INCREASE IN EPIDERMAL ATPASE-POSITIVE LANGERHANS CELLS FOLLOWING TOPICAL APPLICATION OF 70-PERCENT DEACETYLATED CHITIN (DAC-70) IN DNCB-SENSITIZED CONTACT-DERMATITIS IN GUINEA-PIGS - PRELIMINARY-REPORT

Chitin is a polymer of D-glucosamine, beta-poly-N-acetyl D-glucosamine , The chitin derivative, 70% deacetylated chitin (DAC-70), is immunopo tentiating, The present study was conducted to determine the immunoreg ulatory events in skin following topical application of DAC-70 to DNCB -sensitized contact dermatitis in guinea pigs, On the 3rd day of treat ment, DNCB-induced erythema was reduced in all five guinea pigs treate d with 10% or 3.5% DAC-70 ointment, On the 7th day of treatment, ATPas e-positive Langerhans cell (LC) density in epidermal sheets was 1021 /- 131/mm(2) (mean +/- SD) for 10% DAC-70-treated skin, and 1000 +/- 1 30/mm(2) for 3.5% DAC-70-treated skin, both values exceeding 782 +/- 6 5/mm(2) for normal epidermis, The value in DAC-70-treated samples was significantly greater (P < 0.01) than in normal epidermis, DAC-70 thus appears to have an immunoregulatory effect by increasing the number o f epidermal LCs.