Ankylosing spondylitis (AS) is a common, highly heritable, inflammatory arthritis for which HLA-B*27 is the major genetic risk factor, although its role in the aetiology of AS remains elusive. To better understand the genetic basis of the MHC susceptibility loci, we genotyped 7,264 MHC SNPs in 22,647 AS cases and controls of European descent. We impute SNPs, classical HLA alleles and amino-acid residues within HLA proteins, and tested these for association to AS status. Here we show that in addition to effects due to HLA-B*27 alleles, several other HLA-B alleles also affect susceptibility. After controlling for the associated haplotypes in HLA-B, we observe independent associations with variants in the HLA-A, HLA-DPB1 and HLA-DRB1 loci. We also demonstrate that the ERAP1 SNP rs30187 association is not restricted only to carriers of HLA-B*27 but also found in HLA-B*40:01 carriers independently of HLA-B*27 genotype.

Background: Recent consensus emphasizes the importance of studying individuals at risk for rheumatoid arthritis (pre‐RA) and those with early RA (eRA). Periodontal tissues have been recently evaluated, but these studies are limited. To evaluate the periodontal condition, immunoglobulin (Ig)G subclasses against Porphyromonas gingivalis in individuals with pre‐RA and eRA were compared with controls to establish an association between periodontal infection markers and rheumatic activity.Methods: Rheumatologic and periodontal condition was evaluated in 119 individuals with pre‐RA, 48 patients with eRA, and matched controls. P. gingivalis IgG1 and IgG2 were analyzed. C‐reactive protein, erythrocyte sedimentation rate (ESR), rheumatoid factor, anticitrullinated protein antibodies (ACPAs), and RA activity were measured. The groups were compared with McNemar test and paired t‐test. Conditional logistic regression was performed for pre‐RA confounders, and χ² test was used to evaluate periodontal variables and RA activity indices.Results: Pre‐RA individuals showed significantly higher levels of plaque index (P = 0.01) and bleeding on probing (P = 0.03) and higher severity of periodontal disease (P = 0.02). Periodontitis was associated with pre‐RA (odds ratio, 3.39; 95% confidence interval, 1.64 to 7.01) but not with eRA. In pre‐RA, P. gingivalis–specific IgG2 was associated with ACPAs (P = 0.049) and disease severity visual analog scale (P = 0.03). In eRA, IgG2 against P. gingivalis was associated with ESR (P = 0.046) and ACPAs (P = 0.04). P. gingivalis was associated with ACPAs (P = 0.04).Conclusions: This study shows that individuals with pre‐RA have significant inflammatory periodontal involvement. There was a significant association between IgG against P. gingivalis and ACPAs in pre‐RA and markers of RA activity in individuals with eRA.

Objective Human leucocyte antigen (HLA) B27 and HLA-B15 are associated with spondyloarthritis (SpA). Recent Assessment of SpondyloArthritis international Society (ASAS) criteria emphasise a distinction between SpA with axial and peripheral patterns. We analysed whether HLA-A, HLA-B and HLA-DRB1 alleles could associate with these patterns. Methods We studied 100 healthy individuals and 178 patients with SpA according to European Spondyloarthropathy Study Group (ESSG) criteria. Patients were then classified according to ASAS criteria, the axial spondyloarthritis pattern (axSpA) being defined by ascertained sacroiliitis and the peripheral pattern (pSpA) by enthesitis and/or arthritis in extremities. A combined ax/p pattern was also considered. Results Only HLA-B27 and HLA-B15 alleles were associated with SpA. ASAS criteria for axSpA were met in 152 patients (12 with isolated axSpA and 140 with a combined ax/p patterns). When the ASAS peripheral criteria were applied, 161 patients met these criteria (13 with isolated pSpA and 148 with a combined ax/p pattern). HLA-B27 was found in 83% of patients with axSpA and 43% of ax/pSpA patients according to axASAS. HLA-B27 occurred in 7% controls but not in any patient with isolated pSpA. HLA-B15 was encountered in 31% of patients with isolated pSpA and 20% of ax/pSpA patients according to pASAS criteria. Moreover, 2 healthy controls, but none of our patients with isolated axSpA were positive for HLA-B15. Conclusions Our data suggest that the presence of HLA-B15 favours the development of isolated/combined peripheral rather than isolated axSpA, while HLA-B27 promotes an isolated/combined axial disease and excludes a peripheral pattern. HLA-B15 should be considered in addition to HLA-B27 when diagnosing patients with SpA according to ASAS criteria.

Background and Objective: Experimental models suggest the use of different therapy protocols in rheumatoid arthritis (RA) as modulators on periodontal condition. This study evaluated the effects of conventional drug treatment and anti-TNF therapy in patients with RA on microbiological and periodontal condition, establishing the association of markers of periodontal infection with indexes of rheumatic activity. Materials and Methods: One hundred seventy nine individuals with RA were evaluated (62 with anti-TNF- and 115 with only DMARDs). The periodontal evaluation included plaque and gingival indexes, bleeding on probing (BOP), clinical attachment loss (CAL), pocket depth (PD) and subgingival plaque samples for microbiological analysis. Rheumatologic evaluations included a clinical examination, rheumatoid factor (RF), antibodies against cyclic-citrullinated peptides (ACPAs), and activity markers (DAS28-ERS), high sensitive C-reactive protein (hs-CRP), erythrocyte sedimentation rate (ESR). Results: Anti-TNF-alpha therapy influenced periodontal microbiota with a higher frequency of T. denticola (p=0.01). Methotrexate combined with leflunomide exhibited a higher extension of CAL (p=0.005), and anti-TNF-alpha therapy with methotrexate was associated with a lower extension of CAL (p=0.05). The use of corticosteroids exerted a protective effect on the number of teeth (p=0.027). The type of DMARD affected P. gingivalis, T. forsythia and E. nodatum presence. Elevated ACPAs titers were associated with the presence of red complex periodontal pathogens (p=0.025). Bleeding on probing was associated with elevated CPR levels (p=0.05), and ESR was associated with a greater PD (p=0.044) and presence of red complex (p=0.030). Conclusion: Different pharmacological treatments for RA affect the clinical condition and subgingival microbiota.