CD8+ T cells with characteristic T cell receptor beta motif are detected in blood and expanded in synovial fluid of ankylosing spondylitis patients.

Objective: The risk of AS is associated with genomic variants related to antigen presentation and specific cytokine signalling pathways, suggesting the involvement of cellular immunity in disease initiation/progression. The aim of the present study was to explore the repertoire of TCR sequences in healthy donors and AS patients to uncover AS-linked TCR variants. Methods: Using quantitative molecular-barcoded 5'-RACE, we performed deep TCR ß repertoire profiling of peripheral blood (PB) and SF samples for 25 AS patients and 108 healthy donors. AS-linked TCR variants were identified using a new computational approach that relies on a probabilistic model of the VDJ rearrangement process. Results: Using the donor-agnostic probabilistic model, we reveal a TCR ß motif characteristic for PB of AS patients, represented by eight highly homologous amino acid sequence variants. Some of these variants were previously reported in SF and PB of patients with ReA and in PB of AS patients. We demonstrate that identified AS-linked clones have a CD8+ phenotype, present at relatively low frequencies in PB, and are significantly enriched in matched SF samples of AS patients. Conclusion: Our results suggest the involvement of a particular antigen-specific subset of CD8+ T cells in AS pathogenesis, confirming and expanding earlier findings. The high similarity of the clonotypes with the ones found in ReA implies common mechanisms for the initiation of the diseases.

Single high-dose treatment with glucosaminyl-muramyl dipeptide is ineffective in treating ankylosing spondylitis.

Earlier studies have shown that high doses of TNF-alpha increase apoptosis in human autoimmune T-cell clones. Based on these studies, a treatment approach was proposed to reduce or eliminate autoimmune T cells in patients with type 1 diabetes using drugs that temporarily elevate TNF levels. Here, we report the treatment of ankylosing spondylitis patient with a single high oral dose of Likopid (glucosaminyl-muramyl dipeptide), which aimed at increasing the levels of TNF-alpha in order to induce apoptosis of autoreactive T cells. The flow cytometric analysis of blood samples collected before and after treatment demonstrated massive elimination of CD8(+) T cells. However, the treatment did not result in any notable therapeutic effect, and real-time PCR analysis demonstrated that stably expanded T-cell clones that were earlier tracked in this patient were unaffected. This report suggests that the controversial approach to eliminate autoimmune T-cell clones through overstimulation is not effective in treating ankylosing spondylitis.

Spinal inflammation lesions as detected by magnetic resonance imaging in patients with early ankylosing spondylitis are more often observed in posterior structures of the spine.

OBJECTIVE: To study the localization and extent of spinal inflammation in patients with AS in detail. METHODS: This cross-sectional study used standardized clinical tools and MRI, including T1 and T2 fat saturation sequences in both sagittal and axial planes. A simple method of analysis of MRI changes was performed using the principle of 'yes/no' to calculate the changes in vertebral body and posterior structures of spine, including costovertebral and costotransversal joints. RESULTS: Consecutive patients with AS (n = 29), who fulfilled the modified NY criteria, were examined by MRI: 67% male, 93% HLA-B27-positive, median age 27.5 (18-49) years, median disease duration 7.5 (1.5-24) years. Inflammatory back pain (IBP), median duration 36 (1-240) months, with a mean intensity of 40 mm on a visual analogue scale (20-100) was present in 26 patients (89.7%), and the Bath AS Disease Activity Index (BASDAI) was > 40 in 21 patients (72.4%). MRI evidence of spinal inflammation at any site was found in 27 patients (96.5%), whereas radiographic changes were only seen in 6.9% (P < 0.05). Patients with a short history of IBP (n = 11) had significantly more lesions in posterior spinal structures than in vertebral bodies: 90.9 vs 27.2%, respectively (P < 0.003). Isolated changes in posterior spinal structures were seen in eight of these patients (72.7%), whereas, in contrast, patients with a longer history of IBP (n = 18) had significantly more inflammation in vertebral bodies: 88.9 vs 27.2%, respectively (P < 0.01). CONCLUSIONS: Inflammatory MRI lesions in early AS are seen more often in posterior structures of the spine. This may be relevant for the diagnosis of early AS and the early detection of inflammatory spinal involvement.

Contribution of functional KIR3DL1 to ankylosing spondylitis.

Increasing evidence points to a role for killer immunoglobulin-like receptors (KIRs) in the development of autoimmune diseases. In particular, a positive association of KIR3DS1 (activating receptor) and a negative association of KIR3DL1 (inhibitory receptor) alleles with ankylosing spondylitis (AS) have been reported by several groups. However, none of the studies analyzed these associations in the context of functionality of polymorphic KIR3DL1. To better understand how the KIR3DL1/3DS1 genes determine susceptibility to AS, we analyzed the frequencies of alleles and genotypes encoding functional (KIR3DL1*F) and non-functional (KIR3DL1*004) receptors. We genotyped 83 AS patients and 107 human leukocyte antigen (HLA)-B27-positive healthy controls from the Russian Caucasian population using a two-stage sequence-specific primer PCR, which distinguishes KIR3DS1, KIR3DL1*F and KIR3DL1*004 alleles. For the patients carrying two functional KIR3DL1 alleles, those alleles were additionally genotyped to identify KIR3DL1*005 and KIR3DL1*007 alleles, which are functional but are expressed at low levels. KIR3DL1 was negatively associated with AS at the expense of KIR3DL1*F but not of KIR3DL1*004. This finding indicates that the inhibitory KIR3DL1 receptor protects against the development of AS and is not simply a passive counterpart of the segregating KIR3DS1 allele encoding the activating receptor. However, analysis of genotype frequencies indicates that the presence of KIR3DS1 is a more important factor for AS susceptibility than the absence of KIR3DL1*F. The activation of either natural killer (NK) or T cells via the KIR3DS1 receptor can be one of the critical events in AS development, while the presence of the functional KIR3DL1 receptor has a protective effect. Nevertheless, even individuals with a genotype that carried two inhibitory KIR3DL1 alleles expressed at high levels could develop AS.