Neutralization of the eye and skin irritant benzalkonium chloride using UVC radiation.

PURPOSE: Benzalkonium chloride (BAK) is a widely used disinfectant and preservative which is effective against a wide range of viruses (e.g. SARS-CoV and SARS-CoV-2), bacteria and fungi. However, it is toxic to the eye and skin. This study investigated the neutralization of BAK using ultraviolet C (UVC) radiation as an effort to reduce BAK toxicity potential. METHODS: BAK solutions were irradiated with a germicidal UVC lamp at various doses. Human corneal epithelial cells (HCEC) were then exposed to the UVC-irradiated BAK solutions for 5 minutes. After exposure, the cultures were assessed for metabolic activity using PrestoBlue; for cell viability using confocal microscopy with viability dyes; and for tight junction proteins using immunofluorescence staining for zonula occludens (ZO)-1. RESULTS: UVC radiation reduced BAK toxicity on cell metabolic activity in a dose-dependent manner. When the solution depth of BAK was 1.7 mm, the UVC doses needed to completely neutralize the toxicity of BAK 0.005% and 0.01% were 2.093 J/cm2 and 8.374 J/cm2, respectively. The cultures treated with UVC-neutralized BAK showed similar cell metabolic activity and cell viability to those treated with phosphate buffered saline (PBS) (p = 0.806 ∼ 1.000). The expression of ZO-1 was greatly disturbed by untreated BAK; in contrast, ZO-1 proteins were well maintained after exposure to UVC-neutralized BAK. CONCLUSIONS: Our study demonstrates that the cell toxicity of BAK can be neutralized by UVC radiation, which provides a unique way of detoxifying BAK residues. This finding may be of great value in utilizing the antimicrobial efficacy of BAK (e.g. fighting against SARS-CoV-2) while minimizing its potential hazards to human health and the environment.

Ocular toxicology: synergism of UV radiation and benzalkonium chloride.

PURPOSE: To investigate the combined toxic effect of ultraviolet (UV) radiation and benzalkonium chloride (BAK), a common preservative in ophthalmic eye drops, on human corneal epithelial cells (HCEC). METHODS: Cultured HCEC were exposed to different combined and separate UV (280-400 nm) and BAK solutions at relevant human exposure levels. Human exposure to UV can occur before, during, or after eye drop installation, therefore, three different orders of ocular exposures were investigated: UV and BAK at the same time, UV first followed by BAK, and BAK first followed by UV. Control treatments included testing HCEC exposed to BAK alone and also HCEC exposed to UV alone. In addition, phosphate-buffered saline (PBS) was used as a negative control. After exposure, cell metabolic activity of the cultures was measured with PrestoBlue, and cell viability was determined using confocal microscopy with viability dyes. RESULTS: BAK alone reduced the metabolic activity and cell viability of HCEC in a dose- and time-dependent manner. UV alone at a low dose (0.17 J/cm2) had little toxicity on HCEC and was not significantly different from PBS control. However, UV plus BAK showed combined effects that were either greater than (synergistic) or equal to (additive) the sum of their individual effects. The synergistic effects occurred between low dose UV radiation (0.17 J/cm2) and low concentrations of BAK (0.001%, 0.002%, 0.003%, and 0.004%). CONCLUSIONS: This investigation determined that at relevant human exposure levels, the combination of UV radiation (280-400 nm) and BAK can cause synergistic and additive toxic effects on human corneal epithelial cells. This finding highlights the importance of considering the combined ocular toxicity of BAK and solar radiation in the risk assessment of BAK-preserved ophthalmic solutions.

Limitations of lumbar spine MRI in the diagnosis of ankylosing spondylitis.

OBJECTIVES: To assess the value of inflammatory and fatty lesions in the lumbar spine on magnetic resonance imaging (MRI) in differentiating ankylosing spondylitis (AS) from non-inflammatory chronic back pain. METHODS: We reviewed the lumbar spine MR images of 192 consecutive AS patients and 208 non-AS subjects with non-inflammatory chronic back pain. Lesions including vertebral corner inflammatory lesions (CIL), inflammation in posterior elements (PE) of the spine, and fatty deposition lesions (FDL) seen on lumbar spine MRI were scored in a blinded manner. RESULTS: The frequencies of CIL and FDL in AS patients were higher than that in non-AS patients (both p<0.01), but there was no significant difference in the positive rate of inflammation in PE of the spine between two groups. AS patients had higher scores of all three types of lesions than non-AS patients (all p<0.01). Positive likelihood ratio increased as the cut-off score for distinguishing AS from other diseases increased (ranged from 1.14 to 18.42). But the biggest value of area under the receiver operating characteristic curve of all types of lesions was only 62.58%. We also summarised some features of these lesions that may help to distinguish AS from non-inflammatory chronic back pain. CONCLUSIONS: Our study found that the value of inflammatory and fatty lesions (including CIL, inflammation in PE and FDL) seen on lumbar spine MRI in the diagnosis of AS was limited. But the diagnosis of AS would be more convincing if patients had high scores of these three types of lesions (CIL ≥16, and/or inflammation in PE of the spine ≥5, and/or FDL ≥2).

AAV2-Mediated Gene Therapy for Choroideremia: 5-Year Results and Alternate Anti-sense Oligonucleotide Therapy.

PURPOSE: To assess the long-term safety and efficacy of AAV2-REP1 in choroideremia (CHM) patients, and to test a potential antisense oligonucleotide therapy for CHM. DESIGN: Extended, prospective phase 1/2 clinical trial and laboratory investigation. METHODS: Five patients who received a single subfoveal injection of AAV2-REP1 were studied. The long-term safety was evaluated by ophthalmic examination, spectral domain optical coherence tomography, and fundus autofluorescence (FAF) for up to 5 years. Functional and structural changes were determined by different test modalities. Four antisense oligonucleotides (ASOs) were designed to treat the CHM c.1245-521A>G mutation, which was present in 2 patients within this trial. RESULTS: Subject P3 experienced a localized intraretinal immune response that resulted in a significant loss of preserved retinal pigment epithelium (RPE). P4 experienced an exacerbation of peripheral retinoschisis. P2 had a constant ≥15-letter best-corrected visual acuity (BCVA) gain in the treated eye, whereas P5 had ≥15-letter BCVA improvement once in the untreated eye. The preserved FAF areas declined more rapidly in the treated eyes compared to the untreated eyes (P = .043). A customized 25-mer ASO recovered 83.2% to 95.0% of the normal RNA and 57.5% of the normal protein in fibroblasts from 2 trial patients. CONCLUSIONS: Intraretinal inflammation triggered by AAV2-REP1 subretinal injection stabilized after 2 years but resulted in permanent damage to the retinal structure. Long-term progression of the disease was seen in both treated and untreated eyes, casting doubt as to the effectiveness of this approach in late-stage CHM. Alternative approaches such as ASO may have a therapeutic effect in a subgroup of CHM patients.

The Ankylosing Spondylitis Disease Activity Score is a highly discriminatory measure of disease activity and efficacy following tumour necrosis factor-α inhibitor therapies in ankylosing spondylitis and undifferentiated spondyloarthropathies in China.

OBJECTIVE: To validate the clinical value of the new Ankylosing Spondylitis Disease Activity Scores (ASDASs) in assessing the disease activity and efficacy of TNF-α inhibitor in AS and uSpA patients in China. METHODS: Two hundred and thirty patients were included in our study. They consisted of patients with active AS (n = 87) and uSpA (n = 30) participating in a double-blind placebo-controlled randomized clinical trial of etanercept and patients with active AS (n = 58) and uSpA (n = 55) treated with infliximab. The disease activity and treatment effects were assessed by ASDAS, BASDAI, patient global and the acute inflammation score of lumbar and SI joints by MRI. Discriminatory ability of all the measures was analysed by standardized mean difference and t-score. RESULTS: In both the AS and uSpA groups, ASDAS correlated well with patient global score (AS group: r = 0.65-0.72; uSpA group: r = 0.52-0.62), ESR (AS group: r = 0.57-0.81; uSpA group: r = 0.63-0.85) and CRP (AS group: r = 0.51-0.70; uSpA group: r = 0.61-0.76) both at baseline and in changes from baseline to 6 weeks after TNF-α inhibitor treatment. The ASDAS scores outperformed BASDAI, patient global score, ESR, CRP and the acute inflammation score by MRI in differentiating patients with different levels of disease activity and patients with different levels of change in both AS and uSpA groups. There was little difference in performance between the two versions of the ASDAS. CONCLUSION: The new ASDAS is a highly effective measure in assessing disease activity and a great discriminatory measurement to assess the efficacy of TNF-α inhibitor in Chinese AS patients and uSpA patients.

Multicenter validation of the value of BASFI and BASDAI in Chinese ankylosing spondylitis and undifferentiated spondyloarthropathy patients.

The objectives of this study were to evaluate the reliability of Bath ankylosing spondylitis functional index (BASFI) and Bath ankylosing spondylitis disease activity index (BASDAI) in Chinese ankylosing spondylitis (AS) and undifferentiated spondyloarthropathy (USpA) patients. 664 AS patients by the revised New York criteria for AS and 252 USpA patients by the European Spondyloarthropathy Study Group criteria were enrolled. BASDAI and BASFI questionnaires were translated into Chinese. Participants were required to fill in BASFI and BASDAI questionnaires again after 24 h. Moreover, BASDAI and BASFI were compared in AS patients receiving Enbrel or infliximab before and after treatment. For AS group, BASDAI ICC: 0.9502 (95% CI: 0.9330-0.9502, α=0.9702), BASFI ICC: 0.9587 (95% CI: 0.9521-0.9645, α=0.9789). For USpA group, BASDAI ICC: 0.9530 (95% CI: 0.9402-0.9632, α=0.9760), BASFI ICC: 0.9900 (95% CI: 0.9871-0.9922, α=0.9950). In the AS group, disease duration, occipital wall distance, modified Schober test, chest expansion, ESR, and CRP showed significant correlation with BASDAI and BASFI (all P<0.01). In the USpA group, onset age, ESR, and CRP were significantly correlated with BASDAI (all P<0.05), while modified Schober test, ESR, and CRP were significantly associated with BASFI (all P<0.05). The change in BASDAI and BASFI via Enbrel or infliximab treatment showed a significant positive correlation (P<0.01). The two instruments have good reliability and reference value regarding the evaluation of patient's condition and anti-TNF-α treatment response.

Whole exome sequencing reveals putatively novel associations in retinopathies and drusen formation.

Inherited retinal dystrophies (IRDs) affect 1 in 3000 individuals worldwide and are genetically heterogeneous, with over 270 identified genes and loci; however, there are still many identified disorders with no current genetic etiology. Whole exome sequencing (WES) provides a hypothesis-free first examination of IRD patients in either a clinical or research setting to identify the genetic cause of disease. We present a study of IRD in ten families from Alberta, Canada, through the lens of novel gene discovery. We identify the genetic etiology of IRDs in three of the families to be variants in known disease-associated genes, previously missed by clinical investigations. In addition, we identify two potentially novel associations: LRP1 in early-onset drusen formation and UBE2U in a multi-system condition presenting with retinoschisis, cataracts, learning disabilities, and developmental delay. We also describe interesting results in our unsolved cases to provide further information to other investigators of these blinding conditions.

Visual Field Progression in Retinitis Pigmentosa.

Purpose: To retrospectively study the rate of visual field (VF) progression in patients with retinitis pigmentosa (RP) as it relates to different targets and inheritance patterns. Methods: A total of 275 kinetic VF tests were collected from 52 subjects with RP over a period of up to 29 years (mean, 12 years). The VF areas of Goldmann targets V4e, III4e, and I4e were calculated using Photoshop. Differences in the rate of VF loss among different targets and inheritance patterns were compared. Results: There was a significant interocular correlation in both visual acuity (VA) (R2 = 0.739, P < 0.001) and VF area (R2 = 0.815, P < 0.001). The annual rates of decline in VF area for V4e, III4e, and I4e targets were 7.5%, 10.7%, and 12.5%, respectively (all P < 0.001). All of the rates were significantly different from each other (P < 0.001). The mean rate of VF loss was 10.3% (P = 0.009) for autosomal recessive, 2.7% (P = 0.215) for autosomal dominant, and 7.2% (P = 0.009) for X-linked patterns of inheritance. However, the differences among them were not statistically significant (P > 0.05). Based on VF, survival analysis indicated that our patients failed the vision standard for driving and reached legal blindness at the median ages of 37 and 55 years, respectively. Conclusions: The rate of VF loss varies among targets in patients with RP. Fifty percent of patients are not qualified to drive by the age of 37 and become legally blind by the age of 55. These results can be useful for counseling patients with RP as to their potential rate of VF decline.

Quantification of RPE Changes in Choroideremia Using a Photoshop-Based Method.

Purpose: To develop a reliable and efficient method for quantifying the area of preserved retinal pigment epithelium (RPE), facilitating the evaluation of disease progression or response to therapy in choroideremia (CHM). Methods: The fundus autofluorescence images of CHM patients were captured at baseline and 1 year. A Photoshop-based method was developed to allow the reliable measurement of the RPE area. The results were compared with measurements generated by the Heidelberg Eye Explorer 2 (HEYEX2). The areas measured by two independent graders were compared to assess the test-retest reliability. Results: By using the Photoshop-based method, the area of the RPE measured from 64 eyes was seen to decrease significantly (P < 0.001) at a rate of 2.57 ± 3.22 mm2 annually, and a percentage of 8.39% ± 5.24%. The average standard deviations for Photoshop were less than that for HEYEX2 (0.5-1.1 in grader 1; 0.4-1.6 in grader 2), indicating less intragrader variability. The RPE decrease as determined by the Photoshop-based method showed excellent reliability with an intraclass correlation coefficient of 0.944 (95% confidence interval, 0.907-0.966). In Bland-Altman plots, the Photoshop method also exhibited better intergrader agreement. Conclusions: Photoshop-based quantification of preserved RPE area in patients with CHM is feasible and has better test-retest reliability compared with the HEYEX2 method. Translational Relevance: An accurate quantification method for longitudinal RPE change in CHM patients is an important tool for the evaluation of efficacy in any therapeutic trials.

A Genome-Wide SNP Linkage Analysis Suggests a Susceptibility Locus on 6p21 for Ankylosing Spondylitis and Inflammatory Back Pain Trait.

OBJECTIVES: To screen susceptibility loci for ankylosing spondylitis (AS) using an affected-only linkage analysis based on high-density single nucleotide polymorphisms (SNPs) in a genome-wide manner. PATIENTS AND METHODS: AS patients from ten families with Cantonese origin of China were enrolled in the study. Blood samples were genotyped using genomic DNA derived from peripheral blood leukocytes by Illumina HumanHap 610-Quad SNP Chip. Genotype data were generated using the Illumina BeadStudio 3.2 software. PLINK package was used to remove non-autosomal SNPs and to further eliminate markers of typing errors. An affected-only linkage analysis was carried out using both non-parametric and parametric linkage analyses, as implemented in MERLIN. RESULT: Seventy-eight AS patients (48 males and 30 females, mean age: 39±16 years) were enrolled in the study. The mean age of onset was 23±10 years and mean duration of disease was 16.7±12.2 years. Iritis (2/76, 2.86%), dactylitis (5/78, 6.41%), hip joint involvement (9/78, 11.54%), peripheral arthritis (22/78, 28.21%), inflammatory back pain (IBP) (69/78, 88.46%) and HLA-B27 positivity (70/78, 89.74%) were observed in these patients. Using non-parameter linkage analysis, we found one susceptibility locus for AS, IBP and HLA-B27 in 6p21 respectively, spanning about 13.5Mb, 20.9Mb and 21.2Mb, respectively No significant results were found in the other clinical trait groups including dactylitis, hip involved and arthritis. The identical susceptibility locus region spanning above 9.44Mb was detected in AS IBP and HLA-B27 by the parametric linkage analysis. CONCLUSION: Our genome-wide SNP linkage analysis in ten families with ankylosing spondylitis suggests a susceptibility locus on 6p21 in AS, which is a risk locus for IBP in AS patients.

Use of the viability reagent PrestoBlue in comparison with alamarBlue and MTT to assess the viability of human corneal epithelial cells.

INTRODUCTION: PrestoBlue is a new resazurin based reagent to assess cell viability and cytotoxicity. It is claimed to be a fast and highly sensitive assay. Here, we compared PrestoBlue, alamarBlue, and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazonium bromide (MTT) in assessing cell viability of human corneal epithelial cells (HCEC), and investigated the effect of plate color, reading mode, and plate storage on the performance of PrestoBlue assay. METHODS: The viability of different numbers of healthy HCEC and the toxicity of various chemicals on HCEC were evaluated using PrestoBlue (fluorescence), alamarBlue (fluorescence), and MTT (absorbance). The sensitivities of the three assays were compared. In the PrestoBlue assay, three plate colors and two reading modes were used and compared in assessing the toxic effect of sodium dodecyl sulfate (SDS). The PrestoBlue solutions after reaction were stored and measured on day 1, 2, 3, 5, and 7. The fluorescence readings obtained on different days were then compared. RESULTS: Both PrestoBlue and alamarBlue were able to detect 5000 healthy cells after 30min incubation and 1000 cells after 1h, 2h, and 4h incubation; while MTT was able to detect 5000 cells after 3h incubation. In the assessment of the toxicity of various chemicals, PrestoBlue and alamarBlue performed similarly. There was no significant difference between the results obtained by these two reagents. All the three plate colors and two reading modes showed similar results in the PrestoBlue assay in assessing the toxicity of SDS. Plate storage up to 7days did not affect the result of the PrestoBlue assay. CONCLUSION: Our study suggests that in evaluating the viability of HCEC, PrestoBlue is more sensitive than MTT, but similar to alamarBlue. The plate color, reading mode and plate storage up to 7days did not affect the performance of the PrestoBlue assay.

Predictive Factors of Clinical Response of Infliximab Therapy in Active Nonradiographic Axial Spondyloarthritis Patients.

OBJECTIVES: To evaluate the efficiency and the predictive factors of clinical response of infliximab in active nonradiographic axial spondyloarthritis patients. METHODS: Active nonradiographic patients fulfilling ESSG criteria for SpA but not fulfilling modified New York criteria were included. All patients received infliximab treatment for 24 weeks. The primary endpoint was ASAS20 response at weeks 12 and 24. The abilities of baseline parameters and response at week 2 to predict ASAS20 response at weeks 12 and 24 were assessed using ROC curve and logistic regression analysis, respectively. RESULTS: Of 70 axial SpA patients included, the proportions of patients achieving an ASAS20 response at weeks 2, 6, 12, and 24 were 85.7%, 88.6%, 87.1%, and 84.3%, respectively. Baseline MRI sacroiliitis score (AUC = 0.791; P = 0.005), CRP (AUC = 0.75; P = 0.017), and ASDAS (AUC = 0.778, P = 0.007) significantly predicted ASAS20 response at week 12. However, only ASDAS (AUC = 0.696, P = 0.040) significantly predicted ASAS20 response at week 24. Achievement of ASAS20 response after the first infliximab infusion was a significant predictor of subsequent ASAS20 response at weeks 12 and 24 (wald χ(2) = 6.87, P = 0.009, and wald χ(2) = 5.171, P = 0.023). CONCLUSIONS: Infliximab shows efficiency in active nonradiographic axial spondyloarthritis patients. ASDAS score and first-dose response could help predicting clinical efficacy of infliximab therapy in these patients.

Evaluation of Assessment of Spondyloarthritis International Society classification criteria for axial spondyloarthritis in Chinese patients with chronic back pain: results of a 2-year follow-up study.

OBJECTIVE: To evaluate the diagnotic value of the Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axial spondyloarthritis (SpA) in Chinese patients with chronic back pain and without radiographic sacroiliitis in a 2-year follow-up study. METHODS: Patients with chronic back pain ≥ 3 months, onset age ≤ 45 years and without radiographic sacroiliitis were enrolled, and then received 2-year follow-up. All the clinical parameters associated with SpA were recorded. The patients were followed for 2 years and the final diagnosis of axial SpA or non-SpA was confirmed by rheumatologists. Diagnostic concordance between the initial classification according to three classification criteria (ASAS criteria for axial SpA, European Spondylarthropathy Study Group (ESSG) criteria and Amor criteria) and final diagnosis was compared. Diagnostic sensitivity and specificity were compared between the two subsets of ASAS criteria (set 1: sacroiliitis plus more than one SpA feature; set 2: HLA-B27 plus two more SpA features). RESULT: One thousand and sixty-eight patients entered the study and 867 completed the 2-year follow-up (455 axial SpA and 412 non-SpA). The concordance of ASAS criteria was better than ESSG and Amor criteria. Three hundred and thirty-three patients and 335 patients were classified as axial SpA according to the ASAS set 1 and set 2 of criteria, respectively. Further, set 1 of criteria (318/333) showed higher specificity than set 2 critera (279/335) (P = 0.000). CONCLUSION: The ASAS classification criteria for axial SpA showed good concordance in diagnosing Chinese axial SpA patients in this prospective study. Set 1 criteria involving sacroiliitis plus more than one SpA feature had better diagnosing value.

Comparison of the effects of ophthalmic solutions on human corneal epithelial cells using fluorescent dyes.

PURPOSE: To investigate the effect of differently preserved ophthalmic solutions on the viability and barrier function of human corneal epithelial cells (HCEC) using fluorescent dyes. METHODS: HCEC monolayers were exposed to the ophthalmic solutions containing benzalkonium chloride (BAK), edetate disodium, polyquad, stabilized oxychloro complex (Purite), sodium perborate, or sorbic acid for 5 min, 15 min, and 1 h. At 24 h after exposure, the cultures were assessed for metabolic activity using alamarBlue. The enzyme activity, membrane integrity, and apoptosis were evaluated using confocal microscopy. Barrier function was assessed using sodium fluorescein. RESULTS: The metabolic assay showed that the BAK-preserved ophthalmic solutions significantly reduced cell viability after a 5-min exposure compared to the phosphate buffered saline treated control (P<0.05). Using confocal microscopy, the micrographs showed that BAK caused a reduction in the enzyme activity, increased membrane permeability, and decreased the number of viable cells. Ophthalmic solutions with new preservatives had varying time-dependent adverse effects on cell viability, and the preservative-free solution had the least effect on HCEC. Sodium fluorescein permeability showed that HCEC monolayers treated with BAK-preserved solutions were more permeable to sodium fluorescein than those treated by the other ophthalmic solutions (P<0.05). CONCLUSIONS: BAK-preserved solutions had greater adverse effects on metabolic activity, enzyme activity, membrane integrity, cell viability, and barrier function than the solutions that were not preserved with BAK. Our study suggests that BAK-free especially, preservative-free ophthalmic solutions are safer alternatives to BAK-preserved ones.

Adalimumab significantly reduces inflammation and serum DKK-1 level but increases fatty deposition in lumbar spine in active ankylosing spondylitis.

AIM: To investigate whether adalimumab is effective for active ankylosing spondylitis (AS) patients and whether it has an impact on the formation of fatty deposition lesions (FDL) and serum Dickkopf homolog 1 (Dkk-1) level in AS patients. METHOD: This was a randomized, double-blind, placebo-controlled study. Active AS patients received 40 mg adalimumab (n = 26) or placebo (n = 20) every other week during an initial 12-week double-blind period, and all switched to adalimumab treatment for another 12 weeks. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Function Index (BASFI), C-reactive protein (CRP), Ankylosing Spondylitis Disease Activity Scores (ASDAS) and serum DKK-1 levels were measured and magnetic resonance imaging (MRI) of both the lumbar spine and sacroiliac joints were obtained at baseline, week 12 and week 24. Spinal and sacroiliac joint inflammations were evaluated using the Spondyloarthritis Research Consortium of Canada (SPARCC) MRI index, and FDL were assessed in a dichotomous manner. RESULTS: Obvious improvements in clinical assessments (BASDAI, BASFI, CRP and ASDAS reduced, all P < 0.05), as well as MRI inflammation measurements (both lumbar spine and sacroiliac joints SPARCC scores decreased, all P < 0.05) were shown in active AS patients treated by adalimumab for 12 weeks, but FDL in the lumbar spine seen by MRI increased significantly (P < 0.05) accompanied by decrease of serum DKK-1 levels (P < 0.05), while FDL remained stable after the treatment of placebo in AS patients. CONCLUSION: Our study found that adalimumab was highly effective in reducing inflammation in active AS patients, but it was accompanied by the formation of FDL in the lumbar spine and decrease in serum DKK-1 levels.

ERAP1 is associated with ankylosing spondylitis in Han Chinese.

OBJECTIVE: Genetic components play important roles in the incidence and development of ankylosing spondylitis (AS). Aminopeptidase regulator of tumor necrosis factor receptor shedding 1 (ERAP1) was recently found to be associated with AS in North American and British cohorts. We evaluated whether ERAP1 is associated with AS in a Chinese Han population. METHODS: A sample of 50 patients and 50 healthy controls was recruited for preliminary screening for informative single-nucleotide polymorphisms (SNP). Then 6 SNP of suggestive significance in the initial screening were followed up in a large sample of 471 patients with AS and 456 ethnically matched controls. Diagnosis of AS followed the 1984 modified New York criteria. Linkage disequilibrium coefficient (D' and r(2)) and haplotypes were estimated by Haploview. Result. Two SNP (rs27434, p = 0.00039, and rs27529, p = 0.0083) in ERAP1 other than that reported previously were found to be significantly associated with AS. Haplotype analysis using 5 SNP within 1 linkage disequilibrium block identified 2 risk haplotypes (GATGT and GACGT) and 1 protective haplotype (GGTGT) for AS. CONCLUSION: Our study demonstrated that 2 novel SNP in ERAP1 were associated with AS in the Han Chinese population, suggesting that ERAP1 might confer genetic risk for AS in Han Chinese through the common mechanism shared by different populations, although the AS-associated SNP in ERAP1 might be population-specific.

A genome-wide association study in Han Chinese identifies new susceptibility loci for ankylosing spondylitis.

To identify susceptibility loci for ankylosing spondylitis, we performed a two-stage genome-wide association study in Han Chinese. In the discovery stage, we analyzed 1,356,350 autosomal SNPs in 1,837 individuals with ankylosing spondylitis and 4,231 controls; in the validation stage, we analyzed 30 suggestive SNPs in an additional 2,100 affected individuals and 3,496 controls. We identified two new susceptibility loci between EDIL3 and HAPLN1 at 5q14.3 (rs4552569; P = 8.77 × 10(-10)) and within ANO6 at 12q12 (rs17095830; P = 1.63 × 10(-8)). We also confirmed previously reported associations in Europeans within the major histocompatibility complex (MHC) region (top SNP, rs13202464; P < 5 × 10(-324)) and at 2p15 (rs10865331; P = 1.98 × 10(-8)). We show that rs13202464 within the MHC region mainly represents the risk effect of HLA-B*27 variants (including HLA-B*2704, HLA-B*2705 and HLA-B*2715) in Chinese. The two newly discovered loci implicate genes related to bone formation and cartilage development, suggesting their potential involvement in the etiology of ankylosing spondylitis.