Screening of effects of selenomethionine-enriched yeast supplementation on various immunological and chemical parameters of skin and blood in psoriatic patients.

Selenium (Se) is known to affect the immune system, and decreased Se-levels in blood of patients with moderate or severe psoriasis have been reported. In this study, the effect of Se-supplementation (400 micrograms/day for 6 weeks as Se-yeast, containing about 70% selenomethionine, SeMet) on skin and blood Se-content, on skin glutathione peroxidase activity and on various chemical and immunological parameters of blood and skin was investigated in 7 psoriatic patients. Before the SeMet-supplementation, serum and blood Se-levels were at the normal range, but they increased 42-45% during the Se-dosage, while zinc levels remained unchanged. Se-dependent glutathione peroxidase activity in both normal and lesional psoriatic skin remained unchanged during the trial, although a small net Se-uptake was detected. At the same time, a slight but statistically significant increase in the number of CD4+ T-cells was observed in the reticular dermis of the psoriatic lesions whereas the numbers of CD8+, CD11c+, and CD1+ cells were not significantly altered. Also, a relatively high number of patients (3 out of 7) showed a strongly reduced number of gamma/delta T-lymphocytes or increased CD8+ T-cells (2 patients) in peripheral blood. However, SeMet-supplementation was not related to these abnormalities or to the number of other peripheral blood immunocytes or to serum immunoglobulin levels. In addition, no marked effect on the clinical condition of the patients was observed. This pilot study suggests that SeMet may be able to modulate the immunological mechanism of psoriatic lesions by increasing the number of CD4+ T-cells.