Presence Of HLA Research Articles

Individual Immune Response to SARS-CoV-2 Infection-The Role of Seasonal Coronaviruses and Human Leukocyte Antigen.

During the coronavirus pandemic, evidence is growing that the severity, susceptibility and host immune response to SARS-CoV-2 infection can be highly variable. Several influencing factors have been discussed. Here, we investigated the humoral immune response against SARS-CoV-2 spike, S1, S2, the RBD, nucleocapsid moieties and S1 of seasonal coronaviruses: hCoV-229E, hCoV-HKU1, hCoV-NL63 and hCoV-OC43, as well as MERS-CoV and SARS-CoV, in a cohort of 512 individuals. A bead-based multiplex assay allowed simultaneous testing for all the above antigens and the identification of different antibody patterns. Then, we correlated these patterns with 11 HLA loci. Regarding the seasonal coronaviruses, we found a moderate negative correlation between antibody levels against hCoV-229E, hCoV-HKU1 and hCoV-NL63 and the SARS-CoV-2 antigens. This could be an indication of the original immunological imprinting. High and low antibody response patterns were distinguishable, demonstrating the individuality of the humoral response towards the virus. An immunogenetical factor associated with a high antibody response (formation of ≥4 different antibodies) was the presence of HLA A*26:01, C*02:02 and DPB1*04:01 alleles, whereas the HLA alleles DRB3*01:01, DPB1*03:01 and DB1*10:01 were enriched in low responders. A better understanding of this variable immune response could enable more individualized protective measures.

The longitudinal loss of islet autoantibody responses from diagnosis of type 1 diabetes occurs progressively over follow-up and is determined by low autoantibody titres, early-onset, and genetic variants.

The clinical usefulness of post-diagnosis islet autoantibody levels is unclear and factors that drive autoantibody persistence are poorly defined in type 1 diabetes (T1D). Our aim was to characterise the longitudinal loss of islet autoantibody responses after diagnosis in a large, prospectively sampled UK cohort. Participants with T1D [n = 577] providing a diagnosis sample [range -1.0 to 2.0 years] and at least one post-diagnosis sample (<32.0 years) were tested for autoantibodies to glutamate decarboxylase 65 (GADA), islet antigen-2 (IA-2A), and zinc transporter 8 (ZnT8A). Select HLA and non-HLA SNPs were considered. Non-genetic and genetic factors were assessed by multivariable logistic regression models for autoantibody positivity at initial sampling and autoantibody loss at final sampling. For GADA, IA-2A, and ZnT8A, 70.8%, 76.8%, and 40.1%, respectively, remained positive at the final sampling. Non-genetic predictors of autoantibody loss were low baseline autoantibody titres (P < 0.0001), longer diabetes duration (P < 0.0001), and age-at-onset under 8 years (P < 0.01--0.05). Adjusting for non-genetic covariates, GADA loss was associated with low-risk HLA class II genotypes (P = 0.005), and SNPs associated with autoimmunity RELA/11q13 (P = 0.017), LPP/3q28 (P = 0.004), and negatively with IFIH1/2q24 (P = 0.018). IA-2A loss was not associated with genetic factors independent of other covariates, while ZnT8A loss was associated with the presence of HLA A*24 (P = 0.019) and weakly negatively with RELA/11q13 (P = 0.049). The largest longitudinal study of islet autoantibody responses from diagnosis of T1D shows that autoantibody loss is heterogeneous and influenced by low titres at onset, longer duration, earlier age-at-onset, and genetic variants. These data may inform clinical trials where post-diagnosis participants are recruited.

Association of HLA-B27 antigen with clinical and laboratory parameters in patients with juvenile idiopathic arthritis.

Aim To analyse the association of human leukocyte antigen B27 with clinical and laboratory parameters in patients with juvenile idiopathic arthritis (JIA) at the disease onset. Methods A retrospective review of medical records of 25 HLAB27 positive and 25 HLA-B27 negative JIA patients was performed. The diagnosis of JIA was based on the 1997-2001 International League Against Rheumatism (ILAR) criteria. Collected data: age, sex, HLA- B27 antigen presence, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid-factor (RF), antinuclear antibody (ANA), fever, rash, uveitis, enthesitis, inflamed joints and subtype of JIA. Results HLA- B27 positive study group had more boys (p=0.01), higher erythrocyte sedimentation rate (p=0.038), higher presence of fever (p= 0.025) and enthesitis (p=0.024). Any significant difference in age of the disease onset, CRP, ANA, RF, rash, uveitis, inflamed joint and dactylitis was not noticed. The most common subtype of JIA in the HLA-B27 positive patients was ERA (60%). Conclusion This study showed that the presence of HLA- B27 antigen plays a significant role in determining the presenting clinical and laboratory characteristics in JIA patients.

Staphylococcus aureus Alpha-Toxin in Deep Tracheal Aspirates-Preliminary Evidence for Its Presence in the Lungs of Sepsis Patients.

The pore forming alpha-toxin (hemolysin A, Hla) of Staphylococcus aureus (S. aureus) is a major virulence factor with relevance for the pathogenicity of this bacterium, which is involved in many cases of pneumonia and sepsis in humans. Until now, the presence of Hla in the body fluids of potentially infected humans could only be shown indirectly, e.g., by the presence of antibodies against Hla in serum samples or by hemolysis testing on blood agar plates of bacterial culture supernatants of the clinical isolates. In addition, nothing was known about the concentrations of Hla actually reached in the body fluids of the infected hosts. Western blot analyses on 36 samples of deep tracheal aspirates (DTA) isolated from 22 hospitalized sepsis patients using primary antibodies against different epitopes of the Hla molecule resulted in the identification of six samples from five patients containing monomeric Hla (approx. 33 kDa). Two of these samples showed also signals at the molecular mass of heptameric Hla (232 kDa). Semiquantitative analyses of the samples revealed that the concentrations of monomeric Hla ranged from 16 to 3200 ng/mL. This is, to our knowledge, the first study directly showing the presence of S. aureus Hla in samples of airway surface liquid in human patients.

Clonal Hematopoiesis By HLA Class I Allele-Lacking Hematopoietic Stem Cells and Concomitant Aberrant Stem Cells Is Rarely Associated with Clonal Evolution to Secondary Myelodysplastic Syndrome and Acute Myeloid Leukemia in Patients with Acquired Aplastic Anemia

[Background] HLA-class I allele-lacking (HLA[-]) leukocytes are detected in approximately 30% of patients with acquired aplastic anemia (AA), and are thought to represent the involvement of cytotoxic T lymphocyte attack against hematopoietic stem cells (HSCs) in the development of AA, based on the high response rate to immunosuppressive therapy (IST) in patients with such aberrant leukocytes. Similar to glycosylphosphatidylinositol-anchored protein (GPI-AP)-deficient (GPI[-]) leukocytes in patients with paroxysmal nocturnal hemoglobinuria (PNH), HLA(-) leukocytes in AA patients are often clonal or oligoclonal and expand to account for more than 50% of the total leukocytes. Despite such overwhelming proliferation, somatic mutations in driver genes as well as telomere shortening that portend clonal evolution are rarely detected in HLA(-) granulocytes, suggesting the genetic stability of HLA(-) HSCs and the persistence of the immune pressure on HSCs that favors expansion of HLA(-) HSCs (Imi, et al. Blood Adv). However, recent studies from the United States have shown a higher incidence of clonal evolution to secondary myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) in AA patients with HLA(-) leukocytes than in those without such leukocytes, a finding inconsistent with the results of our previous study. Given the high prevalence of HLA(-) leukocytes in AA patients, it is critical to determine whether or not the presence of the aberrant leukocytes is associated with clonal evolution. We therefore addressed this issue by studying the prognosis of a large number of AA patients with or without HLA(-) leukocytes who had been followed for a long term period. We also studied the clonal composition of granulocytes in AA patients with HLA(-) cells, wherein aberrant clones other than HLA(-) cells might be responsible for clonal evolution to MDS/AML. [Methods] We retrospectively analyzed the clinical characteristics of 633 AA patients and peripheral blood samples were examined for the presence of HLA(-) leukocytes using a high-sensitivity flow cytometry (FCM) assay, droplet digital PCR, single-nucleotide polymorphism arrays, or next generation sequencing (NGS) between 2010 and 2020. GPI(-) cells were detected using a high-sensitivity FCM assay as previously described. [Results] HLA(-) granulocytes were detected in 127 (20.1%) of the 633 patients with a median clone size of 16.9% (range, 0.04%-100%); the aberrant granulocytes accounted for greater than 50% of the total granulocytes in 29 (22.8%) of 127 patients. Eighty-nine (70.0%) of the 127 patients possessed aberrant clones other than HLA(-) clones, which included 0.005% to 91.6% GPI(-) cells (n=86), del(13q) cells (n=3), t(1;10) cells (n=1), t(9;13) cells (n=1), inv12 cells (n=1), and trisomy 8 cells (n=1). The prevalence of GPI(-) cells was not significantly different between patients with and without HLA(-) cells (67.7% vs 65.4%). Eighty-five of 102 (83.3%) patients with HLA(-) cells responded to IST, whereas 231 of 318 (72.6%) without HLA(-) cells responded (p&amp;lt;0.05). In 13 patients who had been in hematological remission for more than 7 years, HLA(-) cells and other concomitant aberrant cells accounted for &amp;gt;90% of granulocytes, suggesting that these few escape clones were enough to sustain the hematopoietic function of the patients. The prognosis survey revealed no clonal evolution to MDS/AML in any of the 127 AA patients with HLA(-) leukocytes after a follow-up period of the median 5 years. In contrast, 15 of 234 (6.4%) patients without HLA(-) cells who were trackable evolved to MDS/AML during a median 5 year follow-up. [ Conclusions] The presence of HLA(-) leukocytes and concomitant aberrant clones was not associated with clonal evolution to MDS/AML in Japanese AA patients, even in those possessing a large (&amp;gt;50% of the total granulocyte) HLA(-) cell population. The discrepancy between our results and the data from the United States may be due to the difference in the race and mechanism underlying HLA loss. These data suggest that HSC clones that escape immune attack, such as HLA(-) and GPI(-) clones, are healthy enough to support hematopoiesis for a long term in AA patients. Disclosures Ishiyama: Novartis: Honoraria; Alexion: Research Funding. Yamazaki:Novartis: Honoraria; Kyowa Kirin: Honoraria, Research Funding. Ogawa:Eisai Co., Ltd.: Research Funding; Sumitomo Dainippon Pharma Co., Ltd.: Research Funding; Chordia Therapeutics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Asahi Genomics Co., Ltd.: Current equity holder in private company; Otsuka Pharmaceutical Co., Ltd.: Research Funding; KAN Research Institute, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding. Nakao:Alexion: Research Funding; Kyowa Kirin: Honoraria; Novartis: Honoraria; Symbio: Consultancy.

Diagnosis of spondyloarthritis: Application of criteria in clinical practice

Spondyloarthritis (SpA) is an umbrella term for a group of inflammatory musculoskeletal conditions characterized by predominant involvement of the spine, the lower limb joints, and the entheses. The Assessment of SpA International Society (ASAS) group classifies SpA into axial SpA (axSpA) and peripheral SpA. axSpA was further divided into radiographic SpA and nonradiographic SpA. Classification criteria are meant for research purposes to enroll a homogeneous cohort, unlike diagnostic criteria, which are meant for diagnosing diseases in the community and therefore must include all the heterogeneous manifestations of a disease. Inflammatory low back pain is one of the most important features in history to be elicited in the diagnosis of axSpAs. It should not be used in isolation and always combined with other features of SpA. Magnetic resonance imaging (MRI) is the gold standard and is the only imaging modality capable of detecting both inflammatory and structural changes. A positive MRI finding should be interpreted in the relevant clinical context, and an alternative differential diagnosis for sacroiliitis should be considered if the clinical picture is atypical of SpA. The presence of HLA B 27 in isolation is neither diagnostic of SpAs nor its absence rules out the diagnosis. Erythrocyte sedimentation rate and C-reactive protein are the commonly used biomarkers in SpA but do not always correlate with disease activity. The ASAS criteria have been tested for its validity, though there were concerns regarding its specificity. In this narrative review various criteria available for classifying SpAs have been discussed and their strengths, weaknesses, and usefulness in the diagnosis of SpA in our everyday practice have been appraised . Various referral strategies and usefulness of these criteria and parameters in the Indian context have also been discussed.

Extraskeletal manifestations and the indicators of inflammatory activity and severity in ankylosing spondylitis

Extraskeletal manifestations (ESMs) are commonly observed in ankylosing spondylitis (AS). The available data on the association of ESMs with the inflammatory activity and other clinical parameters of AS are contradictory. Objective : to assess the association of ESMs with the inflammatory activity and other manifestations of AS. Patients and methods . The investigators of the V.A. Nasonova Research Institute of Rheumatology examined a total of 452 patients (363 men and 89 women) diagnosed with AS meeting the New-York criteria (1984). The patients' median age was 31.5 [24; 41] years; median disease onset age, 19.5 [15; 23] years; and disease duration, 11.5 [7; 18] years. HLA B27 was identified in 442 (97.7%) patients. In addition to standard laboratory and instrumental examinations, 172 patients underwent transthoracic echocardiography; Rehberg's test, if indicated; IgA test; histological examination of subcutaneous fat tissue or duodenal mucosa for amyloid; renal ultrasound; colonoscopy; and consultations by an ophthalmologist, a dermatologist, a nephrologist, an urologist, and a gastroenterologist. Uveitis, cardiac involvement (cardiac conduction disturbance, aortic and valvular changes), inflammatory bowel disease (IBD), glomerulonephritis, and psoriasis were considered to be ESMs. The latter were detected in 218 (48%) of the 452 patients; there was uveitis in 140 (30%), cardiac conduction disturbance in 61 (13.4%), psoriasis in 17 (3.7%), IBD in 16 (3.5%), nephritis in 16 (3.5%), and aortic and valvular changes in 71 (41.2%) of the 172 patients. The groups of patients with ESM (n = 218) and without ESM (n=234) were compared with regard to the onset age of AS, the presence of HLA- 27, peripheral arthritis, coxitis, enthesitis, syndesmophytis, fever, anemia, the need for biological agents (BAs) and/or systemic glucocorticoids (GCs), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and erythrocyte sedimentation rate (ESR). Results. The ESM and non-ESM groups were matched for gender, age, duration of AS, and the presence of HLA-В27. No significant differences were found in ESR, BASDAI, and the frequency of coxitis, enthesitis, and syndesmophytis in the spine. The ESM group versus non-ESM group was significantly more frequently observed to have peripheral arthritis in 148 (67.8%) of the 218 patients and in 70 (33.2%) of the 234 patients, respectively (p<0.0001); fever in 34 (15.6%) and 12 (5.1%), respectively (p<0.0001), anemia in 58 (26.6%) and 26 (11.1%), respectively (p<0.0001); GAs and/or systemic GCs were taken by 121 (55.5%) and 58 (24.8%) patients, respectively (p<0.0001). Conclusion. ESMs in patients with AS are associated with peripheral arthritis and inflammatory activity indicators.

Molecular characteristics of methicillin-resistant Staphylococcus aureus nasal carriage from hospitalized patients and medical staff in Isfahan, Iran.

Nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA) has been accounted as one of the main risk factors for the development of complicated nosocomial infections. The present study aimed to determine nasal carriage rate, antimicrobial susceptibility pattern and molecular characteristics of MRSA isolates. This cross-sectional study was performed within 6 months period from July 2015 at 3 hospitals of Isfahan, Iran. Totally, 326 nasal samples were collected by cotton sterile swab from the nasal cavity of participants. Standard microbiological methods were used for identification S. aurues and MRSA isolates. Antibiotic susceptibility pattern was determined by the disc diffusion method according to the CLSI recommendation. Determination of SCCmec typing, agr groups, and virulence genes were performed by PCR method. Overall, 23.6% of cases were S. aureus carriers including, 23.4% (25/107) of HCWs and 23.7% (52/219) of patients. The rate of MRSA nasal carriages among patients was found to be 51.9% and 16% in HCWs. The highest levels of resistance among MRSA isolates were against ampicillin (93.5%) and tetracycline (83.4%); while, the most effective antibiotics were vancomycin and co-trimoxazole with 100% and 71%, susceptibility. The presence of hla and pvl genes was detected in 80.6% and 3.2% of MRSA isolates, respectively. SCCmec types I, III, IV and V were found in 16.1%, 25.8%, 25.8%, and 16.1% of isolates, respectively. Moreover, agr group I was the predominant type with 43.3. Our results showed a high rate of MRSA colonization in hospitalized patients which remains a significant healthcare problem in our region.

OR48 Resolution of conflicting hla assignment due to loss of heterozygosity in the hla region by NGS typing

57 year old female patient diagnosed with acute myeloid leukemia (AML) was referred to bone marrow transplant. Transplant workup and search for compatible unrelated donor was started immediately, along with induction therapy for AML. HLA typing performed from peripheral blood using high-resolution SSO method showed homozygous typing for all loci, except HLA C. However, the quality of the typing data, along with the unusual B and C allele association prompted confirmatory typing by next-generation sequencing (NGS), which revealed the presence of a previously undetected HLA B∗40:01:02 allele at 14%, and confirmed the presence of HLA C∗03:03:01 allele at 16%, consistent with a dramatic allelic imbalance. Research on the patient’s clinical history revealed that at the time of diagnosis and sampling, a significant population of atypical monocytic cells with promonocytes/monoblasts was detected by flow cytometry, accounting for at least 55% of the total leukocytes in the peripheral blood. Genomic microarray testing showed a 35.3 Mb terminal long contiguous stretch of homozygosity 6p25.3p21.31, which includes the HLA locus, resulting in copy-neutral loss of heterozygosity (LOH) acquired likely due to the malignancy. The LOH explains why one HLA haplotype was underrepresented in the initial blood sample acquired before the treatment. Buccal DNA sample was requested and tested with SSO method, which confirmed the presence of the alleles detected by NGS. In addition, confirmatory HLA typing performed 3 months later from peripheral blood post-treatment gave identical results. This supports the finding that the initial typing discrepancy was due to the overwhelming presence of malignant cells with LOH involving the HLA locus in the patient’s peripheral blood, collected before initiation of treatment. NGS typing using the Omixon Holotype platform was able to provide accurate typing of a sample with allelic disequilibrium, and allowed not only for detection but also for quantification of the minor alleles. This case highlights the importance of confirmatory typing pre-transplant for patients with hematological malignancies, since the presence of malignant cells in the peripheral blood may bias typing data if LOH involving the 6p region is present, which is a recurrent finding in patients with aplastic anemia or AML.

Do Electrochemiluminescence Assays Improve Prediction of Time to Type 1 Diabetes in Autoantibody-Positive TrialNet Subjects?

To explore whether electrochemiluminescence (ECL) assays can help improve prediction of time to type 1 diabetes in the TrialNet autoantibody-positive population. TrialNet subjects who were positive for one or more autoantibodies (microinsulin autoantibody, GAD65 autoantibody [GADA], IA-2A, and ZnT8A) with available ECL-insulin autoantibody (IAA) and ECL-GADA data at their initial visit were analyzed; after a median follow-up of 24 months, 177 of these 1,287 subjects developed diabetes. Univariate analyses showed that autoantibodies by radioimmunoassays (RIAs), ECL-IAA, ECL-GADA, age, sex, number of positive autoantibodies, presence of HLA DR3/4-DQ8 genotype, HbA1c, and oral glucose tolerance test (OGTT) measurements were all significantly associated with progression to diabetes. Subjects who were ECL positive had a risk of progression to diabetes within 6 years of 58% compared with 5% for the ECL-negative subjects (P < 0.0001). Multivariate Cox proportional hazards models were compared, with the base model including age, sex, OGTT measurements, and number of positive autoantibodies by RIAs. The model with positivity for ECL-GADA and/or ECL-IAA was the best, and factors that remained significantly associated with time to diabetes were area under the curve (AUC) C-peptide, fasting C-peptide, AUC glucose, number of positive autoantibodies by RIAs, and ECL positivity. Adding ECL to the Diabetes Prevention Trial risk score (DPTRS) improved the receiver operating characteristic curves with AUC of 0.83 (P < 0.0001). ECL assays improved the ability to predict time to diabetes in these autoantibody-positive relatives at risk for developing diabetes. These findings might be helpful in the design and eligibility criteria for prevention trials in the future.

Molecular and phenotypic characteristics of methicillin-resistant Staphylococcus aureus isolated from hospitalized patients.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of infections acquired in both community and hospital settings. In this study, MRSA isolated from different sources of hospitalized patients was characterized by molecular and phenotypic methods. A total of 123 S. aureus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), in vitro antimicrobial susceptibility profile, SCCmec typing and presence of seven virulence factor-encoding genes. REP-PCR fingerprinting showed low relatedness between the isolates, and the predominance of one specific lineage or clonal group was not observed. All isolates were susceptible to teicoplanin and linezolide. All isolates were resistant to cefoxitin and penicillin, and the majority were also resistant to one or more other antimicrobials. Fifty isolates (41.7%) were intermediately resistant to vancomycin. Most isolates harbored SCCmec type II (53.7%), followed by type I (22.8%), type IV (8.1%) and type III (1.6%). All isolates harbored at least two virulence factor-encoding genes, and the prevalence was as follows: coa, 100%; icaA, 100%; hla, 13.0%; hlb, 91.1%, hld, 91.1%; lukS-PV and lukF-PV, 2.4%; and tst, 34.1%. A positive association with the presence of hla and SCCmec type II, and tst and SCCmec type I was observed. This study showed the high virulence potential of multidrug-resistant MRSA circulating in a teaching hospital. A high prevalence of MRSA showing intermediate vancomycin resistance was also observed, indicating the urgent need to improve strategies for controlling the use of antimicrobials for appropriate management of S. aureus infections.

SAT0482 Bone Mineral Density (BMD) Assessment: an Additional Tool for the Diagnosis of Spondyloarthritis (SPA)

BackgroundPatients with Spondyloarthritis (SpA) have an increased risk of osteoporosis, which can be observed at the early stages of the disease, related to a systemic bone effect of inflammation. Diagnosis...

The effect of blood transfusion on pulmonary permeability in cardiac surgery patients: a prospective multicenter cohort study

There is an association between blood transfusion and pulmonary complications in cardiac surgery. Mediators of increased pulmonary vascular leakage after transfusion are unknown. We hypothesized that factors may include antibodies or bioactive lipids, which have been implicated in transfusion-related acute lung injury. We performed a prospective cohort study in two university hospital intensive care units in the Netherlands. Pulmonary vascular permeability was measured in cardiac surgery patients after receiving no, restrictive (one or two transfusions), or multiple (five or more transfusions) transfusions (n=20 per group). The pulmonary leak index (PLI), using (67) Ga-labeled transferrin, was determined within 3 hours postoperatively. Blood products were screened for bioactive lipid accumulation and the presence of antibodies. The PLI was elevated in all groups after cardiac surgery. Transfused patients had a higher PLI compared to nontransfused patients (33×10(-3) ± 20×10(-3) vs. 23×10(-3) ± 11×10(-3)/min, p<0.01). The amount of red blood cell (RBC) products, but not of fresh-frozen plasma or platelets, was associated with an increase in PLI (β, 1.6 [0.2-3.0]). Concerning causative factors in the blood product, neither the level of bioactive lipids nor the presence of antibodies was associated with an increase in PLI. Patient factors such as surgery risk and time on cardiopulmonary bypass did not influence the risk of pulmonary leakage after blood transfusion. Transfusion in cardiothoracic surgery patients is associated with an increase in pulmonary capillary permeability, an effect that was dose dependent for RBC products. The level of bioactive lipids or the presence of HLA or HNA antibodies in the transfused products were not associated with increased pulmonary capillary permeability.

HLA Analysis in Patients with Degenerative Diseases of the Temporomandibular Joint

The aim of this study was to determine the presence of HLA alleles, specifically HLA-DR alleles, and to correlate them with clinical and radiological features of patients with degenerative processes (DP) of the temporomandibular joint (TMJ). The final goal was to determine which allele can be used to identify patients having more aggressive forms of the articular pathologies. Thirty-two (32) Caucasian patients with DP of the TMJ were included in the study. The SSOP (Luminex Corp., Austin, TX) method was used to determine class II HLA alleles. The presence of HLA-II DR in patients with DP of the TMJ was 98%. The presence of HLA was significantly higher in patients with DP of the TMJ than in healthy subjects (66%) (p=0.003). HLA DR52 was significantly more frequent in patients than in healthy individuals (40.62% vs. 13.79%, p=0.041). While the percentage of DR11 positive individuals was also higher among patients than among healthy control subjects, the association with DP of the TMJ was not significant (p=0.220). Patients having the DR52 allele had higher deformation or DP. It was concluded that HLA-DR54 and DR11 alleles are associated with a higher susceptibility to DP of the TMJ, and HLA-DR54 and DR52 are associated with a higher severity of DP.

Low copy-number of complement C4A, the presence of HLA-DR3, and the presence of HLA-DR2 are independent and additive risk factors for human systemic lupus erythematosus (SLE) (93.13)

Abstract The major histocompatibility complex (MHC) in chromosome 6p21.3 has the strongest genetic association with human SLE. This study aims to dissect the roles of MHC genes HLA-DRB1 and complement C4 in SLE. The study population includes 744 SLE patients and 760 unrelated healthy controls of European ancestry. Genomic Southern blot analyses and qPCR were used to determine the gene copy-numbers of total C4, C4A and C4B. Two-digit genotypings for HLA-DRB1 were performed by SSP-PCRs. The copy-numbers for total C4, C4A and C4B vary from 2 to 6, 0 to 5, and 0 to 4, respectively. Lower C4A copy-number (p=2.4x10-13), and increased frequencies of HLA-DRB1*03 (DR3; p=1.5x10-10) and HLA-DRB1*15 (DR2; p=0.032) are associated with SLE. Zero, 1 and ≥2 copies of C4A strongly correlate with homozygous, heterozygous and non-DR3, respectively, in controls (r2=0.435,χ2=374.0; p=1.2x10-79) and in SLE (r2=0.381, χ2=463.9; p=4.2x10-99). Comparing to subjects with non-low C4A (i.e. ≥2 copies), non-DR3 and non-DR2, the odds for SLE with low C4A only (i.e. &amp;lt;2 copies) was 2.22 (95% CI: 1.11-4.43; p=0.031), DR3+ only was 1.81 (1.21-2.71; p=0.004), and DR2+ only was 1.65 (1.26-2.16; p=0.0002). Notably, the odds increased to 2.80 (2.09-3.76; p=3.6x10-12) among subjects with low C4A and DR3, and 2.71 (1.10-6.64; p=0.037) among subjects with low C4A and DR2. In conclusion, low C4A gene copy-numbers, the presence of HLA-DR3 or HLA-DR2 are each independent risk factors with additive effects for SLE.

Short Communication: Selection of Thymidine Analogue Resistance Mutational Patterns in Children Infected from a Common HIV Type 1 Subtype G Source

In HIV-1, thymidine analogue mutations (TAMs) cluster in one of two groups (215Y, 41L, 210W, or 215F, 219E/Q), representing two independent mutational patterns (T215Y and T215F cluster, respectively). The mechanisms by which these pathways are selected are not fully understood. To investigate possible factors driving the selection of the TAMs, we analyzed the TAM patterns with regard to the respective treatment, viral load, and HLA in 18 children all infected from a common source of HIV-1 clade G virus and initially treated with zidovudine. The HIV reverse transcriptase sequences of 14/18 children carried at least one TAM. At first sampling date, the T215Y-linked pattern was observed in five cases and the T215F cluster was seen in nine. During the follow-up period, three patients changed their patterns. Children treated with identical NRTI combinations at the first sampling date developed different pathways. Under AZT/d4T therapies, an association was found between the HLA B*13 (in combination with HLA DRB1*0701) and the mutation T215Y. The mutation T215Y reverted in three out of four patients who discontinued AZT/d4T treatment. We speculate that in the context of these subtype G viruses, the development of the T215Y mutation may be strongly disfavored whereas the presence of HLA B*13 may counteract this effect and permit its development.

Cardiovascular disease is associated with extra-articular manifestations in patients with rheumatoid arthritis

The objective of this study was to examine the clinical and genetic variables associated with extra-articular rheumatoid arthritis (ExRA). This was a cross-sectional study in which 538 Northwestern Colombian patients with rheumatoid arthritis (RA) were included. Information about demographics and clinical characteristics including disease activity, inflammatory markers, co-morbidities, cardiovascular (CV) risk factors, history of familial autoimmunity and therapy was recorded. The presence of HLA "shared epitope" (SE) alleles and TNF gene polymorphism was assessed. A multivariate statistical analysis was performed. ExRA was found in 32% of the patients, of which nodulosis, Sjögren's syndrome, and lung involvement were registered in 21%, 9%, and 4% of patients, respectively. Patients with ExRA were older than patients without it and they presented longer disease duration as well. Thus, an association between disease duration and ExRA manifestations was also observed. Patients with ExRA presented significant higher titers of anti-CCP antibodies as compared to patients without ExRA. Hypertension and thrombosis were significantly associated with ExRA. Never having smoked constituted a protective factor against ExRA onset. Associations between ExRA and the presence of traditional CV risk factors were also found. Our results show that duration of RA, CV disease and high titers of anti-CCP antibodies are associated with ExRA in Colombian patients with RA, and highlight the importance of preventing smoking in those who are prone to develop autoimmune diseases including RA.

Immunocytochemical demonstration of down regulation of HLA class-I molecule expression in human metastatic breast carcinoma.

Deficient expression of HLA class-I molecules observed in many cancers is suggested to influence both disease progression and potential efficacy of T cell-mediated immune therapy. Previous studies have attempted to correlate either primary breast cancer tumor grade with HLA class-I levels or the presence of HLA class-I-deficient cells in metastatic lesions with survival. In this study we evaluated the HLA class-I status of matched primary and secondary breast cancer lesions in order to ask the question: is metastasis of breast cancer associated with down-regulation of HLA class-I expression? Immunocytochemistry analysis shows a definitive correlation between diminished HLA class-I expression and dissemination of breast cancer to tumor-draining lymph nodes: both the total number of HLA class-I+ cells per sample and the levels of expression are dramatically decreased in secondary versus primary tumor lesions. These findings are consistent with the contention that the ability of breast cancer cells to escape the confines of the original tumor lesion requires down-regulation of HLA class-I expression and implies that enhancing HLA class-I expression in secondary breast cancer may have a beneficial effect on T-cell-mediated immunotherapy.

Pesquisa de anticorpos antiplaquetários. As primeiras cem amostras estudadas.

Two types of platelet alloantigens are considered: type I, which refers to platelet alloantigens shared by platelets and other cells; and type II, which comprises the platelet-specific alloantigens. The Human Platelet Alloantigens (HPA) System consists of five diallelic alloantigens and eleven low frequency antigens. According to serological antigen capture assays, immunochemical methods and studies of Molecular Genetics, the glycoproteins (GP) of platelet membrane that are most frequently associated with antibodies are GPIIb-IIIa, GPIb-IX and GPIa-IIa. It is possible to detect platelet antibodies using different laboratory methods. Our experience was restricted to a solid phase system. In this method we used the indirect technique for the screening of alloantibodies and the direct technique for the detection of autoantibodies. The procedure with chloroquine solution was performed in order to differentiate between the presence of HLA and non-HLA platelet specific antibodies. Our comments are based on results obtained in a hundred samples tested throughout a period of eleven months and we briefly review the clinical features related to the diagnosis of autoimmune and alloimmune thrombocytopenia, drug-induced thrombocytopenia and other different factors of platelet destruction. The concepts of transfusional practice applied to emergency situations, platelet refractoriness strategy and the comprehensive management of patients are approached in this work.

Influence of HLA Alleles on the Rate of Progression of Vertically Transmitted HIV Infection in Children: Association of Several HLA-DR13 Alleles with Long-Term Survivorship and the Potential Association of HLA-A2301 with Rapid Progression to AIDS

The influence of host immunogenetics on the outcome of vertically transmitted HIV infection in children was examined in a multicenter cross sectional study of long term survivors and rapid progressors. Sequence-based typing was performed for the DRB1, DQB1 and HLA-A loci. 36.7% of 30 children surviving more than 8 years had one or more of the HLA-DR13 alleles, versus none of 14 rapidly progressing children who died within 2 years of age, p = 0.009, Haldane RR = 17.1. The alleles variably associated with this beneficial response to HIV were: DRB1∗1301, DRB1∗1302, DRB1∗1303 and DRB1∗1310, suggesting that the DR13 effect acted as a dominant trait. An additional 6 children were typed only by the SSOP method resulting in 44.4% of 36 long term surviving children with a DR13 allele and none of 14 rapid progressors, p = 0.002, Haldane RR = 23.3. No single DQB1 allele accounted for the HLA-DR13 allele association. In contrast, the presence of HLA A∗2301 was associated with rapid progression to AIDS, 4% of long term survivors vs. 57.1% of 7 rapid progressors, p = 0.0006, RR = 0.031. Although the sample size is small, the marked differences in allele frequency along with differences between the peptide binding pockets of the HLA-A9 group of alleles including HLA A∗2301 and the remainder of the HLA-A alleles suggest a structural basis for the dominant disadvantageous immune response to HIV conferred by A∗2301.