ࡱ>  Root Entry F@O,-CompObjnWordDocument'ObjectPool',-',-  FMicrosoft Word 6.0 Document MSWordDocWord.Document.69qࡱ_Oh+'0@d    <` (C:\MSOFFICE\WINWORD\TEMPLATE\NORMAL.DOTBHLA-B27 SUBTYPES IN CROATIAN PATIENTS WITH ANKYLOSING SPONDYLITISUprava zܥe= e'"p"pp"p"p"p"p""""""" " "&@""""""""F#H#H#H#.v#%&'T\'&p""""""&"p"p"""""""p""p""F#" "6p"p"p"p""F#"X"HLA-B27 SUBTYPES IN CROATIAN PATIENTS WITH ANKYLOSING SPONDYLITIS Running title: HLA-B27 subtypes and AS in Croatia Zorana Grubi1, Vesna Kerhin-Brkljai1, Porin Peri2, Esma euk-Jelii1, Renata unec1, Andrija Katelan1 1National Referral Organ Transplantation and Tissue Typing Center, 2Clinic for Rheumatology, University Hospital Center Zagreb, Zagreb, Croatia Correspondence to: Zorana Grubi National Referral Organ Transplantation and Tissue Typing Center University Hospital Center Zagreb, Kipatieva 12; HR - 10000 Zagreb; Croatia Sir, The association between ankylosing spondylitis (AS) and HLA-B27 is one of the strongest known association and it has been confirmed in various populations. HLA-B27 is found in about 96% of AS patients, while only 4-12% healthy Caucasians are HLA-B27 positive (1). The study about association between B27 subtypes and AS gave different results in various populations. The results available indicate that alleles B*2701, *2702, *2704, *2705 and *2707 are occurring in AS patients (1, 2). Negative association of B*2706 and *2709 subtypes has been described in patient groups of the Thai and Sardinian population, respectively (2). The frequency of B27 antigen in healthy Croatians is about 12%, while in AS patients it is approximately 90%. The aims of this study was to analyse the distribution of HLA class I antigens and B27 haplotypes in the group of 119 B27+ AS patients and in the group of 165 B27+ healthy individuals and to examine the frequency of B27 subtypes in B27+ AS patients and B27+ healthy controls. A total of 119 unrelated B27+ AS patients and 165 B27+ healthy individuals were included in this study. For all individuals HLA genotyping was performed using segregation data of parental haplotypes. AS patients were clinically diagnosed according to the New York criteria of 1986. All included families were living in the same area for three generations at least. HLA-A and -B typing was performed using the standard microlymphocytotoxity test (MLCT) on local trays (3). PCR-SSP typing for the B27 subtypes was performed using Dynal HLA-B27 high resolution kit (DYNAL, Oslo, Norway) (4). Comparison of HLA class I antigen frequencies between both B27+ groups (AS patients and B27+ healthy individuals) and random controls revealed the increased frequency of HLA-B44 antigen in random healthy controls (p=0.65 and p=0.59, respectively). Results of HLA-A and -B antigen frequencies showed a quite similar distribution in both B27+ groups. An increased frequency of HLA-A9 antigen, observed among Basque, Indian and USA AS patients, was not found in Croatian AS patients (9.1% vs 8.8%, p>0.05) (5). In this study we did not observe HLA-B60 antigen more often than expected in B27+ AS patients as was suggested by Robinson et al (2.8% vs 3.9%, p>0.05). Namely, they reported that B60 increases susceptibility to AS in B27+ patients while it does not seem to be a predisposing factor in the absence of B27 antigen (6). Our results indicate that there are no additional HLA-B alleles that are involved in a synergistic effect with B27 in a population of Croatian AS patients. This lack of agreement about association between AS and other HLA class I alleles could be explained by genetic characteristic of each population reported, but also support the hypothesis that B27 itself is major genetic susceptibility factor for AS. The finding of lower frequency of the HLA-A26, -B27 haplotype in the group of AS patients in comparison to B27+ healthy controls (2.0% vs 5.9%, p<0.05) suggest the potentially protective role of this haplotype in the Croatian AS population. This hypothesis needs to be confirmed on the larger group of patients bearing B27 haplotypes. Molecular typing of HLA-B27 subtypes was performed in a group of 45 unrelated AS patients and in a group of 38 B27+ healthy controls. The Croatian population showed quite similar distribution of B27 subtypes as in other Caucasoid reported so far (1). AS patients possessed similar B27 subtypes as B27+ control individuals. The B*2705 allele was the most common allele in AS patients and B27+ controls (83.3% and 73.7%, respectively), while B*2702 was the second common allele in both groups (12.5% and 23.7%, respectively). The data from different populations suggest that both, B*2702 and B*2705, are positively associated with AS (1, 2). The other two subtypes observed in Croatian AS patients, B*2701 and B*2704, are previously reported as alleles associated with AS. B*2704 subtype is positively associated with AS in Oriental populations but its presence is also reported in Mary population (Finno-Ugorian population from Russia). Thus, it seems that this allele is not only present in Orientals, as was suggested by Lopez-Larrea and which is further supported by this study (2). At this moment it is not possible to make conclusion for positive or non-association between B*2701 and AS because the publishing data are based on a small number of AS patients. Present study did not demonstrate any of B27 alleles as susceptible or protective genetic marker for AS in the Croatian population and it fits into frame about oldness of association between AS and B27. Namely, AS appears to be older than the origin of the B27 subtypes. However, it is necessary to enlarge study on AS patients from different racial groups to make definitive conclusion about this association. For that reason, our data will help to make world-wide picture of distribution of B27 subtypes and will serve for better characterisation of the role of B27 subtypes in pathogenesis of AS. REFERENCES Gonzales-Roces S, Alvarez MV, Gonzales S, Dieye A, Makni H, Woodfield DG, et al. HLA-B27 polymorphism and worldwide susceptibility to ankylosing spondylitis. Tissue Antigens 1997;49:116-23. Lopez-Larrea C, Sujirachato K, Mehra NK, Chiewsilp P, Isarangkura D, Kanga U, et al. HLA-B27 subtypes in Asian patients with akylosing spondylitis. Tissue Antigens 1995;45:169-76. Amos DB, Bashir H, Boyle W, MacQueen M,. Tiilikainen A. A simple microcytotoxicyty test. Transplantation 1969;7: 220-3. Olerup O. HLA-B27 typing by a graoup-specific PCR amplification. Tissue Antigens 1994;43:253-6. De Juan MD, Reta A, Cancio J, Belzungui J, Cuadrado E. HLA-A*9, a probable secondary susceptibility marker to ankylosing spondylitis in Basque patients. Tissue Antigens 1999;53:161-6. Robison WP, van der Linden SM, Khan MA, Rentsch HU, Cats A, Russell A, et al. HLA-Bw60 increases susceptibility to akylosing spondylitis in HLA-B27+ patients. Arthritis Rheum 1989;32:1135-41. .Aࡱ> SummaryInformation( a informatikuUprava za informatiku@=:5-@Y@=:5-@F#Microsoft Word 6.02ࡱ> BCu()+,t u u[hUBCuvuvwxyz*+1) x d<$ h 4h.!K @ Normal ]a c"A@"Default Paragraph Font!!   ,x  XUprava za informatikuC:\RADOVI\B27LET.DOCUprava za informatikuC:\RADOVI\000116.DOC@HP DeskJet 690C Series PrinterLPT1:HPFDJC07HP DeskJet 690C Series Printer7 d,,HP DeskJet 690C Series PrinterLPT1 ,,HP DeskJet 690C Series Printer7 d,,HP DeskJet 690C Series PrinterLPT1 ,,::::@Times New Roman Symbol &Arial&Arial CE"hJFJF$AHLA-B27 SUBTYPES IN CROATIAN PATIENTS WITH ANKYLOSING SPONDYLITISUprava za informatikuUprava za informatikuࡱ>