Displaying publications 1 - 20 of 21 in total

  1. Nurul Izzah, A.R., Zailatul Hani, M.Y., Noormalin, A., Faizal, B., Shahnaz, M., Rosmilah, M.
    Medicine & Health, 2015;10(2):90-97.
    Crab meat is a valuable source of proteins and functional lipids and it is widely consumed worldwide. However, the prevalence of crab allergy has increased over the past few years. In order to understand crab allergy better, it is necessary to identify crab allergens. The aim of the present study was to compare the IgE-binding proteins of raw and cooked extracts of mud crab (Scylla serrata). Raw and cooked extracts of the mud crab were prepared. Protein profiles and IgE reactivity patterns were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting using sera from 21 skin prick test (SPT) positive patients. In SDS-PAGE, 20 protein bands (12 to 250 kDa) were observed in the raw extract while the cooked extract demonstrated fewer bands. Protein bands between 40 to 250 kDa were sensitive to heat denaturation and no longer observed in the cooked extract. In immunoblotting experiments, raw and cooked extracts demonstrated 11 and 4 IgE-binding proteins, respectively, with molecular weights of between 23 and 250 kDa. A heat-resistant 36 kDa protein, corresponding to crab tropomyosin was identified as the major allergen of both extracts. In addition, a 41 kDa heat-sensitive protein believed to be arginine kinase was shown to be a major allergen of the raw extract. Other minor allergens were also observed at various molecular weights.
  2. Rosmilah M, Shahnaz M, Masita A, Noormalin A, Jamaludin M
    Trop Biomed, 2005 Dec;22(2):171-7.
    PMID: 16883284 MyJurnal
    Fish has been recognized as a source of potent allergens both in food and occupational allergy. Lutjanus argentimaculatus (red snapper) and Lutjanus johnii (golden snapper) locally known as merah and jenahak, respectively, are among the most commonly consumed fish in Malaysia. The objective of this study is to identify the IgE-binding proteins and major allergens of these species of fishes. Extracts of both fish species were prepared and fractionated by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). IgE binding patterns were then demonstrated by immunoblotting using sera from patients allergic to the fishes. The raw extracts of both fish produced 26 protein bands. Both species of fishes had similar protein profiles. In cooked extracts, several protein bands in the range of about 40 to 90 kD which were present in the uncooked extracts appeared to be denatured and formed high molecular weight complexes. The immunoblotting of golden snapper and red snapper revealed 16 and 15 various IgE-binding bands, in the range of 151 to 12-11 kD, respectively. A 51 kD protein was identified as a major allergen for both fishes. A 46 kD protein was also demonstrated as a major allergen in golden snapper and a 42 kD protein was also seen as a major allergen in red snapper. A heat-resistant protein of ~12 kD which is equivalent in size with fish parvalbumin was demonstrated only as minor allergen for both fishes.
  3. Zailatul HM, Rosmilah M, Faizal B, Noormalin A, Shahnaz M
    Trop Biomed, 2015 Jun;32(2):323-34.
    PMID: 26691261 MyJurnal
    The purpose of this study was to evaluate the effect of different cooking methods on the allergenicity of cockle and to identify proteins most frequently bound by IgE antibodies using a proteomics approach. Raw, boiled, fried and roasted extracts of the cockle were prepared. The protein profiles of the extracts were obtained by separation using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional gel electrophoresis (2-DE). IgE-immunoblotting was then performed with the use of individual sera from patients with cockle allergy and the major IgE-binding proteins were analyzed by mass-spectrometry. SDS-PAGE of raw extract showed 13 protein bands. Smaller numbers of protein bands were detected in the boiled, fried and roasted extracts. The 2-DE gel profile of the raw extract further separated the protein bands to ~50 protein spots with molecular masses between 13 to 180 kDa and isoelectric point (pI) values ranging from 3 to 10. Immunoblotting of raw extract exhibited 11 IgE-binding proteins with two proteins of 36 and 40 kDa as the major IgE-binding proteins, while the boiled extract revealed 3 IgE-binding proteins. Fried and roasted extracts only showed a single IgE-binding protein at 36 kDa. 2-DE immunoblotting of raw extract demonstrated 5 to 20 IgE reactive spots. Mass spectrometry analysis led to identification of 2 important allergens, tropomyosin (36 kDa) and arginine kinase (40 kDa). Heated extracts showed a reduction in the number of IgE-reactive bands compared with raw extract, which suggest that thermal treatment can be used as a tool in attempting to reduce cockle allergenicity. The degree of allergenicity of cockle was demonstrated in the order raw > boiled > fried ≈ roasted. Two important allergens reacting with more than 50% of patients' sera identified using mass spectrometric approaches were tropomyosin and arginine kinase. Thus, allergens found in this study would help in component based diagnosis, management of cockle allergic patients and to the standardisation of allergenic test products as tools in molecular allergology.
  4. Rosmilah M, Shahnaz M, Zailatul HM, Noormalin A, Normilah I
    Trop Biomed, 2012 Sep;29(3):467-78.
    PMID: 23018510
    Crab is an important source of food allergen. Tropomyosin represents the main crab allergen and is responsible for IgE cross-reactivity between various species of crustaceans. Recently, other new crab allergens including arginine kinase have been identified. However, information on allergens of the local Portunidcrab is not available. Thus, the aim of this study was to identify the major allergens of Portunus pelagicus (blue swimming crab) using the allergenomics approach. Raw and cooked extracts of the crab were prepared from the crab meat. Protein profile and IgE binding pattern were demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from 30 patients with crab allergy. The major allergens of the crab were then identified by two-dimensional electrophoresis (2-DE), followed by mass spectrometry analysis of the peptide digests. The SDS-PAGE of raw extract revealed approximately 20 protein fractions over a wide molecular weight range, while cooked extract demonstrated fewer protein bands. The raw extract also demonstrated a higher number of IgE reactive bands than the cooked extract. A heat-resistant protein of 36 kDa has been identified as the major allergen in both raw and cooked extracts. In addition, a heat-sensitive protein of 41 kDa was also recognized as a major allergen in raw crab. The 2-DE gel profile of the raw extract demonstrated about >100 distinct proteins spots and immunoblotting of the 2-DE profile demonstrated at least 12 different major IgE reactive spots with molecular masses between 13 to 250 kDa and isoelectric point (pI) values ranging from 4.0 to 7.0. The 36 and 41 kDa proteins were identified as the crab tropomyosin and arginine kinase, respectively by mass spectrometry. Therefore, this study confirmed that tropomyosin and arginine kinase are the major allergens of the local Portunid crab, P. pelagicus.
  5. Rosmilah M, Shahnaz M, Patel G, Lock J, Rahman D, Masita A, et al.
    Trop Biomed, 2008 Dec;25(3):243-51.
    PMID: 19287364 MyJurnal
    Royal jelly is widely consumed in the community and has perceived benefits ranging from promoting growth in children and improvement of general health status to enhancement of longevity for the elderly. However, royal jelly consumption has been linked to contact dermatitis, acute asthma, anaphylaxis and death. High prevalence of positive skin tests to royal jelly have been reported among atopic populations in countries with a high rate of royal jelly consumption. The present study is aimed to identify the major allergens of royal jelly. Royal jelly extract was separated by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional electrophoresis (2-D). Immunoblotting of the SDS-PAGE and 2-D profiles were performed to identify the allergenic spots. Spots were then excised from the 2-D gel, digested with trypsin and analyzed by mass spectrometry. The SDS-PAGE of royal jelly extract revealed 18 bands between 10 to 167 kD. Western blot of the fractionated proteins detected 15 IgE-binding bands between 14 to 127 kD with seven major allergens of 32, 40, 42, 49, 55, 60 and 67 kD using serum from 53 subjects with royal jelly allergy. The 2-D gel fractionated the royal jelly proteins to more than 50 different protein spots. Out of these, 30 spots demonstrated specific IgE affinity to the sera tested. Eight spots of the major royal jelly allergens were selected for mass-spectrometry analysis. Digested tryptic peptides of the spots were compared to the amino acid sequence search in protein databases which identified the fragments of royal jelly homologus to major royal jelly protein 1 (MRJ1) and major royal jelly protein 2 (MRJ2). In conclusion, the major allergens of royal jelly are MRJ1 and MRJ2 in our patients' population.
  6. Ho TM, Radha K, Shahnaz M, Singaram SP
    Med J Malaysia, 1993 Sep;48(3):308-12.
    PMID: 8183144
    An indirect enzyme linked immunosorbent assay (ELISA) was developed for the diagnosis of allergy to a house dust mite, Dermatophagoides farinae. The efficacy of the ELISA was then evaluated against a prick test using a commercial allergen. Eighty five suspected allergic rhinitis patients from the Otorhinolaryngology Department, Kuala Lumpur General Hospital, were tested with the ELISA and prick test. Prick test and ELISA results were positive in 84.7% and 80.0% of the patients respectively. The ELISA was found to have 87.5% sensitivity, 61.5% specificity, 92.6% positive predictive value, 47.1% negative predictive value, 7.4% false positive and 52.9% false negative. There was total agreement between the prick test and ELISA for prick test grades of 3+ and 4+. It is concluded that the ELISA is a useful assay for detection of individuals who are highly sensitive to D. farinae.
  7. Azizah MR, Shahnaz M, Zulkifli MN, Nasuruddin BA
    Malays J Pathol, 1995 Dec;17(2):83-6.
    PMID: 8935131
    A study of 101 sera from 69 Malay, 14 Chinese and 18 Indian healthy adult Malaysians was undertaken to determine the frequency of antinuclear antibodies (ANA), antimitochondrial antibodies (AMA), antismooth muscle antibodies (SMA) and antiparietal cell antibodies (APCA). There were 67 females and 34 males with a mean age of 31.7 years (+/-8.6). ANA was assayed by immunofluorescence (IF) using both mouse liver and HEp-2 cell substrates. AMA, SMA and APCA were also tested by IF using composite sections from mouse liver, kidney and stomach substrates. Analysis showed 6.9% were positive for ANA at a titre of 1:40 with HEp-2 while only 1.9% were detected using mouse liver. 9.9% had detectable AMA from titres 1:10 to 1:90. None of them had detectable SMA and only 1 (0.09%) had APCA at a titre of 1:80. This study suggests that a diagnosis of an autoimmune disorder has to be cautiously made taking into consideration that autoantibodies are present in low titres in the healthy population.
  8. Azizah MR, Shahnaz M, Zulkifli MN, Azila MN, Nasuruddin BA
    Med J Malaysia, 1997 Mar;52(1):8-11.
    PMID: 10968047
    Autoantibodies have been known to be detected during pregnancy. The occurrence of autoantibodies during pregnancy was studied in a group of 146 healthy pregnant women from Jan-March 1995. Serum samples were tested for antinuclear (ANA), anti-ds DNA, anti-mitochondrial, anti-smooth muscle and anti-parietal cell antibodies employing the technique of indirect immunofluorescence. Sera from 66 non-pregnant women were used as controls. Among the pregnant group, 2 (1.4%) were found to have ANA positivity in comparison to none in the control group. This difference was found to be not statistically significant. Only 1 (0.7%) was positive for anti-mitochondrial antibody in the pregnant group compared to one in the control group (p > 0.05). However, anti-ds DNA, anti-smooth muscle and anti-parietal cell antibodies were not detected in both groups. All those positive for autoantibodies were in their 2nd trimester. When these cases were followed-up at the end of their pregnancy, none had complicated pregnancies nor infant abnormalities. Our findings suggest that (a) the occurrence of autoantibodies in pregnant women was not significantly different from non-pregnant controls and that (b) maternal autoantibodies did not appear to cause complications during pregnancy or infant morbidity.
  9. Rosmilah M, Shahnaz M, Meinir J, Masita A, Noormalin A, Jamaluddin M
    Int Arch Allergy Immunol, 2013;162(4):299-309.
    PMID: 24193115 DOI: 10.1159/000354544
    The longtail tuna (Thunnus tonggol) is widely consumed in Asia. Parvalbumin, the main major allergen of fish, has been well identified in multiple fish species, yet little is known about the allergenic proteins in T. tonggol. Thus, the aim of this study was to characterize the major allergens of T. tonggol using a proteomics approach.
  10. Nafishah A, Asiah MN, Syimah AT, Mohd Zahari TH, Yasmin A, Normi M, et al.
    Indian J Hematol Blood Transfus, 2014 Jun;30(2):105-10.
    PMID: 24839364 DOI: 10.1007/s12288-012-0213-4
    The World Health Organization (WHO) recommend that all donated blood are to be screened for at least three viral infections [human immunodeficiency virus (HIV), hepatitis C virus (HCV), hepatitis B virus (HBV)]. The National Blood Centre, Kuala Lumpur (NBCKL) aims to reduce transfusion transmitted infections (TTI) as it still remains as one of the major risk for blood transfusion. A cross sectional study was conducted at the National Blood Centre, Kuala Lumpur from 1st January 2009 to 31st June 2010. Data from 581,020 donors were analyzed from year 2004 to 2008. All data were retrieved from NBCKL Blood Bank Information System (BBIS). A total of 201 repeat donors were included in the study based on the inclusion criteria but only 132 repeat donors agreed to participate. Information on sociodemographic, risk factors, knowledge of donors and high risk behavior were extracted from standardize questionnaire. Data were analyzed using SPSS version 14.0. The aim of this study was to determine the predictors of the seropositive infectivity among repeat blood donors at the NBCKL. The results showed Syphilis accounts for the highest and increasing seroconversion rate among other infections from 20.83 % in year 2004 to 44.6 % in year in year 2008. HIV and HCV infection also showed increasing seroconversion rate in 5 years' time from 6.41 % in year 2004 to 17.54 % in year 2008 and 4.8 % in year 2004 to 5.94 % in year 2008 respectively. However, HBV infection alone showed a decreasing seroconversion rate from 20.83 % in year 2004 to 10.4 % in year 2008. Level of donors' awareness regarding high risk factors (activities or behaviour) can lead to higher risk of TTI with significant p value in this predictors model(p 
  11. Dhaliwal JS, Shahnaz M, Azrena A, Irda YA, Salawati M, Too CL, et al.
    Tissue Antigens, 2010 Feb;75(2):166-9.
    PMID: 20196825 DOI: 10.1111/j.1399-0039.2009.01410.x
    One hundred and fifty-eight Kadazan, Iban and Bidayuh individuals registered with the Malaysian Marrow Donor Registry were typed for human leukocyte antigen (HLA)-A, HLA-B and HLA-DR. Six, seven and eight HLA-A alleles as well as 13, 15 and 16 HLA-B alleles were detected in the Kadazan, Bidayuh and Iban, respectively. The most common HLA-A allele in all three groups was HLA-A*24 with a frequency of 0.456, 0.490 and 0.422 in the Kadazan, Bidayuh and Iban, respectively. The most common HLA-B allele detected in the Kadazan was HLA-B*40 with a frequency of 0.333; for the Bidayuh and the Iban it was HLA-B*15 with a frequency of 0.460 and 0.275, respectively. The HLA-DR allele with the highest frequency in the Kadazan was HLA-DR*1502 with a frequency of 0.500. In the Iban and the Bidayuh, HLA-DRB1*1202 was the most common DR allele with frequencies of 0.235 and 0.310, respectively. The two most common haplotypes for the Kadazan are A*34-B*38-DR*1502 and A*24-B*40-DR*0405, whereas for the Bidayuh they are A*24-B*15-DR*1602 and A*24-B*35-DR*1202 and for the Iban they are A*34-*B15-DR*1502 and A*24-B*15-DR*1202.
  12. Dhaliwal JS, Shahnaz M, Too CL, Azrena A, Maiselamah L, Lee YY, et al.
    Asian Pac J Allergy Immunol, 2007 Mar;25(1):47-51.
    PMID: 17891921
    One thousand four hundreds and forty-five Malays registered with the Malaysian Marrow Donor Registry were typed for HLA-A, HLA-B and HLA-DR. Fifteen HLA-A, twenty nine HLA-B and fourteen HLA-DR alleles were detected. The most common HLA-A alleles and their frequencies were HLA-A24 (0.35), HLA-A11 (0.21) and HLA-A2 (0.15). The most common HLA-B alleles were HLA-B15 (0.26), HLA-B35 (0.11) and HLA-B18 (0.10) while the most common HLA-DR alleles were HLA-DR15 (0.28), HLA-DR12 (0.27) and HLA-DR7 (0.10). A24-B15-DR12 (0.047), A24-B15-DR15 (0.03) and the A24-B35-DR12 (0.03) were the most frequent haplotypes. This data may be useful in determining the probability of finding a matched donor and for estimating the incidence of HLA associated diseases.
  13. Azizah MR, Loo CS, Zulkifli MN, Shahnaz M, Zaki M, Nasuruddin BA
    Med J Malaysia, 1998 Sep;53(3):257-62.
    PMID: 10968163
    Thirty-six patients with lupus nephritis (LN) attending the Nephrology Clinic, Hospital Kuala Lumpur were studied for the prevalence of anticardiolipin antibody (ACA) isotypes (IgG and IgM) and other associated antibodies, antinuclear antibody (ANA) and anti-ds DNA antibody and to determine the possible association between serological and clinical parameters. The study population consisted of 20 (55.6%) Malays, 15 (41.7%) Chinese and 1 (2.8%) Indian with a mean age of 31.4 +/- 11.3 years, range 14 to 60 years. The female to male ratio was 11:1. The average time between diagnosis and blood sampling was 4.4 years (range 0.25 to 15 years). Increased ACA levels were found in 20 (55.6%) patients where raised IgG ACA and IgM ACA were observed in 20 (55.6%) and 2 (5.6%) cases respectively. ANA and anti-ds DNA antibodies were detected in 22 (61.1%) and 4 (11.1%) individuals respectively, with the majority (82%) showing a speckled pattern of nuclear staining. However, neither the IgM ACA nor IgG ACA showed any significant association with thrombosis or any other clinical parametres. Our preliminary study indicates that ACA is a frequent finding in lupus nephritis and that the IgG isotype is more prevalent.

    Study site: nephrology Clinic, Hospital Kuala Lumpu
  14. Shahnaz M, Azizah MR, Hasma H, Mok KL, Yip E, Ganesapillai T, et al.
    Med J Malaysia, 1999 Mar;54(1):26-31.
    PMID: 10972001
    Health care workers have been reported to constitute one of the few high-risk groups related to IgE-mediated hypersensitivity associated with the use of latex products. This paper describes the first ever study of prevalence carried out in Malaysia among these workers. One hundred and thirty health care personnel from Hospital Kuala Lumpur were skin tested. Extracts used were prepared from seven different brands of natural rubber latex gloves with varying levels of extractable protein (EPRRIM). Out of the 130 volunteers, 4 (3.1%) had positive skin test to latex with extracts with high levels of EPRRIM (> 0.7 mg/g). The prevalence among the Malaysian health care workers can be considered to be low in comparison to that of some consumer countries as the USA which reported a prevalence of as high as 16.9%.
  15. Siti Nadiah AK, Nor Asiah M, Nur Syimah AT, Normi M, Anza E, Aini AN, et al.
    Transfus Apher Sci, 2013 Dec;49(3):507-10.
    PMID: 24055412 DOI: 10.1016/j.transci.2013.08.004
    Plateletpheresis is a method used to remove platelet from the body either from random volunteer donors, patient's family members or HLA matched donors. A cross sectional study was carried out on 59 plateletpheresis donors aged between 18 and 55 years at National Blood Center (NBC), Kuala Lumpur. We compared the blood parameters before and after plateletpheresis and we found that the platelet count, FVIII, fibrinogen and thrombophilia markers anti-thrombin (AT), protein C and protein S were significantly reduced (p<0.05) with prolonged PT and APTT. There were significant changes in blood coagulation parameters but it is within acceptable range.
  16. Too CL, Tan LK, Heselynn H, Nor-Shuhaila S, Eashwary M, Wahinuddin S, et al.
    Hum Immunol, 2019 Nov;80(11):906-907.
    PMID: 31558331 DOI: 10.1016/j.humimm.2019.09.005
    A total of 194 Southeast Asia Chinese from Peninsular Malaysia were genotyped for HLA-A, -B, -C -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, the HLA-B, HLA-DRB1 and HLA-DQB1 were in Hardy-Weinberg proportions (HWEP) (p > 0.05). We observed significant deviation from HWEP in HLA-A (p 
  17. Nordin O, Donald W, Ming WH, Ney TG, Mohamed KA, Halim NA, et al.
    PLoS One, 2013;8(3):e58805.
    PMID: 23527029 DOI: 10.1371/journal.pone.0058805
    Dengue is the most important mosquito-borne viral disease. No specific treatment or vaccine is currently available; traditional vector control methods can rarely achieve adequate control. Recently, the RIDL (Release of Insect carrying Dominant Lethality) approach has been developed, based on the sterile insect technique, in which genetically engineered 'sterile' homozygous RIDL male insects are released to mate wild females; the offspring inherit a copy of the RIDL construct and die. A RIDL strain of the dengue mosquito, Aedes aegypti, OX513A, expresses a fluorescent marker gene for identification (DsRed2) and a protein (tTAV) that causes the offspring to die. We examined whether these proteins could adversely affect predators that may feed on the insect. Aedes aegypti is a peri-domestic mosquito that typically breeds in small, rain-water-filled containers and has no specific predators. Toxorhynchites larvae feed on small aquatic organisms and are easily reared in the laboratory where they can be fed exclusively on mosquito larvae. To evaluate the effect of a predator feeding on a diet of RIDL insects, OX513A Ae. aegypti larvae were fed to two different species of Toxorhynchites (Tx. splendens and Tx. amboinensis) and effects on life table parameters of all life stages were compared to being fed on wild type larvae. No significant negative effect was observed on any life table parameter studied; this outcome and the benign nature of the expressed proteins (tTAV and DsRed2) indicate that Ae. aegypti OX513A RIDL strain is unlikely to have any adverse effects on predators in the environment.
  18. Noh LM, Nasuruddin BA, Abdul Latiff AH, Noah RM, Kamarul Azahar MR, Norzila MZ, et al.
    Med J Malaysia, 2013;68(1):13-7.
    PMID: 23466760
    To determine the clinical and epidemiological characteristics of patients seen with primary immunodeficiencies referred at four Malaysian Hospitals between 1987 to 2007.
  19. Nurul-Aain AF, Tan LK, Heselynn H, Nor-Shuhaila S, Eashwary M, Wahinuddin S, et al.
    Hum Immunol, 2020 Jun;81(6):263-264.
    PMID: 32312605 DOI: 10.1016/j.humimm.2020.04.004
    A total of 271 Southeast Asia Indians from Peninsular Malaysia were genotyped for HLA-A, -B, -C, -DRB1, and -DQB1 loci using polymerase chain reaction sequence-specific oligonucleotide probe hybridization methods. In this report, HLA-B and HLA-DQB1 was in Hardy-Weinberg proportions (HWEP) (p > 0.05). We observed significant deviation from the HWEP for HLA-A (p 
  20. Tan LK, Too CL, Diaz-Gallo LM, Wahinuddin S, Lau IS, Heselynn H, et al.
    Arthritis Res Ther, 2021 Jan 30;23(1):46.
    PMID: 33514426 DOI: 10.1186/s13075-021-02431-z
    BACKGROUND: Fine-mapping of human leukocyte antigen (HLA) region for rheumatoid arthritis (RA) risk factors has identified several HLA alleles and its corresponding amino acid residues as independent signals (i.e., HLA-A, HLA-B, HLA-DPB1, and HLA-DQA1 genes), in addition to the well-established genetic factor in HLA-DRB1 gene. However, this was mainly performed in the Caucasian and East Asian populations, and data from different Asian regions is less represented. We aimed to evaluate whether there are independent RA risk variants in both anti-citrullinated protein antibody (ACPA)-positive and ACPA-negative RA patients from the multi-ethnic Malaysian population, using the fine-mapping of HLA region strategy.

    METHODS: We imputed the classical HLA alleles, amino acids, and haplotypes using the Immunochip genotyping data of 1260 RA cases (i.e., 530 Malays, 259 Chinese, 412 Indians, and 59 mixed ethnicities) and 1571 controls (i.e., 981 Malays, 205 Chinese, 297 Indians, and 87 mixed ethnicities) from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA) population-based case-control study. Stepwise logistic regression was performed to identify the independent genetic risk factors for RA within the HLA region.

    RESULTS: We confirmed that the HLA-DRB1 amino acid at position 11 with valine residue conferred the strongest risk effect for ACPA-positive RA (OR = 4.26, 95% CI = 3.30-5.49, PGWAS = 7.22 × 10-29) in the Malays. Our study also revealed that HLA-DRB1 amino acid at position 96 with histidine residue was negatively associated with the risk of developing ACPA-positive RA in the Indians (OR = 0.48, 95% CI = 0.37-0.62, PGWAS = 2.58 × 10-08). Interestingly, we observed that HLA-DQB1*03:02 allele was inversely related to the risk of developing ACPA-positive RA in the Malays (OR = 0.17, 95% CI = 0.09-0.30, PGWAS = 1.60 × 10-09). No association was observed between the HLA variants and risk of developing ACPA-negative RA in any of the three major ethnic groups in Malaysia.

    CONCLUSIONS: Our results demonstrate that the RA-associated genetic factors in the multi-ethnic Malaysian population are similar to those in the Caucasian population, despite significant differences in the genetic architecture of HLA region across populations. A novel and distinct independent association between the HLA-DQB1*03:02 allele and ACPA-positive RA was observed in the Malays. In common with the Caucasian population, there is little risk from HLA region for ACPA-negative RA.

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