HLA-B Haplotypes Research Articles

The distribution of polymorphic Alu insertions within the MHC class I HLA-B7 and HLA-B57 haplotypes

There are five polymorphic Alu insertion (POALIN) loci within the major histocompatibility complex (MHC) class I region that have been strongly associated with HLA class I alleles, such as HLA-A1, HLA-A2 and HLA-B57. In order to assess the variability and frequency of POALIN distribution within two common HLA-B haplotypes, we detected the presence of the MHC class I POALIN by PCR in a panel of 15 individuals with HLA-B57 and 47 homozygous individuals with 7.1 AH (HLA-B7, -Cw7, -A3) obtained from the Australian Bone Marrow Donor Registry, and also from four families (25 individuals) containing the HLA-B57 allele. Only two of the 47 HLA-B7 genotypes had a detectable POALIN, whereas all of the HLA-B57 genotypes had at least one or more POALINs present, confirming that certain MHC class I haplotypes are relatively POALIN-free and others are POALIN-enriched. Six distinct HLA-B57 haplotypes, based on differences at the HLA-A locus and three of five POALIN loci, were identified that appear to have evolved by different mechanisms, including either by shuffling different combinations of conserved alpha and beta blocks or by recombination events involving two or more previously generated HLA-B57 haplotypes.

Association of MHC dimorphic Alu insertions with HLA class I and MIC genes in Japanese HLA-B48 haplotypes.

A large proportion of Japanese with the HLA-B48 allele have a MICA gene deletion associated with a MICB null allele within the class I region of the Major Histocompatibility Complex (MHC). Here, we report for the first time a novel positive association between the presence of a polymorphic Alu insertion, AluyMICB, within the first intron of the MICB gene and the MICAdel/MICBnull/HLA-B48 haplotype for five of six well-characterized Japanese cell-lines. The AluyMICB insertion was found to be present at a frequency of 0.242 in 86 Japanese tissue donors and in four of the five individuals with the HLA-B48 allele. The AluyMICB insertion was also associated with at least three different MICB alleles, *0102, *0107N and *0105, and three different HLA-B alleles, B13, B48 and B57, respectively, in the seven Workshop cell-lines (the 4th Asia-Oceania Histocompatibility Workshop, and the 10th International Histocompatibility Workshop) and the six Japanese cell-lines that were selected for this study. Based on the analysis of associations between different polymorphic markers within the beta block, the MICB*0102 allele was inferred to be the ancestral form of the MICB*0105 and MICB*0107N alleles. The AluyMICB polymorphism can now be used to further investigate its relationship with other MICB alleles and consequently their origins. In addition, we have examined the absence and presence of three other polymorphic Alu markers distributed within the alpha block of the class I region of the HLA-B48/AluyMICB haplotype. We conclude that the extended HLA-B haplotypes are best defined by considering multiple genomic sites including the four polymorphic Alu insertions described in this study.

Mapping of the HLA-linked genes controlling the susceptibility to Takayasu’s arteritis

To further define the HLA-linked genes controlling the susceptibility to Takayasu’s arteritis, polymorphisms in five microsatellites around the HLA-B and MICA genes, C1-2-A, MIB, C1-4-1, C1-2-5, and C1-3-1, were investigated in 91 Japanese patients with Takayasu’s arteritis and 248 healthy Japanese controls. It was found that allele 238 of C1-2-A [60.4% in patients vs. 29.8% in controls, odds ratio (OR)=3.59, P c<0.000004], allele 332 of MIB (22.0% vs. 6.1%, OR=4.32, P c<0.0003), allele 208 of C1-2-5 (47.3% vs. 24.6%, OR=2.75, P c=0.001), and allele 291 of C1-3-1 (62.6% vs. 44.8%, OR=2.07, P c<0.02) were significantly associated with the disease. Combined analyses of polymorphisms in the HLA-B and MICA genes with those in the microsatellites suggest that there are two different disease-susceptible loci for Takayasu’s arteritis; one is mapped near the C1-2-A locus and the other is more closely linked to the HLA-B gene than to the MICA gene, because there are at least two different disease-associated HLA-B haplotypes, HLA-B*52 and -B*39.2 haplotypes, in which the disease-associated C1-2-A allele is shared in common.

Functional deficiencies of components of the MHC class I antigen pathway in human tumors of epithelial origin.

An association between oncogenic transformation and repression of different components of the MHC class I antigen processing machinery (APM) have been described in murine model systems. In order to discover whether a similar correlation exists, human tumor cell lines of distinct histology with altered ras protein were analyzed for the expression of APM components utilizing RT-PCR and Western blot analyses. A heterogeneous expression pattern of MHC class I antigens, TAP peptide transporter, proteasome subunits, proteasome activator PA28 and the chaperones calnexin, calreticulin as well as tapasin was displayed by these tumor cell lines. Single or combined deficiencies in the expression and/or function of TAP, LMP2, LMP10 and tapasin were demonstrated in 11 of 12 cell lines studied, whereas the expression of calnexin, calreticulin, beta2-microglobulin, LMP7 and PA28alpha was unaltered or only weakly decreased. The impaired expression of TAP, LMP subunits and tapasin was not associated with altered ras, but resulted in reduced MHC class I surface expression. In particular, a significant allele- and locus-specific downregulation of the HLA-A and HLA-B haplotypes was found. IFN-gamma treatment corrected the TAP, LMP and tapasin deficiencies and enhanced the constitutive PA28alpha, LMP7, calnexin and calreticulin expression which was accompanied with increased levels of MHC class I antigens. Thus, dysregulation rather than structural alterations of different APM components might be one mechanism of colon carcinoma, small cell lung carcinoma and pancreatic carcinoma cell lines to evade immune recognition.

Evolution of chronic recurrent multifocal osteitis toward spondylarthropathy over the long term.

To retrospectively assess, with a sufficiently long followup (mean 11.6 years; median 9 years), the long-term outcome of chronic recurrent multifocal osteitis (CRMO), a multifocal, inflammatory bone disease. Patients included were 8 children/adolescents and 7 adults with no family history of rheumatic disease who had been diagnosed as having CRMO between 1979 and 1995. Ten patients had undergone at least 1 bone biopsy of the lesions, with histologic examination and multiple cultures. In 1996, in addition to an in-depth interview, 12 patients underwent an extensive physical examination, laboratory evaluation, HLA-A, B, C, and DR typing, bone radiography and scintigraphy, and computed tomography scan of the sternoclavicular and sacroiliac joints. Remission was observed in 3 patients. The other 12 patients developed various associations of vertebral (n = 10), sacroiliac (n = 6), anterior thoracic (n = 7), peripheral articular (n = 2), enthesopathic (n = 4), or dermatologic (palmoplantar pustulosis in 3 cases and psoriasis in 2) involvements. Spine involvement was the most common and occurred the earliest (median time to appearance after the onset of osteitis 5.63 years). Clinical sacroiliitis was always unilateral. No patients carried the HLA-B27 haplotype. CRMO responded well to nonsteroidal antiinflammatory drugs. Twelve patients met the European Spondylarthropathy Study Group criteria for spondylarthopathy. After 10 years, CRMO had usually evolved to spondylarthropathy, but with certain features not usually seen in the latter: predominantly, unilateral sacroiliitis, no familial form, and no link with HLA-B27.

Outcomes in anterior uveitis associated with the HLA-B27 haplotype

Objective This study aimed to test the hypothesis that patients presenting with anterior uveitis who are HLA-B27 positive, either with or without associated systemic disease, have a less-favorable outcome than do patients with idiopathic anterior uveitis who are HLA-B27 negative. Design Retrospective case-controlled series. Participants Ninety-seven patients who were HLA-B27 positive with no systemic disease, 94 patients who were HLA-B27 positive with systemic disease, and 72 patients who were HLA-B27 negative who presented with anterior uveitis were studied. Main outcome measures Ocular complications (e.g., secondary glaucoma, cataract formation, pupillary synechiae, vitritis, cystoid macular edema, and optic disc edema), medical and surgical treatment, number of recurrent attacks, and final visual acuity were recorded for all patients. Results The patients who were HLA-B27 positive, either with or without systemic disease, experienced a greater number of complications than did the patients who were HLA-B27 negative. Periocular corticosteroids, systemic corticosteroids, and systemic immunosuppressive chemotherapy were required in a far greater number of HLA-B27-positive patients than in HLA-B27-negative patients (60% vs. 11%, 53% vs. 7%, and 18% vs. 1%, respectively; P < 0.001). The percentage of legally blind eyes was significantly greater in the HLA-B27-positive group, both with and without systemic disease, when compared with the HLA-B27-negative group (11% vs. 2%; P < 0.005). Conclusions The prognosis of anterior uveitis associated with the HLA-B27 haplotype, either with or without associated systemic disease, is less favorable when compared with that of HLA-B27-negative patients with idiopathic anterior uveitis.

MICA gene and ankylosing spondylitis: linkage analysis via a transmembrane-encoded triplet repeat polymorphism.

In order to address the possibility that the MICA gene located 47 kb upstream from HLA-B is involved in the pathogenesis of ankylosing spondylitis (AS), we have investigated microsatellite polymorphism in the transmembrane region of MICA in Caucasian patients with AS. The microsatellite allele consisting of 4 repetitions of GCT/AGC was present at significantly higher frequency in the patient group (Pc<0.0000001) than in the ethnically matched control group. However, the frequency of the (GCT/AGC)4 allele was significantly low in the B27-positive patients than in the B27-positive healthy controls (Pc=0.0145). These observations suggest that B27 itself remains the primary genetic marker for AS, although the significantly dissimilar phenotype frequency of the (GCT/AGC)4 allele in B27-positive patients and healthy individuals may reflect the existence of other genetic factor(s) in the HLA-B27 haplotype involved in the development of AS.

HLA-B27-Associated Uveitis Presenting With Diffuse Vitritis

A 26-year-old man complained of a sudden decrease in vision in the left eye. He had a past medical history of pauciarticular juvenile rheumatoid arthritis with a positive HLA-B27 haplotype and negative antinuclear antibodies and later development of ankylosing spondylitis. His ocular history was unremarkable. An ophthalmic examination revealed a predominant diffuse vitritis (3+) in the left eye. The uveitis improved after treatment with topical and systemic steroids. Following an extensive clinical and laboratory evaluation, a final diagnosis of HLA-B27-associated uveitis was made. Although uncommon, diffuse vitritis can occur in the setting of this uveitis and may be a predominant symptom.

TAP1 and TAP2 polymorphism in HLA-B27-positive subpopulations: no allelic differences in ankylosing spondylitis and reactive arthritis

The polymorphic TAP1 and TAP2 genes encode subunits of the transporter that delivers peptides to the HLA class I molecules. Because the polymorphism of the TAP genes has been shown to affect peptide transport, it has been suggested that TAP genes are potential regulators of the immune response. We studied TAP1 and TAP2 polymorphism in two multifactorial HLAB27-associated diseases, ankylosing spondylitis ( N = 30) and reactive arthritis ( N = 30), in order to establish whether TAP genes are involved in the different pathogenesis of these diseases. Healthy HLA-B27-positive individuals ( N = 55) were chosen as the primary controls and 93 individuals represented the random Finnish population as secondary controls. We found differences between the random and HLAB27-positive populations, thus suggesting that certain TAP alleles are prevalent in HLA-B27 haplotypes. No differences were found between the AS and ReA groups nor between either of them and the healthy HLA-B27-positive controls. Thus it seems unlikely that TAP polymorphism, at the level studied, has a dominant role in the pathogenesis of these diseases. However, a family study is needed in order to determine whether the same TAP complexes are carried by the same haplotypes in these diseases. Human Immunology 44, 236–242 (1995)

Molecular analysis of HLA-B27 haplotypes in caucasoids frequencies of B27-Cw in jewish and spanish populations

PCR in combination with SSO probes was used to analyze the polymorphism in exons 2 and 3 of HLA-B27 subtypes and HLA-C-related alleles in two genetically distant Caucasian groups: Spanish and Jewish populations. AS patients and healthy B27 donors from both populations were analyzed in order to ascertain B27-Cw haplotypes. Three different ancestral haplotypes were found to be represented in both populations: B∗2705/Cw∗0102, B∗2705/Cw∗02022, and B∗2702/Cw∗02022. The B∗2705 (92.5%) was the most frequent allele found in the Spanish population, carried by B∗2705/Cw∗0102 (60.9%) and B2705/Cw∗02022 (30.4%) haplotypes. In contrast, B∗2702 (59.4%) was the most prevalent allele found in the Jewish population and was carried by the B∗2702/Cw∗02022 (63.3%) haplotype. No different allelic and haplotypic distributions were among healthy and AS patients in either Spanish or Jewish populations. The differences found in the distribution of B27 haplotypes among Spanish and Jewish Caucasian populations are consistent with the genetic distance of these ethnic groups. When the Jewish population was subdivided into Ashkenazi (A) and non-Ashkenazi (NA) groups, no significant differences were observed in the distribution of B∗2702/Cw∗02022 haplotype. Minor differences were observed in the underrepresented B∗2705 haplotypes. The present results reflect the ancestral affinities of A and NA Jewish populations. A possible HLA-B27 evolutive pathway in Caucasians is proposed according to the data available for the B27/Cw ancestral haplotypes in Spanish and Jewish groups.

HLA in ankylosing spondylitis: Is HLA-B27 the only MHC gene involved in disease pathogenesis?

Linkage analysis of HLA haplotypes, HLA-B27 subtypes, and a 9.2-kb Pvull B7 restriction fragment length polymorphism (RFLP) (shown previously to be associated with peripheral arthritis in ankylosing spondylitis [AS]) in 115 relatives from 12 multiplex spondyloarthropathy (SNSA) and 2 B27-positive control families showed AS to be linked to HLA-B27 haplotypes. The RFLP segregated with HLA-A3- and HLA-A9-bearing haplotypes (lod score, 10.98; odds in favor of linkage, 9.2 × 10 10:1), although its linkage to AS or other SNSA per se was not seen. The association of HLA-A3/A9 with the RFLP was also seen in 52 AS patients and 92 controls, although no HLA-A, -B, -C, or -DR allele (other than HLA-B27) was significantly increased in frequency. The HLA-B27 subtype seen on all but one of the haplotypes studied was B∗2705, the sole exception being HLA-B∗2702. Although not ruling out a second HLA-A-linked gene influencing the clinical expression of AS, these data fail to support the role of a second MHC-associated gene in the pathogenesis of AS per se.

Clinically silent infections in patients with oligoarthritis: results of a prospective study.

Oligoarticular synovitis of undetermined origin can closely resemble an incomplete form of reactive arthritis/Reiter's syndrome. Eighty three patients with oligoarthritis of undetermined origin were studied prospectively to identify asymptomatic infections potentially triggering the inflammatory response in the synovial fluid. At the time of initial evaluation, 57 (69%) of the patients with oligoarthritis and 4/20 (20%) of the control subjects were carriers of clinically silent infections. Evidence for persistent or prior chlamydial infections was frequently and exclusively found in the study group (30/83 (36%) patients v no controls), whereas undetected urogenital infections with mycoplasma were present in nine (11%) patients and four (20%) controls. Eleven (13%) of the patients carried cellular and humoral responses to Borrelia burgdorferi. The HLA-B27 haplotype represented a major risk factor for the development of oligoarthritis but not for development of sacroiliitis. Re-evaluation after one year showed that the course and outcome of the oligoarticular disease did not correlate with a specific infectious organism and were not affected by antibiotic treatment sufficient to treat the carrier state.

Autoantibodies to HLA B27 in the sera of HLA B27 patients with ankylosing spondylitis and Reiter's syndrome. Molecular mimicry with Klebsiella pneumoniae as potential mechanism of autoimmune disease.

Ankylosing spondylitis (AS) and Reiter's syndrome (RS) both show a strong correlation with the HLA B27 haplotype. We studied whether sharing of homologous amino acid sequences in the HLA B27 antigen with an invading microbe might occur, and if so, what is the biological significance of such homology. In a computer search of the Dayhoff data bank, we found a homology of six consecutive amino acids between HLA B27.1 antigen residues 72-77 and Klebsiella pneumoniae nitrogenase residues 188-193. These shared sequences are hydrophilic, suggesting locations on molecules exposed to the cell surface. Immunochemical analysis showed that 18 of 34 sera from patients with RS (53%) and 7 of 24 sera from patients with AS (29%) contained antibodies that bound to a synthesized peptide sequence representing residues 69-84 of HLA B27.1. In contrast, only 1 of 22 sera from healthy, B27+ controls (5%) contained antibodies to this peptide (p less than 0.01). Sera from three HLA B27- patients with RS did not possess antibodies to the HLA B27 peptide. Additionally, greater than 40% of HLA B27 patients with AS or RS had antibodies to Klebsiella residues 184-193, while none of the normal nonarthritic HLA B27 haplotype subjects did. Our results suggest that an autoimmune response(s) directed against HLA B27.1 may be a pathogenic mechanism in a subset of patients with AS and RS. Further, this response may initially be induced against Klebsiella pneumoniae, a microorganism that shares sequence homology with HLA B27.

HLA-B27 haplotypes in family studies of ankylosing spondylitis.

Although HLA-B27 carries a high relative risk for development of ankylosing spondylitis (AS), most B27 positive individuals do not have spondylitis. One interpretation of this observation is that there may be 2 types of B27, 1 which carries the risk factor and 1 which does not. If this were the case, then with the help of markers closely linked to HLA-B, it might be possible to detect differences between the B27 haplotypes in AS patients and those in healthy probands. We studied 197 members of 18 families with known AS and 110 members of 19 families in which HLA-B27 was present without any known inflammatory spinal disease. HLA antigens A, B, and C and alleles of complement components C2, C4, and Factor B and glyoxalase-1 were determined in all cases. Detailed haplotypes were assigned and their associations with development of the disease were examined. We were unable to identify any distinct HLA-B27 haplotype associated with AS; 2 common haplotypes and several miscellaneous ones were found in both groups. Thinking that the development of AS might be influenced by the other, non-B27 haplotype, we analyzed this and found that there was no detectable influence. The data do not contradict the notion that B27 in whites is a single entity and is itself the susceptibility factor predisposing to the development of ankylosing spondylitis.

Hypothesis: The etiology of ankylosing spondylitis: Does a plasmid trigger the disease in genetically susceptible individuals?

There is at present only one well-documented clue to the pathogenesis of ankylosing spondylitis (AS): the tissue antigen HLA-B27 occurs in about 8% of a normal Caucasian population but is present in over 9 0 ~ of patients with AS and is increased in frequency in Reiter's syndrome and some other seronegative arthropathies [ 1,2]. This important clue, together with the observation that some identical twins are discordant for AS [3] and the frequent finding that certain forms of HLA-B27-associated reactive arthritis follow infections with enteric organisms such as Shigella and Yersinia [4,5] suggests an interplay between an environmental agent and HLA-B27, possibly during the early stages of pathogenesis. The nature of the interaction between a specific cell-surface alloantigen and an environmental agent is still not understood but studies by at least two groups indicate that certain organisms, notably Klebsiella. may be antigenically related to HLA-B27 [6,7] or to a physically closely-associated structure [8,9]. This suggestion is based on the finding that antibodies raised against certain Klebsiella isolates (as well as against some isolates of Salmonella newport. S. (yphimurium, and Shigella sp.. J.K. Prendergast, unpublished results) specifically lyse the HLA-B27-positive lymphocytes of about 8 0 ~ of patients with ankylosing spondylitis and of 60% of those with Reiter's syndrome or asymmetrical peripheral arthritis, but not the HLA-B27-positive lymphocytes of clinically normal individuals [10]. An extension of these studies has shown that B27-positive lymphocytes from normal individuals, which are not normally lysed by antiKlebsiella serum, can be rendered susceptible to lysis following their incubation in the culture filtrate (containing modifying factor) of certain Klebsiella organisms [11]. Further support for the role of an environmental agent in B27Klebsiella interactions is provided by the demonstration that the lymphocytes of clinically normal family members who share the HLA-B27 haplotype with some of their AS-affected siblings, are not lysed by anti-Klebsiella serum [10]. These observations suggest that the modification of B27 is not a direct genetic effect. By contrast, the persistence of the Klebsiella-cross-reactive marker on cultured

Rga (Rodgers) and the HLA Region: Linkage and Associations

In 19 families with 97 children the segregation of Rga (Rodgers) was found to be compatible with Mendelian inheritance and five backcross and 14 intercross families were found among HLA and Bf typed families. Close linkage (lods + 17.82) without recombination was found between Rg and the HLA region, with a direct count of 96 nonrecombinant meioses for Rg-HLA-B. Rg- was strongly associated with HLA-B8 (29 of 30 haplotypes) and probably associated with Bw40, but did occur on other HLA-B haplotypes. By inference Rg- is negatively associated with Ch- (Chido). The Rg-Ch- haplotype has not been observed. Rga and Cha may or may not be coded for by different sites of the same cistron closely linked to HLA-B:C and cannot as yet be excluded from being parts of B or C.