HLA-DRB1*0404 is strongly associated with high titers of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis

OBJECTIVE:To test whether the presence of RA associated HLA-DRB1*0101, HLA-DRB1*0401 and HLA-DRB1*0404 alleles individually influences anti-cyclic citrullinated peptide antibodies (anti-CCP) production. METHODS:The frequency of anti-CCP antibodies was calculated in the sera of 260 RA patients expressing either two (double dose genotypes SE+/SE+), one (single dose genotypes SE+/SE-) or no RA associated HLA-DR alleles (SE-/SE-). Anti-CCP antibodies titers were also determined.RESULTS:RA associated HLA-DR alleles are not mandatory for production of anti-CCP. We found that 68% of SE-/SE- patients were anti-CCP positive. There was no significant difference in anti-CCP between SE negative patient (SE-/SE-) and patients expressing at least one SE (SE+/SE+ and SE+/SE-) (p=0.140). We observed no statistical difference in anti-CCP between RA patients expressing one or two SE (82% vs. 77%, p=0.577). Among SE+/SE-patients, HLA-DRB1*0404 was associated with anti-CCP with a statistically significant difference compared with SE negative patients (90% anti-CCP positive, p=0.02). HLA-DRB1*0404 was also associated with high titers of anti CCP with a statistically significant difference compared with HLA-DRB1*0401 and HLA-DRB1*0101 patients (p=0.025).CONCLUSIONS:The RA-associated HLA-DRB1*0404 allele was the most strongly associated with the presence of anti-CCP in RA sera. Moreover, HLA-DRB1*0404 patients had higher titers of anti CCP than patients with other RA associated HLA-DR alleles.     

Differential association of HLA-DRB1 alleles in Japanese patients with early rheumatoid arthritis in relationship to autoantibodies to cyclic citrullinated peptide

OBJECTIVE: To evaluate the role of HLA-DRB1 genotypes and antibodies to cyclic citrullinated peptides (anti-CCP antibodies) in the development and radiographic progression of Japanese patients with rheumatoid arthritis (RA). METHODS: One hundred and ten patients with early RA (88 female, 22 male) who visited our clinic within 1 year of symptom onset were examined for anti-CCP antibody levels and HLA-DRB1 genotypes. HLA-DRB1 genotypes were also determined in 265 healthy controls. Radiographic progression over a 2-year interval was evaluated using the Larsen's method in 66 patients. RESULTS: Among the 110 patients with early RA, 82 patients (74.5%) were anti-CCP positive. Carrier frequency of HLA-DRB1*0405 was significantly increased in RA patients with anti-CCP antibodies compared with controls and RA patients without anti-CCP antibodies (odds ratio [OR] 3.4, 95% confidence interval [95% CI] 2.0-5.7 and OR 3.3, 95% CI 1.3-8.6, respectively). Carriership of one or two SE alleles was significantly associated with production of anti-CCP antibodies (OR 2.7, 95% CI 1.1-6.7 and OR 9.3, 95% CI 1.1-78.2, respectively). On the other hand, allele frequency of HLA-DRB1*0901 was significantly increased in RA patients without anti-CCP antibodies compared with controls and RA patients with anti-CCP antibodies (OR 2.2, 95% CI 1.1-4.1 and OR 3.0, 95% CI 1.4-6.4, respectively). CONCLUSION: In Japanese patients with RA, HLA-DRB1 SE alleles are associated with production of anti-CCP antibodies and HLA-DRB1 alleles appear to be differently associated with early RA depending on anti-CCP positivity as in Caucasian patients with RA.     

The HLA-DRB1 shared epitope alleles differ in the interaction with smoking and predisposition to antibodies to cyclic citrullinated peptide

OBJECTIVE: The HLA shared epitope (SE) alleles are primarily a risk factor for the presence of antibodies to cyclic citrullinated peptide (anti-CCP antibodies) rather than for the development of rheumatoid arthritis (RA). The SE alleles interact with the environmental risk factor tobacco exposure (TE) for predisposition to anti-CCP+ RA. The objectives of this study were to determine 1) whether different SE subtypes contribute differently to the presence of anti-CCP antibodies, 2) whether different SE subtypes all interact with TE for the development of anti-CCP antibodies, and 3) the effect of TE in relation to the SE alleles and anti-CCP antibodies on the risk of progression from undifferentiated arthritis (UA) to RA. METHODS: We assessed the effect of SE subtypes and TE on the presence and level of anti-CCP antibodies and on the risk of progression from UA to RA in 977 patients with early arthritis who were included in the Leiden Early Arthritis Clinic. RESULTS: The HLA-DRB1*0401, *0404, *0405, or *0408 SE alleles conferred the highest risk of developing anti-CCP antibodies (odds ratio [OR] 5.0, compared with an OR of 2.0 for the HLA-DRB1*0101 or *0102 SE alleles and an OR of 1.7 for the HLA-DRB1*1001 SE allele). Conversely, the TE-SE allele interaction was the strongest for the HLA-DRB1*0101 or *0102 SE alleles and the HLA-DRB1*1001 SE allele. TE in SE+, anti-CCP+ patients correlated with higher levels of anti-CCP antibodies and with progression from UA to RA. In logistic regression analysis, only the presence and level of anti-CCP antibodies were associated independently with RA development. CONCLUSION: The HLA-DRB1 SE subtypes differ in their interaction with smoking and in their predisposition to anti-CCP antibodies. TE contributes to the development of RA in SE+, anti-CCP+ patients, which is explained by its effect on the level of anti-CCP antibodies.     

Regulation of anti-cyclic citrullinated peptide antibodies in rheumatoid arthritis: contrasting effects of HLA-DR3 and the shared epitope alleles

OBJECTIVE: To examine the association between HLA-DRB1 alleles and the production of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) autoantibodies in patients with rheumatoid arthritis (RA). METHODS: We studied 1,723 Caucasian RA patients enrolled in the North American Rheumatoid Arthritis Consortium (NARAC) family cohort and the Study of New Onset Rheumatoid Arthritis (SONORA) cohort. All patients were tested for anti-CCP antibodies (by enzyme-linked immunosorbent assay), RF (by nephelometry), and HLA-DR genotype (by polymerase chain reaction and sequence-specific oligonucleotide hybridization). RESULTS: When controlled for the presence of RF, anti-CCP positivity was strongly associated with the HLA-DRB1 shared epitope (SE). In RF+ patients, the presence of the SE was very significantly associated with anti-CCP positivity, with an odds ratio (OR) of 5.8 and a 95% confidence interval (95% CI) of 4.1-8.3. This relationship was also seen in RF- patients (OR 3.1 [95% CI 1.8-5.3]). In contrast, RF positivity was not significantly associated with presence of the SE independently of anti-CCP antibodies. Strikingly, HLA-DRB1*03 was strongly associated with reduced anti-CCP titers, even after controlling for the presence of the SE and restricting the analysis to anti-CCP+ patients. HLA-DR3 was also associated with anti-CCP- RA in our population. CONCLUSION: The HLA-DRB1 SE is strongly associated with the production of anti-CCP antibodies, but not RF. In contrast, HLA-DR3 alleles are associated with anti-CCP- disease and with lower levels of anti-CCP antibodies, even when controlling for the SE. These data emphasize the complexity of the genetic effects of the major histocompatibility complex on the RA phenotype.     

Rheumatoid arthritis in southern Spain: toward elucidation of a unifying role of the HLA class II region in disease predisposition

OBJECTIVE: To evaluate the contributions of HLA-DQ and -DR polymorphisms to susceptibility to rheumatoid arthritis (RA) in a population in southern Spain, and to compare the value of the shared epitope (SE) and RA protection (RAP) models in accounting for the HLA class II region's contribution to RA predisposition. METHODS: One hundred sixty RA patients and 153 healthy controls were typed for HLA-DRB1 and -DQB1 using high-resolution DNA techniques. Distributions of predisposing DRB1 alleles in patients and control subjects according to the SE model were compared with distributions of predisposing DQ and protective DERAA-positive DRBI alleles according to the RAP model. RESULTS: DQ3 (DQBI*03 and *04 combined with DQA1*03) and DQ5 (DQB1*0501/DQA1*0101) alleles predisposed individuals to RA independently of SE-positive DRB1 alleles. DQ3/3-homozygous individuals had the strongest risk of developing RA. DQ3 molecules predisposed to RA more than did DQ5 molecules. The weaker predisposition mediated by DQ5 included the DRB1*1001-carrying haplotype; no DRB1*1001-homozygous patients were observed. DRBI*0401 played a unique role in the contribution of DQ3-DR4 haplotypes to RA, in spite of its low frequency in southern Spain. CONCLUSION: The low prevalences of RA and of mild disease observed in Spain, and in southern Europe in general, can be explained in great part by the low frequency of DQ3-DR4 haplotypes, especially those carrying DRB1*0401. However, the overall distribution of HLA-DQ and -DR alleles in RA patients compared with control subjects is similar to that in other European and North American populations. A model involving both DQ and DR can best account for the contribution of HLA to RA.     

Influence of HLA polymorphism on persistent remission in rheumatoid arthritis

BACKGROUND: Several studies have reported an association between the presence of the shared epitope (SE) and susceptibility to rheumatoid arthritis (RA). Recent studies have shown that certain HLA-DRB1 alleles in combination with predisposing DQB1 and DQA1 alleles may protect against the development of RA. This model is known as the rheumatoid arthritis protection (RAP) hypothesis. OBJECTIVE: To determine the distribution of HLA-DRB1 and DQB1/DQA1 alleles in a cohort of patients with RA in remission and to determine the association between these HLA alleles and the persistence of remission. PATIENTS AND METHODS: HLA-DRB1 and DQB1 typings were performed in 167 patients with RA in remission, defined according to the American College of Rheumatology criteria. The disease course, as defined by the persistence of remission during a follow up of two years, was compared between subgroups. According to the RAP hypothesis patients were divided into three subgroups: patients carrying predisposing DQ alleles, patients carrying predisposing alleles in combination with protective alleles (DQ(RA+)/DERAA phenotype), and patients lacking the predisposing alleles. According to the SE hypothesis, patients were divided into three subgroups based on whether they were carrying two, one, or no predisposing alleles (SE alleles). RESULTS: Predisposing DQ alleles along with a DERAA-bearing allele were present in 14 (8%) of the 167 patients. At least one SE allele was present in 116 (69%) patients; 34 of them (20%) were carrying two copies. The disease course was not significantly different between the subgroups according to the SE and RAP hypothesis, respectively. CONCLUSION: The frequency of DQ(RA+)/DERAA combinations and of SE alleles in patients with RA clinically in remission was similar to that found in other RA populations. Persistent remission of RA was not associated with any particular HLA subtypes, indicating that HLA typing is not useful for predicting persistent clinical remission.     

An independent role of protective HLA class II alleles in rheumatoid arthritis severity and susceptibility

OBJECTIVE: To prospectively investigate the effect of the DERAA-encoding HLA alleles on disease susceptibility and severity in a large cohort of patients with rheumatoid arthritis (RA), and to differentiate protective effects from non-predisposition by comparing subgroups of patients with an equal amount of predisposition alleles. METHODS: HLA class II alleles were determined in 440 patients with early RA and in 423 healthy controls. In order to study the effect of HLA on disease severity, radiographic joint destruction was evaluated, using the modified Sharp/van der Heijde method, during 4 years of followup. RESULTS: The presence of DERAA-encoding HLA-DRB1 alleles conferred a lower risk of developing RA for both the presence and absence of SE alleles (odds ratio 0.6). At all time points, radiographic destruction was significantly less severe in DERAA-positive patients with 1 SE allele compared with DERAA-negative patients with 1 SE allele. Additionally, a protective effect of DERAA was detected in the groups of patients who were prone to having more severe disease because of the presence of anti-cyclic citrullinated peptide antibodies or because of smoking. CONCLUSION: DERAA-encoding HLA-DRB1 alleles independently protect against RA and are associated with less severe disease.     

HLA haplotype analysis in Finnish patients with rheumatoid arthritis

OBJECTIVE: To further characterize the HLA gene products that play an important role in the pathogenesis of rheumatoid arthritis (RA). METHODS: One hundred thirty-four haplotypes from 67 Finnish RA patients and 77 control haplotypes were analyzed for HLA-DRB1 loci, associated alleles of the HLA-DQB1 locus, alleles of the type 2 transporter-associated antigen processing (TAP2) genes, and HLA-B27. In addition, a panel of microsatellite markers within the HLA class I and class III regions was studied. RESULTS: The frequency of HLA-DRB1*04 in the haplotypes of RA patients was found to be 34% (45 of 134) compared with 14% (10 of 72) in control haplotypes (P = 0.004). The frequency of HLA-DRB1*13 was decreased in RA haplotypes (4%, or 5 of 134) in contrast to control haplotypes (24%, or 17 of 72) (P = 0.000031). The decrease in DRB1*13 was not secondary to the increase in DRB1*04, since it was also found among DRB1*04-negative haplotypes (P < 0.001). The DRB1*13-associated DQB1*0604 allele was similarly decreased in RA haplotypes (P = 0.025). The TAP2I allele of I/J dimorphism was increased in RA patients (85%, or 114 of 134) as compared with controls (69%, or 49 of 71) (P = 0.011). Of the tumor necrosis factor (TNF) microsatellite alleles, TNFa6 and TNFb5 were found to be increased in RA haplotypes (for a6 27% versus 5% in controls [P = 0.00043], and for b5 43% versus 26% in controls [P = 0.037]). CONCLUSION: Both protection-associated and susceptibility-associated alleles can be found among HLA class II genes, and the results suggest that loci outside DR/DQ may contribute to the pathogenesis of RA.     

Evidence for HLA-related susceptibility for stroke in children with sickle cell disease

Cerebral infarction occurs in one quarter of all children with sickle cell anemia (SCA). There is an increased risk of stroke in siblings with SCA, suggesting genetic factors may influence risk of stroke. The authors investigated whether HLA type was associated with risk of stroke in children with SCA. Fifty-three patients with SCA underwent complete HLA typing at both HLA class I (HLA-A, B) and HLA class II (HLA-DR, DQ, DP) loci. Of the 53 patients, 22 had magnetic resonance imagining (MRI)-documented evidence of cerebral infarction, and the remaining 31 patients had negative MRI scans. Comparison of the results of HLA typing between the SCA patients with a positive and those with a negative MRI documented that the 2 groups differed with respect to the class I HLA-B (P =.012), and the class II HLA-DRB1 (P =.0008) and DQB1 (P =.029). Susceptibility associations at the HLA-DRB1 locus included both DR3 alleles, where DRB1*0301 and *0302 were both associated with an increased risk of stroke. Protective associations were found in the DR2 group, where DRB1*1501 was protective for stroke. DQB1*0201, which is in linkage disequilibrium with DRB1*0301, was also associated with stroke. Similarly, DQB1*0602, in linkage disequilibrium with DRB1*1501, was protective. Specific HLA alleles may influence the risk of stroke in children with SCA. HLA typing may prove useful in identifying SCA patients at higher risk for stroke.     

Refining the complex rheumatoid arthritis phenotype based on specificity of the HLA-DRB1 shared epitope for antibodies to citrullinated proteins

OBJECTIVE: The main genetic risk factor for rheumatoid arthritis (RA), the HLA region, has been known for 25 years. Previous research has demonstrated, within the RA population, an association between HLA-DRB1 alleles carrying the shared epitope (SE) and antibodies directed against cyclic citrullinated peptides (anti-CCP antibodies). We undertook this study to make the first comparison of SE allele frequencies in the healthy population with those in RA patients who do or do not harbor anti-CCP antibodies. METHODS: HLA-DRB1 typing was performed in 408 RA patients from the Leiden Early Arthritis Clinic (the Leiden EAC; a Dutch population-based inception cohort in which disease course was followed up over time), in 423 healthy Dutch controls, and in 720 affected members of 341 US multiplex (sibpair) families of Caucasian origin from the North American RA Consortium (NARAC) with well-established disease and fulfilling the American College of Rheumatology classification criteria for RA. The presence of anti-CCP antibodies was determined by enzyme-linked immunosorbent assay. RESULTS: For the Leiden EAC, the odds ratio (OR) describing the association of 2 copies of the SE allele with anti-CCP positivity (using no copies of the SE allele in the healthy control group as the referent) was 11.79 (P < 0.0001), while the OR for 1 SE allele was 4.37 (P < 0.0001). No association with the SE was observed in the Dutch anti-CCP-negative RA patients. For the NARAC families, linkage and association analysis revealed the SE to be associated only with anti-CCP-positive disease and not with anti-CCP-negative disease. Stratified analyses indicated that anti-CCP antibodies primarily mediated association of the SE with joint damage or disease persistence. CONCLUSION: HLA-DRB1 alleles encoding the SE are specific for disease characterized by antibodies to citrullinated peptides, indicating that these alleles do not associate with RA as such, but rather with a particular phenotype.     

Contribution of an adenine to guanine single nucleotide polymorphism of the matrix metalloproteinase-13 (MMP-13) �?7 promoter region to the production of anticyclic citrullinated peptide antibodies in patients with HLA-DRB1*shared epitope-negative rheumatoid arthritis

We examined whether matrix metalloproteinase-13 (MMP-13) contributes to disease susceptibility or severity of rheumatoid arthritis (RA). Eighty-seven patients with RA whose disease duration was <2 years and 71 healthy controls were enrolled in the study. Adenine (A) to guanine (G) single nucleotide polymorphism (SNP) of the -77 MMP-13 promoter region in RA and healthy controls was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Human leukocyte antigen (HLA)-DRB1 genotyping was also performed using the same populations. Anticyclic citrullinated peptide (anti-CCP) antibodies from RA patients at entry were studied, and their relationships were examined. The genotype and allele frequency of SNP of MMP-13 at -77 did not differ between RA patients and healthy controls. We focused on the RA patients who were negative for HLA-DRB1*shared epitope (SE) alleles and found that the seropositivity of anti-CCP antibodies with a titer >25 U/ml was high in the A/A genotype compared with the G/G genotype. The same characteristic was also found in HLA-DRB1*0405 allele-negative patients. Our data suggest that SNP of the -77 MMP-13 promoter region acts as a surrogate marker of anti-CCP antibody production in HLA-DRB1*SE allele-negative RA patients, which may reflect RA severity.     

HLA class II polymorphism in Egyptian children with lymphomas

The major histocompatibility complex (MHC) is a set of closely-linked genes encoded on the short arm of chromosome 6. It is important for understanding human immunological diseases, transplantation and in host defense against infection. The membrane proteins are two types; class I MHC proteins and class II MHC proteins. Strong arguments supporting genetic linkage between susceptibility to lymphomas and human leukocyte antigens (HLA)-class II are reported and give a clue about susceptibility or protection from the disease. AIM: To evaluate the possible changes of HLA class II (DR, DQ) alleles in children with lymphoma. METHODS: Thirty cases were included in this limited study. Nineteen cases of non Hodgkin's lymphoma (NHL) and eleven patients with Hodgkin's lymphoma (HD). Their ages ranged from 1.5 to 15 years. The control group consisted of 121 unrelated healthy subjects for DRB1 alleles and 59 unrelated healthy subjects for DQB1 alleles (only 59 subjects were typed for both DRB1 and DQB1). All cases in the study were assessed by thorough history taking, physical examination and laboratory investigations that included complete blood count, renal function tests, liver function tests, serum uric acid and HLA typing. Patients and controls were typed for HLA class II DRB1 and DQB1 alleles using INNO-LIPA reverse hybridization line probe assay (Innogenetic, Belgium). RESULTS: HLA-DRB1 *0403 and *1301 and HLA-DQB1 *0501,* 0201 and *0301 were significantly increased in patients with NHL when compared with control; whereas HLA-DRB1 *1302 and HLA-DQB1 *0502 and *0602 were significantly decreased when compared with control. In patients with HD, HLA-DRB1 *0403 and *1202 and HLA-DQB1 *0604, *0201 and *0203 were significantly increased when compared with control. CONCLUSIONS: (1) The susceptibility to NHL is related to HLA-DRB1 *0403 and *1301 and HLA-DQB1 *0501,* 0201 and *0301. (2) The susceptibility to HD is related to HLA-DRB1 *0403 and *1202 and HLA-DQB1 *0604, *0201 and *0203. (3) HLA-DRB1 *1302 and HLA-DQB1 *0502 and *0602 may confer protection to NHL. (4) Different HLA alleles may have a role in patients with both groups of lymphoma and further study is needed to better define the possible prognostic value of different HLA associations in patients with lymphomas regarding increased risk in the presence of certain HLA alleles and the possibility for treatment modifications in the future based on the presence or absence of certain HLA alleles.     

Immune response of HLA-DQ8 transgenic mice to peptides from the third hypervariable region of HLA-DRB1 correlates with predisposition to rheumatoid arthritis.

The major histocompatibility complex class II genes play an important role in the genetic predisposition to many autoimmune diseases. In the case of rheumatoid arthritis (RA), the human leukocyte antigen (HLA)-DRB1 locus has been implicated in the disease predisposition. The "shared epitope" hypothesis predicts that similar motifs within the third hypervariable (HV3) regions of some HLA-DRB1 alleles are responsible for the class II-associated predisposition to RA. Using a line of transgenic mice expressing the DQB1*0302/DQA1*0301 (DQ8) genes in the absence of endogenous mouse class II molecules, we have analyzed the antigenicity of peptides covering the HV3 regions of RA-associated and nonassociated DRB1 molecules. Our results show that a correlation exists between proliferative response to peptides derived from the HV3 regions of DRB1 chains and nonassociation of the corresponding alleles with RA predisposition. While HV3 peptides derived from nonassociated DRB1 molecules are highly immunogenic in DQ8 transgenic mice, all the HV3 peptides derived from RA-associated DRB1 alleles fail to induce a DQ8-restricted T-cell response. These data suggest that the role of the "shared epitope" in RA predisposition may be through the shaping of the T-cell repertoire.     

The HLA-DRB1 shared epitope is associated with susceptibility to rheumatoid arthritis in African Americans through European genetic admixture

OBJECTIVE: To determine whether shared epitope (SE)-containing HLA-DRB1 alleles are associated with rheumatoid arthritis (RA) in African Americans and whether their presence is associated with higher degrees of global (genome-wide) genetic admixture from the European population. METHODS: In this multicenter cohort study, African Americans with early RA and matched control subjects were analyzed. In addition to measurement of serum anti-cyclic citrullinated peptide (anti-CCP) antibodies and HLA-DRB1 genotyping, a panel of >1,200 ancestry-informative markers was analyzed in patients with RA and control subjects, to estimate the proportion of European ancestry. RESULTS: The frequency of SE-containing HLA-DRB1 alleles was 25.2% in African American patients with RA versus 13.6% in control subjects (P = 0.00005). Of 321 patients with RA, 42.1% had at least 1 SE-containing allele, compared with 25.3% of 166 control subjects (P = 0.0004). The mean estimated percent European ancestry was associated with SE-containing HLA-DRB1 alleles in African Americans, regardless of disease status (RA or control). As reported in RA patients of European ancestry, there was a significant association of the SE with the presence of the anti-CCP antibody: 86 (48.9%) of 176 patients with anti-CCP antibody-positive RA had at least 1 SE allele, compared with 36 (32.7%) of 110 patients with anti-CCP antibody-negative RA (P = 0.01, by chi-square test). CONCLUSION: HLA-DRB1 alleles containing the SE are strongly associated with susceptibility to RA in African Americans. The absolute contribution is less than that reported in RA among populations of European ancestry, in which approximately 50-70% of patients have at least 1 SE allele. As in Europeans with RA, the SE association was strongest in the subset of African American patients with anti-CCP antibodies. The finding of a higher degree of European ancestry among African Americans with SE alleles suggests that a genetic risk factor for RA was introduced into the African American population through admixture, thus making these individuals more susceptible to subsequent environmental or unknown factors that trigger the disease.     

HLA Class II Polymorphism in Egyptian Children with Lymphomas

The major histocompatibility complex (MHC) is a set of closely-linked genes encoded on the short arm of chromosome 6. It is important for understanding human immunological diseases, transplantation and in host defense against infection. The membrane proteins are two types; class I MHC proteins and class II MHC proteins. Strong arguments supporting genetic linkage between susceptibility to lymphomas and human leukocyte antigens (HLA)-class II are reported and give a clue about susceptibility or protection from the disease.

Aim: To evaluate the possible changes of HLA class II (DR, DQ) alleles in children with lymphoma.

Methods: Thirty cases were included in this limited study. Nineteen cases of non Hodgkin's lymphoma (NHL) and eleven patients with Hodgkin's lymphoma (HD). Their ages ranged from 1.5 to 15 years. The control group consisted of 121 unrelated healthy subjects for DRB1 alleles and 59 unrelated healthy subjects for DQB1 alleles (only 59 subjects were typed for both DRB1 and DQB1). All cases in the study were assessed by thorough history taking, physical examination and laboratory investigations that included complete blood count, renal function tests, liver function tests, serum uric acid and HLA typing. Patients and controls were typed for HLA class II DRB1 and DQB1 alleles using INNO-LIPA reverse hybridization line probe assay (Innogenetic, Belgium).

Results: HLA-DRB1 *0403 and *1301 and HLA-DQB1 *0501,* 0201 and *0301 were significantly increased in patients with NHL when compared with control; whereas HLA-DRB1 *1302 and HLA-DQB1 *0502 and *0602 were significantly decreased when compared with control. In patients with HD, HLA-DRB1 *0403 and *1202 and HLA-DQB1 *0604, *0201 and *0203 were significantly increased when compared with control.

Conclusions: (1) The susceptibility to NHL is related to HLA-DRB1 *0403 and *1301 and HLA-DQB1 *0501,* 0201 and *0301. (2) The susceptibility to HD is related to HLA-DRB1 *0403 and *1202 and HLA-DQB1 *0604, *0201 and *0203. (3) HLA-DRB1 *1302 and HLA-DQB1 *0502 and *0602 may confer protection to NHL. (4) Different HLA alleles may have a role in patients with both groups of lymphoma and further study is needed to better define the possible prognostic value of different HLA associations in patients with lymphomas regarding increased risk in the presence of certain HLA alleles and the possibility for treatment modifications in the future based on the presence or absence of certain HLA alleles.     

Auto-antibodies, HLA and PTPN22: susceptibility markers for rheumatoid arthritis

OBJECTIVE: To analyse the relationship between the presence of auto-antibodies [rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP)], HLA-DRB1 alleles and PTPN22 1858 C/T polymorphism and test the value of their combination as susceptibility markers for rheumatoid arthritis (RA). METHODS: Patients with early arthritis were included. At entry in the cohort or during follow-up, 191 patients fulfilled the criteria for RA and 184 individuals suffered from other arthropathies. RF was measured by nephelometry and anti-CCP antibody by enzyme-linked immunosorbent assay. HLA class II alleles were determined by polymerase chain reaction. Samples were genotyped for PTPN22 1858C/T variants using a TaqMan 5'-allele discrimination assay. RESULTS: The presence of shared epitope (SE) alleles was strongly associated with anti-CCP and RF-positive RA [P = 7.05 x 10(-10), odds ratio (OR) 4.57, 95% confidence interval (CI) 2.76-7.57 and P = 1.68 x 10(-6), OR 2.99, 95% CI 1.89-4.74, respectively). The combination of the PTPN22 1858T variant and anti-CCP antibodies gave a high specificity for the disease, and was significantly associated with RA (P = 8.86 x 10(-5), OR 10.05, 95% CI 1.88-53.73). CONCLUSION: The combination of the T variant of the 1858 polymorphism of the PTPN22 gene in combination with the presence of anti-CCP antibodies, preferentially in a SE-positive individual, is associated with the development of RA.     

Human leukocyte antigens in forms of leprosy among Japanese patients

Human leukocyte antigens (HLA) class II alleles were analyzed among Japanese leprosy patients to ascertain whether immunogenetic differences exist among the leprosy classification forms of Ridley and Jopling. Ninety-three unrelated Japanese leprosy patients (21 lepromatous, 24 borderline lepromatous, 17 mid-borderline, 26 borderline tuberculoid, 5 tuberculoid) and 114 healthy control subjects were investigated. The frequencies of HLA-DRB1*1501, -DRB5*0101, -DQA1*0102 and DQB1*0602 were significantly increased in all of the Japanese leprosy patients. The frequencies of HLA-DRB1*0405, -DQA1*03 and -DQB1*0401 were significantly decreased in the Japanese patients after correction of the p value. Conversely, there were no significantly different distributions of the HLA-DRB1, -DRB5, -DQA1, DQB1 alleles in the five subgroups of these patients. We conclude that HLA class II alleles were not associated with the form of leprosy. Other HLA, a non-HLA gene, and/or environmental factors may play a critical role in the different manifestations of leprosy.     

The HLA-DRB1 shared epitope alleles are primarily a risk factor for anti-cyclic citrullinated peptide antibodies and are not an independent risk factor for development of rheumatoid arthritis

OBJECTIVE: The shared epitope (SE)-containing HLA-DRB1 alleles represent the most significant genetic risk factor for rheumatoid arthritis (RA). Recent studies indicate that the SE alleles are associated with only RA that is characterized by the presence of anti-cyclic citrullinated peptide (anti-CCP) antibodies, and not with anti-CCP-negative disease. In this study we investigated whether the SE alleles contribute to the development of anti-CCP-positive RA, or whether they are associated solely with the presence of anti-CCP antibodies. We therefore determined the influence of the SE alleles and anti-CCP antibodies on the progression from recent-onset undifferentiated arthritis (UA) to RA. METHODS: Patients with recent-onset UA at the 2-week visit (n=570) were selected from the Leiden Early Arthritis Cohort. SE alleles, rheumatoid factor (RF) status, and anti-CCP antibody levels were determined. Progression to RA or other diagnoses was monitored. RESULTS: One hundred seventy-seven patients with UA developed RA during the 1-year followup, whereas the disease in 393 patients remained unclassified or was given other diagnoses. The SE alleles correlated with the presence of anti-CCP antibodies, but not with the presence of RF. Both in SE-positive and in SE-negative patients with UA, the presence of anti-CCP antibodies was significantly associated with the development of RA. More intriguingly, however, no apparent contribution of the SE alleles to the progression to RA was found when analyses were stratified according to the presence of anti-CCP antibodies. In patients with anti-CCP-positive disease, the presence of SE alleles was associated with significantly higher levels of anti-CCP antibodies, suggesting that the SE alleles act as classic immune response genes. CONCLUSION: The SE alleles do not independently contribute to the progression to RA from UA, but rather contribute to the development of anti-CCP antibodies.     

Association of smoking with the constitution of the anti-cyclic citrullinated peptide response in the absence of HLA-DRB1 shared epitope alleles

OBJECTIVE: Smoking is a risk factor for anti-cyclic citrullinated peptide (anti-CCP) antibody-positive rheumatoid arthritis (RA) in patients with HLA-DRB1 shared epitope (SE) alleles. It is unknown whether smoking influences not only the presence of these antibodies, but also other characteristics of the anti-CCP response, such as isotype usage. The aim of this study was to determine the influence of smoking on anti-CCP isotypes in RA patients, and to determine whether this influence is observed in the presence and/or absence of SE alleles. METHODS: IgA, IgM, and IgG subclasses of anti-CCP antibodies were measured by enzyme-linked immunosorbent assay in serum obtained at the first visit to the Leiden Early Arthritis Clinic from 216 patients with anti-CCP-positive RA whose smoking habits were also assessed. HLA genotyping data were available for 202 of these patients. RESULTS: IgA and IgM anti-CCP were more frequent in RA patients who were smokers than in those who were nonsmokers (odds ratio 2.8 and 1.8, respectively). In addition, levels of all isotypes of anti-CCP, except IgG3, were significantly higher (P < 0.05) in smokers. The number of anti-CCP isotypes was higher in smokers compared with nonsmokers, both in SE-negative RA (P = 0.04) and in SE-positive RA (P = 0.07). CONCLUSION: Patients with anti-CCP-positive RA who have a current or former tobacco exposure display a more extensive anti-CCP isotype usage in general, and IgA and IgM in particular, compared with patients with anti-CCP-positive RA who have never smoked. In contrast to its influence on the incidence of anti-CCP positivity, the influence of tobacco exposure on the constitution of the anti-CCP response is significant in SE-negative RA. These findings suggest a differential effect of tobacco exposure on the induction as compared with the propagation of the anti-CCP antibody response.     

Linkage disequilibrium between HLA class II region and autoimmune hepatitis in pediatric patients

BACKGROUND/AIMS: Susceptibility HLA class II alleles associated with autoimmune hepatitis (AIH) were only described in case-control studies. METHODS: The transmission/disequilibrium test was used in 50 simplex families with AIH, to determine if affected offspring received the disease-associated allele more frequently than its alternate. HLA-DRB1 and DQB1 allele genotyping and autoimmune regulator (AIRE) polymorphisms located in exons 6, 8 and 10 were investigated by PCR-based methods. RESULTS: HLA-DRB1*03 allele was significantly transmitted from heterozygous parent to affected offspring (81.5%) with type 1 AIH compared to random expected frequency (50.0%; P=0.004) or to unaffected offspring (42.8%; P=0.03). HLA-DRB1*1301 allele showed an excess transmission to affected children (100%) than expected frequency (P<0.0001) or unaffected offspring (P=0.001). The transmission of DQB1*201 or DQB1*0603 alleles showed significant deviation in patients compared to random frequencies: (84.8%; P<0.0001 for DQB1*0201 or 100%; P<0.0001 for DQB1*0603). HLA-DQB1*0201 showed a strong association with type 2 AIH in children (100.0%, P=0.0005). CONCLUSIONS: HLA-DRB1 gene is the major genetic determinant in HLA class II region for children with type 1 AIH. Type 2 AIH is associated with the HLA-DQB1gene. Finally, AIRE gene abnormality does not contribute to the development of isolated AIH.