Older kidney transplant patients experience less antibody-mediated rejection: a retrospective study of patients with mild to moderate sensitization

Seeking Standardized Definitions for HLA-incompatible Kidney Transplants: A Systematic Review

BACKGROUND

There is no standard definition for "HLA incompatible" transplants. For the first time, we systematically assessed how HLA incompatibility was defined in contemporary peer-reviewed publications and its prognostic implication to transplant outcomes.

METHODS

We combined 2 independent searches of MEDLINE, EMBASE, and the Cochrane Library from 2015 to 2019. Content-expert reviewers screened for original research on outcomes of HLA-incompatible transplants (defined as allele or molecular mismatch and solid-phase or cell-based assays). We ascertained the completeness of reporting on a predefined set of variables assessing HLA incompatibility, therapies, and outcomes. Given significant heterogeneity, we conducted narrative synthesis and assessed risk of bias in studies examining the association between death-censored graft failure and HLA incompatibility.

RESULTS

Of 6656 screened articles, 163 evaluated transplant outcomes by HLA incompatibility. Most articles reported on cytotoxic/flow T-cell crossmatches (n = 98). Molecular genotypes were reported for selected loci at the allele-group level. Sixteen articles reported on epitope compatibility. Pretransplant donor-specific HLA antibodies were often considered (n = 143); yet there was heterogeneity in sample handling, assay procedure, and incomplete reporting on donor-specific HLA antibodies assignment. Induction (n = 129) and maintenance immunosuppression (n = 140) were frequently mentioned but less so rejection treatment (n = 72) and desensitization (n = 70). Studies assessing death-censored graft failure risk by HLA incompatibility were vulnerable to bias in the participant, predictor, and analysis domains.

CONCLUSIONS

Optimization of transplant outcomes and personalized care depends on accurate HLA compatibility assessment. Reporting on a standard set of variables will help assess generalizability of research, allow knowledge synthesis, and facilitate international collaboration in clinical trials.

Intensive Safety Monitoring of Rituximab (Biosimilar Novex® and the Innovator) in Pediatric Patients With Complex Diseases

Although rituximab is widely used off-label for complex pediatric diseases, safety reports are limited. We aimed to report evidence of its use in clinical practice, to describe the incidence of adverse drug reactions (ADR) to rituximab biosimilar Novex^® and innovator, and to identify risk factors for the development of ADR in a real-life follow-up cohort of pediatric patients with complex diseases. We conducted a prospective, longitudinal, observational, single-centre study in patients that received rituximab for any complex disease, and as part of an intensive pharmacovigilance program. Demographic, pharmacological, clinical, and drug-related data were collected for all patients. ADR-free survival, including infusion-related reactions (IRR) and delayed ADR (dADR), was estimated using Kaplan-Meier curves. Risk factors were evaluated by multivariable Cox regression models. In total, 77 patients (<19 y.o.) received 187 infusions of rituximab Novex^® (n = 155) or innovator rituximab (n = 32) for neurologic (Neu), immune-hematologic-rheumatic (IHR), oncologic (O) diseases, and hematopoietic stem-cell transplantation (HSCT) or solid-organ transplantation (SOT). We recorded 29 IRR and 58 dADR that occurred in 27 (35.1%) and 29 (37.7%) patients, respectively. The respiratory tract was the most affected during IRR (29.6%) and hypogammaglobulinemia (37.9 %) was the most frequent dADR. First versus subsequent infusions (HR 5.4, CI95% 2.4-12.1, p<0.05), sex (boys vs. girls, HR 0.3, CI95% 0.1-0.8, and p<0.05), and diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 2.3, CI95% 1.02-5.4, and p < 0.05) were significantly associated with the development of IRR. For dADR, risk factors were diagnosis (Neu-IHR diseases vs. O-HSCT-SOT, HR 0.4, CI95% 0.2-0.9, and p < 0.05) and cumulative body surface area-normalized dosage (HR 1.0003, CI95% 1.0001-1.0006, and p < 0.05). The present is the largest real-world safety assessment of rituximab in Latin-American children with complex diseases supporting its use based on the overall acceptable safety. Identification of risk factors may contribute to optimization of off-label rituximab treatment in pediatrics.

Clinical Relevance of Pretransplant Testing for Anti-Human Leukocyte Antigen Antibodies in Iraqi Renal Transplant Patients

OBJECTIVES

The use of highly sensitive Luminex technology to assess the immunologic risk of renal transplant candidates have greatly added to the ability of stratifying patients and have paved the way to avoid hyperacute antibody-mediated rejection. Our aim was to understand how much the testing for pretransplant anti-HLA antibodies affects the decision for transplant and survival at 1 year posttransplant.

MATERIALS AND METHODS

From January 2014 to June 2017, 336 transplant candidates were tested by complement-dependent cytotoxicity and by the Luminex platform for anti-HLA antibodies in our nephrology and renal transplant center (The Medical City, Baghdad, Iraq). All clinical and laboratory data were noted. Our program is a living-donor, blood group-compatible donor program. All transplant patients (sensitized or not) were followed for 1 year, and the Kaplan-Meier method was used to determine survival rate.

RESULTS

Mean age of the study group was 34.07 ± 12.4 years. Of 336 transplant patients who were tested, there were 63 (18.75%) sensitized patients and 159 (47.35%) nonsensitized patients. Blood transfusion was the main cause of sensitization. Class I anti-HLA antibodies were detected in 54 of 63 sensitized patients (85.7%), and class II anti-HLA antibodies were detected in 39 of 63 sensitized patients (61.9%). Donor-specific antibodies were detected in 33/63 (52.3%). Thirteen sensitized patients (15.3%) underwent transplant. No incidences of hyperacute rejection were recorded. The 1-year survival of the nonsensitized patient group was 90%, whereas survival was 61.5% for the sensitized patient group.

CONCLUSIONS

Pretransplant testing for anti-HLA antibodies is undoubtedly useful for assessment of patient risk, to facilitate decisions regarding patient and donor selection, and to plan treatment strategies. The 1-year survival for sensitized patient was lower than for nonsensitized patients. More knowledge, experience, technology advancements, and support are needed to improve the Iraqi practice of transplanting sensitized patients.

Meeting report of the STAR-Sensitization in Transplantation Assessment of Risk: Naïve Abdominal Transplant Organ subgroup focus on kidney transplantation

The development of de novo donor-specific HLA antibody (dnDSA) is a critical feature contributing to late allograft failure. The complexity of the issue is further complicated by organ-specific differences, detection techniques, reliance of tissue histopathology and changing diagnostic criteria, ineffective therapies, and lack of consensus. To tackle these issues, the Sensitization in Transplantation Assessment of Risk (STAR) 2017 was initiated as a collaboration of the American Society of Transplantation and American Society of Histocompatibility and Immunogenetics consisting of 8 working groups with the goal to provide guidelines on how to assess risk and risk stratify patients based on their potential alloimmune and DSA status. Herein is a summary of discussions by the Naïve Abdominal Working Group, highlighting currently available data and identifying gaps in our knowledge on the development and impact of dnDSA following kidney transplantation.