Waldir Veríssimo da Silva Junior

HLA molecules and nasal carriage of Staphylococcus aureus isolated from dialysis and kidney transplant patients at a hospital in Southern Brazil

BackgroundHealthy individuals can host Staphylococcus aureus in the nasopharynx, body surface and vagina. Most invasive infections by this bacterium are endogenous, caused by strains spread from the nasopharynx of carriers. S. aureus is a pathogen involved in the etiology of hospital- and community-acquired infections. Transplant and dialysis patients are at risk of colonization or infection by multi-resistant S. aureus. Infection is directly linked to individual immunity, and the major histocompatibility complex (MHC) plays a crucial role in determining susceptibility to diseases. Different MHC specificities have been shown to be more frequent in individuals suffering from certain diseases. This study aimed to investigate the association between HLA class I (HLA-A and -B) and class II (HLA-DRB1) molecules and nasal carriage of S. aureus in dialysis and kidney transplant patients at a hospital in Southern Brazil.ResultsThe sample consisted of 70 dialysis and 46 kidney transplant patients, totaling 116 patients. All subjects were typed for HLA molecules using LABType® SSO (One Lambda). Nasal swab samples of S. aureus were isolated from the nasal cavity (both nostrils) of patients undergoing dialysis or kidney transplantation.In renal dialysis patients, HLA-A*02 was the most frequent allele in both carriers (25.5%) and non-carriers (21.2%) of S. aureus. Allele A*68 was not observed in the carrier group, but the allele was observed six times in the non-carrier group (p = 0.0097). Regarding HLA-B and HLA-DRB1, no allele was shown to be involved in protection against or susceptibility to carriage of S. aureus. In kidney transplant patients, allele A*03 was more frequent in the non-carrier (20.83%) than in the carrier (5.88%) group (p = 0.0486). HLA-B*15 was present in carriers (5.88%) and non-carriers (25%) (p = 0.0179). Regarding class II alleles, DRB1*03 appeared to be related to susceptibility to carriage of S. aureus (p = 0.0319).ConclusionsOur findings suggest that HLA-DRB1*03 may be involved in susceptibility to nasal carriage of S. aureus in transplant patients. In addition, HLA-A*68 (dialysis patients) and HLA-A*03 and HLA-B*15 (transplant patients) appear to be associated with increased resistance to S. aureus nasal carriage.

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.

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.

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.