Introduction: The human Leucocyte antigen (HLA) system is the locus of genes that encodes for protein on the surface of the cells that are responsible for regulating the human immune system.They play an important role in disease defense, are a major causeof rejection in organ transplant patients. The first association of HLA to inflammatory diseases was discovered in 1972 correlating it to ankylosing spondylitis. After that numerous studies have been conducted associating more than 100 diseases like ocular and systemic diseases to HLA– B27. Present retrospective study was conducted with the aim of establishing the prevalence of HLA– B27 positivity in patients coming to our diagnostic centre from January 2014 to May 2015. Materials and Methods: This was a retrospective study conducted on 700 patients coming to our diagnostic centre for HLA B27 testing for different clinical conditions from January 2014 to May 2015. Test was performed by flow cytometry and all positive tests were confirmed by PCR Microarray Biochip technology for allele specific disease association. Results: There were 305/700(43.5%) males and 395/700(56.5%) females. Male to female ratio was 0.76:1 . Out of 700 patients included in the study, 82 patients were positive for HLAB27. The positivity rate was 11.7%. 54 were males (65.8%) and 28 (34%) were females. Out of 82 positive cases 56 patients had symptoms of arthritis (68.2%), 15 (18.2%) had 1BD, 5 (6.0%) had ocular symptoms, 4(4.87%) had symptoms of backache, 1 each (1.21%) had nonspecific symptoms. Conclusion: The low rate of positivity of HLA B27 in our study population support the view that HLA B27 should not be used as a routine test. However a larger study involving larger population with different racial and ethnic groups of India is needed to establish the role of HLA B27 as a diagnostic and prognostic marker for arthritis, IBD, uveitis and other inflammatory diseases

Keywords: HLA B27; MHC; IBD; AAU; Ankylosing Spondylitis.