ORIGINAL ARTICLE HLA-DRb1*04 typing by simple in-house PCR-SSP technique for rheumatoid arthritis patients Devaraj Jatteppa Parasannanavar • Avani Yeola • Vandana Pradhan • Anjali Rajyadhaksha • Kanjaksha Ghosh Received: 17 November 2011 / Accepted: 6 May 2012 / Published online: 24 May 2012 Ó Springer-Verlag 2012 Abstract A strong association between rheumatoid arthritis (RA) and human leukocyte antigen (HLA) has been observed in many different populations and that accounts for approximately one-third of the genetic com- ponent of RA susceptibility. The greatest effect comes from DRb1 gene where the strongest association has been found with DRb1*04 (DR4) allele. As serology has some disadvantages over polymerase chain reaction (PCR)-based techniques and commercially available PCR-based kits are expensive, this study was aimed to standardize simple in-house PCR-SSP technique. Accuracy of this test was further checked with standard PCR-SSOP (RLS) results. The frequency HLA-DRb1*04 was significantly increased among RA patients when compared with normal controls. In this study, a very simple, convenient and more cost- effective in-house PCR-SSP technique was standardized for HLA-DRb1*04 typing that is helpful to RA diagnosis in developing countries like India, which can be used as a good screening test. Keywords Rheumatoid arthritis Á PCR-SSP for HLA-DRb1*04 Á Rheumatoid factor (RF) Á Anti–cyclic citrullinated peptide (anti-CCP) Introduction Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disorder that is mainly characterized by peripheral joint pain and swelling, which eventually cul- minates into bone erosion and joint destruction. It affects 1 % of the world population; however, the prevalence varies between 3 and 8 % depending on the environmental and other genetic risk factors. It is also observed that the patients, who exhibit an early onset of the disease, had a higher prevalence of RA among their relatives than those who developed it later in life [1]. RA often presents itself as mono-/oligoarticular disease before becoming polyar- ticular [2]. The disease is more common in women and affects more frequent during the fourth and fifth decades of life and around 80 % of RA patients develop the disease between 35 and 50 years. The genetic factors have been estimated to account for 60 % of the disease risk of RA [3]. Genetic variations are believed to be important in determining both susceptibility to and severity of RA, with the strongest association being observed in human leukocyte antigen (HLA) region, in particular with HLA-DRb1[4]. Stastny [5] had first put forth that RA is associated with HLA-DRw4 (serological group), later various studies have confirmed the association with HLA-DRb1*04 allele among various populations. Earlier studies revealed that DRb1*04 (serological DR4 antigen) has been strongly associated with African, Cau- casian and Asian populations [6–17]. The shared epitope (SE) hypothesis has been proposed to explain susceptibility to RA, based on the observation that HLA-DRb1*04 alleles associated with the disease share a similar amino acid sequence in the third hyper variable region of the HLA-DRb1 molecule [18, 19]. Many studies have attempted to clarify this relationship, but there has been no D. J. Parasannanavar Á A. Yeola Á V. Pradhan Á K. Ghosh (&) National Institute of Immunohaematology ICMR, Mumbai, Maharashtra, India e-mail: kanjakshaghosh@hotmail.com A. Rajyadhaksha Department of Medicine, King Edward Memorial Hospital, Mumbai, Maharashtra, India e-mail: dranjalirajadhyaksha@gmail.com 123 Rheumatol Int (2013) 33:867–870 DOI 10.1007/s00296-012-2448-7