Evaluation of Lewis phenotypes in patients with psoriasis

Background: It seems that there are similar associated diseases in psoriasis and Lewis (b) negative phenotypes such as diabetes mellitus, cardiovascular events, and metabolic syndrome. Therefore, we decided to evaluate the frequency of Lewis henotypes in patients with chronic plaque type psoriasis. A limited number of studies have been previously conducted in this regard. Methods: Fifty patients and 100 age and gender matched control subjects were selected as the study population. Two milliliter of venous blood was collected from each subject to find out the Lewis phenotype and in subjects with the Le (a-b-) henotype, saliva was collected to determine the secretory status. All individuals with the Le (a-b-) phenotype were typed as non-secretor in their saliva by the hemagglutination inhibition assay; therefore, in this study, Lewis (b) positive individuals were considered as secretor and Lewis (b) negative as non-secretor phenotypes. Results: There was a significant difference in the secretory status or Lewis phenotypes between the two groups. ABH on-secretory status Le (a-b-) and Le (a+b-) together or Lewis b negative phenotypes were found in 78% (39 of 50) of the patients and 26% (26 out of 100) of the healthy controls (P<0.0001). The Le (a-b-) phenotype regardless of the secretory status was found in 14 patients with psoriasis (28.0%) and five healthy controls (5.0%), indicating a statistically significant difference (P≤0.0001). Conclusions: Individuals with Lewis b negative phenotypes or non-secretors are at risk of developing psoriasis. Inheriting Le/b antigen may have a protective role in patients with psoriasis.