Role of Th2 cytokines, RANTES and eotaxin in AIDS-associated eosinophilic folliculitis.

The pathogenesis of AIDS-associated eosinophilic folliculitis is still unknown. The expression of chemokines and Th2-type cytokines is increased in other conditions associated with tissue eosinophilia and in allergic reactions. We evaluated the mRNA expression by reverse transcriptase polymerase chain reaction of two Th2 cytokines (interleukin-4 and interleukin-5) and of two chemokines (RANTES and eotaxin) in the skin of 6 patients with AIDS-associated eosinophilic folliculitis; the tissue localization of eotaxin was shown by immunohistochemistry. We demonstrated the increased expression of interleukin-4, interleukin-5, RANTES and eotaxin in lesional skin of the patients compared to normal skin of HIV+ individuals. We concluded that a Th2 pattern is present in AIDS-associated eosinophilic folliculitis. The cytokine milieu in this disease may favour a Th2 immune response to an unknown antigen, whereby RANTES and eotaxin act in synergy with interleukin-4 and interleukin-5 to mediate tissue inflammation.