Matthew J. Everly

Bortezomib provides effective therapy for antibody- and cell-mediated acute rejection.

Background. Current antihumoral therapies in transplantation and autoimmune disease do not target the mature antibody-producing plasma cell. Bortezomib is a first in class proteosomal inhibitor, that is Food and Drug Administration approved, for the treatment of plasma cell-derived tumors that is multiple myeloma. We report the first clinical experience with plasma cell-targeted therapy (bortezomib) as an antirejection strategy. Methods. Eight episodes of mixed antibody-mediated rejection (AMR) and acute cellular rejection (ACR) in six transplant recipients were treated with bortezomib at labeled dosing. Monitoring included serial donor-specific antihuman leukocyte antigen antibody (DSA) levels and repeated allograft biopsies. Results. Six kidney transplant patients received bortezomib for AMR and concomitant ACR. In each case, bortezomib therapy provided (1) prompt rejection reversal, (2) marked and prolonged reductions in DSA levels, (3) improved renal allograft function, and (4) suppression of recurrent rejection for at least 5 months. Moreover, immunodominant DSA (iDSA) (i.e., the antidonor human leukocyte antigen antibody with the highest levels) levels were decreased by more than 50% within 14 days and remained substantially suppressed for up to 5 months. One or more additional DSA were present at lower concentrations (non-iDSA) in each patient and were also reduced to nondetectable levels. Bortezomib-related toxicities (gastrointestinal toxicity, thrombocytopenia, and paresthesias) were all transient. Conclusions. Bortezomib therapy: (1) provides effective treatment of AMR and ACR with minimal toxicity and (2) provides sustained reduction in iDSA and non-iDSA levels. Bortezomib represents the first effective antihumoral therapy with activity in humans that targets plasma cells.

Incidence and impact of de novo donor-specific alloantibody in primary renal allografts.

Background To date, limited information is available describing the incidence and impact of de novo donor-specific anti–human leukocyte antigen (HLA) antibodies (dnDSA) in the primary renal transplant patient. This report details the dnDSA incidence and actual 3-year post-dnDSA graft outcomes. Methods The study includes 189 consecutive nonsensitized, non-HLA-identical patients who received a primary kidney transplant between March 1999 and March 2006. Protocol testing for DSA via LABScreen single antigen beads (One Lambda) was done before transplantation and at 1, 3, 6, 9, and 12 months after transplantation then annually and when clinically indicated. Results Of 189 patients, 47 (25%) developed dnDSA within 10 years. The 5-year posttransplantation cumulative incidence was 20%, with the largest proportion of patients developing dnDSA in the first posttransplantation year (11%). Young patients (18–35 years old at transplantation), deceased-donor transplant recipients, pretransplantation HLA (non-DSA)–positive patients, and patients with a DQ mismatch were the most likely to develop dnDSA. From DSA appearance, 9% of patients lost their graft at 1 year. Actual 3-year death-censored post-dnDSA graft loss was 24%. Conclusion We conclude that 11% of the patients without detectable DSA at transplantation will have detectable DSA at 1 year, and over the next 4 years, the incidence of dnDSA will increase to 20%. After dnDSA development, 24% of the patients will fail within 3 years. Given these findings, future trials are warranted to determine if treatment of dnDSA-positive patients can prevent allograft failure.

Abrogation of anti-HLA antibodies via proteasome inhibition.

Background. Current treatments for autoantibody-mediated diseases (i.e., systemic lupus erythematosus) and alloantibodies (in transplant) are minimally effective. Although they deplete naïve B cells, plasmablasts, and transiently reduce antibody concentrations, they are minimally effective against long-lived, antibody-producing plasma cells. In transplantation, plasma cells produce antibodies directed against human leukocyte antigen (HLA) antigens causing poor allograft survival. We report the first clinical experience with a plasma cell depleting therapy, bortezomib, to abrogate anti-HLA antibodies in transplantation (outside of rejection) in an attempt to improve long-term allograft survival. Methods. Eleven patients with anti-HLA alloantibodies were treated with bortezomib. All patients underwent plasmapheresis to aid in removal of antibodies and to determine the effect of bortezomib. Serial measurements of anti-HLA antibody levels were conducted weekly by single antigen bead on Luminex platform. Results. Bortezomib treatment elicited substantial reduction in both donor-specific antibody (DSA) and non-DSA levels. Antibodies were directed against DSA in 8 of 11 cases. Mean time to antibody appearance was 2 months posttransplant. Within 22 days (median) from treatment initiation, 9 of 11 patients’ antibody levels dropped to less than 1000 mean fluorescence intensity. Of two patients without successful depletion, all had peak mean fluorescence intensity more than 10,000. At a mean follow-up of approximately 4 months posttreatment, all patients have stable graft function. Minimal transient side effects were noticed with bortezomib in the form of gastrointestinal toxicity, thrombocytopenia, and paresthesias. Conclusions. Bortezomib therapy effectively abrogates anti-HLA antibodies. Hence, removal of antibodies, by proteasome inhibition, represents a new treatment strategy for transplantation and may have benefit in autoimmune-related disease.

HLA-specific antibodies developed in the first year posttransplant are predictive of chronic rejection and renal graft loss.

Background. Evidence shows posttransplant antibodies lead to renal allograft failure, but does the time elapsed between transplantation and antibody development impact allograft survival? This is the first study showing importance of when antibodies appear. Methods. Serial sera were collected during 17 years (1991–2008) from two groups of patients, one whose allograft failed due to chronic rejection containing 25 patients (230 sera) and a control group consisting of 25 graft functioning patients (305 sera) who were matched by transplant date to a patient whose graft failed. Results. The median follow-up for failure patients was 7.1±4.8 years and 11.8±4.4 years for controls. Human leukocyte antigens alloantibodies appeared in 24 of 25 (96%) of the failed patients and 48% of the controls (P<0.0001). Time to antibodies also differed between groups. Fifteen (60%) patients from the failure group developed antibodies by 1 year compared with none in the control group. Hazard ratio of antibodies present in 1-year posttransplant from multivariate analysis for allograft loss was 7.77 (P<0.001).Ten-year renal allograft survival in early antibody developers (<1 year) was 27% vs. 80% in the late antibody developers. Conclusions. Overall, human leukocyte antigens antibody development within 1-year posttransplantation markedly lowers allograft survival compared with later antibody development. Therefore, monitoring early antibodies is useful.

The role of immunoglobulin-G subclasses and C1q in de novo HLA-DQ donor-specific antibody kidney transplantation outcomes.

Background Anti–HLA-DQ antibodies are the predominant HLA class II donor-specific antibodies (DSAs) after transplantation. Recently, de novo DQ DSA has been associated with worse allograft outcomes. The aim of this study was to determine the further complement-binding characteristics of the most harmful DQ DSA. Methods Single-antigen bead technology was used to screen 284 primary kidney transplant recipients for the presence of posttransplantation DQ DSA. Peak DSA sera of 34 recipients with only de novo DQ DSA and of 20 recipients with de novo DQ plus other DSAs were further analyzed by a modified single-antigen bead assay using immunoglobulin (Ig)-G subclass-specific reporter antibodies and a C1q-binding assay. Results Compared with recipients who did not have DSA, those with de novo persistent DQ-only DSA and with de novo DQ plus other DSAs had more acute rejection (AR) episodes (22%, P=0.005; and 36%, P=0.0009), increased risk of allograft loss (hazards ratio, 3.7, P=0.03; and hazards ratio, 11.4, P=0.001), and a lower 5-year allograft survival. De novo DQ-only recipients with AR had more IgG1/IgG3 combination and C1q-binding antibodies (51%, P=0.01; and 63%, P=0.001) than patients with no AR. Furthermore, the presence of C1q-binding de novo DQ DSA was associated with a 30% lower 5-year allograft survival (P=0.003). Conclusions The presence of de novo persistent, complement-binding DQ DSA negatively impacts kidney allograft outcomes. Therefore, early posttransplantation detection, monitoring, and removal of complement-binding DQ might be crucial for improving long-term kidney transplantation outcomes.

Posttransplant Lymphoproliferative Disorder

Objective: To define and discuss the pathogenesis, clinical presentation, diagnosis, risk factors, and current preventive and treatment strategies of post-transplant lymphoproliferative disorder (PTLD). Data Sources: MEDLINE was searched for articles published from January 1966 to July 2007. Search terms used include posttransplant lymphoproliferative disease, posttransplant malignancy, antiviral agents, interferon-alfa, rituximab, immunosuppression, chemotherapy, radiation, and surgery. Additional articles were identified by a hand search of references. Study Selection and Data Extraction: Studies in English of pediatric and adult solid organ transplantation populations published were selected and analyzed. Data from these studies and information from review articles were included in this review. Data Synthesis: PTLD occurs in 1–20% of organ recipients following solid organ transplantation. PTLD risk factors include recipient pretransplant Epstein–Barr virus (EBV) negative serostatus, type of transplant, intensity of immunosuppression, and age. The PTLD presentation is variable. Some patients present asymptomatically; in others, early symptoms can be nonspecific. To prevent PTLD, minimizing immunosuppression burden and using antiviral agents active against EBV are useful strategies. PTLD treatment may require reduction of immunosuppression, radiation, surgical excision, monoclonal antibodies, interferon-alfa, and chemotherapy. Conclusions: Screening for patients at risk and balancing the intensity of immunosuppressive regimens against the risk of rejection can substantially reduce the risk of developing PTLD. If PTLD occurs, an individualized treatment plan including decreased immunosuppression and other agents should be chosen based on the severity and extent of disease

Alloantibody and Autoantibody Monitoring Predicts Islet Transplantation Outcome in Human Type 1 Diabetes

Long-term clinical outcome of islet transplantation is hampered by the rejection and recurrence of autoimmunity. Accurate monitoring may allow for early detection and treatment of these potentially compromising immune events. Islet transplant outcome was analyzed in 59 consecutive pancreatic islet recipients in whom baseline and de novo posttransplant autoantibodies (GAD antibody, insulinoma-associated protein 2 antigen, zinc transporter type 8 antigen) and donor-specific alloantibodies (DSA) were quantified. Thirty-nine recipients (66%) showed DSA or autoantibody increases (de novo expression or titer increase) after islet transplantation. Recipients who had a posttransplant antibody increase showed similar initial performance but significantly lower graft survival than patients without an increase (islet autoantibodies P < 0.001, DSA P < 0.001). Posttransplant DSA or autoantibody increases were associated with HLA-DR mismatches (P = 0.008), induction with antithymocyte globulin (P = 0.0001), and pretransplant panel reactive alloantibody >15% in either class I or class II (P = 0.024) as independent risk factors and with rapamycin as protective (P = 0.006) against antibody increases. DSA or autoantibody increases after islet transplantation are important prognostic markers, and their identification could potentially lead to improved islet cell transplant outcomes.

Beyond histology: lowering human leukocyte antigen antibody to improve renal allograft survival in acute rejection.

Background. The common endpoint in the treatment of antibody-mediated rejection (AMR) is functional reversal (creatinine levels). Reduction of human leukocyte antigen (HLA) antibody strength is not commonly considered as an essential endpoint for AMR resolution. The purpose of this study was to determine whether reduction in HLA antibody intensity in patients with histologic AMR reversal influences long-term renal allograft survival. Methods. Renal allograft recipients were included if he or she had a biopsy diagnosis of AMR (between August 2000 and October 2008) and serial evaluation for HLA antibodies prebiopsy and postbiopsy. Antibody reduction was defined as mean fluorescence intensity decrease more than 50% in highest intensity antibody after AMR therapy and the absence of new antibody formation. Patients were treated with plasmapheresis, thymoglobulin/OKT3, and corticosteroids. Survival analysis was performed using STATA/MP v10 (College Station, TX). Results. Twenty-eight patients were analyzed. Antibody reduction failed to occur in 22 of 28 cases. Baseline characteristics were similar between groups. Antibody nonresponders had significantly shorter allograft survival time (61.4 months) compared with antibody responders (no failures) (P=0.04, log-rank test). Conclusions. In conclusion, failure to significantly reduce antibody levels and prevent new formation was strongly predictive of allograft loss. This observation suggests that the therapeutic intervention that reduces antibody production may prolong graft survival in transplantation.

β-Blocker Underuse in Secondary Prevention of Myocardial Infarction

OBJECTIVE To review the clinical benefits of β-blockers as secondary prevention following a myocardial infarction (MI) and to address the reasons that clinicians are reluctant to use β-blockers in specific patient populations. DATA SOURCES MEDLINE was searched for articles published from January 1966 to October 2002. Relevant studies were identified by systematic searches of the literature for all reported studies of associations between β-blocker underuse and secondary prevention of MI. Additional studies were identified by a hand search of references of original or review articles. STUDY SELECTION AND DATA EXTRACTION English-language human studies were selected and analyzed. DATA SYNTHESIS Associations were observed in studies of β-blocker use as secondary prevention of MI. A lower rate of β-blocker treatment occurred in older patients and in patients with comorbid conditions such as diabetes, heart failure, chronic obstructive pulmonary disease, asthma, and peripheral arterial disease. In addition, underuse was attributed to the perception of high rates of adverse events associated with β-blockers. β-Blocker use as secondary prevention of an MI can lead to a 19–48% decrease in mortality and up to a 28% decrease in reinfarction rates. Nonetheless, β-blockers are significantly underused in many patient populations due to concomitant disease states. Due to their normal physiologic deterioration, the elderly are at an increased risk of low cardiac output and bradycardia when given a β-blocker; therefore, they should be started on a low dose that is then slowly titrated. In diabetic patients, β-blockers can impair glucose control leading to hypoglycemia; therefore, post-MI diabetic patients must routinely monitor their blood glucose levels. In patients with decompensated heart failure, β-blocker use can lead to further cardiac depression, but lower oral starting doses with slow titration can reduce this risk. β-Blockers can induce bronchospasm in patients with chronic obstructive pulmonary disease or asthma, but cardioselective β-blockers and appropriate use of medications such as albuterol can minimize these effects. Finally, in patients with peripheral arterial disease, with the exception of hypertensive patients with Reynauds phenomenon, β-blockers can be used safely. The only absolute contraindications to β-blockers are severe bradycardia, preexisting sick sinus syndrome, second- and third-degree atrioventricular block, severe left ventricular dysfunction, active peripheral vascular disease with rest ischemia, or reactive airway disease so severe that airway support is required. CONCLUSIONS Overall, the cardiovascular benefits of β-blockers as secondary prevention of MI significantly outweigh the risks associated with their use.

Impact of IgM and IgG3 anti-HLA alloantibodies in primary renal allograft recipients.

Background With standard IgG donor-specific anti-HLA antibody (DSA) testing, it is unclear which immunoglobulin-G (IgG) DSA positive patients will fail. We looked further into the immune response by studying immunoglobulin-M (IgM) and IgG subclass 3 (IgG3) DSA to determine if these identify the IgG DSA patients at highest risk for allograft loss. Methods In 189 consecutively transplanted primary renal allograft recipients, sera were collected sequentially pre- and posttransplant. Of the 189, 179 patients had sera available to retrospectively test for anti-HLA IgG, IgM, and IgG3 antibodies via LABScreen single-antigen bead assay and were included in the study. All patients had a negative crossmatch. Per patient, all DSA (IgM, IgG3, and IgG) refers to the same serologic specificity. Results Overall, 100 (56%) patients developed an alloimmune response (IgM or IgG DSA positive, or both). Ninety-five patients developed IgM DSA and 47 patients developed IgG DSA. IgM DSA was detected in 42 of 47 patients with IgG DSA. IgM DSA alone did not increase the allograft loss risk, whereas IgG DSA did (P=0.002). Once IgG DSA appeared, IgM DSA persisted in 33 patients and an isotype switch to IgG3 positive DSA occurred in 25 patients. Patients with IgM persistent IgG3 positive DSA (n=19) were more likely to have allograft failure than those without (P=0.02). Conclusion This study shows the evolution of the humoral immune response from IgM to IgG DSA posttransplant. We found that development of IgM persistent IgG3 positive DSA identifies the most dangerous IgG DSA subpopulation.