Association of Cw11 in Japanese patients with psoriasis vulgaris

HLA-Cw6 increases the risk of psoriasis and early onset before twenty-seven years of age among the Vietnamese population

Psoriasis is a chronic inflammatory skin disease that affects people all over the world. It is linked to the HLA-Cw6 allele, which is more common in Caucasians than in Asians and varies across ethnic groups. We investigated the association between the disease severity and the onset age of HLA-Cw6 prevalence in Vietnamese psoriasis patients. In 121 psoriasis patients and 30 healthy controls, we looked at the relationship between HLA-Cw6 and clinical features. We found that patients with psoriasis had significantly higher levels of HLA-Cw6 (64.5%) than controls (26.7%) (p=0.0001), with an odds ratio of 4.98 (2.04-12.15). Positive HLA-Cw6 patients had a significantly lower mean age of psoriasis onset than negative HLA-Cw6 patients. Patients with mild psoriasis (100%) were more likely to have the AA genotype, while patients with moderate to severe psoriasis (47.2% and 59.0%, respectively) and those with high PASI scores (55.1% and 54.1%, respectively) were more likely to have the TA genotype. Thus, HLA-Cw6 is a major genetic risk factor for psoriasis in Vietnamese patients, especially early-onset cases. Variations in HLA-Cw6 genotypes also affect disease severity.

Psoriasis Patients with Specific HLA-Cw Alleles and Lower Plasma IL-17 Level Show Improved Response to Topical Lindioil Treatment

Purpose

Lindioil, a medicine refined from indigo naturalis (a herb used in Chinese medicine), is effective in treating severe psoriasis; however, responses vary across individual patients. We aim to investigate genetic predispositions associated with treatment response to topical Lindioil among patients with psoriasis and correlations with plasma cytokine patterns.

Patients and Methods

We enrolled 72 psoriasis patients treated with Lindioil ointment and analyzed the human leukocyte antigen class C (HLA-Cw) genotypes and plasma cytokine expression patterns. We developed regression models of treatment response, defined as Psoriasis Area and Severity Index (PASI) 75, to examine correlations among HLA-Cw alleles, cytokine levels, and treatment response to Lindioil.

Results

Patients harboring HLA-Cw*06:02 were significantly more likely to respond to Lindioil (P = 0.02, odds ratio [OR]: 6.88), whereas Lindoil was ineffective in those harboring HLA-Cw*01:02 (P = 0.01, OR: 0.28). Patients who were HLA-Cw*06:02-positive or HLA-Cw*01:02-negative had better PASI scores and body surface area (BSA) improvement (73.3% vs 44.4%, P<0.001) following an 8-week treatment period. Psoriasis patients achieving PASI 75 after 8 weeks presented with lower baseline plasma interleukin-17 (IL-17) levels than those who did not achieve PASI 75 (PASI 75: 11.28 pg/mL vs PASI <75: 15.82 pg/mL, P = 0.05).

Conclusion

Our findings suggest that the presence of the HLA-Cw*06:02 or HLA-Cw*01:02 alleles and plasma IL-17 levels are predictive markers of treatment response to Lindioil ointment in patients with psoriasis.

HLA-Cw1 and Psoriasis

Psoriasis is a chronic inflammatory skin condition with regional and ethnic differences in its prevalence and clinical manifestations. Human leukocyte antigen (HLA)-Cw6 is the disease allele conferring the greatest risk to psoriasis, but its prevalence is lower in Asian individuals. Recent studies have found associations between HLA-Cw1 and some Asian populations with psoriasis, especially Southern Chinese. HLA-Cw6 was associated with type I early-onset psoriasis, guttate psoriasis, Koebner phenomenon, and better response to methotrexate, interleukin (IL)-12/23, IL-17, and IL-23 targeting drugs. In contrast, HLA-Cw1 positivity has been associated with erythrodermic psoriasis, pustular psoriasis, and the axial type of psoriatic arthritis. Furthermore, HLA-Cw1 was more frequently associated with high-need patients who did not respond to conventional therapies. No known trigger factor nor autoantigen has been identified for HLA-Cw1 positivity. However, HLA-Cw1 has been linked to some viral agents. For example, cytotoxic T lymphocytes recognize multiple cytomegalovirus pp65-derived epitopes presented by HLA alleles, including HLA-C*01:02. In addition, cytomegalovirus can lead to severe exacerbation of psoriatic skin disease. The proposed interaction between viral infection, HLA-Cw1, and psoriasis is through the killer cell immunoglobulin-like receptors of natural killer cells. Given the diverse nature of psoriasis pathogenesis and the difference in HLA-Cw prevalence in different racial groups, more studies are needed to confirm the role of HLA-Cw1 in psoriasis.

Psoriasis in Skin of Color: Insights into the Epidemiology, Clinical Presentation, Genetics, Quality-of-Life Impact, and Treatment of Psoriasis in Non-White Racial/Ethnic Groups

Psoriasis is a chronic inflammatory skin condition affecting diverse racial/ethnic groups throughout the world. Large population-based studies suggest that psoriasis occurs most often in individuals of European ancestry, followed by black and Hispanic individuals, although the true prevalence of psoriasis in non-white individuals is likely underestimated. Despite similarities in psoriasis between ethnic groups, there are notable differences in the presentation, quality-of-life impact, and treatment of psoriasis with important implications for the management of non-white individuals. Overall, heterogeneity in psoriasis susceptibility alleles, in combination with cultural and socioeconomic factors, may explain these differences. In this article, we review the epidemiology, clinical presentation, genetic polymorphisms, quality-of-life impact, and treatment nuances of psoriasis in patients with skin of color.

HLA-Cw6 and psoriasis

Psoriasis is a multifactorial disease with a strong genetic background. HLA-Cw6 is one of the most strongly associated psoriasis susceptibility alleles. It is repeatedly observed to affect disease course, phenotypic features, severity, comorbidities and treatment outcomes. To the best of our knowledge, the roles of HLA-Cw6 in psoriasis have not yet been thoroughly reviewed. The worldwide frequency of the HLA-Cw6 allele varies greatly, with it being generally higher in white people than in Asians. The allele is associated with type I early-onset psoriasis. Stress, obesity and streptococcal pharyngitis are commonly observed in HLA-Cw6-positive patients. Phenotypically, HLA-Cw6 has been found to be associated with guttate psoriasis. In addition, patients carrying the allele are more likely to have arm, leg and trunk involvement, and the Koebner phenomenon. Patients with psoriatic arthritis with HLA-Cw6 more often have early onset and tend to show cutaneous symptoms before musculoskeletal symptoms. HLA-Cw6-positive patients have been shown in several studies to be more responsive to methotrexate and ustekinumab. However, this difference in ustekinumab efficacy was only moderate in a post-hoc analysis of a pivotal phase III study. HLA-Cw6 positivity also tends to be less frequent in high-need patients who fail conventional therapy. Small studies have also investigated the role of HLA-Cw6 in remission of psoriasis during pregnancy, and with the comorbidities of photosensitivity and atherosclerosis. Given the diverse nature of psoriasis pathogenesis, as well as the difference of HLA-Cw6 positivity in different ethnic groups, more studies are needed to confirm the role of HLA-Cw6 in psoriasis.

Genetic associations of psoriasis in a Pakistani population

BACKGROUND

Genetic predisposition to psoriasis, an inflammatory skin disease affecting 0·2-4% of the world population, is well established. Thus far, 41 psoriasis susceptibility loci reach genome-wide significance (P ≤ 5 × 10(-8) ). Identification of genetic susceptibility loci in diverse populations will help understand the underlying biology of psoriasis susceptibility.

OBJECTIVES

The primary objective of this study was to examine psoriasis susceptibility associations previously reported in Chinese and caucasian populations in a Pakistani cohort.

METHODS

Blood samples and phenotype data were collected from psoriasis cases and controls in Islamabad, Pakistan. DNA was isolated and genotypes of selected susceptibility markers were determined. The data were analysed using χ(2) tests or logistic regression for psoriasis association.

RESULTS

HLA-Cw6 showed the strongest association [odds ratio (OR) 2·43, P = 2·3 × 10(-12) ]. HLA-Cw1 showed marginally significant association (OR 1·66, P = 0·049), suggesting that the HLA-Cw1-B46 risk haplotype may be present in the Pakistani population. Three other loci (IL4/IL13, NOS2, TRAF3IP2) showed nominally significant association (P < 0·05).

CONCLUSIONS

HLA-Cw6 is strongly associated with psoriasis susceptibility in the Pakistani population, as has been found in every other population studied. In addition, HLA-Cw1 showed marginal association, reflecting the relative geographical proximity and thus likely genetic relatedness to other populations in which the HLA-Cw1-B46 haplotype is known to be associated. A larger cohort and a denser marker set will be required for further analysis of psoriasis associations in the South Asian population.

HLA Antigens in Omani Psoriasis Vulgaris Patients

OBJECTIVES

To determine the frequency of different HLA-antigens in patients with plaque psoriasis in the Omani Arab population.

METHODS

Fifty four Omani patients clinically diagnosed with plaque psoriasis attending the dermatology outpatient clinic in Al-Nahdah Hospital (the tertiary dermatology centre in Oman) were selected for HLA studies.

RESULTS

HLA-B52 was present in 20.4% of patients 11/54 and in 5% of controls without psoriasis 5/100. For the association p was <0.004 and the relative risk (RR) was 4.86.

CONCLUSION

Psoriasis does not appear to be associated universally with the same HLA antigens. The association of HLA-B52 with plaque psoriasis in Omani patients compares with the HLA-Cw6, -Bw57 and -DR7 preponderance in most other ethnic groups.

HLA alleles in Brazilian patients with fissured tongue

BACKGROUND

Fissured tongue (FT) is a clinical condition manifested by numerous little furrows on the tongue's surface. Previously, the authors observed an association with HLA-C×06 in psoriasis (PS) and benign migratory glossitis (BMG); however, HLA-C was not surveyed in FT.

OBJECTIVE

This study investigated the association between HLA alleles and FT.

METHODS

Thirty-three FT bearers were studied, after evaluation of criteria for inclusion. These patients did not present PS, BMG or any other conditions associated with FT. The control group (CG) was composed of 561 individuals with HLA-A, 560 individuals with HLA-B, 168 individuals with HLA-C, 564 individuals with HLA-DRB1 and 390 individuals with HLA-DQB1. Samples from these individuals were processed to extract DNA. The HLA classes I and II were determined using the reverse line blot technique. The frequencies of HLA antigens found in patients were compared with the CG using Fisher's exact test.

RESULTS

The comparison of the frequencies of HLA antigens found in the patient groups and in CG revealed no association with any of the alleles studied, except for HLA-A*01, which exhibited a decreased frequency in patient groups. HLA-C*06 was detected in 7.57% of FT patients and 10.42% of the CG (not significant).

CONCLUSION

The lack of association of FT with HLA-C*06 reinforces the proposal that this disease does not have a common genetic factor in the triad of BMG, FT and PS.

Comparison of MHC class I risk haplotypes in Thai and Caucasian psoriatics shows locus heterogeneity at PSORS1

Earlier studies have shown that psoriasis in Japan and Thailand is associated with two different major histocompatibility complex (MHC) haplotypes - those bearing HLA-Cw6 and those bearing HLA-Cw1 and HLA-B46. In an independent case-control sample from Thailand, we confirmed the association of psoriasis with both haplotypes. No association was seen in Thai HLA-Cw1 haplotypes lacking HLA-B46, nor was HLA-Cw1 associated with psoriasis in a large Caucasian sample. To assess whether these risk haplotypes share a common origin, we sequenced genomic DNA from a Thai HLA-Cw1-B46 homozygote across the ∼300 kb MHC risk interval, and compared it with sequence of a HLA-Cw6-B57 risk haplotype. Three small regions of homology were found, but these regions share equivalent sequence similarity with one or more clearly non-risk haplotypes, and they contain no polymorphism alleles unique to all risk haplotypes. Differences in psoriasis phenotype were also observed, including lower risk of disease, greater nail involvement, and later age at onset in HLA-Cw1-B46 carriers compared with HLA-Cw6 carriers. These findings suggest locus heterogeneity at PSORS1 (psoriasis susceptibility 1), the major psoriasis susceptibility locus in the MHC, with HLA-Cw6 imparting risk in both Caucasians and Asians, and an allele other than HLA-Cw1 on the HLA-Cw1-B46 haplotype acting as an additional risk variant in East Asians.

Sequence and haplotype analysis supports HLA-C as the psoriasis susceptibility 1 gene

Previous studies have narrowed the interval containing PSORS1, the psoriasis-susceptibility locus in the major histocompatibility complex (MHC), to an approximately 300-kb region containing HLA-C and at least 10 other genes. In an effort to identify the PSORS1 gene, we cloned and completely sequenced this region from both chromosomes of five individuals. Two of the sequenced haplotypes were associated with psoriasis (risk), and the other eight were clearly unassociated (nonrisk). Comparison of sequence of the two risk haplotypes identified a 298-kb region of homology, extending from just telomeric of HLA-B to the HCG22 gene, which was flanked by clearly nonhomologous regions. Similar haplotypes cloned from unrelated individuals had nearly identical sequence. Combinatorial analysis of exonic variations in the known genes of the candidate interval revealed that HCG27, PSORS1C3, OTF3, TCF19, HCR, STG, and HCG22 bore no alleles unique to risk haplotypes among the 10 sequenced haplotypes. SPR1 and SEEK1 both had messenger RNA alleles specific to risk haplotypes, but only HLA-C and CDSN yielded protein alleles unique to risk. The risk alleles of HLA-C and CDSN (HLA-Cw6 and CDSN*TTC) were genotyped in 678 families with early-onset psoriasis; 620 of these families were also typed for 34 microsatellite markers spanning the PSORS1 interval. Recombinant haplotypes retaining HLA-Cw6 but lacking CDSN*TTC were significantly associated with psoriasis, whereas recombinants retaining CDSN*TTC but lacking HLA-Cw6 were not associated, despite good statistical power. By grouping recombinants with similar breakpoints, the most telomeric quarter of the 298-kb candidate interval could be excluded with high confidence. These results strongly suggest that HLA-Cw6 is the PSORS1 risk allele that confers susceptibility to early-onset psoriasis.

Molecular diversity of HLA-Cw alleles in the Maratha community of Mumbai, Maharashtra, western India

Recent advances suggest a significant role for the HLA-C locus as a target of alloreactions after bone marrow transplantation. The biological importance of products of the HLA-C locus, both as transplant antigens and as ligands for natural killer (NK) cells, is well established. A total of 10 different serologically defined HLA-Cw antigen specificities (Cw1-Cw10) are encoded by the C locus; however, there are now 151 different alleles that can be identified by molecular methods. Serological definition of Cw alleles therefore includes 20-50% blanks, which cannot be detected by the available antisera. We used the molecular method of polymerase chain reaction (PCR)-based sequence-specific amplification and probe hybridization to define Cw alleles in 91 individuals from the Maratha community, and compared the data with data for 92 serologically typed Maratha individuals from India. We identified Cw*12, Cw*14, Cw*15, Cw*16 and Cw*18, along with the serologically identified Cw*01, Cw*02, Cw*03, Cw*04, Cw*06 and Cw*07 alleles. The HLA-Cw blank allele frequency in the Maratha was reduced from 0.5706 to 0.00. Furthermore, by using a molecular technique, it was possible to identify novel allele subtypes, such as Cw*0104, Cw*0203 and Cw*0707, and a high frequency of Cw* 1801 in the Maratha community compared with other Indian and world populations. Our results will have clinical implications in related and unrelated HLA-matched bone marrow transplantation in India.

Study of alanine-73 and aspartate-9 of HLA-C locus in Saudi psoriasis patients, using sequence-specific primers (PCR-SSP)

Alanine at residue 73 (Ala-73) and aspartate at residue 9 (Asp-9) are characteristic to both Cw6 and Cw7 alleles of HLA-C gene and have been suggested as possible markers for psoriasis vulgaris (PsV). However, the results from various ethnic groups/populations are contradictory and inconclusive. In this study, an attempt has been made to examine the association between HLA-C (Ala-73 and Asp-9) and susceptibility to PsV among Saudi patients. Genomic DNA was extracted from 25 Saudi PsV patients and 75 control subjects. Polymerase chain reaction (PCR) was performed to amplify HLA-C sequences using earlier reported primers, C133P and C243PR. Sequence-specific primers were used to specifically detect nucleotide coding for Ala-73 and Asp-9 in all the subjects. The results showed significantly higher frequency of Asp-9 (84.0 % versus 61.3 %) in PsV patients as compared to controls (p < 0.05, 2-tailed Fisher's exact test). The frequencies of Ala-73 among PsV patients (92 %) and controls (88 %) did not differ significantly.

Strong association of HLA-Cw6 allele with juvenile psoriasis in Polish patients

Association of psoriasis vulgaris with HLA-C is not equally strong in different human populations. It has not yet been studied in Polish patients at DNA level, but only by serology that is inadequate for HLA-C. Therefore, we examined the distribution of HLA-C alleles by means of low resolution PCR-SSP in 102 Polish psoriatics and 123 healthy controls. We have found significantly higher representation of HLA-Cw*06 (odds ratio, 18.73; P(cor)<0.001) and significantly lower representation of HLA-Cw*07 (odds ratio, 0.41; P(cor)<0.038) in patients than in controls. Association of HLA-Cw*06 with psoriasis was even stronger in early age at onset (0-20 years) group: odds ratio, 77.71; P(cor)<0.001. Therefore, our population seems to belong to those with strong association of psoriasis with HLA-Cw*06.

The immunogenetics of the seronegative spondyloarthropathies

In none of the rheumatic diseases has the genetic contribution to pathogenesis been so well characterized as in the seronegative spondyloarthropathies. Most important has been the elucidation of the structure and effect on disease expression of HLA-B27, where 11 subtypes have been distinguished to date. These vary in frequency in different ethnic groups and seem to show differential disease associations. The high frequency of this gene in patients with the seronegative spondyloarthropathies, especially ankylosing spondylitis (AS) and Reiter's syndrome (RS)/reactive arthritis (ReA), has emerged as probably the best example of a disease association with a hereditary marker. Other HLA genes, in addition to HLA-B27, have been implicated in psoriasis and psoriatic arthritis. These include those from the HLA-C locus and from HLA-DR. In addition, recent family studies have implicated other genes outside the MHC that further enhance the susceptibility to AS.

Serological and molecular analysis of HLA class I and II alleles in Thai patients with psoriasis vulgaris

The HLA class I and class II alleles in 67 patients with type I psoriasis vulgaris, 23 patients with type II psoriasis vulgaris and 140 healthy individuals were analyzed. The frequencies of HLA-A2, -B46, -B57 and DQB1*0303 were significantly increased in type I psoriasis compared to the controls (Pc<0.05). Molecular analysis of HLA-A2 alleles showed an increase in HLA-A*0207 and a decrease in HLA-A*0203 in type I psoriasis. HLA-DQB1*0301 was significantly decreased in type I psoriasis compared to the normal controls (Pc<0.05). No association of any alleles with type II psoriasis was observed. This data demonstrated two susceptible haplotypes: HLA-A1-B57-DRB1*0701-DQA1*0201-DQB1*0303 (AH57.1) and HLA-A2-B46-DRB1*0901-DQA1*0301-DQB1*0303 (AH46.1) for type I psoriasis in the Thai population. Besides, the haplotype AH46.1 was also associated with type II psoriasis.

Analysis of HLA class II and TAP alleles in Japanese patients with psoriasis vulgaris

We investigated HLA class II and transporter associated with antigen processing (TAP) alleles in eighty-five unrelated Japanese patients with psoriasis vulgaris and fifty-two healthy controls using the polymerase chain reaction-restriction fragment length polymorphism method. The frequencies of DRB1*1502 and DQB1*0601 were increased in the patient group (DRB1*1502; 21% vs 12%, p < 0.05, DQB1*0601; 35% vs. 21%, p < 0.05), while the frequencies of DRB1*0406 and TAP2*E were decreased in the patients (DRB1*0406; 2% vs 9%, p < 0.05, TAP2*E; 4% vs 11%, p < 0.05). However, none of these remained significant after p values were corrected for the number of comparisons made (pc > 0.05). We also analysed specific amino acids on HLA class II molecules, but no significant difference was found between the two groups. Our previous reports clarified that aspartate at residue 9 (48% vs 20%, p < 0.002) and alanine at residue 73 (81% vs 48%, p < 0.0001) on HLA-C molecules were strongly associated with Japanese patients with PsV. These specific amino acids on HLA-C molecules are supposed to play more important roles compared with HLA class II and TAP alleles in the development of psoriasis vulgaris.

Study of aspartate at residue 9 of HLA-C molecules in Japanese patients with psoriasis vulgaris

The frequency of aspartate at residue 9 (Asp-9) of HLA-C molecules was investigated among 75 Japanese patients with psoriasis vulgaris and 50 healthy controls. We developed a technique of polymerase chain reaction sequence-specific primer (PCR-SSP) amplification of genomic DNA for HLA-C alleles with a codon for Asp-9. The specificity of amplification was confirmed by direct sequencing of the amplified products and amplification from total RNA (RT-PCR). Asp-9 was positive in all individuals with Cw6 and/or Cw7, but negative in the others, indicating that Asp-9 was specific to Cw6 and Cw7 antigens in our subjects. The frequency of Asp-9 was significantly increased in the patient group (48% vs. 20%; P < 0.002). The frequency of alanine at residue 73 (Ala-73), which was positive for Cw4, Cw6, Cw7, and some C blanks, was also increased in our previous study (81% vs. 48%; P < 0.0001). Asp-9 is located on a beta sheet of alpha 1 domain of HLA-C molecule and influences the peptide binding of the C pocket of the groove together with Ala-73. Both Asp-9 and Ala-73 could contribute to the disease susceptibility to psoriasis vulgaris in the immune responses.

Immunogenetic profile of psoriasis vulgaris: association with haplotypes A2,B13,Cw6,DR7,DQA1*0201 and A1,B17,Cw6,DR7,DQA1*0201

Psoriasis vulgaris is a skin disease with an immunological and genetic background present in 1-3% of the population. We studied the genetic susceptibility to psoriasis vulgaris in Finns with serological HLA typing and genomic HLA class II typing of the DQ and DP loci to evaluate the risk of developing psoriasis. The haplotypes most frequently distinguishing between psoriatics and controls were those that carried Cw6 (P < 10(-8)), DQA1*0201 (P = 9.3 x 10(-6)) and DR7 (P = 3.9 x 10(-5)). The two most frequent marker haplotypes were A2,B13,Cw6,DR7, DQA1*0201 and A1,B17,Cw6,DR7,DQA1*0201, which were not found among the control subjects. A deficit of haplotype B8,DR3,DQ2 (2 out of 124 in the patients versus 15 out of 106 in the controls, P = 1.5 x 10(-4)) was found, and this was in accordance with a slightly decreased frequency of DQA1*0501 (P = 3.1 x 10(-2)), which was usually linked with this haplotype. These results stimulate the research for a genetic resistance factor in psoriasis. Thus, this report sheds further light on the immunogenetic background of psoriasis in Finland. We conclude that the inheritance of psoriasis has a polygenic mode, in which the Cw6,DR7,DQA1*0201 combination seems to be important (P = 7.5 x 10(-7), relative risk 24.4, aetiological factor 0.29).

Do specific pockets of HLA-C molecules predispose Jewish patients to psoriasis vulgaris?

BACKGROUND

Psoriasis vulgaris was reported to be associated with a specific alanine residue at position 73 of HLA-C alleles in Japanese patients.

OBJECTIVE

Our purpose was to determine the role of HLA genes in susceptibility to psoriasis vulgaris in the Israeli Jewish population.

METHODS

Twenty-eight Israeli patients were analyzed for their HLA class I and II specificities by means of serologic and molecular methods.

RESULTS

All patients possessed in their HLA-C antigens an alanine residue at position 73 (p < 0.002). A significantly increased frequency of HLA-Cw6 and of Cw7 was also observed among the patients (p < 0.02).

CONCLUSION

Our study clearly shows that alanine in position 73 is significantly associated with psoriasis vulgaris in Jewish patients. Cw6 and Cw7 have a unique antigen-binding pocket containing both alanine at position 73 and a negatively charged aspartic acid at position 9. These residues are most probably important in determining the conformation of the C pocket and in turn the nature of the peptide bound to it. We suggest that this combination confers the highest risk of the development of psoriasis vulgaris.

Alanine at position 73 of HLA-C is associated with psoriasis vulgaris in Finland

A close association was found between a specific sequence of HLA-C and psoriasis vulgaris in Finnish patients (chi 2 = 18.4, P = 1.78 x 10(-5)). This sequence codes for alanine at position 73 of the HLA-C molecule in the antigen binding cleft, and alanine may play a role in susceptibility to the disease.

Molecular diversity of the HLA-C locus in unrelated marrow transplantation

The diversity of HLA-C exon-2 alleles in 56 HLA-A, B, DRB and DQB1-matched patient-unrelated marrow donor pairs was examined by non-cloning polymerase chain reaction-based sequencing of genomic DNA. This method allows simultaneous analysis of both alleles in heterozygous samples. All Cw5-positive individuals encoded a sequence which differed from the published Cw*0501 sequence at position 61. Among 82 samples assigned a single antigen by serologic testing, 64 (78%) were heterozygous for two distinct alleles when tested by sequencing. Cw*1202, 1601 and 15 were identified in samples for which no phenotype could be assigned (C "blank"). Finally, 7 of the 56 HLA-A, B, DRB, DQB1-matched pairs (12.5%) were mismatched for one or both HLA-C alleles. We conclude that sequence-based methods constitute the optimal strategies for typing HLA-C alleles in the unrelated marrow transplant population.

The molecular basis for reactivity of anti-Cw1 and anti-Cw3 alloantisera with HLA-B46 haplotypes

HLA haplotypes containing the HLA-B46 allele react with both anti-Cw1 and anti-Cw3 alloantisera, a pattern of reactivity defined as the Cw11 antigen and postulated to involve either a distinctive Cw11 allele or a duplicated HLA-C locus. From serological characterization of CIR cells transfected with B46 cDNA we now demonstrate that the anti-Cw3 reactivity with these haplotypes is solely due to the B46 molecule and not to an HLA-C molecule. Furthermore, isolation and characterization of HLA-C mRNA from cells expressing B46 strongly suggest that anti-Cw1 reactions are directed against the product of a conventional Cw1 allele. The antigenic cross-reactivities of B46 with B62 and Cw3 correlate with its chimaeric primary structure, which is identical to that of B62, except in the alpha 1 helix where it is identical to both Cw3 and Cw1. The structure, distribution and genetic linkage of B46 indicate it is of recent, Asian origin and is the result of a gene conversion, involving Cw1 as the donor gene and B62 as the recipient. These results demonstrate that the Cw11 antigen neither corresponds to a novel HLA-C allele nor a duplicated HLA-C locus, but to a combination of epitopes contributed by linked Cw1 and B46 alleles. The nucleotide sequence we previously and erroneously attributed to a distinct Cw11 allele is now demonstrated to encode Cw8. Isolation of the cDNA clone with this sequence from a library made from a cell homozygous for the B46 haplotype was probably an artefact of contamination.

Specific nucleotide sequence of HLA-C is strongly associated with psoriasis vulgaris

The association of specific HLA-C nucleotide sequences with psoriasis vulgaris was investigated in 75 Japanese patients by the polymerase chain reaction method, followed by slot-blot hybridization using two specific oligonucleotide probes. The synthesized nucleotide primers were C180P, 5'-GACCGGGAGACACAGAAGTACAAG-3' (coding for amino acid residues 61 to 68 of the alpha 1 domain of the HLA-C molecule) and C243PR, 5'-GCTCTGGTTGTAGTAGCCGCG-3' (residues 82 to 88), respectively. The amplified sequence detected with the probe C208A (5'-AGGCACAGGCTGACCGA-3'), including the coding region for alanine at position 73, was significantly increased in frequency in the patients compared with the healthy individuals (81% versus 48%, relative risk = 4.7, chi 2 = 15.3, p less than 0.0001). This specific nucleotide sequence is common to Cw6 and Cw7, but some other HLA-C alleles including Cw4 and C blank (Cx52) also proved to have this sequence. It is suggested that alanine at position 73 of HLA-C molecules can be a good marker for psoriasis vulgaris and that this residue may play an important role in determining susceptibility to this disease.

Study of HLA class I, class II and complement genes (C2, C4A, C4B and BF) in Japanese psoriatics and analysis of a newly-found high-risk haplotype by pulsed field gel electrophoresis

Genetic polymorphisms of HLA antigens and HLA-linked serum complement components (C2, C4A, C4B and BF) were investigated in 79 Japanese patients suffering from psoriasis. HLA typing revealed increased frequencies of HLA-A1, A2, B39, Bw46, Cw6, Cw7 and Cw11. Among complement components, positive associations were obtained with C4A4 and C4B2 and a negative association with BFF. The major histocompatibility complex haplotype (supratype), HLA-A2-Cw11-Bw46-C2C-BFS-C4A4-C4B2-DRw8 is purported to be a new high-risk haplotype in Japanese patients with psoriasis. Analysis of patients with this supratype via pulsed field gel electrophoresis showed the existence of specific, extensive DNA deletions near HLA-DR genes, but no disease-specific patterns could be observed by means of this technique. The newly-found high-risk haplotype indicates racial and ethnic differences among psoriatic patients.