HLA-G and anti-HCV in patients on the waiting list for kidney transplantation.

PURPOSE: Human leukocyte antigen (HLA)-G is a non-classic major histocompatibility complex HLA class I molecule. HLA-G may have tolerogenic properties which are linked to epigenetic-sensitive pathways. There is a correlation of sHLA-G levels and graft acceptance in transplantation studies. There are previous data on correlation of sHLA-G with graft rejection as well as with viral infections such as hepatitis C virus (HCV) in kidney transplanted patients. Here, we report the sHLA-G expression in patients on the waiting list for kidney transplantation, with and without anti-HCV compared to a control group. METHODS: Serum of 67 patients on the waiting list for kidney transplantation (n = 43 with anti-HCV and n = 24 without anti-HCV) was analyzed. Among these patients, n = 39 were on the waiting list for the first transplantation, while n = 28 were patients who returned in the list. The control group included n = 23 blood donors with anti-HCV (n = 13) and without anti-HCV (n = 10). RESULTS: The expression of sHLA-G was significantly lower in the control group (39.6 ±â€¯34.1 U/ml) compared to both - patients on the waiting list for the first transplantation (62.5 ±â€¯42.4 U/ml, p=0.031) and patients who returned in the list (76.7 ±â€¯53.9 U/ml, p=0.006). No significant differences were observed in all anti-HCV positive groups. A positive linear correlation between sHLA-G and TNF-α, and patient age was observed. CONCLUSIONS: Serum sHLA-G values were significantly increased in both - patients on the waiting list for the first transplantation and patients who returned in the list, as compared to control group. Our findings confirm the key tolerogenic role of sHLA-G levels as epigenetic-related marker for measuring the state of kidney allograft acceptance.

Occult Hepatitis Infection in Transfusion Medicine: Screening Policy and Assessment of Current Use of Anti-HBc Testing.

HBV still represents a global risk factor in transfusion medicine. The residual risk of HBV is not limited to pre-seroconversion window period but it extends to donors with occult HBV infection (OBI) characterized by the presence of HBV DNA in liver and by the absence of the virus surface antigen. Each country developed an appropriate blood screening policy according to local HBV prevalence, yields of infectious units per different screening methods and cost-effectiveness. We underline the need of maintaining a high level of attention for OBI carrier identification in all blood banks worldwide where the screening procedures are generally based on a combination of both serological markers and nucleic acid amplification test. In this context, markers such as hepatitis B surface antibodies and hepatitis B core antibodies (anti-HBc) might be useful, although the use of this latter is highly debated and still controversial. Our aim is to give an overview on the relevant diagnostic approaches for the routine screening for HBV focusing on the feasibility of anti-HBc testing as precautionary measure in preventing OBI transmission worldwide. In our tailored algorithm, the loss of about 1% of 'anti-HBc only' donors, does not significantly affect the blood supply while improving recipient safety.

The epigenetic promise to improve prognosis of heart failure and heart transplantation.

Heart transplantation is still the only possible life-saving treatment for end-stage heart failure, the critical epilogue of several cardiac diseases. Epigenetic mechanisms are being intensively investigated because they could contribute to establishing innovative diagnostic and predictive biomarkers, as well as ground-breaking therapies both for heart failure and heart transplantation rejection. DNA methylation and histone modifications can modulate the innate and adaptive immune response by acting on the expression of immune-related genes that, in turn, are crucial determinants of transplantation outcome. Epigenetic drugs acting on methylation and histone-modification pathways may modulate Treg activity by acting as immunosuppressive agents. Moreover, the identification of non-invasive and reliable epigenetic biomarkers for the prediction of allograft rejection and for monitoring immunosuppressive therapies represents an attractive perspective in the management of transplanted patients. MiRNAs seem to fit particularly well to this purpose because they are differently expressed in patients at high and low risk of rejection and are detectable in biological fluids besides biopsies. Although increasing evidence supports the involvement of epigenetic tags in heart failure and transplantation, further short and long-term clinical studies are needed to translate the possible available findings into clinical setting.

Anti-HLA Antibodies Testing on Solid Phase: Comparative Evaluation of Different Kit Vendors Through Luminex Technology.

OBJECTIVES: For decades, the detection of anti-HLA antibodies in candidates for solid-organ transplant has been performed with the traditional complement-dependent cytotoxicity method; this assay has been then integrated with the introduction of solid-phase assays. Over the past 20 years, the Luminex assay has become the most widely used in clinical laboratories due to both increased sensitivity and specificity versus enzyme-linked immunosorbent assay. However, even the Luminex technique has shown some critical issues, and choosing the most reliable method still remains challenging. In this study, we verified the concordance of the results obtained in detecting anti-HLA antibodies with 2 kit vendors that provide reagents for the Luminex platform. MATERIALS AND METHODS: We used 314 serum samples from patients on wait lists for solid-organ transplant. Sera were tested with LABScreen Mixed-LSM12 (One Lambda-Thermo Fisher, Canoga Park, CA, USA) and LIFECODES LifeScreen Deluxe-LMX (Gen-Probe-Immucor, Stanford, CT, USA),which we indicated as vendor A and vendor B, respectively. Anti-HLA class I and class II antibody analyses were conducted by verifying the concordance of the results with Cohen kappa coefficient statistics and confidence interval. RESULTS: The kappa coefficient statistics showed "substantial" reliability for class I (0.61; confidence interval, 0.50-0.73) and "moderate" reliability for class II (0.56; confidence interval, 0.43-0.69). There were no considerable differences in results between the 2 kits regarding overall assignment of negativity or positivity of a sample. Discordant data between positive values for a test and negative for the other were found for samples with weak antibody positivity. CONCLUSIONS: Some discordant data were probably attributable to several factors such as the composition of the kits, the antibody titer in the serum, whether sera were diluted, different washing methods, and type of plate used.

Comparison of performance of two Treponema pallidum automated chemiluminescent immunoassays in blood donors.

The recrudescence of syphilis is leading to the development of new serological tests. The goal of this study was to compare the performance of the more recent Elecsys Syphilis assay, the Electro Chemiluminescence Immunoassay (ECLIA), with the former Architect Syphilis TP assay, the Chemiluminescent Microparticle Immunoassay (CMIA), for the detection of antibodies against Treponema pallidum in blood donors. Serum samples of 5543 voluntary blood donors were screened in parallel with two tests. All repeatedly reactive (RR) samples by one or both assays were further analysed for confirmation by immmunoblot INNO-LIA and TPHA. Of 32 RR samples by CMIA, 21 were confirmed positive; of 21 RR samples by ECLIA, 20 were confirmed positive. The sensitivities of CMIA and ECLIA were 100% and 95.24% (95% CI = 85.71-100), respectively, not significant (p > 0.05). The specificity and predictive positive value (PPV) of CMIA were 99.86% (95% CI = 99.74-99.94) and 72.41%, respectively, while the specificity and PPV of ECLIA were both 100%, being statistically significant (p = 0.01 for both). The overall agreement was 99.80% and the Cohen's kappa coefficients was 0.79. In conclusion, the recent Elecsys Syphilis assay could represent another reliable assay for blood donor screening.

Comprehensive assessment of sensitizing events and anti-HLA antibody development in women awaiting kidney transplantation.

BACKGROUND: Alloimmunization remains a critical factor which affects the success of kidney transplantation. Patients awaiting solid organ transplantation may develop anti-HLA antibodies after pregnancies, transfusions and previous events of transplantations. AIM: We evaluated the effects of different sensitizing events on the anti-HLA antibody production and the potential role of patient HLA alleles in the context of antibody development in both the overall and pregnancy sensitized groups. MATERIAL AND METHODS: We retrospectively stratified 411 women on waiting list for kidney transplantation by route of sensitization. The presence of anti-HLA antibodies was evaluated by Solid Phase Assay and HLA typing was performed by serological and molecular methods. RESULTS: In our study population, 54% of women had anti-HLA antibodies. We found that the 51.6% of women with pregnancy only, 44% of women with transfusion only and 100% of women with a history of transplantation only developed anti-HLA antibodies. Pregnancy only resulted significantly associated with all anti-HLA antibody development such as anti-A, -B, -C, -DR, -DP as well as anti-DQB and -DQA antibodies. We investigated the influence of patient HLA alleles on the antibody development in the overall study population. Patients expressing HLA A*32 (p=0.024, OR=0.42), B*14 (p=0.035, OR=0.44), HLA-B*44 (p=0.026, OR=0.51) and DRB1*01 (p=0.029, OR=0.55) alleles produced anti-HLA antibodies less frequently compared to subjects with other alleles. In the pregnancy only group, B*14 (p=0.010, OR=0.12) and B*51 (p=0.005, OR=0.24) alleles were associated with a low risk of anti-HLA antibody development, while A*11 (p=0.033, OR=3.56) and DRB1*04 (p=0.022, OR=3.03) alleles seem to represent a higher risk. CONCLUSIONS: Pregnancy still remains a strong sensitizing event in women awaiting kidney transplantation. The anti-HLA antibody development in pregnancy appears to be associated with the expression of particular HLA alleles.

Syphilis detection: evaluation of serological screening and pilot reverse confirmatory assay algorithm in blood donors.

Serological assays are still considered the most useful tests in the diagnosis of syphilis. Since no single serological assay is able to provide a satisfactory result, in our laboratory we have evaluated the usefulness of a commercially-available immunoblot to diagnose syphilis infection among blood donors. From October 2012 to June 2013, 4572 blood donors were screened for syphilis with an automated chemiluminescent microparticle immunoassay (CMIA). To confirm the presence of treponemal antibodies, CMIA-reactive sera were tested by standard Treponema pallidum haemagglutination assay (TPHA). In addition, an alternative confirmatory test - the immunoblot INNO-LIA assay was introduced in our laboratory. Since two additional positives among CMIA-reactive-TPHA-negative samples were found, we concluded that the INNO-LIA immunoblot allowed a better detection of syphilis compared to TPHA. A confirmatory strategy based on the use of two treponemal assays could meet the screening requirements for blood donors as well as in our centre.

Lights and shadows of anti-HLA antibodies detected by solid-phase assay.

Recently, management of patients awaiting solid organ transplantation has taken advantages after the development of more sensitive and accurate solid phase assays which have supported the historic complement dependent cytotoxicity. This approach has allowed the detection of antibodies in patients previously considered negative. The use of the single antigen beads resulted in a more accurate anti-human leukocyte antigen (HLA) antibody characterization. The detection of anti-HLA antibodies specific for C, DQ and DP loci that were not so well characterized has been possible through the implementation of the single antigen assay. The assessment of HLA compatibility has been expanded through the introduction of "epitope matching" concept and the definition of the unacceptable antigens for a more adequate evaluation of donor-recipient compatibility. However, the clinical impact of pre-formed and de novo anti-HLA antibodies detected by solid phase assays is still controversial due to the drawback related to result interpretation. Until today, the unresolved issues concern if all antibodies affect the medium and long term clinical outcome. An open debate on the clinical relevance of anti-HLA antibodies detected by single-antigen beads highlights needing to further investigations. Here, we describe the novel applications and the improvements of the solid-phase assay use.

Screening tests for hepatitis B virus, hepatitis C virus, and human immunodeficiency virus in blood donors: evaluation of two chemiluminescent immunoassay systems.

Automated chemiluminescent immunoassays (CLIAs) are useful for the detection of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus 1/2 antigen/antibodies (HIV 1/2 Ag/Ab) in blood donor screening. Eight hundred and forty serum samples were tested for hepatitis B surface antigen (HBsAg), HCV antibodies (anti-HCV), and HIV1/2 Ag/Ab in parallel using 2 different CLIAs (Abbott Architect i2000SR and Roche Cobas e411). The concordance between the 2 systems was high (Cohen's kappa 0.97 for HBsAg, 0.77 for anti-HCV, 0.92 for HIV1/2 Ag/Ab) and the specificity and the positive predictive value were comparable. Among the 12 discrepant results, 11 were false-positive and 1 (reactive by Architect) was true-positive for anti-HCV. Positivity for HBV DNA, HCV RNA, and HIV RNA was recorded in 90.9%, 38.9%, and 100% of true-positive samples, respectively. This study represents the first stringent comparison between Architect i2000SR and Cobas e411 in blood donors. We observed a good correlation and high agreement among HBV, HCV, and HIV with the 2 automated systems.

Association between human leukocyte antigen class I and II alleles and hepatitis C virus infection in high-risk hemodialysis patients awaiting kidney transplantation.

Recent evidences have shown that several host genetic factors influence susceptibility or protection to hepatitis C virus (HCV) infection. There are controversial data regarding the associations of human leukocyte antigens (HLA) and the clearance or progression of HCV. The aim of this study was to investigate whether particular HLA molecules were associated with HCV infection in recipients awaiting kidney transplantation considered at high-risk to infection due to protracted hemodialysis treatment. To this purpose, 301 kidney recipients with HCV infection and 1103 uninfected recipients were examined for HLA class I and II molecules. In our case-control study, HLA-A(*)26 is positively associated with HCV infection while HLA-A(*)29, -B(*)40 and -DRB1(*)01 are negatively associated with HCV infection. Multiple logistic regression analysis demonstrated that age (OR = 1.02; 95% CI = 1.01-1.04; p < 0.00), HLA-A(*)26, -A(*)29, -B(*)40 and -DRB1(*)01 [(OR = 1.54; 95% CI = 1.03-2.30; p = 0.03); (OR = 0.50; 95% CI = 0.26-0.99; p = 0.05); (OR = 0.42; 95% CI = 0.23-0, 7; p = 0.01); (OR = 0.62; 95% CI = 0.41-0, 94; p = 0.03); respectively] are independent predictors of HCV infection. Our results suggest that particular HLA molecules, as host genetic factors, may have a relationship with susceptibility or protection to HCV infection also in recipients awaiting kidney transplantation.

Heart transplant with donor-specific antibody after immunoadsorption plus rituximab: a case report.

Different desensitization strategies are available for treating patients with preformed human leukocyte antigen (HLA) antibodies. A highly presensitized heart recipient received immunoadsorption and rituximab therapy. The patient, with end-stage heart failure, was positive only for antibodies of HLA class I (anti-A2, A10, B17), and Luminex platform (One Lambda kit) showed a panel-reactive antibody score of 64%. The patient's serum was tested repeatedly in both complement-dependent cytotoxicity and flow-cytometry crossmatches against cells from different potential organ donors. The results of these crossmatches were positive on flow cytometry when tested with HLA-A2, A10, and B17 but were still negative on cytotoxicity. The patient was treated with a desensitization regimen; this treatment immediately decreased antibody levels of 70% and the patient subsequently received a transplant with donor-specific HLA antibody (HLA-A2). After more than 2 years, graft function remains normal and the clinical status of the patient is stable.

Methodologies for anti-HLA antibody screening in patients awaiting kidney transplant: a comparative study.

OBJECTIVES: The relevance of anti-HLA antibodies in patients awaiting kidney transplants is well recognized. During the past 40 years, kidney transplant candidates have been tested for these antibodies, and the choice of the detection assay has become essential. Recently, the pioneer method, the complement-dependent cytotoxicity, has been integrated but has not been replaced by more-sensitive solid-phase assays, such as the enzyme-linked immunosorbent assay and the bead-based technology (ie, flow cytometry: FlowPRA, and FlowAnalyzer: Luminex). MATERIALS AND METHODS: We compared the sensitivity and antibody specificity of these 4 techniques for detecting panel-reactive antibodies in a population of 101 consecutive patients awaiting a renal transplant (which had already resulted positive in a prescreening analysis). RESULTS: Sera positive for class I and class II antibodies were 62 and 90 as assessed by the complement-dependent cytotoxicity method, 76 and 58 by using enzyme-linked immunosorbent assay, 83 and 65 with Flow-panel-reactive antibodies, and 90 and 79 by Luminex. Luminex gave more positive scores than the others for class I HLA antibodies, whereas complement-dependent cytotoxicity revealed more positives for those of class II. CONCLUSIONS: Although Luminex appears more efficient among these assays, our results indicate that use of multiple methods is still the best approach for characterizing the immunologic status of these patients.