Domain structure of erythrocyte membranes in psoriasis: an EPR study

Membrane fluidity of erythrocytes from psoriatic patients in active and inactive period of the disease was studied by electron paramagnetic resonance (EPR). Comparison of simulated and experimental EPR spectra of erythrocyte membranes from controls and psoriatics showed that they are essentially superimposition of three components; two regions with a high degree of order of the lipid acyl chains and one region with poor alignments of hydrocarbon chains (with a small order parameter). In psoriatic erythrocytes not only the portion of the most rigid domain was enlarged, but also the order parameter of this domain was increased, while the order parameters of two other domains were the same than in normal erythrocytes. Results obtained in this article showed that the portion of the most rigid domain (W(A)) better correlated with polymorphonuclear elastase (PMN elastase) than with PASI score. Additionally, correlation between PMN elastase and W(A) in the active period of the disease was observed to be higher than in the inactive period. Therefore, portion of the most ordered domain (W(A)) seems to be a good marker for evaluation of the disease activity in psoriatic patients.