[Immunogenetics of psoriasis: update]. / Immunogénétique du psoriasis : actualités.

BACKGROUND: Psoriasis is a chronic inflammatory skin disease often benign, affecting 2-3% of the total world population. Psoriasis is a multifactorial disease. AIM: To present recent advances in the immunologic mechanisms and susceptibility genes involved in the pathogenesis of psoriasis. METHODS: We presented a literature review of recent genetic and immunological basis of psoriasis to better understand the pathomecanisms of this disease and discuss the contribution of the Tunisian work in this area. RESULTS: Recent works focalized mainly in immunology and genetics. Current progresses in molecular biology have allowed to better characterize the immunogenetic abnormalities in psoriasis. CONCLUSION: Psoriasis is a multifactorial disease model in which environmental factors (psychological, climate, traumatic, infectious, and viral) seem to be triggering factors when associated with a particular immunogenetics predisposition.

Family-based association study in Tunisian familial psoriasis.

BACKGROUND: The pathogenesis of all forms of psoriasis remains obscure. Segregation analysis and twin studies together with ethnic differences in disease frequency all point to an underlying genetic susceptibility to psoriasis, which is both complex and likely to reflect the action of a number of genes. MATERIALS AND METHODS: In the present study, we performed a family-based association study, and a transmission dysequilibrium test using the PLINK program, in a set of seven Tunisian multiplex families using a panel of 96 single-nucleotide polymorphisms localized in several regions across the genome. Ninety-five of them were reported to be associated with psoriasis in different populations. RESULTS: Besides the confirmation of association between previous associated regions: 6p, 1p, 2p, 13q, 14q, and 20p, and cutaneous psoriasis, we identified a new association with the rs1249564 in the IL17RD gene. CONCLUSION: Our results support the complex genetic basis of psoriasis.

Association analysis of LCE3C-LCE3B deletion in Tunisian psoriatic population.

An association between a common deletion comprising the late cornified envelope LCE3B and LCE3C genes (LCE3C_LCE3B-del) and psoriasis has been reported in Caucasian and Asian populations. To investigate whether this deletion plays a role in the genetic of psoriasis in Tunisian population, we determined the LCE3C_LCE3B-del genotype in 180 Ps patients and 208 healthy controls from different regions of Tunisia. The LCE3B and LCE3C gene variant was determined in the patients through PCR amplification and the SPSS software package. The frequency of the LCE3C_LCE3B-del was similar between patients and healthy controls. Subanalyses by family history revealed that the frequency of LCE3C_LCE3B-del was significantly higher in patients with a positive family history than in control individuals, as well as in individuals with a positive family history versus those without in the case cohort. However, no significant difference was observed between psoriatic patients with no family history and controls. We also evaluated the relationship between LCE3C_LCE3B-del and PSORS1. No significant epistatic effect was observed suggesting that there was no significant epistasis of the two loci in the Tunisian population. Our findings indicate that the LCE3C_LCE3B-del might play a role in familial psoriasis in the Tunisian population.