Powles AV, Murphy GM, Rutman AJ, Haffenden G, Rosin RD, Hawk JL, Fry L.
DOI: 10.2340/0001555569482486

The effect of artificial sunlight on the number and HLA class II expression of Langerhans´ cells was studied in 10 patients with malignant melanoma and 10 control volunteers. The total number of Langerhans´ cell decreased in both groups but at 96 h there was a greater and significant decrease (p less than 0.01) in the number of Langerhans´ cells in the melanoma group, compared with controls. This decrease persisted and was still greater in the melanoma group (p less than 0.02) at one week post-irradiation. There was a rise in Langerhans´ cell count over the following 3 weeks in both groups. Unexpectedly, during this period in the melanoma group-but not controls-there was a significant median peak rise above pre-irradiation levels (p less than 0.001). Alteration in the response of Langerhans´ cells to sunlight may play a part in the aetiology of malignant melanoma.