HLA-B27 Typing Research Articles

Impact of HLA-B51 on Uveitis and Retinal Vasculitis: Data from the AIDA International Network Registries on Ocular Inflammatory Disorders

ABSTRACT Purpose The clinical relevance of human leukocyte antigen (HLA) subtypes such as HLA-B51 on Behçet’s disease (BD)-related uveitis and non-infectious uveitis (NIU) unrelated to BD remains largely unknown. Methods Data were prospectively collected from the International AIDA Network Registry for BD and for NIU. We assessed differences between groups (NIU unrelated to BD and positive for HLA-B51, BD-related uveitis positive for HLA-B51 and BD-related uveitis negative for HLA-B51) in terms of long-term ocular complications, visual acuity (VA) measured by best corrected visual acuity (BCVA), anatomical pattern, occurrence of retinal vasculitis (RV) and macular edema over time. Results Records of 213 patients (341 eyes) were analyzed. No differences in complications were observed (p = 0.465). With regard to VA, a significant difference was detected in median BCVA (p = 0.046), which was not maintained after Bonferroni correction (p = 0.060). RV was significantly more prevalent in NIU-affected patients who tested positive for HLA-B51, irrespective of the systemic diagnosis of BD (p = 0.025). No differences emerged in the occurrence of macular edema (p = 0.99). Conclusions Patients with NIU testing positive for HLA-B51 exhibit an increased likelihood of RV throughout disease course, irrespective of a systemic diagnosis of BD. The rate of complications as well as VA are comparable between NIU cases unrelated to BD testing positive for HLA-B51 and uveitis associated with BD. Therefore, it is advisable to perform the HLA-B typing in patients with NIU or retinal vasculitis, even in the absence of typical BD features.

Association between HLA-B*27:04 and genetic susceptibility to ankylosing spondylitis in Hunan Province.

Human leukocyte antigen (HLA) B27 is a susceptibility allele of ankylosing spondylitis (AS), and HLA-B27 antigen typing is an important indicator for clinical diagnosis of AS, but current typing methods such as sequence specific primer polymerase chain reaction (PCR-SSP) still possess limitation. Therefore, this study aims to analyze the correlation between B27 subtypes and susceptibility to AS in Hunan Province by applying high-resolution polymerase chain reaction-sequence-based typing (PCR-SBT). Peripheral blood of 116 patients with suspected AS (suspected AS group) and 121 healthy volunteers (control group) admitted to the Second Xiangya Hospital from January 2020 to December 2020 were collected for HLA-B genotyping by PCR-SBT. Among the patients in the suspected AS group, 23 patients were finally diagnosed with AS (confirmed AS group), and the remaining 93 undiagnosed patients served as the non-confirmed AS group. PCR-SBT and PCR-SSP were used to detect HLA-B27 typing in 116 patients with suspected AS, and the results of the 2 methods were compared. The HLA-B27 allele frequency in the suspected AS group was significantly higher than that in the control group [11.63% vs 2.48%; P<0.001, odds ratio (OR)=5.18, 95% confidence interval (CI) 2.097 to 12.795]. B*27:04, B*27:05, B*27:06, and B*27:07 were detected in the suspected AS group and the control group. The frequency of the B*27:04 allele in the suspected AS group was significantly higher than that in the control group (9.48% vs 1.24%; P<0.001, OR=8.346, 95% CI 2.463 to 28.282). The positive rate of B27 in the suspected AS group and the confirmed AS group (B27+/+ and B27+/-) was significantly higher than that in the control group (χ2=16.579, P<0.001; χ2=94.582, P<0.001, respectively). Among the confirmed AS group, 21 were HLA-B27 carriers, and the B27 positive rate in the confirmed AS group was 91.3%. PCR-SBT could achieve high resolution typing of the HLA-B gene locus, with higher sensitivity, specificity, positive predictive value, negative predictive value, and accuracy than PCR-SSP. PCR-SBT typing analysis shows a strong correlation between HLA-B * 27:04 and AS in Hunan province. The PCR-SBT method can be used as the preferred option for the auxiliary diagnosis of clinical AS.

Seventy-five years of service: an overview of the College of American Pathologists' proficiency testing program in histocompatibility and identity testing.

The Histocompatibility and Identity Testing Committee offers an overview of the College of American Pathologists' (CAP) Proficiency Testing (PT) program, commemorating its significant 75th anniversary in 2024. The CAP PT program has undergone significant growth and evolution over the years, ultimately achieving Centers for Medicare and Medicaid Services approval. In 1979, CAP's partnership with the American Association for Clinical Histocompatibility Testing marked a pivotal moment, leading to the creation of the first proficiency testing survey in 1980. This laid the foundation for various PT programs managed by the CAP Histocompatibility and Identity Testing Committee, including HLA antibody testing, HLA molecular typing, engraftment monitoring, parentage/relationship testing, HLA disease associations and drug risk, and HLA-B27 typing. Each program's distinctive considerations, grading methodologies, and future prospects are detailed here, highlighting the continual evolution of histocompatibility and identity testing PT to support emerging technologies and evolving laboratory practices in the field.

Evaluation of Human Leukocyte Antigen-B27 Expression in Patients with Spondylopathy/ Spondylitis by Flowcytometry

Introduction: The role of immune mediated injury in pathogenesis of Ankylosing Spondylitis (AS) is well established. HLA B27, a Major Histocompatibility Complex (MHC) class I molecule is one of the major genetic risk factors associated with the disease. Various techniques are used for testing HLA-B27 which includes Polymerase Chain Reaction (PCR) based tests, Enzyme Linked Immunosorbent Assay (ELISA) and flowcytometry. Flowcytometry has gained popularity due to ease of procedure, shortened turnaround time and costeffectiveness. Aim: The aim of the present study was to assess the sensitivity and specificity of flowcytometry for HLA-B27 detection, taking PCR assay as the gold standard along with its association with demographic, clinicopathological and radiological parameters. Materials and Methods: This was a prospective study conducted in Department at Pathology of Shri Guru Ram Rai Institute of Medical and Health Sciences, Dehradun, India, for a period of 18 months from January 2020 to June 2021. The study included 51 patients for which HLA-B27 typing was done cases by flowcytometry and Sequence Specific Allele (SSA) PCR/ Real time PCR on peripheral blood samples. The association of HLA-B27 with clinical features {Inflammatory Back Pain (IBP), arthritis, psoriasis, uveitis, dactylitis, Inflammatory Bowel Disease (IBD), cervicitis, urethritis, diarrhoea) along with MRI findings (sacroiliitis)}, laboratory findings {C-reactive protein and Erythrocyte Sedimentation Rate (ESR)} was evaluated. The performance analysis parameters of flowcytometry were evaluated both by excluding and including the cases in grey zone taking PCR as gold standard. Statistical testing was conducted with SPSS 20.0. Chi-square test or Fisher’s-exact test were used and a p-value of less than 0.05 was taken as significant. Results: A significant association of HLA-B27 was seen only with IBP (p-value= 0.001) and sacroiliitis (p-value= 0.03). Of the 22 (43.1%) patients positive for HLA-B27 by PCR, 18(81.8%) patients were positive while the remaining 4(18.1%) were in grey zone by flowcytometry. Of the 29(56.9%) patients testing negative by PCR, 27(93.1%) patients were negative, one (3.4%) was in grey zone and one (3.4%- false positive) tested positive for HLA-B27 by flowcytometry. Sensitivity and specificity of flowcytometry for detection of HLA-B27 was found to be 100% and 96.4% respectively when grey zone cases were excluded. Conclusion: The study brings to light that flowcytometry is a fairly specific and sensitive method for HLA-B27 detection with a high Negative Predictive Value (NPV) (100%) and Positive Predictive Value (PPV) (94.7%). In the COVID-19 era, it reiterates the importance of flowcytometry for HLA-B27 especially when PCR is overburdened.

Juvenile Idiopathic Arthritis and Its HLA Association: A Study from Bangladesh

Background: HLA alleles may have association with overall JIA including specific sub-types. Determation of HLA DRB1, DPB1, DQA1, DQB1 and B27, may be helpful to diagnose JIA cases where diagnostic dilemma is present. The aim of the study was to find out the association of HLA alleles with JIA and its subtypes. Methods: This cross sectional study was conducted in the department of Pediatrics, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, from April 2020 to March 2021. A total of 50 cases and 25 controls attending pediatric rheumatology clinic and pediatric OPD were enrolled in the study. Data were collected by a pre-designed questionnaire containing socio-demographic, clinical and laboratory parameters. HLA DR-B1, DQ-A1, DQ-B1 and B27 typing were done for the cases and controls from blood samples by polymerase chain reaction sequence specific primer (PCR-SSP) method. Data were analyzed by SPSS version 26. Frequency, percentage, chi square test and Fisher exact tests were done for statistical analysis. Results: HLA DR-B1_10 had significant positive association whereas HLA DR-B1_03 and B1_16 had negative association with overall JIA cases. Poly-articular JIA, oligo-articular JIA and ERA had association with HLA DRB1_01, B1_08 and B1_12 respectively. HLA DQA1-01 and A1_02 had positive association. However, DQ-A1_06 was negatively associated with JIA cases. Oligo JIA was positively associated with HLA DQ-A1_01, whereas poly JIA and ERA had association with A1_02. Though, HLA DQ_B1 had no association with overall JIA cases, analysis showed association of poly JIA with DQ-B1_04. Frequency of HLA DQ-B1_02 and 03 were higher among ERA cases, though not significant, but they had strong association with HLA B27. Conclusion: HLA associations were present with overall JIA and each sub-groups had different patterns of HLA associations including some protective roles.

Association between HLA-B27 and peripheral spondyloarthritis phenotype: results from the ASAS perSpA study

ObjectiveTo analyse the influence of HLA-B27 in the phenotypical expression of peripheral spondyloarthritis (pSpA).MethodThis is an observational cross-sectional study using data from the Assessment of SpondyloArthritis international Society perSpA registry,...

Association Between Human Leukocyte Antigen Polymorphism and Human Papillomavirus Infection in Brazilian Women.

Background Human papillomavirus (HPV) infection is a necessary cause for cervical cancer, but a majority of genital HPV infections clear spontaneously. Human leukocyte antigen (HLA) polymorphism influences immune response and genetic susceptibility, and its association with cervical cancer was extensively investigated, but few reports focused on HPV infection. Methods We performed molecular typing of HLA-A, HLA-B, HLA-DQB1, and HLA-DRB1 genes as well as of HPV in 1226 women enrolled in the Ludwig-McGill cohort study and investigated the influence on cumulative HPV positivity. HPV types were grouped according to Alphapapillomavirus subgenera that exhibit similar tissue tropism and biological behavior concerning cancer risk. The associations between HLA polymorphisms and HPV infections were estimated using unconditional logistic regression analysis adjusted for age and race. Results HLA-B*08 and HLA-DRB1*15:01 were negatively associated with HPV positivity, and similar effects were observed for HPV subgenus 2 only, which includes HPV16. HLA-DRB1*08:07 was associated with overall HPV infection and subgenus 2 positivity. The haplotypes HLA-B*08-DRB1*03:01-DQB1*02:01 and HLA-DRB1*08:07-DQB1*04:02 were negatively and positively associated with cumulative HPV positivity, respectively. Conclusions Our data suggest that HLA class I and II polymorphism can influence HPV natural infection.

Clinical and instrumental characteristics of axial involvement in psoriatic arthritis in real-life clinical practice

Objective: to evaluate clinical and instrumental characteristics of axial lesion in psoriatic arthritis (PsA) in real-life clinical practice.Subjects and methods. Examination were made in 52 patients (32 men and 20 women) with back pain recorded either at the time of their admission or in their medical histories. The inflammatory back pain (IBP) was diagnosed according to the Assessment of SpondyloArthritis international Society (ASAS) criteria. Back pain lasting over three months without meeting the ASAS criteria was taken to be chronic back (chrBP). Hands, feet, pelvis, cervical spine (CSP) and lumbar spine (LSP) were X-rayed. Erosions, osteolysis, and periarticular osteo-proliferative lesions were evaluated applying PsA-modified Sharp/van der Heijde score (SHS). Sacroiliitis (SI) was considered radiologically significant (r-sSI) when it was bilateral grade II or higher, or unilateral grade III or higher by Kellgren. 15 patients without r-sSI had their sacroiliac joints (SIJs) scanned using magnetic resonance imaging (MRI). Syndesmophytes, paravertebral ossifications, constriction and ankylosis of the CSP zygapophysial joints were considered to be radiological signs of psoriatic spondylitis. HLA-B27 typing was performed in 45 patients.Results and discussion. IBP was identified in 34 (66.7%), chrBP in 17 (33.3%) patients; 15 patients (28.8%) were of advanced age (over 40) at the onset of IBP/chrBP; 30 cases (57.7%) had r-sSI; in 18 cases SI was not detected. 13 out of 30 r-sSI patients (43.3%) didn’t suffer IBP. Erosions were detected in 38 (76%) patients, osteolysis in 13 (26%) and osteo-proliferative lesions in 18 (36%) patients. Average SHS was 82.79±64.77 correlating with the presence of r-sSI (r=0,46; p&lt;0,05). Correlation of r=0.35 was found between r-sSI and the spine limited mobility according to Bath Ankylosing Spondylitis Metrology Index (BASMI); r-sSI was detected with much higher statistical significance in the presence of periarticular osteo-proliferative lesions than in the absence of such (р=0.02). In PsA patients having periarticular osteolysis, axial lesion in the form of asymmetric syndesmophytes was detected ten times more frequently than in those not having it (OR=10; 95% CI: 1.63–61.327). In CSP, syndesmophytes developed two times more frequently than in LSP (p=0.01). Discrete CSP lesions in the absence of any LSP changes was observed in 30% of cases. SI was MRI detected in 2 (13.3%) patients. In 9 (18.0%) patients axial lesions were observed without SI. 15 patients (33.3%) were HLA-B27 positive. A set of specific PsA axial skeletal involvement features were revealed: possibility of oligosymptomatic clinical presentation; patient’s advanced age at the back pain onset; association with severe destructive peripheral arthritis; and more pronounced CSP lesions as compared to LSP. An alternative phenotype patient group (18%) without X-ray or MRI SI but with spine involvement was identified. Key words: psoriatic arthritis; axial lesion&gt;˂ 0,05). Correlation of r=0.35 was found between r-sSI and the spine limited mobility according to Bath Ankylosing Spondylitis Metrology Index (BASMI); r-sSI was detected with much higher statistical significance in the presence of periarticular osteo-proliferative lesions than in the absence of such (р=0.02). In PsA patients having periarticular osteolysis, axial lesion in the form of asymmetric syndesmophytes was detected ten times more frequently than in those not having it (OR=10; 95% CI: 1.63–61.327). In CSP, syndesmophytes developed two times more frequently than in LSP (p=0.01). Discrete CSP lesions in the absence of any LSP changes was observed in 30% of cases. SI was MRI detected in 2 (13.3%) patients. In 9 (18.0%) patients axial lesions were observed without SI. 15 patients (33.3%) were HLA-B27 positive. A set of specific PsA axial skeletal involvement features were revealed: possibility of oligosymptomatic clinical presentation; patient’s advanced age at the back pain onset; association with severe destructive peripheral arthritis; and more pronounced CSP lesions as compared to LSP. An alternative phenotype patient group (18%) without X-ray or MRI SI but with spine involvement was identified.

Abstract 26 HLA Analysis of the Australian Cord Blood Banks: How Diverse Are Donors?

IntroductionThe network of public cord blood banks (CBB) in Australia, known as AusCord, is comprised of CBB located in Brisbane, Sydney, and Melbourne. The network stores almost 37,000 cord blood units (CBU) and has released more than 1,300 for transplantation.ObjectiveThe objectives of this study were (1) to determine the relative diversity of HLA allele subtypes, tissue types, and haplotypes at each of the banks and between the banks and (2) to identify common tissue types and haplotypes that could be utilized for clinical research and development of third party cell therapy products.MethodsHLA data was obtained for 36,782 CBU stored in the AusCord inventory. To standardize data format, high-resolution typing was converted to 2-digit typing. HLA allele subtypes were ranked from most to least common. A subset of Indigenous Australian and Pacific Islander HLA allele subtypes was interrogated to determine whether increased frequency correlated with declared ethnicity. Tissue types were separated into CBU that had HLA-A, HLA-B, HLA-C, and HLA-DRB1 typing (21,815 total) and CBU that did not have HLA-C typing (36,782 total). CBU tissue types were interrogated in 3 separate groups: searchable, searched, and released inventory. Haplotypes were confirmed where maternal typing was available (3,105 CBU).ResultsEthnicity screening for donors and strategic location of collection sites servicing ethnic minority communities resulted in banking of Indigenous Australian and Pacific Islander HLA. At a bank and network level, there was a similar frequency of specific HLA subtypes; however, when considering the tissue types, there was vast diversity (~75% unique with 8 allele typing). Whilst there is diversity, there was also a fraction of the inventory that exhibited repetitive tissue types that could be utilized for clinical research.DiscussionThe study demonstrates that cord blood collections are able to boost storage of diverse tissue types in, and unique to, a multicultural population such as Australia. This finding can guide policy development and funding, as well as operational decisions at the CBB. Furthermore, CBB are well positioned to support research and development activity aimed at discovery of new applications for cord blood units through supply of GMP grade cryopreserved products exhibiting common tissue types and haplotypes.

Distribution of HLA-B Alleles and Haplotypes in Qatari: Recommendation for Establishing Pharmacogenomic Markers Screening for Drug Hypersensitivity.

Human leukocyte antigen (HLA) proteins are present at the cellular surface of antigen-presenting cells and play a crucial role in the adaptive immune response. Class I genes, specifically certain HLA-B alleles, are associated with adverse drug reactions (ADRs) and are used as pharmacogenetic markers. Although ADRs are a common causes of hospitalization and mortality, the data on the prevalence of HLA-B pharmacogenetics markers in Arab countries are scarce. In this study, we investigated the frequencies of major HLA-B pharmacogenomics markers in the Qatari population. Next-generation sequencing data from 1,098 Qatari individuals were employed for HLA-B typing using HLA-HD version 1.4.0 and IPD-IMGT/HLA database. In addition, HLA-B pharmacogenetics markers were obtained from the HLA Adverse Drug Reaction Database. In total, 469 major HLA-B pharmacogenetic markers were identified, with HLA-B*51:01 being the most frequent pharmacogenetic marker (26.67%) in the Qatari population. Moreover, HLA-B*51:01 is associated with phenytoin- and clindamycin-induced ADRs. The second most frequent pharmacogenetic marker was the HLA-B*58:01 allele (6.56%), which is associated with allopurinol-induced ADRs. The third most frequent pharmacogenetic marker was the HLA-B*44:03 allele, which is associated with phenytoin-induced ADRs. The establishment of a pharmacogenetics screening program in Qatar for cost effective interventions aimed at preventing drug-induced hypersensitivity can be aided by the highly prevalent HLA-B pharmacogenetic markers detected here.

Correlation between the ankylosing spondyloarthritis disease activity score (ASDAS) and status of HLA-B27 and its subtype associated, to assess severity of spondyloarthritis

Introduction: Ankylosing Spondylitis is a chronic and progressive inflammatory disease of the spine and enthesis affecting skeletal and extra skeletal tissues and is largely associated with HLA B27. However, more than 95% of individuals in the general population with this gene never develop Ankylosing Spondylitis. A lot of studies have shown that HLA B27 reveals remarkable polymorphism with an ever-increasing number of alleles and atleast 105 subtypes of HLA B27 is now known. Correlating the severity of Ankylosing Spondylitis using ASDAS score with the presence of a particular subtype of HLA B27 can help in segregating a high-risk population and subjecting them to an aggressive and early onset treatment for greater therapeutic benefits and thus reducing the disability burden on the society.Objective: To study the correlation between the disease severity and the HLA-B27 subtype associated. Thus, studying the influence of a particular HLA-B27 subtype on the disease severity that would be quantified using ASDAS.Method: This is retrospective as well as a prospective study in which fifty consecutive patients of Ankylosing spondylitis of 16 years of age and older were recruited into the study along with Fifty healthy controls. HLA B27 typing and subtyping of all patients and controls was done by PCR Sequence specific primer method. Ankylosing Spondylitis Disease Activity Score (ASDAS) was determined using Clinical data of the patients and Erythrocyte Sedimentation Rate (ESR). The frequencies of different HLAB27 subtype and its comparison with disease severity (ASDAS) were done using Chi-square test and one way Analysis of Variance test. Further, Bonferroni post hoc test was applied for multiple comparisons of each subtype. All statistical analyses were performed using SPSS for windows. Statistical tests were two sided and significant level with p< 0.05 was considered significant. Result: Out of 50 patients of Ankylosing spondylitis, HLA-B27 was positive in 46 individuals (92%) in which the frequency of each subtype was: HLA B2705 (67.4%), HLAB2704 (17.4%), HLAB2702 (8.7%) and HLAB2707 (6.5%). Among the 2 healthy controls who were found to be HLAB27 positive, both of them were of HLAB2705 subtype. Further, One way Analysis of Variance and Post HOC test was used to determine statistical significant difference between the means of Ankylosing Spondylitis Disease Activity Score (ASDAS) for the each HLAB27 subtypes revealed that HLAB2704 is associated with a higher disease severity scores among its natives as compared to the other commonly found subtypes. Although, HLAB2705 by virtue of it being the commonest subtype found in our study was found in all the three severity groups, while HLAB2702 and HLAB2707 was associated with less severe disease states.Conclusion: HLAB27 association with Ankylosing Spondylitis has been emphasized with HLA B2705 being more prevalent in Indian population. The correlation between the disease severity and the HLA-B27 subtype associated has been established with respect to HLA B2704 subtype .The study highlights that it is possible to predict the course of Ankylosing Spondylitis with the knowledge of the HLAB27 subtype of the patient.

Recurrence of axial spondyloarthritis among first-degree relatives in a prospective 35-year-follow-up family study

ObjectiveThe lifetime recurrence rate (RR) of axial spondyloarthritis (axSpA) among first-degree relatives (FDR) and the effect of proband’s gender, HLA-B27 and radiographic status is unclear. Our 35-year-follow-up family study has...

Clinical and Epidemiological Aspects of Ankylosing Spondylitis Patients in a Single Center in Baghdad

Ankylosing spondylitis is a chronic inflammatory disease with axial involvement but also may present as a peripheral arthritis and extraarticular manifestations. Objective: To assess clinical aspects of ankylosing spondylitis patients and different associated demographic variables in Baghdad teaching hospital. Patients and methods: A cross-sectional study was carried out in Baghdad teaching hospital which includes 402 patients (≥ 18 years old) with a clinical diagnosis of AS according to Assessment of Spondylo Arthritis International Society for AS were involved in this study from June/2019 to June/2021. Demographic data and disease characteristics, presence of extra-articular manifestations (past and present) and measurement of disease activity was done by BASDAI, erythrocyte sedimentation rate (mm/h) and C-reactive protein (mg/L). In addition, HLAB27 typing was reported. Results: The age of onset for males was 24.87±8.8 and for females25.97±8.6 years, HLA typing HLA-B27 were 49.55% and 35.38% in males and females respectively and the association was found to be statistically significant (P. value =0.031). While family history was reported at 25.82% and 34.33% in males and females correspondingly. 75.07% of males compared to 71.38% of females were treated with Anti TNF therapy. Females had later onset of disease than males with lower percentage of HLA B27 positivity. Recommendation: more comprehensive assessment with advanced diagnostic and treatment standards.

Clinical Features and Prevalence of Spondyloarthritis in a Cohort of Italian Patients Presenting with Acute Nongranulomatous Anterior Uveitis.

Purpose To describe the clinical features of acute nongranulomatous anterior uveitis (NGAU) patients and to estimate the prevalence of concomitant spondyloarthritis (SpA). Methods Retrospective study of consecutive patients affected by NGAU referred to the Ocular Immunology Unit of the AUSL-IRCCS di Reggio Emilia, Italy, between January 2016 and January 2019. All patients underwent ophthalmic evaluation and blood test with HLA-B27 typing and were referred to a rheumatologist to identify any undiagnosed SpA. SpA was classified according to the Assessment of SpondyloArthritis international Society (ASAS) criteria in axial or peripheral SpA. Patients were divided into two groups: NGAU with associated SpA (SpA+) and NGAU without SpA (SpA-). Clinical and demographic features of the two groups, including sex, HLA-B27, family history of rheumatic disease, uveitis laterality, course, and severity of ocular inflammation, complications, and treatment, were compared. Results Ninety-nine patients with NGAU were enrolled, of whom 36 (36%) with a diagnosis of SpA: 14 with peripheral SpA and 22 with axial SpA. The prevalence of SpA was higher in HLA-B27-positive patients than in HLA-B27-negative patients (50% vs. 15%, p < 0.0001). The multivariate logistic regression (R2 = 0.28) for SpA diagnosis identified as significant predictive factors: age at diagnosis (odds ratio [OR] = 0.95, 95% confidence interval [CI]: 0.91-0.99) and HLA-B27+ (OR = 5.32, 95% CI: 1.80-15.70). Conclusions Our results confirmed the high prevalence of undiagnosed SpA in patients with NGAU, suggesting that, regardless of HLA-B27 status, in the presence of IBP and/or peripheral arthritis, patients with NGAU must be referred to the rheumatologist to allow earlier diagnosis.

Can presence of HLA type I and II alleles be associated with clinical spectrum of CHIKV infection?

Host immune response and virulence factors are key to disease susceptibility. However, there are no known association studies of human leukocyte antigen (HLA) class I and II alleles with chikungunya virus (CHIKV) infection in the Latin American population. Here, we aimed to identify HLA alleles present in patients with CHIKV infection versus healthy controls as well as the allelic association with the clinical spectrum of the disease. We conducted a cross-sectional analysis of a community cohort and included patients aged 18 years and older with serologically confirmed CHIKV infection. HLA typing of HLA-A, HLA-B, and HLA-DRB1 alleles was performed. Two-by-two tables were used to establish associations between allele presence and clinical characteristics. Data from 65 patients with confirmed CHIKV infection were analyzed for HLA typing. CHIKV infection was significantly associated with the presence of HLA-A*68 [p=.005; odds ratio (OR): 8.90; 95% confidence interval (CI): 1.88-42.13], HLA-B*35 (p=.03; OR: 2.01; 95% CI: 1.06-3.86), HLA-DRB*01 (p<.001; OR: 5.70; 95% CI: 1.95-16.59), HLA-DRB1*04 (p<.001; OR: 7.37; 95% CI: 3.33-16.30), and HLA-DRB1*13 (p=.004; OR: 3.75; 95% CI: 1.50-9.39) alleles in patients versus healthy subjects. A statistically significant relationship was found between the presence of a rash on the face or abdomen and the presence of HLA-DRB1*04 (p=.028; OR: 3.2; 95% CI: 1.11-9.15 and p=.007; OR: 4.33; 95% CI: 1.45-12.88, respectively). Our study demonstrated that, in our cohort, HLA type I and type II alleles are associated with CHIKV infection, and an HLA type II allele is associated with dermatological symptoms. Further research is needed to establish a path for future investigation of genes outside the HLA system to improve knowledge of the pathophysiology of CHIKV infection and its host-pathogen interaction.

Assessment of HLA-B genetic variation with an HLA-B leader tool and implications in clinical transplantation

AbstractSequence variation in the HLA-B gene is critically linked to differential immune responses. A dimorphism at -21 of HLA-B exon 1 gives rise to leader peptides that are markers for risk of acute graft-versus-host disease, relapse, and mortality after unrelated donor and cord blood transplantation. To optimize the selection of stem cell transplant sources based on the HLA-B leader, an HLA-BLeader Assessment Tool (BLEAT) was developed to automate the assignment of leader genotypes, define HLA-B leader match statuses, and rank order candidate stem cell sources according to clinical risk. The base cohort consisted of 9 417 614 registered donors from the Be The Match Registry with HLA-B typing. Among these donors, the performance of BLEAT was assessed in 1 098 358 donors with sequence data for HLA-B exon 1 (2 196 716 haplotypes). The accuracy of leader assignment was then assessed in a second cohort of 1259 patients and their unrelated transplant donors. We furthermore established the frequencies of HLA-B leader genotype (MM, MT, TT) representations in broad racial categories in the 9.42 million donors. BLEAT has direct applications for the selection of optimal stem cell sources for transplantation and broad utility in basic and clinical research in pharmacogenomics, vaccine development, and cancer and infectious disease studies of human populations.

Association of Bw4/Bw6 mismatch across class I HLA loci with renal graft outcomes in first time transplants

Bw4 and Bw6 are strongly immunogenic epitopes routinely assigned based on HLA-B typing results per Organ Procurement and Transplantation Network (OPTN) policies. These public epitopes and their variants are shared by some cross-reactive HLA-A and -C antigens. Although epitope mismatch has been associated with poor transplant outcomes, previous studies did not find such associations for Bw4/6 mismatch as defined by HLA-B antigens only. We hypothesized that a broader definition for Bw4/Bw6 mismatch that includes cross-reactive HLA-A and -C antigens may reveal the risk associated with these epitopes. In this retrospective cohort study, we examined kidney transplantations between 2000 and 2016 in the OPTN database and determined the association of Bw4/6 mismatch across all class I HLA antigens and renal graft outcomes. Even by this broader definition, Bw4/6 mismatch was not independently associated with 1-year graft rejection (adjusted OR: 0.99, 95%CI 0.93–1.06) or death-censored graft survival (adjusted HR: 1.02, 95%CI 1.00–1.05). There was no significant association among recipients who were already sensitized at transplant either. Our findings suggest that Bw4/6 mismatch alone is not associated with poor renal graft outcomes despite their strong immunogenicity, and the load of epitope mismatches over a certain threshold is likely required to cause adverse clinical consequences.

Integration of Whole Exome and RNA Sequencing Identifies Neoepitope Vaccine Candidates in >90 Percent of Follicular Lymphoma Patients

Background:Follicular lymphoma (FL) is the most common indolent non-Hodgkin's lymphoma. FL is often responsive to standard treatment but remains incurable with conventional therapies, and may transform into more aggressive lymphoma types. The mutational processes that leads to lymphomagenesis and progression also produce tumor-specific mutant antigens (TSMAs) that can be targeted by the immune system to control malignancies. Personalized cancer vaccines designed for these TSMAs represent a promising new strategy for treatment of FL. However, the feasibility of this approach and precisely how to optimize effective vaccine design, informed by next-generation sequencing data, is not fully understood. We hypothesize that (tumor/normal) whole exome sequencing (WES) and (tumor) RNA sequencing (RNA-Seq) can be used to predict patient HLA typing and neoepitopes to engineer personalized cancer vaccines for FL.Methods:Using genomic DNA and RNA from FL patient biopsy specimens, we performed WES and RNA-Seq on fresh frozen primary or relapsed tumor samples from 33 FL patients with matched normal skin. This sequencing achieved >20x coverage for >75% of the targeted regions with a mean coverage of 76x. From this analysis, we identified an average of 145 somatic mutations per patient (range: 15-419). RNA-seq data allowed us to identify the expressed neoantigens. To determine the patient's HLA-A, HLA-B and HLA-C typing we used both OptiType and ATHLATES, achieving concordance between these algorithms of 80%, 94.29% and 90%, respectively. We used the Variant Effect Predictor (VEP) software for annotation of protein-coding effect of variants. Epitope predictions were performed for each patient's mutation(s) against all 6 of their HLA class I alleles using pVAC-Seq, version 4.0.8 (Hundal et al. Genome Med. 2016). Mutations were condensed to the single best neoepitope candidate. All patient-predicted peptides for a single variant were filtered to identify high quality candidates using the following criteria: (1) HLA binding affinity IC50 ≤ 500 nmol/L; (2) normal/tumor DNA/RNA coverage > 10; (3) normal DNA variant allele frequency (VAF) < 2; (4) tumor DNA/RNA VAF > 10; and (5) gene and transcript expression > 0.Results:High quality neoepitopes were predicted for all but three patients (90.9%). Five or more neoepitope candidates were identified for 22 (66.7%) patients with a mean of 12 predicted peptides per patient (range: 0-33). Overall, 80% (342) of the total predicted patient peptides arose from missense mutations and the remaining 20% (81) from indels. Predicted neoepitopes were identified in genes known to be recurrently mutated in lymphoma, including CREBBP, KMT2D, TNFRSF14, BCL2, BCL7A, EZH2, ARID1A/B, ATP6V1B2, CD22, CD79B, CXCR4, HIST1H1/H2 family members, HVCN1, IRF8, MEF2B, POU2F2, POU2AF1, PIM1, RRAGC, TP53, ZNF608, and IGLL5.Conclusion:Peptides suitable for cancer vaccine generation were identified for 90.9% (30 of 33 patients) of our cohort via next-generation sequencing, pVAC-Seq and filtering techniques. These neoepitopes include those which arose from genes known to be recurrently mutated in follicular lymphoma. Collectively, these findings suggest that most follicular lymphoma patients will be candidates for clinical trials that incorporate personalized cancer vaccines. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Similar Probabilities of Failure to Reach Transplantation and Transplant Outcomes after HLA-Identical Sibling or Unrelated Donor Transplant in Patients with Acute Myeloid Leukemia: A Single Institution Evaluation of a Donor Selection Algorithm

IntroductionThe increasing use of alternative donors has expanded allogeneic hematopoietic stem cell transplantation (HSCT) eligibility in patients with acute myeloid leukemia (AML) without HLA-identical siblings (matched-SIB). However, optimal donor selection remains controversial and current practice is largely based on transplantation centres' experience. Unrelated donor (URD) HSCT is associated with longer waiting times to transplantation than umbilical cord blood or haploidentical HSCT, but the impact of HSCT delays on transplantation rates and survival outcomes is unclear in this setting. In this study we evaluated the performance of a donor selection algorithm consisting in the allocation of patients with AML without matched-SIB to fully matched (8/8) or mismatched (7/8) URD.MethodsRetrospective analysis including adult patients with AML who received approval for first-time allogeneic HSCT with myeloablative conditioning at our institution between January 2011 and February 2017. Matched-SIB was the preferred donor choice for all patients. Fully matched (8/8) or mismatched (7/8) URD were selected through high-resolution HLA-A, HLA-B, HLA-C and DRB1 typing for those patients without an available matched-SIB. Non-parametric cumulative incidence and Kaplan-Meier estimates were obtained to assess transplantation and overall survival (OS) rates, respectively. Fine-Gray competing risks regression was used to identify predictors of failure to reach transplantation. Age, intention-to-treat (ITT) and disease status at the time of transplantation approval were included in the multivariate analysis.ResultsTable 1 summarizes the characteristics of the 113 eligible patients during the study period. Fifty-seven patients (50.4%) were allocated to a matched-SIB donor, whereas URD search was started in the remaining 56 patients (49.6%) without an available matched-SIB. Thirty patients (26.5%) failed to reach transplant after the approval to undergo transplantation. Figure 1 shows the cumulative incidence functions of transplantation from time of approval (Gray's p = 0.06). The estimated probabilities to reach transplantation were 74% and 71% for patients with or without a matched-SIB donor. Median time to HSCT from transplantation approval was shorter in patients with a matched-SIB donor (100 versus 136 days). Disease status at the time of transplantation approval was the only predictor of failure to reach transplantation in the multivariate analysis (sHR for any disease status versus CR1 = 1.69, p = 0.04). The 3-year OS from time of transplantation approval in the ITT population was 35% (28% versus 41% for patients with or without a matched-SIB donor, respectively; log rank p = 0.39), while the 3-year OS from time of transplantation was 46% (46% versus 54% for patients who underwent a matched-SIB HSCT or an URD HSCT, respectively; log rank p = 0.46).Conclusions8/8 or 7/8 URD selection in patients with AML without an available matched-SIB led to increased times to transplantation but did not have an impact on the probability of failure to reach transplantation and did not result in inferior survival outcomes in comparison with patients with a matched-SIB. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comparison of Next-Generation Sequencing-Based Human Leukocyte Antigen Typing with Clinical Flow Cytometry and Allele-Specific PCR Melting Assays for HLA-B27 Genotyping.

Due to the strong association between ankylosing spondylitis and Human Leukocyte Antigen (HLA)-B27, accurate identification of HLA-B27 is important in the diagnosis of patients with suspected spondyloarthritides. For this study, we compared a high-resolution HLA-B typing method to the clinical flow cytometry and allele-specific PCR melting assays to determine clinical benefits of high-resolution testing. Residual clinical samples submitted for HLA-B27 testing by flow cytometry were tested by single-locus HLA-B genotyping using next-generation sequencing (NGS), and PCR with melting curve analysis, currently used as a reflex test for indeterminate flow cytometry results. Fifty out of the 51 samples (98%) positive by flow cytometry confirmed as HLA-B27 positive by PCR melting assay and by NGS. The sample that did not confirm was genotyped as HLA-B*07:02. All the samples negative by flow cytometry were confirmed as HLA-B27 negative by both PCR melting assay and NGS. For the group that was indeterminate by flow cytometry, 84.5% (n = 49) typed as positive for HLA-B27, while 15.5% (n = 9) were negative for HLA-B27 but positive for HLA-B*07:02. NGS was the only method able to distinguish between pathogenic and nonpathogenic HLA-B27 variants, in contrast to the flow cytometry or the PCR melting assays. Single-locus NGS is superior to flow cytometry and PCR melting assay for the unambiguous identification of HLA-B27 variants, and uniquely able to distinguish between pathogenic and nonpathogenic B27 alleles. Due to its high accuracy, it may be a feasible superior alternative to flow cytometry and traditional molecular methods for clinical HLA-B27 testing.