Climatotherapy at the Dead Sea is a remittive therapy for psoriasis: combined effects on epidermal and immunologic...

The beneficial effect of climatotherapy at the Dead Sea (CDS) for psoriasis has been established clinically but there is a striking lack of studies assessing its in vivo effect at the molecular and cellular levels.

We sought to study the response of activated immunologic cells and keratinocytes in psoriatic lesions to CDS.

A total of 27 patients with chronic, stable, plaque-type psoriasis treated with CDS for 28 consecutive days were evaluated with the Psoriasis Area and Severity Index score and quantitative histologic measures.

After 4 weeks of treatment, the overall Psoriasis Area and Severity Index score decreased by 81.5%. Complete clearance was achieved in 48% of the patients, and moderate to marked improvement in 41%. The average duration of remission was 3.3 months. Histologically, there was an overall reduction in malpighian layer thickness by 63.4%, and keratinocyte hyperplasia, assessed by Ki-67 cell cycle antigen expression, decreased by 78%; residual cell proliferation was confined mainly to the basal layer. These changes were accompanied by normalization of keratin 16 expression in 90% of the patients. T lymphocytes were almost totally eliminated from the epidermis (depletion of >90% of CD3(+) and CD25(+) cells), with only a low number remaining in the dermis (depletion of 69.4% of CD3(+) cells and 77.4% of CD25(+) cells). This reduction in activated T cells was accompanied by a marked reduction in HLA-DR expression by epidermal keratinocytes.

CDS is a highly effective and remittive treatment for moderate to severe plaque-type psoriasis, leading to a reversal of both pathologic epidermal and immunologic activation.