Patricia Keiko Saito

Torque teno virus among dialysis and renal-transplant patients

Patients who undergo dialysis treatment or a renal transplant have a high risk of blood-borne viral infections, including the Torque teno virus (TTV). This study identified the presence of TTV and its genome groups in blood samples from 118 patients in dialysis and 50 renal-transplant recipients. The research was conducted in a hospital in the city of Maringá, state of Paraná. The viral DNA, obtained from whole blood, was identified by using two nested Polymerase Chain Reactions (PCR). The frequencies of TTV were 17% and 36% in dialysis patients using the methodology proposed by Nishizawa et al . (1997) and Devalle and Niel (2004) , respectively, and 10% and 54% among renal-transplant patients. There was no statistically significant association between the frequency of the pathogen and the variables: gender, time in dialysis, time since transplant, blood transfusions, and the concomitant presence of hepatitis B, for either the dialysis patients or the renal-transplant recipients. Among dialysis patients and renal-transplant recipients, genogroup 5 was predominant (48% and 66% respectively), followed by genogroup 4 (37% and 48%) and genogroup 1 (23% and 25%). Genogroup 2 was present in both groups of patients. Some patients had several genogroups, but 46% of the dialysis patients and 51% of the renal-transplant recipients had only a single genogroup. This study showed a high prevalence of TTV in dialysis patients and renal-transplant recipients.

Evaluation of the Humoral Immune Response to Human Leukocyte Antigens in Brazilian Renal Transplant Candidates

Pre-transplant sensitization to human leukocyte antigens (HLA) is a risk factor for graft failure. Studies of the immunological profile related to anti-HLA antibodies in Brazilian renal transplant candidates are few. In this study, we evaluated the humoral immune response to HLA antigens in 269 renal transplant candidates, in Paraná State, Brazil. The HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO) combined with Luminex technology, using an SSO-LABType commercial kit (One Lambda, Inc., Canoga Park, CA, USA). The percentages of panel-reactive antibodies (PRA) and the specificity of anti-HLA antibodies were determined using the LS1PRA and LS2PRA commercial kits (One Lambda, Inc.). The PRA-positive group consisted of 182 (67.7%) patients, and the PRA-negative group of 87 (32.3%) patients. The two groups differed significantly only with respect to gender. Females were the most sensitized. Among the 182 patients with PRA- positive, 62 (34.1%) were positive for class I and negative for class II, 39 (21.4%) were negative for class I and positive for class II, and 81 (44.5%) were positive for both classes I and II. The HLA-A*02, A*24, A*01, B*44, B*35, B*15, DRB1*11, DRB1*04 and DRB1*03 allele groups were the most frequent. The specificities of anti-HLA antibodies were more frequent: A34, B57, Cw15, Cw16, DR51, DQ8 and DP14. This study documented the profile of anti-HLA antibodies in patients with chronic renal failure who were on waiting lists for an organ in Paraná, and found high sensitization to HLA antigens in the samples.

Prevalence of Torque teno virus in healthy donors of Paraná State, southern Brazil

Objective To determine the prevalence of the Torque teno virus in healthy donors in the northern and northwestern regions of the state of Paraná, southern Brazil. Methods The Torque teno virus was detected by a nested polymerase chain reaction using a set of oligoprimers for the N22 region. Results The prevalence of the virus was 69% in 551 healthy blood donors in southern Brazil. There was no statistically significant difference between the presence of the virus and the variables gender, ethnicity and marital status. There was significant difference in the prevalence of the virus regarding the age of the donors (p-value = 0.024) with a higher incidence (74.7%) in 18- to 24-year-old donors. Conclusion A high prevalence of Torque teno virus was observed in the population studied. Further studies are needed to elucidate the routes of contamination and the clinical implications of the virus in the healthy population.

Complement‐Dependent Cytotoxicity (CDC) to Detect Anti‐HLA Antibodies: Old but Gold

The criterion (gold) standard to detect anti‐human leukocyte antigen (HLA) antibodies is the complement‐dependent cytotoxicity (CDC) assay. Recently, more sensitive methods have been used for the same purpose.

MICA diversity and linkage disequilibrium with HLA-B alleles in renal-transplant candidates in southern Brazil

The major histocompatibility complex (MHC) class I chain-related gene A (MICA) is located centromerically to the human leukocyte antigen (HLA)-B. The short distance between these loci in the MHC indicates the presence of linkage disequilibrium (LD). Similarly to the HLA, the MICA is highly polymorphic, and this polymorphism has not been well documented in different populations. In this study, we estimated the allelic frequencies of MICA and the linkage disequilibrium with HLA-B alleles in 346 renal-transplant candidates in southern Brazil. MICA and HLA were typed using the polymerase chain reaction-sequence-specific primer method (PCR-SSO), combined with the Luminex technology. A total of 19 MICA allele groups were identified. The most frequent allele groups were MICA*008 (21.6%), MICA*002 (17.0%) and MICA*004 (14.8%). The most common haplotypes were MICA*009-B*51 (7.8%), MICA*004-B*44 (6.06%) and MICA*002-B*35 (5.63%). As expected from the proximity of the MICA and HLA-B loci, most haplotypes showed strong LD. Renal patients and healthy subjects in the same region of Brazil showed statistically significant differences in their MICA polymorphisms. The MICA*027 allele group was more frequent in renal patients (Pc = 0.018, OR: 3.421, 95% CI: 1.516–7.722), while the MICA*019 allele group was more frequent in healthy subjects (Pc = 0.001, OR: 0.027, 95% CI: 0.002–0.469). This study provided information on the distribution of MICA polymorphisms and linkage disequilibrium with HLA-B alleles in Brazilian renal-transplant candidates. This information should help to determine the mechanisms of susceptibility to different diseases in patients with chronic kidney disease, and to elucidate the mechanisms involved in allograft rejection associated with MICA polymorphisms in a Brazilian population.

HLA‐A, HLA‐B, and HLA‐DRB1 Allele and Haplotype Frequencies in Renal Transplant Candidates in a Population in Southern Brazil

Very few studies have examined the diversity of human leukocyte antigens (HLA) in the Brazilian renal transplant candidates.

P029 : HLA-A, -B, -DRB1 ALLELE AND HAPLOTYPE FREQUENCIES IN RENAL TRANSPLANT CANDIDATES IN A POPULATION IN SOUTHERN BRAZIL

Aim To evaluate the diversity of alleles and haplotypes of HLA-A, -B and -DRB1 in renal transplant candidates in a population in southern Brazil. Methods The frequencies of the HLA-A, -B and -DRB1 alleles and haplotypes were studied in 522 patients with chronic renal failure, renal transplant candidates, registered at the Transplant Centers in north/northwestern Parana State, southern Brazil. Patients were classified according to ethnic group (319 whites [Caucasians], 134 mestizos [mixed race descendants of Europeans, Africans and Amerindians; browns or “pardos”] and 69 blacks). The HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO), combined with Luminex technology. Results In the analysis of the total samples, 20 HLA-A, 32 HLA-B and 13 HLA-DRB1 allele groups were identified. The most frequent allele groups for each HLA locus were HLA-A ∗ 02 (25.4%), HLA-B ∗ 44 (10.9%) and HLA-DRB1 ∗ 13 (13.9%). The most frequent haplotypes were HLA-A ∗ 01-B ∗ 08-DRB1 ∗ 03 (2.3%), A ∗ 02-B ∗ 44-DRB1 ∗ 07 (1.2%) and A ∗ 03-B ∗ 07-DRB1 ∗ 11 (1.0%). Significant differences ( p ∗ 68, B ∗ 08 and B ∗ 58 allele frequencies among ethnic groups. Conclusions Data from this study provide knowledge of the frequencies of the HLA-A, -B and -DRB1 allele and haplotypes in renal transplant candidates from north/northwestern Parana state, southern Brazil.

7-P: EVALUATION OF THE HUMORAL IMMUNE RESPONSE TO HUMAN LEUKOCYTE ANTIGENS (HLA) IN BRAZILIAN RENAL TRANSPLANT CANDIDATES

Aim To evaluate the humoral immune response to HLA antigens in Brazilian renal transplant candidates. Methods The humoral immune response to HLA antigens was studied in 269 renal transplant candidates from the north/northwest of Parana state, Brazil. HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO), combined with Luminex technology using the LABType SSO kit (One Lambda, Inc., Canoga Park, CA, USA). Panel reactive antibodies (PRA) and HLA-specific antibodies determination were performed using the LABScreen (Luminex technology) LS1PRA and LS2PRA kits (One Lambda, Inc.). The Fisher’s exact test and Student’s t-test were used to compare the demographic characteristics and potential risk factors for anti-HLA antibody production (pregnancies, blood transfusions and previous transplants) between PRA-positive and PRA-negative groups. Results One hundred and eighty two (67.7%) patients had positive PRA. Potential risk factors for anti-HLA antibody production showed no significant differences between PRA-positive and PRA-negative groups. Only gender was statistically different between these groups, showing that female group was the most sensitized (p Conclusions The data of this study allowed the knowledge of HLA antibodies profile in renal transplant candidates from the Parana State (Brazil), showing high sensitization to HLA antigens. Further studies are needed to evaluate the influence of alloreactivity and HLA polymorphisms in the end-stage renal disease and the evolution of transplantation.

77-P : THE POLYMORPHISM OF LEUKOCYTE AND ERYTHROCYTE ANTIGENS IN NEPHROPATHIC PATIENTS FROM SOUTHERN BRAZIL

Aim The aim of this study was to evaluate the polymorphisms of human leukocyte antigen (HLA) and Duffy erythrocyte antigen in nephropathic patients from southern Brazil. Methods One hundred and eighty three chronic kidney patients from southern Brazil participated in this study. HLA typing was performed using the LABType SSO kits locus HLA-A, -B and-DRB1 (One Lambda, Inc.). Duffy phenotypes were defined by the gel agglutination method using monoclonal anti-Fya and anti-Fyb antisera. Fisher’s exact test was employed for statistical analysis. Odds Ratio (OR) and Confidence Interval (CI) at 95% were calculated. Data from other studies with healthy individuals (voluntary bone marrow donors) were used for the comparison of analysis. Results In the analysis of the total samples, Fy(a+b+) phenotype was the most frequent (35%) and Fy(a-b-) phenotype was the rarest (5%). Nineteen HLA-A, 30 HLA-B and 13 HLA-DRB1 allele groups were identified. The 15 most frequent HLA allele groups were HLA-A∗01, A∗02, A∗03, A∗11, A∗24, HLA-B∗07, B∗15, B∗35, B∗44, B∗51, HLA-DRB1∗03, DRB1∗04, DRB1∗07, DRB1∗11 and DRB1∗13. The frequencies of Fy(a+b-) and Fy(a+b+) phenotypes of this study compared with healthy individuals from the same region, showed statistically significant difference with p Conclusions The polymorphism of these two markers when compared between the nephropathic patients from southern Brazil and other studies, suggest that the Duffy antigen and HLA allele groups may be engaged with chronic kidney disease (CKD). Further studies are needed to evaluate the influence of these markers in the evolution of CKD, as well as the evolution of transplantation.