Hyperthermia Depletes Epidermal Langerhans Cells and Modulates Contact Hypersensitivity Reaction in Mice

This study was designed to investigate the effect of local hyperthermia on contact hypersensitivity (CHS) and elucidate it's mechanism through assessment of number of epidermal LCs and transfer of spleen cells. Depilated dorsal skin of mouse was immersed into controlled water bath at 52 ℃ for 30 seconds in vivo. The number of epidermal LCs was counted by adenosine triphosphate staining, and CHS to 2,4-dinitro-l-fluorobenzene was assessed by ear swelling and transfer of spleen cells.

The number of LCs was significantly reduced 1 to 3 days after the hyperthermia treatment and recovered to normal 5 days after the treatment. CHS was significantly suppressed in mice sensitized 5,7, or 10 days after hyperthermia treatment, but the suppression was meager in mice sensitized 1 or 3 days after the treatment. There is a discord between the number of LCs and degree of CHS.

When mice received spleen cells from hyporesponsive donors, CHS was remarkably sup-pressed in the recipient mice compared with positive control. These findings suggest that tfeatment of local hyperthermia suppress CHS in mice, which may be associated with the induction of suppressor cells. The nature of the discord between the the number of LCs and degree of CHS in this investigation remains to be cleared by further studies.