Impact of allele-specific anti-human leukocyte antigen class I antibodies on organ allocation.

Technological advances in the field of histocompatibility have allowed us to define anti-human leukocyte antigen (HLA) antibody specificity at the allelic level. However, how allele-specific antibodies affect organ allocation is poorly studied. We examined allelic specificities of class I HLA antibodies in 6726 consecutive serum samples from 2953 transplant candidates and evaluated their impact on the corresponding crossmatch and organ allocation. Out of 17 class I HLA antigens represented by >1 allele in the LABScreen single antigen bead assay, 12 had potential allele-specific reactivity. Taking advantage of our unbiased cohort of deceased donor-candidate testing (123,135 complement-dependent cytotoxicity crossmatches between 2014 and 2017), we estimated that the presence of allele-specific antibody detected using a single antigen bead assay (median fluorescence intensity, >3000) against only the rare allele was a poor predictor of a positive complement-dependent cytotoxicity crossmatch, with a positive predictive value of 0% to 7%, compared with 52.5% in allele-concordant class I HLA antibodies against A or B locus antigens. Further, we confirmed allele-specific reactivity using flow crossmatch in 3 scenarios: A11:01/A11:02, A68:01/A68:02, and B44:02/B44:03. Our results suggest that allele-specific antibodies may unnecessarily exclude transplant candidates (up to 10%) from organ offers by overcalling unacceptable antigens; incorporation of selective reactivity pattern in allocation may promote precision matching and more equitable allocation.

Sexual health activism: the motivations of near-peer volunteer educators working to promote positive understandings of gender and sexuality in UK secondary schools.

This paper explores and theorises education-based workshops delivered in secondary schools in support of a relationships and sex education curriculum that aims to bring forth more positive understandings and experiences of gender and sexuality. We cast this work as a form of sexual health activism, with our paper deepening understanding of how the motivations of those engaged in this form of activism interface with the decision to invest time in this work. Based on interviews with 40 workshop facilitators in England and Wales we argue that this form of sexual health activism is motivated by facilitators' life experiences as well as the desire to make the world a better place. As such, this form of work can function as a means of 'caring for' both past selves and future generations, thus functioning simultaneously as a form of self-care and a form of 'societal care work'. Ultimately, these activities may be understood as a form of 'extra-clinical' healthcare practice, with leading gender and sexual health workshops serving as an important means of solidifying health students' identities as both healthcare providers and activists for social change.

Preformed Donor-specific Antibodies Against HLA Class II and Graft Outcomes in Deceased-donor Kidney Transplantation.

BACKGROUND: Many kidney transplant centers in the United States report both HLA class I and II antibodies detected by sensitive solid-phase assays (SPAs) to United Network for Organ Sharing as unacceptable antigens, significantly reducing the compatible donor organ pool and prolonging waiting time for highly sensitized patients. However, the clinical relevance of all detected donor-specific antibodies (DSAs) by SPA is not unequivocal, because fluorescence intensity does not always accurately reflect antibody pathogenicity. Our center does not exclude patients from transplantation based on DSA class II. METHODS: We performed a retrospective analysis in 179 deceased-donor kidney transplant recipients with solely DSA class II before transplant and patients without DSA and compared graft survival, rejection, and clinical outcomes. Patient survival was also compared with matched controls on the waiting list. RESULTS: Patients transplanted with DSA class II showed a clear survival benefit compared with matched patients who remained on dialysis or were waitlisted on dialysis/transplanted at 5 years (100%, 34%, and 73%, respectively). After a mean follow-up of 5.5 years, there was no significant difference in death-censored graft survival between transplanted patients without DSA and those with preformed DSA class II (adjusted HR 1.10; 95% confidence interval, 0.41-2.97), although the incidence of rejection was higher in recipients with DSA class II (adjusted HR 5.84; 95% confidence interval, 2.58-13.23; P < 0.001). Serum creatinine levels at 1, 3, and 5 years posttransplant did not differ between groups. No predictors of rejection were found, although patients who received basiliximab induction therapy had higher incidence of rejection (100%) compared with those who received antithymocyte globulin (52%). CONCLUSIONS: We conclude that for highly sensitized patients, deceased-donor kidney transplantation with DSA class II yields a survival benefit over prolonged waiting time on dialysis. Instead of listing DSA class II as unacceptable antigens, an individual approach with further immunologic risk assessment is recommended.

Clinical Outcomes of Lung Transplantation in the Presence of Donor-Specific Antibodies.

Rationale: There is significant variation in approach to pre-lung transplant donor-specific antibodies (DSA), with some centers declining to cross any DSA. We implemented a protocol for transplantation for candidates with pretransplant DSA so long as a prospective complement-dependent cytotoxicity crossmatch was negative, regardless of number, specificity, class, or mean fluorescence intensity.Objectives: To compare post-transplant outcomes including overall survival, chronic lung allograft dysfunction-free survival, antibody-mediated rejection, and acute cellular rejection in lung transplant recipients where pretransplant DSA was and was not present.Methods: This was a single-center retrospective cohort study. For recipients with pretransplant DSA, if the prospective complement-dependent cytotoxicity crossmatch was negative, the donor offer was accepted and plasmapheresis was performed within 24 hours of transplantation and continued until retrospective crossmatch results returned. Immunosuppression and post-transplant management were not otherwise modified.Results: Of the 203 included recipients, 18 (8.9%) had pretransplant DSA. The median DSA mean fluorescence intensity was 4,000 (interquartile range, 2,975-5,625; total range, 2,100-17,000). The median number of DSA present per patient was one (interquartile range, 1-2). The presence of pretransplant DSA was not associated with increased mortality (hazard ratio, 1.2; 95% confidence interval [CI], 0.4-3.4) or decreased chronic lung allograft dysfunction-free survival (hazard ratio, 1.1; 95% CI, 0.6-2.1). Recipients with pretransplant DSA were more likely to require prolonged mechanical ventilation (adjusted odds ratio, 7.0; 95% CI, 2.3-21.6) and to have antibody-mediated rejection requiring treatment (adjusted odds ratio, 7.5; 95% CI, 1.0-55.8).Conclusions: A protocol of accepting donor offers for lung transplant candidates with preformed, complement-dependent cytotoxicity crossmatch-negative DSA is associated with increased need for prolonged mechanical ventilation and antibody-mediated rejection without affecting short-term overall or chronic lung allograft dysfunction-free survival.

The Presence of Pretransplant HLA Antibodies Does Not Impact the Development of Chronic Lung Allograft Dysfunction or CLAD-Related Death.

BACKGROUND: Development of donor-specific antibodies (DSA) after lung transplantation is associated with antibody mediated rejection, acute cellular rejection, and bronchiolitis obliterans syndrome; however, the significance of circulating antibodies before transplant remains unclear. METHODS: We performed a retrospective cohort study including recipients of primary lung transplants between 2008 and 2012. We assessed the impact of circulating HLA and noncytotoxic DSA detected before transplant on development of Chronic Lung Allograft Dysfunction (CLAD) or CLAD-related death. RESULTS: 30% of subjects had circulating class I antibodies alone, 4% Class II, and 14.4% class I and class II at mean fluorescent intensity greater than 1000. Nine percent of the subjects had DSA class I, 9% class II, and 2.4% both DSA classes 1 and 2. Neither the presence of circulating antibodies (adjusted hazard ratio, 0.87; 95% confidence interval, 0.50-1.54) nor the presence of DSA (adjusted hazard ratio, 1.56; 95% confidence interval, 0.77-3.18) before transplant at mean fluorescent intensity greater than 1000 was associated with the development of CLAD or CLAD-related death. CONCLUSIONS: Although in previous studies we have shown an increased incidence of antibody-mediated rejection in patients with pretransplant DSA, neither the presence of HLA antibodies nor DSA translated to an increased risk of allograft dysfunction or death if prospective crossmatch testing was negative. Prospective studies are needed to define the impact of pretransplant sensitization on lung transplant recipients.

Association of Donor and Recipient Telomere Length with Clinical Outcomes following Lung Transplantation.

BACKGROUND: Patients with short telomere syndromes and pulmonary fibrosis have increased complications after lung transplant. However, the more general impact of donor and recipient telomere length in lung transplant has not been well characterized. METHODS: This was an observational cohort study of patients who received lung transplant at a single center between January 1st 2012 and January 31st 2015. Relative donor lymphocyte telomere length was measured and classified into long (third tertile) and short (other tertiles). Relative recipient lung telomere length was measured and classified into short (first tertile) and long (other tertiles). Outcome data included survival, need for modification of immunosuppression, liver or kidney injury, cytomegalovirus reactivation, and acute rejection. RESULTS: Recipient lung tissue telomere lengths were measured for 54 of the 79 patients (68.3%) who underwent transplant during the study period. Donor lymphocyte telomeres were measured for 45 (83.3%) of these recipients. Neither long donor telomere length (hazard ratio [HR] = 0.58, 95% confidence interval [CI], 0.12-2.85, p = 0.50) nor short recipient telomere length (HR = 1.01, 95% CI = 0.50-2.05, p = 0.96) were associated with adjusted survival following lung transplant. Recipients with short telomeres were less likely to have acute cellular rejection (23.5% vs. 58.8%, p = 0.02) but were not more likely to have other organ dysfunction. CONCLUSIONS: In this small cohort, neither long donor lymphocyte telomeres nor short recipient lung tissue telomeres were associated with adjusted survival after lung transplantation. Larger studies are needed to confirm these findings.

Antibodies against HLA-DP recognize broadly expressed epitopes.

HLA matching and avoidance of pre-transplant donor-specific antibodies are important in selection of donors for solid organ transplant. Solid phase testing with single antigen beads allows resolution of antibody reactivity to the level of the allele. Single antigen bead testing results at a large transplant center were reviewed to identify selective reactivity patterns of anti-HLA antibodies. Many HLA-DP antibodies were identified in the context of other HLA antibodies, but some sera had antibodies against only HLA-DP. B cell flow crossmatch testing was positive for 2 out of 9 sera with HLA-DP antibodies. Many patterns of reactivity corresponded to epitopes in hypervariable regions C and F of DPB1, but some matched epitopes in other regions or DPA1. Through analysis of single antigen bead testing from a large number of patients, we report that anti-HLA-DP antibodies predominantly recognize broadly cross-reactive epitopes. The United Network for Organ Sharing has mandated HLA-DP typing on all deceased kidney donors, and HLA-DP epitopes should be considered as the major antigens for avoidance of pre-transplant donor-specific antibodies.

Impact of pretransplant anti-HLA antibodies on outcomes in lung transplant candidates.

RATIONALE: The prevalence of anti-HLA antibodies in lung transplant candidates and their impact on waitlist and transplant outcomes is not known. OBJECTIVES: We examined the prevalence of pretransplant anti-HLA antibodies at varying thresholds and evaluated their impact on outcomes before and after lung transplantation. METHODS: We performed a single-center retrospective cohort study including all patients listed for lung transplantation between January 2008 and August 2012. Per protocol, transplant candidates were assessed by solid phase LABscreen mixed Class I and II and LABscreen Single Antigen assays. MEASUREMENTS AND MAIN RESULTS: Among 224 patients, 34% had anti-HLA antibodies at mean fluorescent intensity (MFI) greater than or equal to 3,000 (group III), and 24% had antibodies at MFI 1,000 to 3,000 (group II). Ninety percent of the patients with pretransplant anti-HLA antibodies had class I antibodies, whereas only seven patients developed class II alone. Patients in group III were less likely to receive transplants than patients without any anti-HLA antibodies (group I) (45.5 vs. 67.7%, P = 0.005). Wait time to transplant was longer in group III than group I, although this difference did not meet statistical significance, and waitlist mortality was similar. Among transplant recipients, antibody-mediated rejection (AMR) was more frequent in group III than in group II (20% vs. 0%, P = 0.01) or group I (6.3%, P = 0.05). CONCLUSIONS: The presence of anti-HLA antibodies at the high MFI threshold (>3,000) was associated with lower transplant rate and higher rates of AMR. Screening for anti-HLA antibodies using the 3,000 MFI threshold may be important in managing transplant candidates and recipients.

ATG induction is associated with an increase in anti-HLA antibodies after kidney transplantation.

Anti-human histocompatibility antigen antibodies (HLA-Ab) are deleterious after kidney transplant and may be increased after T-cell depleting agents are given. A retrospective case control study was conducted to evaluate increase in HLA-Ab in 27 kidney transplant recipients who had received antithymocyte globulin (ATG) induction compared with 27 control subjects. A greater than 10% increase in class I or class II HLA-Ab was found in 6 (22.2%) of ATG subjects versus only 1 (3.7%) of non-ATG subjects (p = 0.05). In females, 6/14 ATG subjects developed increased HLA-Ab > or =10% compared with none of the control subjects (p = 0.016). In sensitized subjects, 4/10 in the ATG group developed increased HLA-Ab > or =10% versus none of the controls (p = 0.043). There was no difference in number or severity of acute rejection episodes or estimated glomerular filtration rate 6 months after transplant between the two treatment groups. We conclude that ATG induction may result in increased posttransplant HLA-Ab, particularly in subjects at higher immunologic risk. Further studies are necessary to determine the natural history, clinical consequences, appropriate therapy, and mechanisms responsible for HLA-Ab in this setting.

Ribotoxic stress activates p38 and JNK kinases and modulates the antigen-presenting activity of dendritic cells.

Initiation of adaptive immunity requires activation of dendritic cells (DC) by "danger" signals. This study examines the functional consequences of activating a cellular stress response in human DC. Anisomycin, a potent inducer of this "stress" response, selectively activates p38 kinase in DC at low concentrations, and both p38 kinases and JNKs at higher concentrations. Activation of p38, was accompanied by an increase in the potency of dendritic cells to activate T cells. In contrast to LPS, anisomycin had no effect on the expression of several DC activation markers. Anisomycin synergised with LPS in driving release of IL-12 and TNF-alpha. Anisomycin also enhanced the formation of clusters between DC and T cells. Enhanced cytokine release and clustering were both inhibited by the selective p38 alpha and p38 beta inhibitor SB203580. This study demonstrates that the cellular stress response, mediated via p38 kinases, plays an important role in the regulation of several aspects of DC function.

Investigations into the role of anti-HLA class II antibodies in TRALI.

BACKGROUND: TRALI is thought to be triggered by recipient-specific anti-HLA class I or antibodies against neutrophils in donor plasma. Recently, anti-HLA class II have also been implicated. The prevalence of anti-HLA class II was investigated in normal volunteer platelet donors and in two nonfatal TRALI cases utilizing a flow-based assay. Potential target antigens also were investigated. STUDY DESIGN AND METHODS: Commercial flow cytometry-based assays (FlowPRA, One Lambda, Inc.) for anti-HLA class I and II were compared with standard lymphocytotoxicity tests. Subsequently, 151 volunteer platelet donors and two clinical cases of TRALI were screened with FlowPRA. Immunohistochemical studies were performed on lung tissue from a surgical case, an autopsy case, and a fatal TRALI case. RESULTS: The FlowPRA assays showed moderate concordance for anti-HLA class I (kappa = 0.448) and good concordance for class II antibodies (kappa = 0.801), when compared to standard lymphocytotoxicity assays. Ten and 9 percent of female platelet donors were positive for anti-HLA class I and class II, respectively. Two nonfatal cases of TRALI showed both anti-HLA class I and anti-HLA class II. Immunohistochemical analysis of a TRALI case revealed granulocyte aggregation in alveolar capillaries with activated vascular endothelial cells. HLA class II antigen expression was not present on vascular endothelium or intravascular WBCs; however, strong expression was seen on alveolar macrophages. CONCLUSION: FlowPRA assays often detect anti-HLA class I not detected by conventional lymphocytotoxicity assays. These assays reveal anti-HLA class II in normal female donor plasma and in sera implicated in TRALI. Immunohistochemical studies failed to reveal endothelial or intravascular-WBC HLA class II antigen expression in lung tissue derived from TRALI cases or controls, but demonstrated HLA class II expression on pulmonary macrophages.