Plasmacytoid dendritic cells in angiolymphoid hyperplasia with eosinophilia

Background: angiolymphoid hyperplasia with eosinophilia(alhe) is characterized by irregularly-shaped blood vesselswith an inflammatory infiltrate. while absent from normal skin,plasmacytoid dendritic cells (pdcs) infiltrate the skin upon injuryand during several infectious, inflammatory, and neoplasticentities. in addition to providing anti-viral resistance, pdcs linkthe innate and adaptive immune responses. in kimura’s disease(kd), pdcs have been reported to occur. here, we investigatepdcs in alhe.methods: five alhe and comparable 4 kd cases wereimmunohistochemically tested for pdc occurrence and type iifn production using anti-bdca-2 and anti- myxovirus proteina (mxa) antibodies, respectively. a semiquantitative scoringsystem was used.results: plasmacytoid dendritic cells were present in all alheand kd cases with no statistically significant differences, whilemxa expression was weak and patchy in most alhe and kdcases.conclusions: pdcs are recruited into the lesions of alhe. despitethe diminished ability to produce type i ifns, the consistentpresence of pdcs in all alhe cases is in favor of some role ofthese cells in alhe pathogenesis.