Intravenous immune globulin treatment inhibits crossmatch positivity and allows for successful transplantation of incompatible organs in living-donor and cadaver recipients

Management of the sensitized pediatric renal transplant candidate

Kidney transplantation is the treatment of choice for patients with ESRD as it is associated with improved patient survival and better quality of life, especially in children. There are several barriers to a successful transplant including organ shortage, anatomic barriers, and immunologic barriers. One of the biggest immunologic barriers that precludes transplantation is sensitization, when patients have antibodies prior to transplantation, resulting in positive crossmatches with donor. 30%-40% of adult patients on the wait list are sensitized. There is a growing number of pediatric patients on the wait list who are sensitized. This poses a unique challenge to the pediatric transplant community. Therefore, attempts to perform desensitization to remove or suppress pathogenic HLA antibodies resulting in acceptable crossmatches, and ultimately a successful transplant, while reducing the risk of acute rejection, are much needed in these children. This review article aims to address the management of such patients both prior to transplantation, with strategies to overcome sensitization, and after transplantation with monitoring for allograft rejection and other complications.

Desensitization in Crossmatch-positive Kidney Transplant Candidates

Access to kidney transplantation is limited by HLA-specific sensitization. Desensitization strategies enable crossmatch-positive kidney transplantation. In this review, we describe clinical experience gained over the last 20 y using desensitization strategies before kidney transplantation and describe the different tools used (both drugs and apheresis options), including IVIg, rituximab, apheresis techniques, interleukin-6 interference, proteasome inhibition, enzymatic degradation of HLA antibodies, complement inhibition, and B cytokine interference. Although access to transplantation for highly sensitized kidney transplantation candidates has been vastly improved by desensitization strategies, it remains, however, limited by the recurrence of HLA antibodies after transplantation and the occurrence of antibody-mediated rejection.

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.

Belatacept-Based Maintenance Immunosuppression Controls the Post-Transplant Humoral Immune Response in Highly Sensitized Nonhuman Primates

Preexisting donor-specific antibodies (DSA) to MHC antigens increase the risk of antibody-mediated rejection (AMR) in sensitized transplant recipients and reduces graft survival. Pretransplant desensitization with costimulation blockade and proteasome inhibition has facilitated transplantation in our preclinical nonhuman primate (NHP) model. However, long-term graft survival is limited by rebound of DSA after transplantation. In this study, we performed kidney transplants between highly sensitized, maximally MHC-mismatched NHPs (n=14). At kidney transplantation, primates received T cell depletion with rhesus-specific anti-thymocyte globulin (rhATG; n=10) or monoclonal anti-CD4 and anti-CD8 antibodies (n=4). Maintenance immunosuppression consisted of belatacept and tacrolimus (n=5) or belatacept and rapamycin (n=9) with steroids. Rebound of DSA post-kidney transplantation was significantly reduced compared with maintenance immunosuppression with tacrolimus, mycophenolate, and steroids. Protocol lymph node biopsy specimens showed a decrease in germinal center activity, with low frequencies of T follicular helper cells and class-switched B cells after kidney transplantation. Combined belatacept and rapamycin was superior in controlling viral reactivation, enabling weaning of ganciclovir prophylaxis. Tacrolimus was associated with increased morbidity that included cytomegalovirus and parvovirus viremia and post-transplant lymphoproliferative disorder. All primates in the tacrolimus/belatacept group failed discontinuation of antiviral therapy. Overall, belatacept-based immunosuppression increased AMR-free graft survival by controlling post-transplant humoral responses in highly sensitized NHP recipients and should be further investigated in a human clinical trial.

Strategies to Overcome HLA Sensitization and Improve Access to Retransplantation after Kidney Graft Loss

An increasing number of patients waitlisted for kidney transplantation have a previously failed graft. Retransplantation provides a significant improvement in morbidity, mortality, and quality of life when compared to dialysis. However, HLA sensitization is a major barrier to kidney retransplantation and the majority of the highly sensitized patients are waiting for a subsequent kidney transplant. A multidisciplinary team that includes immunogeneticists, transplant nephrologists and surgeons, and adequate allocation policies is fundamental to increase access to a kidney retransplant. A review of Pubmed, ScienceDirect, and the Cochrane Library was performed on the challenges of kidney retransplantation after graft loss, focusing on the HLA barrier and new strategies to overcome sensitization. Conclusion: Technical advances in immunogenetics, new desensitization protocols, and complex allocation programs have emerged in recent years to provide a new hope to kidney recipients with a previously failed graft.

Viral-specific cytotoxic T-cell responses in HLA-sensitized kidney transplant patients maintained on everolimus and low dose tacrolimus

BACKGROUND

Maintenance with "everolimus + reduced dose tacrolimus" (Ev + Tac_low ) was reported to reduce the risk of viral infections compared to (Tac + MMF). Here we examined viremia and viral-specific T-cell (viral-Tc) responses in patients treated with Ev + Tac_low v. Tac + MMF in highly-HLA sensitized patients.

METHODS

HLA sensitized (HS) kidney transplant patients were monitored pre- and post-transplant for viremia (CMV, BK and EBV) by PCR in 19 Ev + Tac_low and 48 Tac + MMF patients. For CMV PCR analysis, we compared infection rates in 19 Ev + Tac_low patients to 48 CMV D+/R- (#28) or CMV D-/R- (#20) Tac + MMF patients. CMV-Tc and EBV-Tc were evaluated by cytokine flow cytometry, and DSA levels by Luminex for selected patients in both groups.

RESULTS

CMV, EBV viremia rates were similar in Ev + Tac_low v. Tac + MMF patients, but BKV rates were significantly higher in Ev + Tac_low patients. No patient in either group developed BKAN or PTLD. CMV- & EBV-Tc decreased significantly after alemtuzumab induction but returned to pre-treatment levels 1-2 months post-transplant in most patients. de novo DSA was similar in both groups as were patient and graft survival and graft rejection.

CONCLUSIONS

CMV-Tc, EBV-Tc were similar in Ev + Tac_low and Tac + MMF patients. EBV and CMV viremia rates were similar over 1 year. BKV rates were significantly higher in Ev + Tac_low patients suggesting no benefit for Ev + Tac_low in enhancing viral specific Tc effector functions or limiting viral infections. This article is protected by copyright. All rights reserved.

Desensitization Regimen Consisting of High-Dose Intravenous Immunoglobulin, Plasmapheresis, and Rituximab (an Anti-CD20 Antibody), Without Eculizumab and/or Bortezomib, in 41 Highly Sensitized Kidney Transplant Recipients

OBJECTIVES

Antibody-mediated rejection in patients with positive crossmatches can be severe and result in sudden onset of oliguria, leading to graft loss. In an attempt to prevent posttransplant oliguria, we adopted a preoperative desensitization protocol involving the use of high-dose intravenous immunoglobulin/plasmapheresis and the anti-CD20 antibody, rituximab, in 41 transplant recipients with positive crossmatch test results.

MATERIALS AND METHODS

We retrospectively examined the clinical courses of the 41 kidney transplant recipients, paying special attention to renal graft function, urine volume, and changes in the titers of donor-specific antibodies.

RESULTS

Four grafts were lost during an average of 4.5-year follow-up. Average graft function was excellent, with a serum creatinine level of 1.3 ± 0.4 mg/dL. Sufficient urine output, with no oliguria or anuria, was achieved postoperatively in 40 of the 41 patients. However, among the 34 patients who underwent graft biopsies, the biopsies revealed acute antibody-mediated rejection in 21 patients (62%), and chronic antibodymediated rejection in 10 patients (30%).

CONCLUSIONS

The high-dose intravenous immunoglobulin treatment included in our desensitization protocol was shown to be safe and effective for achieving successful transplant outcomes and allowed the avoidance of more aggressive B-cell-targeted treatments, such as C5 inhibitors and/or proteosome inhibitors, for preventing posttransplant oliguria and anuria.

Therapeutic Potential of HLA-I Polyreactive mAbs Mimicking the HLA-I Polyreactivity and Immunoregulatory Functions of IVIg

HLA class-I (HLA-I) polyreactive monoclonal antibodies (mAbs) reacting to all HLA-I alleles were developed by immunizing mice with HLA-E monomeric, α-heavy chain (αHC) open conformers (OCs). Two mAbs (TFL-006 and TFL-007) were bound to the αHC’s coated on a solid matrix. The binding was inhibited by the peptide ¹¹⁷AYDGKDY¹²³, present in all alleles of the six HLA-I isoforms but masked by β2-microglobulin (β2-m) in intact HLA-I trimers (closed conformers, CCs). IVIg preparations administered to lower anti-HLA Abs in pre-and post-transplant patients have also shown HLA-I polyreactivity. We hypothesized that the mAbs that mimic IVIg HLA-I polyreactivity might also possess the immunomodulatory capabilities of IVIg. We tested the relative binding affinities of the mAbs and IVIg for both OCs and CCs and compared their effects on (a) the phytohemagglutinin (PHA)-activation T-cells; (b) the production of anti-HLA-II antibody (Ab) by B-memory cells and anti-HLA-I Ab by immortalized B-cells; and (c) the upregulation of CD4+, CD25+, and Fox P³+ T-regs. The mAbs bound only to OC, whereas IVIg bound to both CC and OC. The mAbs suppressed blastogenesis and proliferation of PHA-activated T-cells and anti-HLA Ab production by B-cells and expanded T-regs better than IVIg. We conclude that a humanized version of the TFL-mAbs could be an ideal, therapeutic IVIg-mimetic.

A virtual crossmatch-based strategy for perioperative desensitisation in lung transplant recipients with preformed donor-specific antibodies: 3-year outcome

BACKGROUND

Preformed donor-specific antibodies (DSAs) are associated with worse outcome after lung transplantation (LTx) and migvaht limit access to LTx. A virtual crossmatch (CXM)-based strategy for perioperative desensitisation protocol has been used for immunised LTx candidates since 2012 at Foch hospital. We compared the outcome of desensitised LTx candidates with high DSA mean fluorescence intensity (MFI) and those with low or no preformed DSAs, not desensitised.

METHODS

For all consecutive LTx recipients (January-2012/March-2018), freedom from CLAD and graft survival were assessed by Kaplan-Meier analysis and Cox multivariate analysis.

RESULTS

We compared outcomes for desensitised patients with high preformed DSAs (n=39) and those with no (n=216) or low pre-formed DSAs (n=66). The desensitisation protocol decreased the level of immunodominant DSA (class I/II) at 1, 3, and 6 month post-LTx (p<0.001, p<0.01, p<0.001, respectively). Freedom from CLAD and graft survival at 3 years was similar in the desensitised group as a whole and other groups. Nevertheless, incidence of CLAD was higher with persistent high- than cleared high-level (p=0.044) or no DSAs (p=0.014). Conversely, graft survival was better with cleared high DSAs than persistent high-, low-level, and no pre-formed DSAs (p=0.019, p=0.025, and p=0.044, respectively). On multivariate analysis, graft survival was associated with cleared high DSAs (HR: 0.12 [95%CI: 0.02-0.85] versus no DSAs, p=0.035) and CLAD with persistent DSAs (HR: 3.04 [1.02-9.17] versus no preformed DSAs, p=0.048).

CONCLUSION

The desensitisation protocol in LTx recipients with high preformed DSAs was associated with satisfactory outcome, with cleared high pre-formed DSAs after desensitisation identified as an independent predictor of graft survival.

Center-level Variation in HLA-incompatible Living Donor Kidney Transplantation Outcomes

BACKGROUND

Desensitization protocols for HLA-incompatible living donor kidney transplantation (ILDKT) vary across centers. The impact of these, as well as other practice variations, on ILDKT outcomes remains unknown.

METHODS

We sought to quantify center-level variation in mortality and graft loss following ILDKT using a 25-center cohort of 1358 ILDKT recipients with linkage to Scientific Registry of Transplant Recipients for accurate outcome ascertainment. We used multilevel Cox regression with shared frailty to determine the variation in post-ILDKT outcomes attributable to between-center differences and to identify any center-level characteristics associated with improved post-ILDKT outcomes.

RESULTS

After adjusting for patient-level characteristics, only 6 centers (24%) had lower mortality and 1 (4%) had higher mortality than average. Similarly, only 5 centers (20%) had higher graft loss and 2 had lower graft loss than average. Only 4.7% of the differences in mortality (P < 0.01) and 4.4% of the differences in graft loss (P < 0.01) were attributable to between-center variation. These translated to a median hazard ratio of 1.36 for mortality and 1.34 of graft loss for similar candidates at different centers. Post-ILDKT outcomes were not associated with the following center-level characteristics: ILDKT volume and transplanting a higher proportion of highly sensitized, prior transplant, preemptive, or minority candidates.

CONCLUSIONS

Unlike most aspects of transplantation in which center-level variation and volume impact outcomes, we did not find substantial evidence for this in ILDKT. Our findings support the continued practice of ILDKT across these diverse centers.

Eplet-based virtual PRA increases transplant probability in highly-sensitized patients

BACKGROUND

The reduced access of highly-sensitized (HS) patients to kidney transplantation (KTx) is one of the major challenges for transplant community. Therefore, the aim of our study was to estimate the impact of three different vPRA calculations, assessed traditionally and using eplet-based analysis, in donor offers.

METHODS

At 01-01-2020, 157 HS patients are waitlisted for deceased donor KTx and were included in this study. Total vPRA (vPRAt) was calculated considering all patient allosensitization history, using 1 k MFI cut-off. Current vPRA (vPRAc) refers only to the last year SAB assays, using 1 k MFI cut-off. For eplet vPRA (vPRAe) every SAB assay was analyzed by HLAMatchmaker and HLAfusion software. Matching runs have been performed taking vPRA calculation as unacceptable antigens (UAs).

RESULTS

All patients had at least one previous sensitizing event and patients with 100% vPRA were predominantly candidates for retransplantation (P < 0.001), had higher PRA-CDC (P < 0.001), and longer dialysis vintage waiting time (P < 0.001). Inter-group movement analysis between vPRA measures showed that 70 (45%), 124 (79%) and 80 (51%) patients were reclassified to a lower group when considering vPRAt to vPRAc, vPRAt to vPRAe and vPRAc to vPRAe, respectively. The median percentage of change in estimated number of match runs needed for 95% probability of finding an acceptable donor was significantly more pronounced by increasing vPRAt intervals, when considering the reclassification from vPRAt to vPRAe (P < 0.001) or vPRAc to vPRAe (P = 0.045), while from vPRAt to vPRAc it was not (P = 0.899).

CONCLUSIONS

Our study demonstrated that the use of total or current vPRA calculations are impairing HS patients, by decreasing transplant probability, leading to dramatically longer waiting times, when compared to eplet based vPRA.

Natural soluble human leukocyte antigen class I in donor serum neutralizes donor-specific HLA alloantibodies in recipient serum

Background

Human leukocyte antigen (HLA) molecules are cell-bound but can be identified in a soluble form. These soluble HLA (sHLA) molecules have an immunomodulatory function. We investigated whether natural sHLA in donor serum can neutralize donor-specific HLA alloantibodies (DSAs) in recipient serum.

Methods

Neutralizing effects of donor serum on DSAs in recipient serum were measured using inhibition assay principle of flow cytometric crossmatch (FCXM), performed using sera from 143 kidney transplant recipients and their donors. The adding of donor serum to recipient serum yielded lower mean fluorescence intensity (MFI) ratios (test/control) than when diluent was added [Roswell Park Memorial Institute (RPMI) or third-party serum], which was presumed to be caused by the neutralizing effects of sHLA.

Results

In the recipient group with class I DSAs alone (N=14), donor serum addition to recipient serum resulted in lower T cell MFI ratios [2.25 (1.31‒32.51)] than those observed on RPMI addition [3.04 (1.33‒125.39), P<0.05]. In the recipient group with class II DSAs alone (N=27), donor serum addition showed no significant difference in B cell MFI ratios [5.03 (1.41‒103.53)] compared to diluent addition: RPMI [4.50 (1.34‒145.98)] or third-party serum [5.08 (1.44‒138.47)], P>0.05 for both.

Conclusion

Using inhibition FCXM, we verified that natural sHLA class I in donor serum neutralizes DSAs in recipient serum. However, no neutralizing effects of sHLA class II were revealed in this study. These potentially beneficial effects of sHLA infused via blood-derived products should be considered when desensitizing highly HLA-sensitized patients.

Desensitization strategies: is it worth it?

Preformed donor-specific antibodies (DSAs) limit access to transplantation for thousands of renal transplant patients. While kidney paired donation offers the best strategy for patients with a living donor, for very highly sensitized patients and those without living donors, a strategy of desensitization offers the best hope of transplantation. Removal of DSAs with plasmapheresis, intravenous immunoglobulin and anti-CD20 antibodies can permit successful transplantation. While the clinical outcomes remain inferior to compatible transplant and the costs are significantly greater, when compared with long-term dialysis treatment, these strategies are offer improved survival and are cost-effective given nationally accepted benchmarks.

Successful Third Kidney Transplant After Desensitization for Combined Human Leucocyte Antigen (HLA) and ABO Incompatibility: A Case Report and Review of Literature

BACKGROUND In the present era, kidney transplantation across immunological barriers (ABO incompatibility and human leucocyte antigen (HLA) incompatibility) is a successful strategy to provide transplantation to immunologically high-risk patients. The safety and outcome of crossing both ABO and HLA barriers simultaneously in a retransplantation scenario is rarely reported from the developing world. CASE REPORT A 30-year-old female underwent a third living donor kidney transplantation. Her previous 2 transplants being lost to chronic allograft nephropathy. The transplantation was done across a simultaneous blood group as well as HLA incompatibility. The donor was the mother who was blood group B, with the recipient being blood group O. The complement dependent cytotoxicity crossmatch of the pair was negative but the flow cross match for T as well as B lymphocytes was positive. The mean fluorescence intensity value for class I antigens was 6951 and that for class 2 antigens was 7534. The patient underwent a desensitization procedure including rituximab, plasmapheresis and intravenous immunoglobulin pre-transplantation. The pre-transplantation isohemaglutunin titer was <1: 8 and the donor specific antibody against class 1 antigens was <2200 and <770 against class 2 antigens. Induction was done with anti-thymocyte globulin in the dose of 3 mg/kg in 2 divided doses. The patient is maintained on triple immunosuppression with tacrolimus, prednisolone and mycophenolate mofetil. After a follow-up period of 5 months, she maintains a good graft function with serum creatinine of 1.01 mg/dL. CONCLUSIONS With the advances in the desensitizing procedures in the developing world, kidney transplantation across a combined HLA and ABO incompatible barrier can be offered to these highly sensitized patients, even in case of retransplantation.

Successful Desensitization of T cell Flow Cytometry Crossmatch Positive Renal Transplant Recipients Using Plasmapheresis and Super High-Dose Intravenous Immunoglobulin

Background

High-dose IVIG (2 g/kg) alone or low-dose IVIG (100 mg/kg) in conjunction with plasma exchange is typically administered as a renal transplantation desensitization therapy. Herein, we monitored changes in T cell and B cell flow cytometry crossmatch (FCXM) to assess the effects of short-term super high-dose IVIG (4 g/kg) administration with plasmapheresis before living-donor renal transplantation.

Methods

Seventeen patients, each showing positive T cell FCXM (median ratio, ≥ 1.4) after 2 rounds of double-filtration plasmapheresis, received 4-day regimens of IVIG (1 g/kg per day) over 1-week periods. T cell and B cell FCXM determinations were obtained after every IVIG dose and again up to 4 weeks after initiating IVIG to ascertain negative conversion of T cell FCXM (median ratio < 1.4). The primary study endpoint was the percentage of patients achieving T cell FCXM-negative status after the 4-dose IVIG regimen.

Results

Upon completion (4 g/kg total) or discontinuation of IVIG administration, 8 (47.1%) of 17 patients displayed negative T cell FCXM. Based on Kaplan-Meier estimates, the cumulative T cell FCXM-negative conversion rate 4 weeks after IVIG administration initiation was 60.3%. The T cell FCXM-negative conversion rates after cumulative doses of 1, 2, 3, and 4 g/kg IVIG were 29.4%, 35.3%, 56.3%, and 46.7%, respectively.

Conclusions

Desensitization of donor-specific antibody-positive renal transplant recipients seems achievable in only a subset of recipients through IVIG dosing (1 g/kg × 4) within 1 week after double-filtration plasmapheresis. The T cell FCXM-negative conversion rate resulting from a cumulative IVIG dose of 3 g/kg or greater surpassed that attained via conventional single-dose IVIG (2 g/kg) protocol. This short-term high-dose IVIG desensitization protocol may be an alternative to conventional protocols for recipients with donor-specific antibody.

Interleukin-6, A Cytokine Critical to Mediation of Inflammation, Autoimmunity and Allograft Rejection: Therapeutic Implications of IL-6 Receptor Blockade

The success of kidney transplants is limited by the lack of robust improvements in long-term survival. It is now recognized that alloimmune responses are responsible for the majority of allograft failures. Development of novel therapies to decrease allosensitization is critical. The lack of new drug development in kidney transplantation necessitated repurposing drugs initially developed in oncology and autoimmunity. Among these is tocilizumab (anti-IL-6 receptor [IL-6R]) which holds promise for modulating multiple immune pathways responsible for allograft injury and loss. Interleukin-6 is a cytokine critical to proinflammatory and immune regulatory cascades. Emerging data have identified important roles for IL-6 in innate immune responses and adaptive immunity. Excessive IL-6 production is associated with activation of T-helper 17 cell and inhibition of regulatory T cell with attendant inflammation. Plasmablast production of IL-6 is critical for initiation of T follicular helper cells and production of high-affinity IgG. Tocilizumab is the first-in-class drug developed to treat diseases mediated by IL-6. Data are emerging from animal and human studies indicating a critical role for IL-6 in mediation of cell-mediated rejection, antibody-mediated rejection, and chronic allograft vasculopathy. This suggests that anti-IL-6/IL-6R blockade could be effective in modifying T- and B-cell responses to allografts. Initial data from our group suggest anti-IL-6R therapy is of value in desensitization and prevention and treatment of antibody-mediated rejection. In addition, human trials have shown benefits in treatment of graft versus host disease in matched or mismatched stem cell transplants. Here, we explore the biology of IL-6/IL-6R interactions and the evidence for an important role of IL-6 in mediating allograft rejection.

Implementation of a National Priority Allocation System for Hypersensitized Patients in Spain, Based on Virtual Crossmatch: Initial Results

Access to kidney transplantation for patients with high levels of antibodies against HLA is a major challenge. This issue makes it difficult to detect compatible donors for those patients in a certain geographical area. Consequently, hypersensitized patients remain on the waiting list for long periods and their quality of life deteriorates. Our purpose was to increase access to transplantation for highly sensitized patients by developing a national priority allocation system based on virtual crossmatch. Between June 15, 2015, and May 15, 2016, 675 patients on the kidney transplant waiting list with calculated panel-reactive antibodies ≥98% and undergoing dialysis for at least 12 months were included in the study; 86.1% of the patients had previously received at least one transplant. Solid-phase immunoassays were used to identify class I and II HLA antibodies in all patients. Participating hospitals assigned to the program one of the kidneys of every identified brain-dead real donor between 18 and 70 years old. Survival data were collected for the recipients transplanted between June 15, 2015, and December 31, 2015. In all, 475 (290 male and 185 female) brain-dead donors were assigned to the program. Virtual crossmatch was negative for 191 (41%) donors, 149 offers were accepted, and 102 (21.8%) kidneys were transplanted. At the end of the study, patient and graft survival were both 93.4%. The implementation of a national prioritization system based on virtual crossmatch increased access to transplantation for highly sensitized patients, with excellent results in terms of patient and graft survival.

Impact of Desensitization on Antiviral Immunity in HLA-Sensitized Kidney Transplant Recipients

Viral infections represent significant morbidity and mortality factors in kidney transplant recipients, with CMV, EBV, and BKV infections being most common. Desensitization (DES) with IVIg and rituximab with/without plasma exchange followed by kidney transplantation with alemtuzumab induction increased successful transplant rates in HLA-sensitized patients but may represent an increased risk for viral infections due to severe lymphocyte depletion. Here, we report on the posttransplant viral infection status in 372 DES versus 538 non-DES patients. CMV and EBV viremia were significantly lower in DES patients, while BKV viremia was similar. This trend was observed primarily in CMV sero(-), EBV sero(+), and sero(-) patients. No patient developed PTLD. The incidence of BKAN, allograft, and patient survival was similar in both groups. These viral infections were not associated with subsequent allograft rejection which occurred within 6 months after the infection. Conclusions. The IVIg + rituximab desensitization combined with alemtuzumab induction with triple immunosuppression maintenance does not increase the risk for CMV, EBV, and BKV infections. Possible factors include, in addition to posttransplant antiviral prophylaxis and PCR monitoring, presence of memory T cells and antibodies specific to CMV and likely EBV, NK cell-mediated ADCC despite lymphocyte depletion, elimination of EBV and CMV reservoirs by rituximab and alemtuzumab, and use of IVIg with antiviral properties.

Prolongation of Cardiac Allograft Survival by Endometrial Regenerative Cells: Focusing on B-Cell Responses

Endometrial regenerative cells (ERCs) have been recently evaluated as an attractive candidate source for emerging stem cell therapies in immunosuppression, but their role in immunoregulation is not fully understood. The present study was designed to investigate their effects, especially on B-cell responses in heart transplantation. In this study, ERCs were noninvasively obtained from menstrual blood. Heart transplantation was performed between C57BL/6 (H-2^b ) donor mice and BALB/c (H-2^d ) recipients. B-cell activation and antibody levels were determined using fluorescence-activated cell sorting, enzyme-linked immunosorbent assay and ELISpot. In this study, we demonstrated that ERCs negatively regulated B-cell maturation and activation in vitro without affecting their viability. ERC treatment prolonged cardiac allograft survival in mice, which was correlated with a decrease in IgM and IgG deposition and circulating antidonor antibodies, as well as with reduction in frequencies of antidonor antibody-secreting CD19⁺ B cells. In addition, upon ex vivo stimulation, B cells from ERC-treated heart transplant recipients had impaired proliferation capacity and produced less IgM and IgG antibody. Moreover, ERC treatment of mice receiving ovalbumin (OVA)-aluminum hydroxide vaccine resulted in significant lower numbers of anti-OVA IgG antibody-secreting splenic B cells and lower anti-OVA antibody titres. Our results indicate that therapeutic effects of ERCs may be attributed at least in part by their B-cell suppression and humoral response inhibition, suggesting the potential use of ERCs for attenuating antibody-mediated allograft rejection. Stem Cells Translational Medicine 2017;6:778-787.

Management of sensitized pediatric patients prior to renal transplantation

BACKGROUND

Data on renal allograft outcome in sensitized children are scarce. We report the clinical courses of four children who received desensitization therapy prior to renal transplantation in our institution.

METHODS

Between 2009 and 2011, four pediatric patients with stage 5 chronic kidney disease received desensitization therapy due to: (1) positive donor-specific antibodies (DSA) and/or crossmatches with potential living donors, (2) more than three positive crossmatches with deceased donors or (3) high calculated panel-reactive antibody of >80 %. Desensitization with rituximab, intravenous immunoglobulin and bortezomib was performed in all patients. Induction therapy included combinations of plasmapheresis and/or alemtuzumab or anti-thymocyte globulin. Standard post-transplant medications included tacrolimus, mycophenolate mofetil and prednisolone.

RESULTS

Post-transplant screening revealed DSA in three patients. Biopsy showed no evidence of rejection at 1 month in two patients, one of whom developed chronic active antibody-mediated rejection 4.5 years later. One patient developed borderline acute cellular rejection at 1 month, but the serum creatinine level was stable and DSA disappeared without treatment 1 month later, with stable long-term allograft function at 3 years. Estimated or measured glomerular filtration rate of the patients ranged between 30 and 75 ml/min/1.73 m(2) after 1 to 4.5 years.

CONCLUSIONS

The four sensitized patients reported here who received desensitization therapy had successful renal transplants with a low risk of immediate post-transplant rejection. Overall, long-term allograft functions and complications from immunosuppression were encouraging.

Factors Predicting Risk for Antibody-mediated Rejection and Graft Loss in Highly Human Leukocyte Antigen Sensitized Patients Transplanted After Desensitization

BACKGROUND

Desensitization with intravenous immunoglobulin and rituximab (I+R) significantly improves transplant rates in highly sensitized patients, but antibody-mediated rejection (ABMR) remains a concern.

PATIENTS AND METHODS

Between July 2006 and December 2012, 226 highly sensitized patients received transplants after desensitization. Most received alemtuzumab induction and standard immunosuppression. Two groups were examined: ABMR (n = 181) and ABMR (n = 45, 20%). Risk factors for ABMR, pathology, and outcomes were assessed.

RESULTS

Significant risks for ABMR included previous transplants and pregnancies as sensitizing events, donor-specific antibody (DSA) relative intensity scores greater than 17, presence of both class I and II DSAs at transplant and time on waitlist. The ABMR showed a significant benefit for graft survival and glomerular filtration rate at 5 years (P < 0.0001). Banff pathology characteristics for ABMR patients with or without graft loss did not differ. C4d versus C4d ABMR did not predict graft loss (P = 0.086). Thrombotic microangiopathy (TMA) significantly predicted graft failure (P = 0.045). The ABMR episodes were treated with I+R (n = 25), or, in more severe ABMR, plasma exchange (PLEX)+I+R (n = 20). Graft survival for patients treated with I+R was superior (P = 0.028). Increased mortality was seen in ABMR patients experiencing graft loss after ABMR treatment (P = 0.004). The PLEX + Eculizumab improved graft survival for TMA patients (P = 0.036).

CONCLUSION

Patients desensitized with I+R who remain ABMR have long-term graft and patient survival. The ABMR patients have significantly reduced graft survival and glomerular filtration rate at 5 years, especially TMA. Severe ABMR episodes benefit from treatment with PLEX + Eculizumab. The DSA-relative intensity scores at transplant was a strong predictor of ABMR. Donor-specific antibody avoidance and reduction strategies before transplantation are critical to avoiding ABMR and improving long-term outcomes.

Early and Sustained Reduction in Donor-Specific Antibodies in Desensitized Living Donor Kidney Transplant Recipients: A 3-Year Prospective Study

BACKGROUND

Desensitization with IVIG and rituximab allows acceptable graft survival in sensitized kidney transplant recipients with preexisting donor-specific antibodies (DSAs) and a positive crossmatch. There is little published data reporting the durability of DSA removal in kidney transplant recipients treated with IVIG and rituximab.

METHODS

We conducted a 3-year prospective DSA monitoring study in living donor kidney recipients with preexisting DSA to assess the durability of DSA removal after a perioperative protocol of IVIG and rituximab. All recipients had flow crossmatch titers less than 1:32. Data were analyzed using linear mixed effects models and Kaplan-Meier survival methods.

RESULTS

The longitudinal database comprised 210 mean fluorescence intensity (MFI) determinations. Forty-two DSAs were identified in 29 patients. Pretreatment MFI averaged 4715 ± 3962 (range, 947-20 129). At 1 month posttransplant, 18 patients (62%) had a complete response (MFI < 1000) and an additional 9 patients (31%) had a partial response (MFI reduced but >1000). There was a 46% reduction (P < 0.001) in DSA MFI at 1 month posttransplant that was sustained throughout the 3-year follow-up period and was observed for both class I and II DSAs regardless of pretreatment MFI levels. With a mean posttransplant follow-up of 1048 ± 574 days, 3-year patient and graft survivals were 95% and 90%. Four patients (14%) had acute rejection between days 125 and 560.

CONCLUSIONS

Desensitization with IVIG and rituximab results in early and sustained DSA removal over a 3-year posttransplant period in living donor kidney transplant recipients with pretransplant DSA and a positive crossmatch, excellent patient and graft survivals and a low incidence of acute rejection.

Kidney transplantation in highly sensitized patients

BACKGROUND

Desensitization, a term loosely referring to a collection of antibody reduction and B-cell depletional therapies aimed at improving rates of transplantation in highly HLA and ABO-incompatible transplant recipients, has seen significant growth in the last decade. Advancements relate to an increasing unmet medical need for FDA-approved therapies, advancements in antibody detection methodologies and improved renal pathological assessments of antibody-mediated rejection (ABMR).

SOURCES OF DATA, AREAS OF AGREEMENT AND CONTROVERSY

Data reviewed include collective summaries of experience with high-dose intravenous immunoglobulin (IVIG), B-cell depletion with rituximab and the use of plasma exchange with low-dose IVIG. Consensus suggests that these protocols are the most commonly used while experiences with other agents (i.e. bortezomib) are evolving. Controversy exists as to the extent of resources required, expense and outcomes of desensitization protocols.

GROWING POINTS OR AREAS TIMELY FOR DEVELOPING RESEARCH

Here we review and synthesize data from evolving protocols and summarize developments of novel biologics aimed at modification of B-cells, antibodies and complement activation which will likely improve desensitization and treatment of ABMR.

Equipoise: ethical, scientific, and clinical trial design considerations for compatible pair participation in kidney exchange programs

Compatible living donor/recipient pair participation (CPP) in kidney exchange (KE) transplantation may substantially increase transplant volumes and significantly mitigate the O blood group donor shortage in KE. Initial ethical analysis did not support CPP for two primary reasons: (1) KE would be "unbalanced," and (2) the possibility of undue influence experienced by the compatible pair living donor. Recent developments with CPP (modeling studies and small clinical experiences), have demonstrated substantial potential for increasing KE volumes. This encouraged us to reconsider initial ethical concerns, with a focus on the potential for a design of a prospective CPP clinical trial. This ethical reconsideration led us to conclude that the concept of unbalanced kidney exchanges (manifested primarily by differential benefit between compatible and incompatible pairs) is no longer as clear cut as originally conceived. In addition, application of two concepts substantially diminishes ethical concerns including: (1) "quasi-compatible" pairs, and (2) a priori definition of mitigating factors. We conclude that genuine uncertainty exists regarding whether kidney exchange is best performed with or without compatible pair participation and that a clinical trial is therefore warranted.

Interference of therapeutic antibodies used in desensitization protocols on lymphocytotoxicity crossmatch results

BACKGROUND

Therapeutic antibodies used to desensitize patients awaiting a human leukocyte antigen (HLA) or ABO-mismatched graft are suspected to interfere with the lymphocytotoxicity crossmatch (LCT-XM) test when they are present in the tested sera because of their potential ability to activate or inhibit the complement.

METHODS

The most frequent therapeutic antibodies (Abs) used in desensitization protocols (intravenous immunoglobulins, rituximab, basiliximab, eculizumab, antithymocyte globulin) were added to a negative- or a positive-control serum at various concentrations, and tested in vitro in a LCT-XM test.

RESULTS

Rituximab turned the LCT-XM positive on B cells at 0.2 μg/mL and antithymocyte globulin turned the LCT-XM positive with T and B cells at 20 μg/mL and 200 μg/mL, respectively. Treatment with dithiothreitol sera, supplemented with rituximab (0.2 and 2 μg/mL) and antithymocyte globulins (20 and 200 μg/mL), partially or totally reduced this positive interference. Intravenous immunoglobulin, eculizumab, and basiliximab did not trigger any interference with the negative control serum. In a positive LCT-XM, eculizumab did not annihilate activation of the rabbit complement. Intravenous immunoglobulins (25 g/L) could partially or totally reduced lysis score of positive crossmatch with weak lysis scores.

CONCLUSION

If eculizumab within the serum did not annihilate rabbit complement activation and basiliximab did not interfere with the crossmatch reaction, treatments based on rituximab, antithymocyte globulin and intravenous immunoglobulins need to be taken into account when interpreting a positive or negative crossmatch test.

An update on ABO-incompatible kidney transplantation

ABO-incompatible kidney transplantation is nowadays a well-established procedure to expand living donor transplantation to blood group incompatible donor/recipient constellations. In the last two decades, transplantation protocols evolved to more specific isohaemagglutinin elimination techniques and established competent antirejection protection protocols without the need of splenectomy. ABOi kidney transplantation associated accommodation despite isohaemagglutinin reappearance, C4d positivity of peritubular capillaries as well as the increased incidence of bleeding complications is currently under intense investigation. However, most recent data show excellent graft survival rates equivalent to ABO-compatible kidney transplantation outcome.

Suppression of allo-human leucocyte antigen (HLA) antibodies secreted by B memory cells in vitro: intravenous immunoglobulin (IVIg) versus a monoclonal anti-HLA-E IgG that mimics HLA-I reactivities of IVIg

B memory cells remain in circulation and secrete alloantibodies without antigen exposure > 20 years after alloimmunization postpartum or by transplantation. These long-lived B cells are resistant to cytostatic drugs. Therapeutically, intravenous immunoglobulin (IVIg) is administered to reduce allo-human leucocyte antigen (HLA) antibodies pre- and post-transplantation, but the mechanism of reduction remains unclear. Recently, we reported that IVIg reacts with several HLA-I alleles and the HLA reactivity of IVIg is lost after its HLA-E reactivity is adsorbed out. Therefore, we have generated an anti-HLA-E monoclonal antibody that mimics the HLA-reactivity of IVIg to investigate whether this antibody suppresses IgG secretion, as does IVIg. B cells were purified from the blood of a woman in whose blood the B memory cells remained without antigen exposure > 20 years after postpartum alloimmunization. The B cells were stimulated with cytokines using a well-defined culture system. The anti-HLA-E monoclonal antibody (mAb) significantly suppressed the allo-HLA class-II IgG produced by the B cells, and that this suppression was far superior to that by IVIg. These findings were confirmed with HLA-I antibody secreted by the immortalized B cell line, developed from the blood of another alloimmunized woman. The binding affinity of the anti-HLA-E mAb for peptide sequences shared (i.e. shared epitopes) between HLA-E and other β2-microglobulin-free HLA heavy chains (open conformers) on the cell surface of B cells may act as a ligand and signal suppression of IgG production of activated B memory cells. We propose that anti-HLA-E monoclonal antibody may also be useful to suppress allo-HLA IgG production in vivo.

Desensitization for solid organ and hematopoietic stem cell transplantation

Desensitization protocols are being used worldwide to enable kidney transplantation across immunologic barriers, i.e. antibody to donor HLA or ABO antigens, which were once thought to be absolute contraindications to transplantation. Desensitization protocols are also being applied to permit transplantation of HLA mismatched hematopoietic stem cells to patients with antibody to donor HLA, to enhance the opportunity for transplantation of non-renal organs, and to treat antibody-mediated rejection. Although desensitization for organ transplantation carries an increased risk of antibody-mediated rejection, ultimately these transplants extend and enhance the quality of life for solid organ recipients, and desensitization that permits transplantation of hematopoietic stem cells is life saving for patients with limited donor options. Complex patient factors and variability in treatment protocols have made it difficult to identify, precisely, the mechanisms underlying the downregulation of donor-specific antibodies. The mechanisms underlying desensitization may differ among the various protocols in use, although there are likely to be some common features. However, it is likely that desensitization achieves a sort of immune detente by first reducing the immunologic barrier and then by creating an environment in which an autoregulatory process restricts the immune response to the allograft.

Intravenous human immunoglobulin treatment of serum from HLA-sensitized patients in kidney transplantation

OBJECTIVE

Intravenous immunoglobulin (IVIG) products are known to have beneficial immunomodulatory effects on several inflammatory and autoimmune disorders. These effects could be attributed to a different inhibitory action on complement factors, but other mechanisms could be implicated, e.g., immunocomplexes development and/or anti-idiotypic antibodies. Positive results on the reduction of anti-Human Leukocyte Antigens (HLA) antibodies in highly sensitized patients have also been found. The present study focuses on the effect of IVIG on the reduction of Panel Reactive Antibody level and crossmatch positivity in sensitized patients awaiting kidney transplantation.

METHODS

The study was performed adapting an in vitro assay on sensitized patients' sera in waiting list for kidney transplantation. Sera of twelve highly sensitized patients were evaluated for the cytotoxicity inhibition after 10% IVIG treatment.

RESULTS

A reduction of anti- HLA antibody levels was observed in 75% (9/12) of treated patients in vitro, while 25% (3/12) resulted unresponsiveness. Particularly, our data showed a significantly higher Panel Reactive Antibody reduction for T lymphocytes (p<0.010) than B lymphocytes (p<0.032).

CONCLUSIONS

In this study, we have used an in vitro assay to investigate susceptibility to desensitization with IVIG treatment of sensitized patient sera. These findings reveal that the variable effect of IVIG on reducing Panel Reactive Antibody in our immunized patients could be attributed to a different inhibitory action on complement, likely due to the type and the titre of anti-HLA antibodies.

The concept of a composite perioperative quality index in kidney transplantation

BACKGROUND

Public reporting of patient and graft outcomes in a national registry and close Centers for Medicare and Medicaid Services oversight has resulted in transplantation being a highly regulated surgical discipline. Despite this, transplantation surgery lacks comprehensive tracking and reporting of perioperative quality measures. Therefore, the aim of this study was to determine the association between a kidney transplantation centers' perioperative quality benchmarking and graft and patient outcomes.

STUDY DESIGN

This was an analysis of 2011 aggregate data compiled from 2 national datasets that track outcomes from member hospitals and transplantation centers. The transplantation centers included in this study were composed of accredited US kidney transplantation centers that report data through the national registry and are associate members of the University HealthSystem Consortium.

RESULTS

A total of 16,811 kidney transplantations were performed at 236 centers in the United States in 2011, of which 10,241 (61%) from 93 centers were included in the analysis. Of the 6 perioperative quality indicators, 3 benchmarked metrics were significantly associated with a kidney transplantation center's underperformance: mean ICU length of stay (C-statistic 0.731; p = 0.002), 30-day readmissions (C-statistic 0.697; p = 0.012) and in-hospital complications (C-statistic 0.785; p = 0.001). The composite quality index strongly correlated with inadequate center performance (C-statistic 0.854; p < 0.001, R(2) = 0.349). The centers in the lowest quartile of the quality index performed 2,400 kidney transplantations in 2011, which led to 2,640 more hospital days, 4,560 more ICU days, 120 more postoperative complications, and 144 more patients with 30-day readmissions, when compared with centers in the 3 higher-quality quartiles.

CONCLUSIONS

An objective index of a transplantation center's quality of perioperative care is significantly associated with patient and graft survival.

Combined use of rituximab and plasmapheresis pre-transplant increases post-transplant infections in renal transplant recipients with basiliximab induction therapy

INTRODUCTION

We investigated the effect of combined use of rituximab (RTX) and plasmapheresis (PP) pre-transplant on post-transplant infection.

METHODS

A total of 196 patients undergoing living-donor kidney transplantation at Seoul St. Mary's Hospital, all of whom underwent basiliximab induction therapy, were included in the study. They were divided into 3 groups: RTX/PP/intravenous immune globulin (IVIG) (the RPI group; n = 53), RTX monotherapy (the RTX group; n = 14), and control (the CONT group; n = 129). We compared the post-transplant infections in the 3 groups.

RESULTS

The overall prevalence of infection was significantly higher, and the infection-free survival rate was lower, in the RPI group compared with the RTX or CONT groups (P < 0.05). A trend toward more severe bacterial infections was seen in the RPI group compared with the other groups, and fungal infections developed only in the RPI group. After anti-rejection therapy, a significantly higher rate of infection developed in the RPI group than in the other groups (P < 0.05). In addition, the RPI group was an independent risk factor for the development of infection.

CONCLUSION

Our results show that in the setting of basiliximab induction, the use of combined RTX and PP therapy pre-transplant significantly increases the risk for post-transplant infection.

Improving outcomes in patients with lupus and end-stage renal disease

The development of lupus-related end-stage renal disease (ESRD) confers the highest mortality rates among individuals with lupus. Lupus-related ESRD is also associated with higher morbidity and mortality rates compared with non-lupus ESRD. We review the evidence that persistent lupus activity, hypercoagulability, and continuing immunosuppression may contribute to unfavorable outcomes in dialysis and renal transplantation among lupus patients. Robust epidemiologic studies are needed to develop individualized evidence-based approaches to treating lupus-related ESRD. In the meantime, managing lupus-related ESRD presents a significant challenge for clinicians and requires a team approach involving nephrologists and rheumatologists. Goals of therapy after developing ESRD should include continuing monitoring of lupus activity, minimizing corticosteroid exposure, and choosing the most appropriate renal replacement therapy based on patient's risk profile and quality-of-life considerations.

Treatment update of sensitized pediatric kidney transplant recipients: a review

Sensitization of recipients is an increasing problem in children. Some case series in children exist comparing the diverse desensitizing protocols. These protocols include intravenous immunoglobulin, cytomegalovirus immune globulin, plasmapheresis, and some adjunctive therapies such as rituximab. Desensitizing protocols have advantages and disadvantages. Clinical trials are required to determine suitable protocols for sensitized pediatric recipients. We performed a systematic review of these protocols in children. A massive search was done in PubMed, Embase, and the Cochrane library system. The results of these studies are compared.

Five-year outcomes in living donor kidney transplants with a positive crossmatch

Renal transplant candidates with high levels of donor-specific anti-HLA antibodies have low transplantation rates and high mortality rates on dialysis. Using desensitization protocols, good short-term outcomes are possible in "positive crossmatch kidney transplants (+XMKTx)", but long-term outcome data are lacking. The aim of the current study was to determine actual 5-year graft outcomes of +XMKTx. We compared graft survival and the functional and histologic status of 102 +XMKTx to 204 -XMKTx matched for age and sex. Actual 5-year death-censored graft survival was lower in the +XMKTx group (70.7% vs. 88.0%, p < 0.01) and chronic injury (glomerulopathy) was present in 54.5% of surviving grafts. Graft survival was higher in recipients with antibody against donor class I only compared with antibody against class II (either alone or in combination with class I) (85.3% vs. 62.6%, p = 0.05) and was similar to -XMKTx (85.3 vs. 88.0%, p = 0.64). Renal function and proteinuria ranged across a wide spectrum in all groups reflecting the different histological findings at 5 years. We conclude that when compared to -XMKTx, +XMKTx have inferior outcomes at 5 years, however, almost half of the surviving grafts do not have glomerulopathy and avoiding antibodies against donor class II may improve outcomes.

Successful isolated intestinal transplantation in sensitized recipients with the use of virtual crossmatching

We evaluated virtual crossmatching (VXM) for organ allocation and immunologic risk reduction in sensitized isolated intestinal transplantation recipients. All isolated intestine transplants performed at our institution from 2008 to 2011 were included in this study. Allograft allocation in sensitized recipients was based on the results of a VXM, in which the donor-specific antibody (DSA) was prospectively evaluated with the use of single-antigen assays. A total of 42 isolated intestine transplants (13 pediatric and 29 adult) were performed during this time period, with a median follow-up of 20 months (6-40 months). A sensitized (PRA ≥ 20%) group (n = 15) was compared to a control (PRA < 20%) group (n = 27) to evaluate the efficacy of VXM. With the use of VXM, 80% (12/15) of the sensitized patients were transplanted with a negative or weakly positive flow-cytometry crossmatch and 86.7% (13/15) with zero or only low-titer (≤ 1:16) DSA. Outcomes were comparable between sensitized and control recipients, including 1-year freedom from rejection (53.3% and 66.7% respectively, p = 0.367), 1-year patient survival (73.3% and 88.9% respectively, p = 0.197) and 1-year graft survival (66.7% and 85.2% respectively, p = 0.167). In conclusion, a VXM strategy to optimize organ allocation enables sensitized patients to successfully undergo isolated intestinal transplantation with acceptable short-term outcomes.

Clinical applications of immunoglobulin: update

Human immunoglobulin is the most used blood product in the clinical practice. Immunoglobulin applications have increased quickly since the elucidation of its immunomodulatory and antiinflammatory properties which turned this blood product into a precious tool in the treatment of numerous diseases that present with humoral immune deficiency or that cause immune system dysfunction. Currently, the approved indications for Ig are: primary immunodeficiencies, secondary immunodeficiencies (multiple myeloma or chronic lymphoid leukemia), Kawasaki syndrome, immune thrombocytopenic purpura, Guillain Barré syndrome, graft-versus-host disease following bone marrow transplantation and repeat infections in HIV children. On the other hand, there are numerous "off-label" indications of immunoglobulin, which represent 20-60% of all clinical applications of this drug. It is important to study all these indications and, above all, the scientific evidence for its use, in order to provide patients with a new therapeutic option without burdening the health system. This review results from a wide selection of papers identified in the Pubmed and Lilacs scientific electronic databases. A group of descriptors were used from human immunoglobulin to the names of each disease that immunoglobulin is clinically applied. Our main objective is to list the numerous indications of immunoglobulin, both authorized and "off-label" and to analyze these indications in the light of the most recent scientific evidence.

Prevention of antibody-mediated kidney transplant rejection

There is increasing evidence that antibody-mediated rejection is the major cause of late kidney graft failure. Prevention of antibody-mediated allograft damage has therefore become an important issue in kidney transplantation. Such prevention starts already before transplantation with the avoidance of sensitizing events. When a patient is already sensitized, precise characterization of alloantibodies and exact HLA typing of the donor at the time of transplantation are mandatory. To ensure timely and successful transplantation of highly sensitized patients, desensitization, and inclusion in special programs such as the Eurotransplant Acceptable Mismatch Program should be considered. After transplantation, close monitoring of kidney function, testing for the de novo development or changing characteristics of alloantibodies, and attention to non-adherence to immunosuppression is obligatory. In the current overview, we discuss the currently available measures for the prevention of antibody-mediated kidney graft rejection.

Cardiac antibody-mediated rejection

Many factors limit short- and long-term survival after pediatric heart transplantation. Historically, attention had been directed toward T-cell responses and acute cellular rejection. Presence of pretransplant antibodies against HLA is associated with increased donor wait times and poor post-transplant outcomes. Therapies aimed to mitigate circulating antibodies include plasmapheresis, protein A immunoadsorption columns, intravenous immune globulin, rituximab, and bortezomib. The negative effects of B cells, HLA antibodies, and AMR and potential interventions are the focus of this review article.

The immune-modulator AS101 reduces anti-HLA antibodies in sera of sensitized patients: a structural approach

BACKGROUND

Significant efforts are dedicated to identification of agents that eliminate anti-HLA antibodies (Ab) from sera of transplant candidates. Antibody titer following in vitro incubation of sera with desensitizing agents has shown to reflect the probability that a patient would benefit from clinical de-sensitization protocols. AS101 is a non-toxic, synthetic, organic tellurium compound. The aim of this research was to assess the ability of AS101 to reduce anti-HLA Abs and to identify patients likely to benefit from this effect.

METHODS

Sera of sensitized patients awaiting transplant were incubated in the presence of AS101. Measured mean fluorescence intensity (MFI) represents reactivity of anti HLA Abs in the serum, as detected by the Luminex platform. The repertoire of HLA antigen epitopes was recognized using HLA Matchmaker software.

RESULTS

AS101 Incubation caused a significant Ab titer decrease in approximately two thirds of the samples. The median Class I and II MFI decrease among the responding samples was 16.7% and 14%, respectively (p<0.05). HLA Matchmaker analysis of the patients' class I epitope sequences revealed apparent amino-acid differences between the patterns of the responding and non-responding patients.

CONCLUSION

In vitro incubation of sera in the presence of AS101 causes a decrease in the anti-HLA Ab's reactivity in several patient samples. Sera most likely to demonstrate this effect are characterized by a moderate MFI level and a distinct antibody reactivity pattern specific for defined HLA antigen epitopes. These results support further investigation of AS101 as a potential agent for desensitization of humoral reactivity prior to transplantation.

Intragraft gene expression in positive crossmatch kidney allografts: ongoing inflammation mediates chronic antibody-mediated injury

We studied intragraft gene expression profiles of positive crossmatch (+XM) kidney transplant recipients who develop transplant glomerulopathy (TG) and those who do not. Whole genome microarray analysis and quantitative rt-PCR were performed on RNA from protocol renal allograft biopsies in three groups: (1) +XM/TG+ biopsies before and after TG; (2) +XM/NoTG; and (3) negative crossmatch kidney transplants (control). Microarray comparisons showed few differentially expressed genes between paired biopsies from +XM/TG+ recipients before and after the diagnosis of TG. Comparing +XM/TG+ and control groups, significantly altered expression was seen for 2447 genes (18%) and 3200 genes (24%) at early and late time points, respectively. Canonical pathway analyses of differentially expressed genes showed inflammatory genes associated with innate and adaptive immune responses. Comparing +XM/TG+ and +XM/NoTG groups, 3718 probe sets were differentially expressed but these were over-represented in only four pathways. A classic accommodation phenotype was not identified. Using rt-PCR, the expression of inflammatory genes was significantly increased in +XM/TG+ recipients compared to the +XM/NoTG and control groups. In conclusion, pretransplant donor-specific anti-HLA antibodies results in a gene expression profile characterized by inflammation and cellular infiltration and the majority of +XM grafts are exposed to chronic injury.