Human leukocyte Antigen-B*27 allele subtype prevalence and disease association of ankylosing spondylitis among south indian population

Association of Genetic Marker HLA-B27 with Spondyloarthritis In A Tertiary Care Centre In South India

Human leukocyte antigens (HLA) are gene products found in the major histocompatibility complex, aiding in differentiation of “self” from “non-self” antigens, and is crucial for the communication between immune cells of the human body. HLA-B27, in specific, has a strong interrelation with different types of Spondyloarthritis (SpA). The aim of this study is to study the frequency of HLA-B27 in suspected Spondyloarthritis patients presenting with axial and peripheral joint involvement, who attended our tertiary care centre from August-2017 to January-2021. Patients fulfilling Assessment of Spondyloarthritis International Society (ASAS) criteria for Spondyloarthritis were included in the study, and were further classified into Spondyloarthritis sub-groups. Blood samples were collected for CRP and ESR tests along with HLA-B27 detection by RT-PCR method. Magnetic resonance imaging was done for sacroiliac joints in patients with lower back pain. Analysis of 289 samples of SpA patients revealed 156 (54%) to be HLA-B27 positive and 133 (46%) to be HLA-B27 negative. There were 98 patients (63%) with Ankylosing spondylitis, 33 (21%) had Reactive arthritis, 19 (12%) had Psoriatic arthritis, 6 (4%) had Undifferentiated Spondyloarthritis, and inflammatory bowel disease was diagnosed in 0% in HLA-B27 positive Spondyloarthritis patients. The frequency of HLA-B27 among the Spondyloarthritis (SpA) patients in our study was found to be 54% (156), more common clinical manifestation in men belonging to the age group of 16-25 years positive patients. Ankylosing spondylitis (AS) was found to be the most common sub-groups observed among the SpA patients.

Prevalence of HLA-B*27 subtypes in the Tamil population of India with Ankylosing spondylitis and its correlation with clinical features

INTRODUCTION

HLA-B*27 is strongly associated with Ankylosing spondylitis (AS). Its subtypes show considerable geographic and ethnic difference. The main aim of this study was to assess the frequency of subtypes of HLA-B*27 in the Indian Tamil AS patients.

METHODS AND MATERIALS

Adult AS patients positive for HLA-B*27 were considered for the study. The high-resolution typing to define HLA-B*27 subtypes were done using Invitrogen B kits from One Lambda (SeCore® Sequencing Kits, Thermo Fisher, United States).

RESULTS AND CONCLUSION

Prevalence of subtypes identified were HLA-B*27:04 (52.2%), HLA-B*27:05 (41.6%), HLA-B*27:07 (3.5%) and HLA-B*27:02 (2.7%). All subtypes showed disease predisposition for males. The most common extra articular manifestation seen was enthesitis in HLA-B*27:04 and HLA-B*27:05. Uveitis was mainly associated with HLA-B*27:05 and dactylitis with HLA-B*27:04. A significant peripheral joints involvement for female and axial joint involvement for males was seen in HLA-B*27:04. Our study establishes the prevalence of HLA-B*27 subtypes and the associated clinical phenotypes among the Indian Tamil population. Considering the variability of presentation, organ involvement, and disease course in different subtypes and across ethnicities it is critical to define these associations in the ethnic populations we treat for their appropriate care considering the significant negative health and socioeconomic effects of AS.

Detection of Human Leukocyte Antigen B27 by Flowcytometry in Patients With Suspected Ankylosing Spondylitis in a Tertiary Care Centre

Introduction Human leukocyte antigen B27 (HLA-B27) is strongly implicated in the pathogenesis of ankylosing spondylitis (AS). Hence, HLA-B27 testing is routinely used in the diagnosis of AS. Objectives We aimed to establish the frequency of HLA-B27 in AS patients by flow cytometry and relate the differences between B27+ and B27- cases to the serum concentrations of rheumatoid arthritis factor (RA), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Methods  The study population included a total of 210 patients who visited the tertiary health care center. The peripheral blood samples obtained from AS patients were subjected to a qualitative two-color direct immunofluorescence method using the HLA-B27/CD3 antibody for the rapid detection of HLA-B27 antigen expression in erythrocyte-lysed whole blood in FACSCalibur flow cytometer (Becton Dickinson, USA). Results Out of 210 AS patients, the distribution of HLA-B27 positivity was observed only in 46 (22%) patients. The remaining 164 patients (78.1%) were negative for HLA-B27. Of the 46 HLA positive patients, 39 (25.34%) were males and only seven (12.5%) were females. In both sexes, HLA-B27 frequency was significantly higher in the age group 21-30 years, followed by 41-50 years. The current study also revealed a significant association between sex and age of onset of HLA‑B27 detection in patients with suspected AS. Disease activity was not significantly correlated with RA, ESR, and CRP. Conclusions The detection of HLA-B27 by flow cytometry proved to be a reliable test in the screening of AS in the Indian population.