EXPRESSION OF MXA PROTEIN IN INFLAMMATORY DERMATOSES

The human MxA protein can be detected in the cytoplasm of IFN-alpha/be ta-treated cells, whereas other cytokines, including IFN-gamma, ate po or inducers. Because IFN-alpha/beta is predominantly synthesized in re sponse to viral infections, MxA protein should be detectable in virall y infected tissue. Biopsy specimens (n = 64) of 12 different dermatose s were therefore screened with an MxA-specific monoclonal antibody on formalin-fixed, paraffin-embedded and microwave-treated tissue section s, As expected, high amounts of MxA protein were found in acute viral skin lesions (chickenpox, Herpes tester, and Herpes labialis). In addi tion, MxA protein was also detected in some inflammatory skin lesions of unknown etiology (lupus erythematosus, lichen planus, Schoenlein-He nnoch's anaphylactoid purpura and psoriasis). MxA protein was not foun d in non-viral infections (bacterial, mycotic, and parasitic) and was also not detectable in various other dermatoses (eczema, scleroderma, urticaria, granulomatous and bullous disorders). MxA staining proved a reliable, sensitive histochemical viral marker for infectious dermato ses. The positive results in non-infectious inflammatory dermatoses mi ght implicate viral involvement or activation of the IFN system by thu s far unknown mechanisms.