasis in a model such as HIV in which certain elements of the immune system are stripped away or altered may help us better understand the pathogenic mechanisms and potential treatment targets for psoriasis vulgaris.