HLA-B5 and B21 antigens in aortoarteritis

Revisited HLA and non-HLA genetics of Takayasu arteritis--where are we?

Takayasu arteritis (TAK) is an immune-mediated vasculitis affecting large arteries first reported in 1908 from Japan. Case reports of familial onset of TAK from Japan and other countries indicated genetic contribution to TAK onset beyond ethnicity. Genetic studies of TAK have been performed mainly addressing the human leukocyte antigen (HLA) locus. HLA genetic studies of TAK that have previously been reported are reviewed in this manuscript. HLA-B*52:01 is associated with TAK beyond population. Many of the associations other than HLA-B*52:01 can be explained by a haplotype with HLA-B*52:01. HLA-B*67:01 is a novel susceptibility HLA-B allele to TAK confirmed in the Japanese population. Further independent associations are suggested in the HLA locus. Involvement of the 171st and 67th amino acid residues with TAK onset has been indicated. The 67th amino acid may explain the difference in susceptibility effects to TAK and Behçet's disease between HLA-B*52:01 and *51:01. HLA-B*52:01 is associated not only with TAK susceptibility but also with clinical phenotypes. Recent genome-wide association studies of TAK revealed multiple non-HLA susceptibility genes. In particular, the IL12B region seems to have a central role in TAK onset and its progression. Whether TAK and giant cell arteritis (GCA), the other vasculitis affecting large arteries, are the same disease is an interesting question to address in spite of different clinical manifestations between the two diseases. GCA is associated with HLA-DR4, which is not associated with TAK. GCA is not associated with HLA-Bw52. These two diseases seem not to share non-HLA susceptibility loci based on the recent genetic studies.

Immunogenetic analysis of Takayasu arteritis in Indian patients

The distribution of HLA-A, B, C and DR antigens was determined in a cohort of 104 unrelated Indian patients with Takayasu arteritis (TA) belonging to the North Indian states of Punjab, Haryana, Uttar Pradesh and Delhi. The data was compared with healthy controls belonging to the same ethnic group. In addition, polymorphism in the MHC class I chain related A (MIC A) gene was studied in a group of 25 TA patients and 40 healthy controls. The data revealed a strong association of the disease with HLA-B5 (chi2=22.5, P<1 x 10(-6), RR=3.08) as well as its two common serological subtypes, B51 (chi2=20.5) and B52 (chi2=18.5). No particular association was observed with any of the five alleles of the MIC A gene, nor any linkage disequilibrium could be established with these alleles and those of HLA-B locus in this population. The observation suggest that HLA linked genes are definitely involved in the development of Takayasu arteritis and that the disease in Indian subjects is associated with HLA-B5 and its two serological subtypes, B51 as well as B52.

Recurrent aortic valve prosthesis dehiscence secondary to aortoarteritis: three case reports and literature review

We report three young Chinese male patients who underwent aortic valve replacement for severe aortic regurgitation of subacute onset, complicated by recurrent dehiscence of the aortic valve prosthesis, due to aortitis. One of the three patients underwent aortic valve replacement three times and progression of the prosthesis dehiscence was arrested with the use of corticosteroids. A review of the literature on the prognosis and treatment of aortoarteritis with particular reference to the management of recurrent valvular dehiscence is discussed.

Direct role of HLA-B5 in influencing susceptibility to Takayasu aortoarteritis

To investigate genetic factors involved in the pathogenesis of Takayasu arteritis (TA), North Indian patients belonging to the states of Punjab, Haryana, Uttar Pradesh and Delhi were examined for HLA-class I and class II antigens and the data compared with healthy controls from the same ethnic group. Additionally, DNA typing was performed using polymerase chain reaction/sequence specific oligonucleotide probe (PCR-SSOP) technique to evaluate the distribution of molecular alleles in the healthy Indian population as compared to orientals and Western caucasoids. The frequency of HLA-B5 was significantly increased in patients as compared to controls (chi 2 = 32.5, corrected P value, Pc = 3 x 10(-6), relative risk = 4.3). Serological splitting of B5 into B51 and B52 did not reveal an association with any of the two subtypes. Weak association was also noticed with DR8 in the patient group (chi 2 = 8.2, Pc = 0.05). Distribution of the molecular subtypes of various HLA-B and DR alleles indicated that although the Indian population is essentially caucasoid, it comprises of an admixture of both caucasoid as well as oriental alleles/haplotypes. The observations clearly suggest that (a) HLA-linked genes are involved in the development of Takayasu arteritis, and (b) rather than a subtype of B5, the whole molecule or its closely linked gene(s) influence susceptibility to TA.

Current status of Takayasu arteritis in India

The clinical features of 106 patients of Takayasu arteritis (TA) seen over a period of 16 years are documented (65 females and 41 males). The mean age was 27.3 +/- 9.2 years. Hypertension was the commonest mode of presentation (51.3%) and was detected in 82 patients (77.4%) at the time of presentation. Vascular bruits were heard in 72 patients (67.9%) and 13 patients (12.3%) were in congestive heart failure. Aortography was performed in 95 patients. Based on the extent of involvement, Type I (branches of aortic arch) was seen in 7 (6.6%) patients, Type II (aortic arch, its branches and descending thoracic aorta) in 7 (6.6%) patients, Type III (descending thoracic aorta and abdominal aorta) in 4 (3.8%) patients, Type IV (abdominal aorta only) in 29 (27.3%) patients and Type V (aortic arch, descending thoracic aorta and abdominal aorta) in 59 (55.7%) patients. Therapeutic modalities included antihypertensive drug therapy in 81 patients, antitubercular drugs in 8 patients, steroids in 16 patients and cyclophosphamide in one patient. Response to steroids was satisfactory in 5 of these 16 patients while the lesions of vasculitis healed in the patient who was treated with cyclophosphamide. Surgical interventions included nephrectomy and autotransplantation of kidney in 3 patients each and revascularization in 4 patients and angioplasty in 4 patients. In the area of pathogenesis of this disease, a high activity of protein kinase C(PKC), an increased intracellular calcium and inositol 1,4,5 triphosphate in both unstimulated and stimulated T cells of TA was observed. These findings suggest an activation of PKC-calcium pathway in TA.

Hereditary factors of Takayasu arteritis

Takayasu arteritis is a chronic vasculitis characterized by a clinical pulseless condition and is predominant in young female patients. Its loci is found mainly in Asian countries, and its etiology is still unknown. Our experiences of cases of twin sisters with Takayasu arteritis led us to suppose that hereditary factors participate in the pathophysiology of this disease. Population and family-incidence studies employing HLA analysis in Japan have focused on an complotype Aw24-DW52-C4A2-C4BQ0-Dw12 which was in disequilibrium with Takayasu arteritis. Clinical features and clinical courses were found to be intimately related to this complotype. Recent studies on HLA typing in other countries have also suggested the important roles of hereditary factors in this morbid condition and international collaborative studies on these hereditary factors are now under way.

Takayasu arteritis in Korean children: Clinical report of seventy cases

Seventy cases of Takayasu arteritis in Korean children are reported. There were 57 females and 13 males (male-to-female ratio; 1:4.4). The youngest patient was a 3-year-old female. Family history was positive in one patient. The most common chief complaints on admission were dyspnea, headache, palpitation, and edema which were due to hypertension and congestive heart failure. Hypertension was seen in 65 out of 70 patients (92.8%). The abdominal aorta, thoracic aorta, and renal arteries were the most commonly involved sites in these children. Two patients had nephrotic syndrome. The frequency of positive tuberculin reaction was much higher in children with Takayasu arteritis compared with the general population, and the intensity of the reaction was also stronger. The majority of the patients required immediate medical treatment to control congestive heart failure due to hypertension at initial presentation. When ESR was elevated, corticosteroid was administered. Surgical treatment showed good results in six out of ten cases. Percutaneous intraluminal angioplasty was effective for lowering the blood pressure in six out of nine cases. In three cases, restenosis occurred and angioplasty was repeated in two cases.

HLA Typing of Takayasu arteritis in Korea

Takayasu arteritis occurs with a strong predilection for women and particular geographic areas, and as related to the etiology of the disease, association of HLA antigens has been suggested. In the present study, the authors investigated the association of Takayasu arteritis with class I and class II HLA antigens in 59 Korean patients with this disease. Increased frequencies of HLA-Bw52 (chi 2 6.213, P < 0.02), Cw6 (chi 2 4.132, P < 0.05), DR7 (chi 2 4.506, P < 0.04), and DQw2 (chi 2 7.327, P < 0.01) were observed in the patient group as compared to the control group of healthy Koreans. In the Korean population, 2 risk factors in the HLA system for developing this disease appear to be (1) Bw52 and (2) DR7 and a probable haplotype of Cw6, B13, DR7, DQw2. Previous studies of the Japanese population revealed association of Bw52 and class II HLA antigens (DR2, Dw12), which are in linkage disequilibrium with Bw52. It is of interest that in the Korean population, class II antigens (DR7, DQw2), which are not linked to BW52, are associated with the disease. This finding suggests that the disease susceptibility gene of Takayasu arteritis is located between the HLA-B locus and HLA-DR, DQ loci.