Serum osteoprotegerin and its gene polymorphisms in patients with Takayasu's arteritis: a bicentric cross-sectional study.

INTRODUCTION: Takayasu's arteritis (TAK) patients are at an elevated risk of metabolic syndrome and cardiovascular diseases (CVD). Currently, there are no well-validated biomarkers to assess this risk in this population. Previous research in different cohorts has linked serum levels of osteoprotegerin (OPG) and its polymorphisms to accelerated atherosclerosis and a marker of poor prognosis in CVD. Thus, we assessed this protein as a potential biomarker of CVD in TAK patients. OBJECTIVES: To evaluate the serum levels of OPG and its SNPs (single nucleotide polymorphisms) in TAK patients and healthy controls, and to associate these parameters with clinical data. METHODS: This bicentric cross-sectional study included TAK patients who were compared with healthy individuals (control group). The serum levels of OPG and the frequency of OPG SNPs [1181G > C (rs2073618), 245 A > C (rs3134069), 163T > C (rs3102735), and 209 C > T (rs3134070)] were compared between the both groups and associated with clinical data. RESULTS: In total, 101 TAK patients and 93 controls were included in the study. The serum levels of OPG (3.8 ± 1.9 vs. 4.3 ± 1.8pmol/L, respectively; P = 0.059), and its four polymorphisms were comparable between both groups. In an additional analysis of only TAK patients, serum OPG levels and its four genes were not associated with any CVD parameters, except for higher OPG levels among patients without dyslipidemia. CONCLUSION: No significant differences were observed in serum OPG levels or in the genotype frequencies of OPG SNPs between the patient and control groups. Similarly, no correlation was found between laboratory parameters and clinical data on CVD risk in TAK patients.

Dysregulation of long non-coding RNAs in Takayasu arteritis: A proof-of-concept study.

Takayasu arteritis (TAK) is a rare systemic vasculitis primarily affecting the aorta and its major branches. Early diagnosis is critical to prevent severe vascular complications, yet current biomarkers are insufficient. This proof-of-concept study explores the potential of long non-coding RNAs (lncRNAs) in TAK, an area largely unexplored. In this cross-sectional study, 53 TAK patients, 53 healthy controls, and 10 rheumatoid arthritis (RA) patients were enrolled. Clinical evaluations, disease activity assessments, and lncRNA expression levels were analyzed. TAK patients exhibited significant dysregulation in several lncRNAs, including THRIL (19.4, 11.1-48.8 vs. 62.5, 48.6-91.4 arbitrary units [a.u.]; p < 0.0001), HIF1A-AS1 (4.5, 1.8-16.6 vs. 26.5, 19.8-33.7 a.u.; p < 0.0001), MALAT-1 (26.9, 13.8-52.5 vs. 92.1, 58.5-92.1 a.u.; p < 0.0001), and HOTAIR (8.0, 2.5-24.5 vs. 36.0, 30.0-43.8 a.u.; p < 0.0001), compared to healthy controls. Notably, HOTAIR (area under the ROC curve [AUC] = 0.825), HIF1A-AS1 (AUC = 0.820), and THRIL (AUC = 0.781) demonstrated high diagnostic potential with superior specificity (approximately 95%). While lncRNAs showed diagnostic promise, no significant correlations with TAK activity were observed. Comparative analysis with RA patients revealed distinct lncRNA expression patterns. This study unveils significant dysregulation of lncRNAs THRIL, HIF1A-AS1, and HOTAIR in TAK patients, underscoring their potential as biomarkers and opening avenues for further research into the mechanistic roles of these lncRNAs in TAK pathogenesis.

Polymorphisms in TNFAIP3, but not in STAT4, BANK1, BLK, and TNFSF4, are associated with susceptibility to Takayasu arteritis.

BACKGROUND: Takayasu arteritis (TAK) is considered a rare disease characterized by nonspecific inflammation of the large arteries, especially the aorta and its major branches. Because TAK is an autoimmune disease (AD), it could share susceptibility loci with other pathologies such as systemic lupus erythematosus (SLE), and rheumatoid arthritis (RA), among others. Widely explored polymorphisms in non-HLA genes, including TNFAIP3, STAT4, TNFSF4, BANK1, and BLK have been consistently associated with both SLE and RA, but they have not been evaluated in TAK. OBJECTIVE: The aim of our study was to investigate whether TNFAIP3, STAT4, BANK1, BLK, and TNFSF4 polymorphisms are associated with susceptibility to TAK. METHODS: The TNFAIP3 rs2230926T/G and rs5029924C/T, STAT4 rs7574865G/T, BANK1 10516487G/A, BLK rs2736340T/C, rs13277113A/G, and TNFS4 rs2205960G/T polymorphisms were genotyped in 101 cases and 276 controls by using a TaqMan SNP genotyping assay. An association analysis was performed. RESULTS: The TNFAIP3 rs2230926T/G and rs5029924C/T polymorphisms were in complete linkage disequilibrium and turned out to be risk factors for TAK (OR = 4.88, p = 0.0001). The STAT4, BANK1, BLK, and TNFSF4 polymorphisms were not associated with the disease. CONCLUSIONS: This is the first study documenting an association of TNFAIP3 rs2230926T/G and rs5029924C/T with TAK. Our results provide new information on the genetic bases of TAK.

Lack of Association between Cytokine Genetic Polymorphisms in Takayasu's Arteritis in Mexican Patients.

Aim: To investigate the relation between polymorphisms in the interleukin 10 (IL)-10, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß and interferon (IFN)-γ genes and Takayasu's arteritis in the Mexican population. Methods: A case-control study was performed to investigate the associations of IL-10, TNF-α, TGF-ß and IFN-γ polymorphisms in a sample of 52 Takayasu's arteritis patients, diagnosed according to the criteria of the American College of Rheumatology and EULAR PRINTO criteria when the patients were under 18 years of age; 60 clinically healthy unrelated Mexican individuals by the 5' exonuclease TaqMan polymerase chain reaction. Polymorphic haplotypes were constructed after linkage disequilibrium analysis. Results: Significant differences were not found in the distribution for genotype and allele frequencies of the polymorphisms studied between healthy controls and Takayasu´s arteritis patients. Likewise, significant associations were not detected in the haplotype analysis with the different genes studied. Conclusions: These findings suggest that the polymorphisms in IL-10, TNF-α, TGF-ß and IFN-γ might not contribute to the susceptibility of Takayasu´s arteritis in the Mexican population.

Takayasu Arteritis: Recent Developments.

PURPOSE OF REVIEW: Takayasu arteritis (TA) is a granulomatous inflammatory disorder that affects large vessels, especially aorta and its proximal branches. Its diagnosis can be extremely challenging due to the non-specificity of the systemic inflammatory manifestations during the early phase of the disease and usually follows an insidious clinical course until the emergence of vascular ischemic complications. RECENT FINDINGS: Its pathogenesis has been better delineated in recent years, especially the role of HLA-B*52 allele in certain ethnic groups, as well as the use of biological therapy, and surgical revascularization. Recent findings are discussed in depth. Clinical and epidemiological aspects of TA, recent developments in pathogenesis, and therapy are presented.

An association study in PTPN22 suggests that is a risk factor to Takayasu's arteritis.

OBJECTIVES: Takayasu's arteritis (TA) represents a rare autoimmune disease (AD) characterized by systemic vasculitis that primarily affects large arteries, especially the aorta and the aortic arch and its main branches. Genetic components in TA are largely unknown. PTPN22 is a susceptibility loci for different ADs; however, the role of different PTPN22 single-nucleotide polymorphisms (SNPs) in the susceptibility to TA is not clear. METHODS: We evaluated the PTPN22 R620W (C1858T), R263Q (G788A), and - 123G/C SNPs in a group of patients with TA and in healthy individuals from Mexico. Our study included 111 patients with TA and 314 healthy individuals. Genotyping was performed with the 5' exonuclease (TaqMan®) assay. RESULTS: Our data showed that the PTPN22 R620W polymorphism is a risk factor for TA (CC vs. CT: OR 4.3, p = 0.002, and C vs. T: OR 4.1, p = 0.003); however, the PTPN22 R263Q and - 1123G/C polymorphisms are not associated with this AD. In addition, the PTPN22 CGT haplotype, which carries the minor allele of the PTPN22 C1858T variant, was also associated with TA susceptibility. CONCLUSION: This is the first report documenting an association between PTPN22 R620W and TA.

Takayasu arteritis in paediatrics.

Takayasu arteritis is an idiopathic chronic granulomatous panarteritis predominantly affecting the aorta and its main branches. Although idiopathic, genetic contribution to disease susceptibility is being increasingly recognised. Rare in children, Takayasu arteritis is a worldwide disease with significant morbidity and mortality. Its diagnosis is a challenge and requires awareness of the condition as clinical features at presentation are non-specific and assessing disease activity is difficult. In the inflammatory stage, treatment is essential to prevent the insidious course and vascular damage: stenotic, occlusive lesions, aneurysms, and aortic regurgitation. New imaging modalities, such as CT scan, MRI, and 18F-fluorodeoxyglucose positron emission tomography, have expanded the possibilities for non-invasive diagnosis and monitoring; however, digital subtraction arteriography remains the gold standard for the diagnosis of Takayasu arteritis. Steroids are the first-line medical treatment. The combined use of methotrexate, cyclophosphamide, azathioprine, mycophenolate mofetil, and biological agents is common. Revascularisation therapy should be considered in uncontrolled hypertension secondary to renal artery stenosis, symptomatic coronary ischaemia, cerebrovascular disease, severe aortic regurgitation, limb ischaemia, and aneurysms at risk of rupture, using surgical or endovascular procedures and taking into consideration that complications, especially restenosis, are frequent. Disease activity increases the likelihood of complications after revascularisation. Surgical intervention has shown better long-term outcomes, although the endovascular approach is evolving. The aim of this review was to describe key points of the diagnosis, treatment, and follow-up of Takayasu arteritis in childhood.

PON1 gene polymorphisms and plasma PON1 activities in Takayasu's arteritis disease.

BACKGROUND: Takayasu's arteritis (TA) is a chronic inflammation that affects the large vessels; however, its etiology is still unknown. Human serum paraoxonase hydrolyzes oxidized lipids into low-density lipoproteins and could therefore be associated with the prevalence of inflammation processes. Therefore, the purpose of study was to elucidate the influence of PON1 gene polymorphisms and plasma PON1 activities in Takayasu's arteritis disease. METHODS: Fifty-four patients with TA and 173 clinically healthy Mexicans were studied. The PON1 polymorphism was determined by the TaqMan PCR method. PON1 activity was assessed spectrophotometrically by paraoxon (p-nitrophenylphosphate) hydrolysis. RESULTS: In TA patients, the frequency of PON1(192R) allele (51% vs. 39%, P=0.043, OR=1.60, 95% CI=1.03-2.47), PON1(55M) allele (21% vs. 6.6%, P=0.0001, OR=3.80, 95% CI=2.03-7.10), and PON1(-108T) (60.1% vs. 46%, P=0.011, OR 1.79 (95% CI=1.15-2.79) were significantly higher than in healthy controls. PON1 activity was significantly lower for PON in TA vs. controls (136.14 vs. 322.79 µmol min(-1) ml(-1), P=0.001, showing a decreasing activity in all genotypes in TA patients with respect to the control subjects. CONCLUSIONS: These results show significantly lower PON1 activity associated with HDL-C in TA patients, this activity could be depending on PON1 genotypes; showing that QR/LM/CT has the lowest hydrolytic activity toward paraoxon meanwhile, PON1(192,55,-108) genetic variations are related with reduced PON1 activities, these could be factors contributing to the development of TA disease.

The interleukin-1 gene cluster polymorphisms are associated with Takayasu's arteritis in Mexican patients.

Takayasu's arteritis (TA) is a chronic inflammatory arteritis of unknown etiology involving mainly the aorta and its major branches. The interleukin (IL) 1ß and IL-1 receptor antagonist have been playing an important role as regulators of inflammation. We investigated whether the polymorphisms at the IL-1B and IL-1RN gene cluster were associated with the genetic susceptibility to develop TA. We analyzed the IL-1B, IL-1F10.3, and IL-1RN polymorphisms in a sample of 58 TA patients, and 248 clinically healthy unrelated Mexican individuals by 5' exonuclease TaqMan polymerase chain reaction. Polymorphic haplotypes were constructed after linkage disequilibrium analysis. We found increased frequencies of different polymorphisms (C allele and TC genotype of IL-1F10.3; TT genotype of IL-1RN.4; C allele and TC genotype of IL-1RN6.1; G allele of IL-1RN6.2 and haplotypes "1T" and "1C" of IL-RN VNTR and IL-1RN6.1) in the group of TA when compared to healthy controls. On the other hand, decreased frequency of IL-1-511 TC genotype was found in the TA group compared to controls. IL-1B and IL-1RN gene polymorphisms could be involved in the risk of developing TA in the Mexican population. These associations were independent of the affected vessels.

Arterite de Takayasu em uma lactente com história de dois familiares acometidos / Takayasu's arteritis in an infant with a family with three affected siblings

Objetivos: Por um período consecutivo de 27 anos, 5367 pacientes foram acompanhados na Unidade de Reumatologia Pediátrica do Instituto da Criança. Destes, 17 (0,003%) casos tiveram o diagnóstico de arterite de Takayasu. Uma delas (0,0001%) apresentou antecedentes familiares desta vasculite primária e será descrita. Descrição: Os autores reportam uma lactente do sexo feminino, com história familiar de três irmãos acometidos por arterite de Takayasu. Esta paciente, com 8 meses de idade, apresentou acidente vascular encefálico, hipertensão arterial com diferença de pressão arterial nos quatro membros e redução dos pulsos periféricos. As provas de atividade inflamatória foram elevadas: velocidade de hemossedimentação 37 mm/1ª hora e proteína C reativa 19 mg/L. A angiorressonância evidenciou estenoses de aorta infra-renal, artérias carótidas, artérias cerebral anterior direita e renais, preenchendo os novos critérios de arterite de Takayasu. O tratamento foi realizado com corticoterapia, metrotrexate, pulsoterapia com ciclofosfamida e anti-hipertensivos, com melhora discreta da hipertensão. Conclusão: Arterite de Takayasu é uma vasculite rara em um serviço terciário de reumatologia pediátrica e este diagnóstico deve ser considerado em lactente com doença vascular e redução dos pulsos arteriais...

Objectives: For a period of 27 consecutive years, 5079 patients were followed at the Pediatric Rheumatology Unit of the Instituto da Criança. Of these, 17 (0.003%) cases had a diagnosis of Takayasu’s arteritis. One (0.0001%) had family history of primary vasculitis and will be described. Description: The authors report a female infant with familial history of three siblings affected by Takayasu’s arteritis. This patient’s at 8-month-old had stroke, hypertension with blood pressure differences in all four limbs and reduction of peripheral pulses. The evidence of inflammatory activity was high: erythrocyte sedimentation rate 37 mm/1st hour and C-reactive protein 19 mg/L. The magnetic resonance imaging showed stenosis of the infrarenal aorta, carotid arteries, right anterior cerebral arteries and kidney, filling the new criteria of Takayasu’s arteritis. The treatment was carried out with steroids, methotrexate, intravenous cyclophosphamide and anti-hypertensive drugs, with a slight improvement in hypertension. Conclusion: Takayasu’s arteritis is a rare vasculitis in a tertiary pediatric rheumatology and this diagnosis should be considered in children with vascular disease and reduction of arterial pulses...

Comparative study of the residues 63 and 67 on the HLA-B molecule in patients with Takayasu's arteritis and tuberculosis.

Takayasu's arteritis (TA) and tuberculosis (TB) have been associated with major histocompatibility complex genes, especially HLA-B alleles. However, different HLA-B alleles have been detected in these diseases. The aim of the study was to compare the distribution of the residues 63 and 67 on the HLA-B molecule in patients with TA and TB in order to establish a genetic relationship between these two diseases. HLA-B sequences obtained in 30 patients with TB were compared to those previously reported in TA and healthy controls. 8 out of 30 TB patients studied (26.6%) presented at least one allele with glutamic acid at position 63 and serine at position 67. This was observed in 73% of the TA patients (p = 0.0005). Ten TB (10/30 = 33.3%) and two TA patients (2/26 = 7.7%) did not show similarity at the mentioned positions (p = 0.019). This preliminary study suggests a difference in the distribution of the residues 63 and 67 of the HLA-B alleles in patients with TA and TB.

Comparison distribution of HLA-B alleles in mexican patients with takayasu arteritis and tuberculosis.

A possible relationship between Takayasu arteritis (TA) and Tuberculosis (Tb) has been suggested. Both diseases present similar chronic inflammatory lesions and occasionally granulomas on the arterial walls. The genetic relationship between these two diseases has not been explored before, however, both diseases have been associated with human leukocyte antigen (HLA) alleles. Therefore, the aim of the present study was to analyze the distribution of HLA-B alleles in TA (n = 40) and Tb (n = 34) patients and healthy controls (72 exposed and 99 nonexposed). HLA-B alleles were determined by reverse dot blot. The statistical methods used included the Chi(2), and odds ratio (OR) with 95% confidence intervals. In spite of the loose clinical relationship between TA and Tb, we did not detected any genetic relationship between them when the HLA-B alleles were analyzed in these groups of patients. On the contrary, we detected distinct specific HLA-B alleles for each disease. TA was characterized by HLA-B39, -B44, and -B52, pulmonary Tb by HL-B35 and extrapulmonary Tb by HLA-B39 and -B40. This preliminary study suggests a difference in the distribution of HLA-B alleles in patients with TA and Tb.

Comparative study of the residues 63 and 67 on the HLA-B molecule in patients with Takayasu's Arteritis.

Takayasu's Arteritis (TA) has been associated with the Major Histocompatibility Complex (MHC) genes; nevertheless, results in several populations have been heterogeneous. Studies both in Mexican and Asian populations suggest that residues at positions 63 (glutamic acid) and 67 (serine) of the HLA-B molecule could be the genetic markers for TA. In the present work, we analyzed the sequence of HLA-B alleles in 26 TA patients and 62 healthy controls. HLA-B subtyping analysis showed that all B52 alleles were B*5201, whereas only one HLA-B39 allele was B*3902. Sequencing of HLA-B alleles showed that 19 out of 26 patients studied (73.0%) presented at least an allele with glutamic acid at position 63 and serine at position 67. This condition was observed in only 21.0% of the healthy controls (pC = 0.00001, OR = 10.23). Out of the seven remaining patients, one presented glutamic acid at position 63 and four showed serine at position 67. Two patients (2/26 = 7.7%) and 24 healthy controls (24/62 = 38.7%) did not show similarity at the mentioned positions (pC = 0.016, OR = 0.13). These data corroborate the participation of positions 63 and 67 in the genetic susceptibility to TA and explain the high heterogeneity of alleles associated with the disease in several populations.

[Alleles of the major histocompatibility system associated with susceptibility to the development of Takayasu's arteritis]. / Alelos del sistema principal de histocompatibilidad relacionados con la susceptibilidad al desarrollo de la arteritis de Takayasu.

OBJECTIVE: Since 1972, the relationship between HLA alleles and the susceptibility for Takayasu arteritis (TA) has been studied on different populations. Hence the results up to date are heterogeneous, the objective of the present review is to analyze the relationship between the presence of HLA alleles and the susceptibility for the development of TA considering the ethnic origin of the studied populations. MATERIAL AND METHODS: We carried out a bibliographic review from clinical articles of case and controls studies on different populations on which the relationship between HLA alleles and the susceptibility for TA was studied, published since 1972 until February 2000. RESULTS: We reviewed articles of studies on Asian, Arab, North-American and Mexican Mestizo populations. On Asian populations TA was associated with HLA-A31, -B52, -B39, -B5 and -DR2, on Arabs with HLA-A2, -A9, -B35 and -DR7, on North-Americans with HLA-DR4 and on Mexican Mestizo with HLA-B5, -B52 and -DR6. On the other hand, recent reports establish that several HLA-B alleles (HLA-B52 and HLA-B39) associated with the disease share some residues important on the antigen presentation. CONCLUSIONS: Hence the heterogeneity of the results obtained up to date, it stands out the increase on HLA-B52 and HLA-DR4 reported on ethnically different populations. More recent data point the possible participation of an epitope located on the peptide-binding site of the HLA-B molecule (positions 63 and 67) that seems to be shared by several alleles associated with the disease. These residues might be participating on the presentation of an unknown antigen that would unchain the disease on the genetically susceptible individuals group.

Immunogenetics and clinical aspects of Takayasu's arteritis patients in a Mexican Mestizo population.

OBJECTIVE: The aim of the present work was to study the association between HLA alleles and Takayasu's arteritis in Mexican Mestizo patients. METHODS: The study included 26 Mexican Mestizo patients with Takayasu's arteritis and 99 healthy unrelated individuals. HLA-A, -B and -DR alleles were determined by polymerase chain reaction PCR-SSP RESULTS: Increased gene frequencies were demonstrated for HLA-B15(p=0.009,pC=0.020,OR=3.24,EF=11.9%) and HLA-B52 (p=0.008, pC=0.027, OR=5.16, EF=7.7%), and a decreased frequency for the HLA-A24 allele in patients compared to normal controls (p=0.035, pC=NS, PF=11.1%). When HLA typing was correlated to clinicalfeatures in 24 cases, wefound an increasedfrequencies of HLA-DR14 in patients with systemic arterial hypertension (p=0.005, pC=0.004, OR=24.6, EF=38.3%) and HLA-A2 on patients with pulmonary involvement (p=0.034, pC=0.036, OR=3.67, EF=40.4%) when compared to patients without these clinical manifestations. CONCLUSION: These data confirm HLA-B52 as a relevant susceptibility allele for Takayasu's arteritis and suggest that HLA-B15 could be important as a marker of the disease in Mexican patients. Other class I and/or class II alleles could also be relevant as markers for the clinical features present in these patients.

Association of HLA-DRB1*1602 and DRB1*1001 with Takayasu arteritis in Colombian mestizos as markers of Amerindian ancestry.

We performed HLA Class I and Class II typing in 16 patients (15 women, one man) with a confirmed diagnosis of Takayasu arteritis. We did not find any of the previously described associations with HLA-B52, and/or HLA-DRB1*1301 alleles. However, in our patients, HLA-DRB1*1602 and HLA-DRB1*1001 were significantly increased. The association of Takayasu arteritis with Amerindian and Asian HLA-DRB1 alleles (DRB1*1602 and DRB1*1001) in the Colombian mestizo patients reported here, and with HLA-B*3906 previously reported in Mexicans, suggest the possibility that some HLA and disease associations are markers for ethnicity of a population carrying a disease gene which is present in an admixed population with the disease.

DNA sequencing of HLA-B alleles in Mexican patients with Takayasu arteritis.

Takayasu arteritis (TA) is characterized by a 'pulseless' condition and occurs frequently in young females from Asian and South American countries. It has been associated with Mayor Histocompatibility Complex (MHC) genes in different populations. Recent data indicate direct participation of HLA-B alleles in the susceptibility to the disease. This fact was explored in an associative study with TA to establish if some region in the exon 2, intron 2 or in the exon 3 of HLA-B alleles is common in the alleles associated with TA and at the same time to know if a specific sequence or an epitope, more than an allele, would be responsible for the susceptibility to this vasculitis. We studied HLA-B alleles of 12 Mexican patients with TA using PCR-SSP and sequencing. The analysis by PCR-SSP in 12 patients showed that five of them showed the B*15 allele, three the B*40 allele and two the B*39 allele, the remaining two presented the B*44 allele. Sequence analysis enabled us to define that the B*39 subtypes are B*3908; B*15 subtypes are B*1510, B*1515, B*1522 and B*1531; and the B*40 subtypes are B*4005 and B*4008. An individual with B*51 (B*5107) and another with B*52 (B*5201) alleles were also identified. The sequences of the intron 2 seem be heterogeneous. Analysis at the 63 and 67 positions of HLA-B alleles showed that 9 of them have similarity in some of these positions with the residues detected in the B*5201 and B*3902 alleles associated with TA in Asian populations. The results indicate that there is heterogeneity in the alleles associated with TA in Mexicans but, in spite of that heterogeneity, the alleles associates can be separated into three groups: B*39, B*15 and B*40, whose subtypes are rare and apparently of recent generation in Mexico, probably by recombination events at intron 2 level. The sequences analysis also shows that most of the alleles detected in the Mexican patients share two epitopes described in the susceptibility alleles in Asian populations, suggesting that these epitopes could be responsible for the susceptibility to develop the disease in spite of the allele in which are found.

Intron 2 and exon 3 sequences may be involved in the susceptibility to develop Takayasu arteritis.

We studied Major Histocompatibility Complex (MHC) Class I and Class II genes in seven Mexican Mestizo patients with Takayasu arteritis. Takayasu arteritis is an uncommon condition in Mexican Mestizo, however, previous studies report association of the disease in this population with Human Leukocyte Antigen (HLA)-B39 and HLA-DRB1*1301. The results in the present study show that the haplotypes of the Mexican Mestizo patients with Takayasu arteritis are very heterogeneous, even when the disease is much more rare in Mexico than in Japan. The sequence analysis of HLA-B39 shows that Mexican patients exhibit the HLA-B*39061 and HLA-B*39062 subtypes. These subtypes are more common in Mexico than in Japan, where the predominant subtype is HLA-B*3901. Interestingly, HLA-B*39061 and B-39062 share the 3' end of intron 2 and the 5' end of exon 3 with HLA-B*5101 and B*52012, alleles associated to Takayasu arteritis in Japanese. This fact suggests that Takayasu arteritis patients may share a specific sequence rather than a specific allele, even when the gene involved in the susceptibility to develop Takayasu arteritis may be a neighboring gene located between the genes related at present time with the disease, i.e. a gene located between MHC Class I and Class II regions.

HLA-DR6 (possibly DRB1*1301) is associated with susceptibility to Takayasu arteritis in Mexicans.

Takayasu arteritis is characterized by a "pulseless" condition and occurs frequently in young females from Asian and South American countries. This disease has been found to be linked with major histocompatibility complex (MHC) antigens in Japanese individuals. In the present study we compared gene frequencies of class I, class II, and class III MHC genotypes in patients with Takayasu arteritis and ethnically matched healthy controls. Serological typing was confirmed by molecular typing at the DNA level. We found significant increases in the frequencies of human leucocyte antigen (HLA)-DR6 and HLA-B62 in patients compared to the healthy controls (P corrected [C] = 0.0007, relative risk [RR] = 5.08; PC = 0.05, RR = 3.13 respectively). However, since the number of patients was considerably lower than the number of controls this can be considered as a tendency and not a true association. On the other hand, we found a significantly decreased frequency of HLA-DR4 in patients compared to healthy controls (PC = 0.04, RR = 0.34). At the DNA level, all DR6-positive individuals were HLA-DRB1*1301 whereas controls were HLA-DRB1*1301 (4.2%). Takayasu arteritis in Mexicans is probably associated with the HLA-DR6 (DRB1*1301) gene.