91-P

Abstract

Aim Classic Pars Planitis (CPP) is a common form of intermediate uveitis of unknown etiology. It is characterized by a chronic mild inflammation in the anterior chamber, vitritis, retinal flebitis and snowbanking at least in one eye, without any systemic association. The prevalence of CPP is 14.8% of all uveitis seen at the Mexican Referral Center. We previously showed the contribution of DRB1 ∗ 0802-DQB1 ∗ 0402 in the expression of CPP. Thus, the aim of the study was to look for the involvement of KIR genes and KIR-HLA combinations in the disease. Methods Seventy six PP patients and 164 healthy controls were included. CPP was diagnosed according to the international criteria.The presence of 14 KIR genes was assessed on DNAs extracted from PB, using a SSP system & four multiplex reactions. HLA typing was performed with a Luminex PCR-SSOP. The frequency of each KIR gene was determined by direct counting. The A & B haplotypes were deduced from the genotype data as describe elsewhere. The gene content and haplotype frequencies were compared using the SPSS17 software. Results No difference was found in gene or KIR-HLA combinations distribution between the groups. However, the BB haplotype was found significantly increased in the patients (HF = 26.3 in CPP Vs. 14.6% in C, p = 0.04, OR = 2.02). No deviation was observed either, in the telomeric or centromeric gene clusters or their combinations. Conclusions It is shown for the first time, the contribution of the BB haplotype group in the susceptibility to CPP. This haplotype is prevalent in Amerindian groups and Natives from Australia and India and has a higher content of activating KIRs than the A haplotype. We suggest that either CPP has indeed an autoimmune component, or that the activating KIRs may be involved in triggering the inflammatory response in the chamber of the eye, since NK cells are capable of interacting with a number of cell types which have the potential to drive the chronic inflammation, through cytokine production and direct cell-cell contact.