A novel allele, HLA-B*51:220, identified in an individual from south of Brazil.

Novel allele, HLA-B*51:220 generated by a gene conversion event was identified in a Brazilian individual.

HLA polymorphisms and risk of red blood cell alloimmunisation in polytransfused patients with sickle cell anaemia.

BACKGROUND: Red blood cell (RBC) alloimmunisation is an event that may occur due to factors such as numerous blood transfusions, age, gender and genetic factors such as human leukocyte antigen (HLA). AIMS/OBJECTIVES: The aim of the present study was to investigate the possibility of alloimmunisation to red blood cell group antigens associated with the HLA of individuals and to relate alloimmunisation to risk factors. METHODS: A total of 172 polytransfused patients with sickle cell anaemia (SCA) (44 alloimmunised, 128 non-alloimmunised) participated in this study. Blood group genotyping was performed by the DNA microarray method and HLA genotyping by polymerase chain reaction - specific sequence of oligonucleotides. RESULTS: The number of transfusions received directly influenced the incidence of alloimmunisation, and the most common alloantibodies were against Rh (48·8%) and Kell (17%) systems. The HLA-C*06 and HLA-DQB1*03 variants were significantly higher in alloimmunised patients. The HLA-DRB1*04 and HLA-DRB1*11 were more often found in individuals who developed the alloantibodies anti-Fya and anti-K, respectively. CONCLUSION: This study suggests that polytransfused patients with SCA possessing the HLA-DQB1*03 and HLA-C*06 allele variants are more susceptible to alloimmunisation. In addition, HLA-DRB1*04 and HLA-DRB1*11 alleles were seen to be associated with the production of anti-Fya and anti-K antibodies, respectively.

A novel HLA allele, HLA-DRB1*13:204, detected in a Brazilian unrelated hematopoietic stem cell donor.

The HLA-DRB1*13:204 allele differs from HLA*13:64 by two nucleotide substitutions at positions 181 and 189 in the exon 2.

Allele and haplotype frequencies of HLA-A, B, C, DRB1 and DQB1 genes in polytransfused patients in ethnically diverse populations from Brazil.

The red blood transfusion is a practice often used in patients with haematological and oncological diseases. However, the investigation of human leucocyte antigen (HLA) system frequency in these individuals is of great importance because multiple transfusions may lead to HLA alloimmunization. Brazil is a country that was colonized by many other ethnicities, leading to a mixed ethnicity and regionalized population. In view of the importance of HLA typing in these patients, the aim of this study was to investigate the allele and haplotype frequencies from polytransfused patients from three different regions from Brazil. HLA-A, HLA-B, HLA-C, HLA-DRB1 and HLA-DQB1 genotyping of 366 patients was performed by PCR-SSO, based on the Luminex technology (One Lambda(®) ), and the anti-HLA class I and class II antibodies were analysed using LabScreen Single Antigen Antibody Detection (One Lambda, Inc.). Allele and haplotype frequencies of polytransfused patients of three regions from Brazil were obtained using the Arlequin program. The most frequent allele frequencies observed were HLA-A*02, A*03, B*15, B*35, B*51, C*07, C*04, C*03, DRB1*13, DRB1*11, DRB1*07, DRB1*03, DRB1*01, DQB1*03, DQB1*02, DQB1*06 and DQB1*05. There were differences between the groups for allele variants HLA-B*57 (between Group 1 and Group 2) and HLA-C*12 (between Group 1 and Group 3). The most frequent haplotypes found in the sample were HLA-A*01B*08DRB1*03, DRBI*07DQB1*02, DRB1*01DQB1*05, DRB1*13DQB1*06 and A*02B*35. HLA class I and II antibodies were detected in 77.9% and 63.9% patients, respectively, while the both alloantibodies were detected in 62 (50.9%) patients. In conclusion, the HLA typing for polytransfused patients in each region has a great importance, as seen in this study; individuals from different regions from Brazil have HLA distribution not completely homogeneous.

JAK2 46/1 haplotype is associated with JAK2 V617F--positive myeloproliferative neoplasms in Brazilian patients.

INTRODUCTION: This study aimed to verify the association between the JAK2 46/1 haplotype (V617F positive) and some hematological parameters in BCR-ABL-negative chronic myeloproliferative neoplasms (cMPNs) in our population. METHODS: The blood samples obtained from the patients with cMPN were genotyped for the JAK2 V617F mutation and JAK2 rs10974944 SNP screening using a PCR-RFLP assay. RESULTS: The JAK2 V617F mutation was detected in 80.15% of patients. The G variant of rs10974944 was more frequent in all MPNs, especially those that were JAK2 V617F positive, than in the control population. We also compared the 46/1 haplotype status in each MPN disease entity, polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF), and MPNu with controls. The G allele frequency relative to controls was significantly enriched in patients with PV and ET, but not in those with PMF and MPNu. PV and ET patients especially, all of whom had the JAK2 V617F mutation, showed significant excess of the G allele. The frequency of JAK2 V617F mutation was associated with elevated hematological parameters, but when we analyze the occurrence of the mutation and the presence of the G allele, just the high hemoglobin was significantly. CONCLUSION: In agreement with previous reports, JAK2 46/1 haplotype for JAK2 V617F was associated with cMPN positive in Brazilian patients.

New associations: INFG and TGFB1 genes and the inhibitor development in severe haemophilia A.

INTRODUCTION: The development of factor VIII (FVIII) inhibitor is the main complication of replacement therapy in patients with haemophilia A (HA). A ratio of 5-7% of individuals HA develops antibodies (inhibitors) against the FVIII infused during the treatment, thereby reducing their pro-coagulant activity. The immunomodulatory cytokine genes have been related to the risk of development of alloantibodies in several studies, mainly in HA with severe form. AIM: We investigated the polymorphisms in regulatory regions of cytokine genes (IL1A, IL1B, IL1R, IL1RA, IL4RA, IL12, INFG, TGFB1, TNF, IL2, IL4, IL6, IL10) that could influence the risk of developing inhibitors in patients with severe HA. METHODS: The genotyping of cytokine genes of 117 patients with HA was performed by polymerase chain reaction with sequence-specific primers (PCR-SSP) using the protocol recommended by the manufacturer (Invitrogen kit Cytokines(®) , Canoga Park, USA) RESULTS: From the cohort of 117 patients with severe HA, 35 developed inhibitors. There was a higher frequency of +874 T allele in INFG and of +869 TT and TG/TG in TGFB1 genes on patients with inhibitors. CONCLUSION: This suggests that polymorphisms in INFG and in TGFB1 genes are related to risk of developing inhibitor, and could contribute to a genetic profile of the individual HA for the risk of inhibitors development to FVIII.

Role of omega-3 polyunsaturated fatty acids in the production of prostaglandin E2 and nitric oxide during experimental murine paracoccidioidomycosis.

There has recently been increased interest in the potential health effects of omega-3 polyunsaturated fatty acids on the immune system. Paracoccidioidomycosis is the most important endemic mycosis in Latin America. Macrophages have a fundamental role and act as first line of organism defense. The purpose of this study was to analyze the effect of n-3 fatty acids on the production of PGE2 and NO by mice infected with Pb18 and fed a diet enriched with LNA for 8 weeks. To study the effect of omega-3 fatty acids on macrophage activity during experimental paracoccidioidomycosis, mice were infected with Pb18 and fed a diet supplemented with LNA. PGE2 in the serum of animals was analyzed and NO in the supernatants of macrophages cultured and challenged in vitro with Pb18 was measured. Omega-3 fatty acids seemed to decrease the production of PGE2 in vivo in the infected group fed an LNA-supplemented diet during the 4th and 8th weeks of the experiment. At the same time, we observed an increase in synthesis of NO by peritoneal macrophages in this group. Omega-3 fatty acids thus appear to have an immunomodulatory effect in paracoccidioidomycosis.

Protective effect of HLA-DRB1 11 and predisposition of HLA-C 04 in the development of severe liver damage in Brazilian patients with chronic hepatitis C virus infection.

The objective of this study was to investigate human leucocyte antigen (HLA) genes in patients chronically infected with hepatitis C virus (HCV) and to analyse the possible role of these genes in the progression of chronic hepatitis C. One hundred and forty-five (145) Brazilian patients infected only with HCV genotype 1 were evaluated. HLA class I (A, B, C) and class II (DRB1, DQA1, DQB1) typing were carried out by PCR-SSO, through Luminex technology. Associations were found with protection against development of liver damage by both DRB1 11 (5.0% versus 18.2%, P=0.0016, OR=0.23, CI 95% = 0.09-0.58; Pc=0.0208) and DRB1 11-DQA1 05-DQB1 03 haplotype (4.2% versus 15.3%, P=0.0032; OR = 0.24, CI 95% = 0.08-0.64). Liver damage was associated with HLA-C 04 in patients with <20 years of infection (38.4% versus 9.1%, P = 0.002, OR = 6.25, CI 95%=1.97-19.7; Pc=0.0238). It is concluded that HLA alleles can influence the development of liver damage in HCV type-1 chronically infected Brazilian patients.

Influence of HLA alleles in response to treatment with pegylated interferon-alpha and ribavirin in patients with chronic hepatitis C.

The objective of this study was to analyse the possible role of HLA polymorphism of chronically infected hepatitis C virus patients in the response outcome to treatment with pegylated interferon-alpha plus ribavirin. To that end, 144 Brazilian patients infected only with genotype 1 of the virus were treated with pegylated interferon-alpha at 1.5 µg kg(-1) in conjunction with ribavirin (1000 mg if patient weight was <75 kg and 1250 mg if >75 kg) for 48 weeks. The patients did not have concomitant HBV or HIV infections or liver disease, did not undergo previous antiviral treatment, and were followed up for 24 weeks after the end of treatment to assure they presented a sustained virological response. Patients were classified according to response to treatment in responsive (SVR), nonresponsive (NRS) and relapsers (REL). HLA class I and class II typing were carried out through PCR-SSO using Luminex technology. A statistically higher frequency of DRB1*11 patients was observed in the SVR group (39.6% vs. 14.3%P = 0.0012; Pc = 0.0156; OR = 3.94; 95% CI = 1.8-8.8). HLA-DQB1*03 patients were also more frequent in the SVR group, but the P value lost significance after Bonferroni correction (62.3% vs. 41.7%P = 0.024; Pc = 0.14, OR = 2.3; 95% CI = 1.14-4.60). HLA class II antigens can positively influence the response to treatment with pegylated interferon-alpha and ribavirin.

Influence of class I and II HLA alleles on inhibitor development in severe haemophilia A patients from the south of Brazil.

Congenital haemophilia A is a chromosome-linked recessive disorder caused by the deficiency or reduction of factor VIII (FVIII) pro-coagulant activity. During treatment, some patients develop alloantibodies (FVIII inhibitors) that neutralize the action of exogenously administered FVIII. Currently, the presence of these inhibitors is the most serious adverse event found in replacement therapy. Some studies have suggested that genetic factors influence the development of the FVIII coagulation inhibitors. To identify the class I and II alleles that may be influencing the formation of inhibitors in severe haemophilic patients. Genotyping of the class I (HLA-A, -B and -C) and class II (HLA-DRB1, -DQA1 and -DQB1) alleles of 122 patients with severe haemophilia A, including 36 who had developed antibodies to factor VIII, was performed. After the comparison of the group without inhibitors and the group with inhibitors, HLA-C*16 [Odds ratio (OR) = 7.73; P = 0.0092] and HLA-DRB1*14 (OR = 4.52; P = 0.0174) were found to be positively associated with the formation of the inhibitors. These results confirm that HLA alleles are involved in inhibitor production and could be used as a tool for recognition of groups at high risk of possible inhibitor development in Southern Brazilian haemophilic patients.

HLA and MICA genes in patients with tuberculosis in Brazil.

Major histocompatibility complex (MHC) genes have been investigated because of their crucial role in the defense against pathogens and their high degree of polymorphism. We performed a case-control study to assess a genetic association of MHC genes with susceptibility to tuberculosis (TB). The allelic lineages HLA-A*02 and B*18 were significantly less frequent in TB patients (n = 112, 44.6% women) than in controls (n = 224, 51.5% women): 18.8% vs 26.5%; odds ratio (OR) = 0.64; P = 0.037 and 2.7% vs 6.9%; OR = 0.37; P = 0.041. The negative association with haplotype HLA-B*18-MICA*018 (2.3% patients vs 6.4% controls; OR = 0.34; P = 0.035) was significant as a consequence of strong linkage disequilibrium (D' = 0.827 for patients and 0.923 for controls). These findings suggest a trend toward protection of the HLA-A*02 and HLA-B*18 alleles.

Association between killer-cell immunoglobulin-like receptor genotypes and leprosy in Brazil.

The aim of this study was to investigate the role of killer cell immunoglobulin-like receptor (KIR) genes in leprosy immunopathogenesis. Genotyping of KIR and human leukocyte antigen (HLA) genes was performed by polymerase chain reaction with sequence-specific oligonucleotide probes in 165 leprosy patients. Both activating KIR2DS2 and KIR2DS3 frequencies were higher in tuberculoid leprosy (TT) patients than in lepromatous leprosy (LL) patients, and the inhibitory KIR with its ligand, KIR2DL1-C2/C2, was elevated in TT patients in comparison to all other leprosy subgroups and controls. However, a negative association between KIR2DL3-C1 and KIR2DL3-C1/C1 and the TT group was identified. Borderline patients exhibited a higher frequency of KIR3DL2-A3/11 than the controls and LL patients, and a lower frequency of KIR2DL1-C2 than the controls and TT subgroup. Some KIR-HLA genotypes could be associated to the development of clinical forms of leprosy and should be investigated further.

IL2 and TNFA gene polymorphisms and the risk of graft-versus-host disease after allogeneic haematopoietic stem cell transplantation.

This study aimed to analyse the association of gene polymorphisms with the outcome of allogeneic haematopoietic stem cell transplantation. We studied 122 donor/recipient pairs who received HLA-identical transplants from siblings at the Universidade Estadual de Campinas, Brazil, between June 1996 and June 2006. Donor/recipient alleles for TNFA-238 and IL2-330/+166 single-nucleotide polymorphisms (SNP) were analysed by PCR-SSP. No association was observed between the risk of acute graft-versus-host disease (GVHD) and these SNP. However, our findings suggest that the polymorphism of promoter gene TNFA-238GA is associated with the occurrence and severity of chronic GVHD. The probability of chronic GVHD in patients with GA genotype at position -238 of TNFA gene is 91.7% in contrast to 59.4% in patients with GG genotype (P = 0.038). In patients with donor GA genotype the probability of chronic GVHD is 90.8%, and 57.9% in patients with donor GG genotype (P = 0.038). The probability of extensive chronic GVHD in patients with TNFA-238GA is 91.7% compared with 46.3% in patients with TNFA-238GG (P = 0.0046). In patients with donor GA genotype at position -238 of the TNFA gene, it is 81.7%, compared with 44.5% in patients with donor GG genotype (P = 0.016). However, further studies with more patients are required to identify cytokine gene polymorphisms and their association with transplant-related complication in Brazil, particularly due to ethnic background, the relatively low power of detection of genetic markers of this study, and the complexity of the MHC region.

Correlation of mixed lymphocyte culture with chronic graft-versus-host disease following allogeneic stem cell transplantation.

The purpose of the present study was to evaluate the mixed lymphocyte culture as a predictive assay of acute and chronic graft-versus-host disease (GVHD). We studied 153 patients who received a first bone marrow transplantation from human leukocyte antigen-identical siblings. Acute GVHD was observed in 26 of 128 (20.3%) patients evaluated and chronic GVHD occurred in 60 of 114 (52.6%). One-way mixed lymphocyte culture (MLC) assays were performed by the standard method. MLC results are reported as the relative response (RR) from donor against patient cells. The responses ranged from -47.0 to 40.7%, with a median of 0.5%. The Kaplan-Meier probability of developing GVHD was determined for patients with positive and negative MLC. There was no significant difference in incidence of acute GVHD between the groups studied. However, the incidence of chronic GVHD was higher in recipients with RR >4.5% than in those with RR < or =4.5%. The Cox Proportional Hazards model was used to examine the effect of MLC levels on incidence of chronic GVHD, while adjusting for the potential confounding effect of others suspected or observed risk factors. The relative risk of chronic GVHD was 2.5 for patients with positive MLC (RR >4.5%), 2.9 for those who received peripheral blood progenitor cells as a graft, and 2.2 for patients who developed previous acute GVHD. MLC was not useful for predicting acute GVHD, but MLC with RR >4.5% associated with other risk factors could predict the development of chronic GVHD, being of help for the prevention and/or treatment of this late complication.

Correlation of mixed lymphocyte culture with chronic graft-versus-host disease following allogeneic stem cell transplantation

The purpose of the present study was to evaluate the mixed lymphocyte culture as a predictive assay of acute and chronic graft-versus-host disease (GVHD). We studied 153 patients who received a first bone marrow transplantation from human leukocyte antigen-identical siblings. Acute GVHD was observed in 26 of 128 (20.3 percent) patients evaluated and chronic GVHD occurred in 60 of 114 (52.6 percent). One-way mixed lymphocyte culture (MLC) assays were performed by the standard method. MLC results are reported as the relative response (RR) from donor against patient cells. The responses ranged from -47.0 to 40.7 percent, with a median of 0.5 percent. The Kaplan-Meier probability of developing GVHD was determined for patients with positive and negative MLC. There was no significant difference in incidence of acute GVHD between the groups studied. However, the incidence of chronic GVHD was higher in recipients with RR >4.5 percent than in those with RR <=4.5 percent. The Cox Proportional Hazards model was used to examine the effect of MLC levels on incidence of chronic GVHD, while adjusting for the potential confounding effect of others suspected or observed risk factors. The relative risk of chronic GVHD was 2.5 for patients with positive MLC (RR >4.5 percent), 2.9 for those who received peripheral blood progenitor cells as a graft, and 2.2 for patients who developed previous acute GVHD. MLC was not useful for predicting acute GVHD, but MLC with RR >4.5 percent associated with other risk factors could predict the development of chronic GVHD, being of help for the prevention and/or treatment of this late complication

Association of leprosy with HLA-DR2 in a Southern Brazilian population

The association between HLA specificities and leprosy was investigated in a Southern Brazilian population. One hundred and twenty- one patients and 147 controls were typed for HLA-A, B, Cw, DR and DQ. Patients were subdivided into the following subgroups, according to clinical, histological and immunological criteria: lepromatous (N = 55), tuberculoid (N = 32), dimorphous (N = 20), and indeterminate (N = 14). The frequencies of HLA specificities were compared between the total group of patients and controls, and between the same controls and each subgroup of patients. After correction of the probabilities, deviations were not significant, except for the DR2 specificity, which presented a frequency of 44.2 per cent in the total group of patients and 56.3 per cent in the subgroup of individuals with the tuberculoid form of the disease, compared to 23.3 per cent in the controls. Stratified analysis showed that the increased DR2 frequency in the total group of patients was due to the subgroups with the tuberculoid and dimorphous forms. The relative risk of tuberculoid leprosy for DR2-positive individuals was 4.2, and the etiologic fraction of DR2 was 0.429. In conclusion, a positive association of the DR2 specificity with the tuberculoid form of leprosy, but not with the lepromatous, dimorphous, or indeteterminate forms, was demonstrated in this Southern Brazilian population.

Association of leprosy with HLA-DR2 in a Southern Brazilian population

The association between HLA specificities and lweprosy was investigated in a Southern Brazilian population. One hundred and twenty-one patients and 147 controls were typed for HLA-A, B, Cw, DR and DQ. Patients were subdivided into the following subgroups, according to clinical, histological and immunological criteria: lepromatous (N=55), tuberculoid (N=32), dimorphous (N=20), and indeterminate (N=14). The frequencies of HLA specificities were compared between the total group of patients and controls, and between the same controls and each subgroup of patients. After correction of the probabilities, deviations were not significant, except for the DR2 specificity, which presented a frequency of 44.2% in the total group of patients and 56.3% in the subgroup of invididuals with the tuberculoid from of the disease, compared to 23.3% in the controls. Stratified analysis showed that the increased DR2 frequency in the total group of patients was due to the subgroups with the tuberculoid and dimorphus forms. The relative risk of tuberculoid leprosy for DR2-positive individuals was 4.2 and etiologic fraction of DR2 was 0,429. In conclusion, a positive association of the DR2 specificity with the tuberculoid form of leprosy, but not with the lepromatous, dimorphous, or indeterminate forms, was demonstrated in this Southern Brazilian population