Clinical aspects of intravenous immunoglobulin use in solid organ transplant recipients

Pre-Existing Intrarenal Parvovirus B19 Infection May Relate to Antibody-Mediated Rejection in Pediatric Kidney Transplant Patients

Viral infections can lead to transplant dysfunction, and their possible role in rejection is described. In total, 218 protocol biopsies performed in 106 children at 6, 12 and 24 months after transplantation were analyzed according to Banff '15. RT-PCR for cytomegalovirus, Epstein-Barr virus, BK virus and Parvovirus B19 was performed on blood and bioptic samples at the time of transplant and each protocol biopsy. The prevalence of intrarenal viral infection increases between 6 and 12 months after transplantation (24% vs. 44%, p = 0.007). Intrarenal Parvovirus B19 infection is also associated with antibody-mediated rejection (ABMR) (50% ABMR vs. 19% T-cell-mediated rejection, p = 0.04). Moreover, Parvovirus infection is higher at 12 months of follow-up and it decreases at 48 months (40.4% vs. 14%, p = 0.02), while in 24% of grafts, Parvovirus is already detectable at the moment of transplantation. Intrarenal Parvovirus B19 infection seems to be related to ABMR in pediatric kidney recipients. The graft itself may be the way of transmission for Parvovirus, so performance of a PCR test for Parvovirus B19 should be considered to identify high-risk patients. Intrarenal Parvovirus infection presents mainly during the first-year post-transplantation; thus, we recommend an active surveillance of donor-specific antibodies (DSA) in patients with intrarenal Parvovirus B19 infection during this period. Indeed, it should be considered a treatment with intravenous immunoglobulins in patients with intrarenal Parvovirus B19 infection and DSA positivity, even in the absence of ABMR criteria for kidney biopsy.

Preventative effect of TSPO ligands on mixed antibody-mediated rejection through a Mitochondria-mediated metabolic disorder

BACKGROUND

Immune-mediated rejection was the major cause of graft dysfunction. Although the advances in immunosuppressive agents have markedly reduced the incidence of T-cell-mediated rejection after transplantation. However, the incidence of antibody-mediated rejection (AMR) remains high. Donor-specific antibodies (DSAs) were considered the major mediators of allograft loss. Previously, we showed that treatment with 18-kDa translocator protein (TSPO) ligands inhibited the differentiation and effector functions of T cells and reduced the rejection observed after allogeneic skin transplantation in mice. This study we further investigate the effect of TSPO ligands on B cells and DSAs production in the recipients of mixed-AMR model.

METHODS

In vitro, we explored the effect of treatment with TSPO ligands on the activation, proliferation, and antibody production of B cells. Further, we established a heart-transplantation mixed-AMR model in rats. This model was treated with the TSPO ligands, FGIN1-27 or Ro5-4864, to investigate the role of ligands in preventing transplant rejection and DSAs production in vivo. As TSPO was the mitochondrial membrane transporters, we then investigated the TSPO ligands effect on mitochondrial-related metabolic ability of B cells as well as expression of downstream proteins.

RESULTS

In vitro studies, treatment with TSPO ligands inhibited the differentiation of B cells into CD138⁺CD27⁺ plasma cells; reduced antibodies, IgG and IgM, secretion of B cells; and suppressed the B cell activation and proliferation. In the mixed-AMR rat model, treatment with FGIN1-27 or Ro5-4864 attenuated DSA-mediated cardiac-allograft injury, prolonged graft survival, and reduced the numbers of B cells, including IgG⁺ secreting B cells, T cells and macrophages infiltrating in grafts. For the further mechanism exploration, treatment with TSPO ligands inhibited the metabolic ability of B cells by downregulating expression of pyruvate dehydrogenase kinase 1 and proteins in complexes I, II, and IV of the electron transport chain.

CONCLUSIONS

We clarified the mechanism of action of TSPO ligands on B-cell functions and provided new ideas and drug targets for the clinical treatment of postoperative AMR.

Trends in cardiovascular medicine: Update on cardiac transplantation

Advanced heart failure affects more than 250,000 people in the United States alone and is associated with high risk of morbidity and mortality. Cardiac transplantation provides a cure for patients with advanced disease but has historically been limited by donor availability. Recent changes in the allocation system as well as advances in donor selection, procurement and desensitization protocols have served to widen the donor pool and increase the availability of cardiac transplantation for those in need. This review provides an update on recent advances in cardiac transplantation.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Parvovirus B19-Associated Severe Anemia in Adult Liver Transplant Recipients: A Case Series and Review of the Literature

Background: Parvovirus B19 (B19V) infection is a rare cause of severe anemia in liver transplant recipients. However, few studies have systematically reviewed reported cases and summarized experience in managing this disease. Objective: We described a retrospective case series of eight adult liver transplant recipients with B19V-associated severe anemia and performed a literature review of epidemiology, etiology, clinical courses, diagnosis, treatment options available, and outcomes of B19V-associated anemia in adult liver transplant recipients. Patients and Methods: We systematically reviewed articles describing adult liver transplant recipients with B19V-associated anemia from PubMed and ScienceDirect databases from database inception to May 2022. Results: Eight articles containing 23 cases were identified in addition to eight cases from our center for a total of 31 patients (mean age, 45.7 ± 9.7 years; 74.2% male). Eighty-seven percent developed transfusion-dependent anemia within two months after liver transplantation (LT). Fever and progressive anemia are among the major manifestations. Intravenous immunoglobulin (IVIG)-based therapy was given to all patients and the treatment protocols varied among different centers. Except for two cases who died of comorbidities, 17 patients obtained long-term recovery from anemia after one course of treatment and six (19%) experienced relapses that were reversed by repeated courses of IVIG therapy. Two recipients presented with IVIG-associated side effects and two developed acute cellular rejection (ACR) after reduction of immunosuppression. Conclusions: B19V infection should be suspected early as a cause of severe anemia of unknown etiology in adult liver transplant recipients. The clearance of B19V typically lags behind recovery of anemia, and inadequate clearance of virus after cessation of IVIG appears to be a potential risk of anemia recurrence. Moreover, more attention should be paid to the side effects of high-dose IVIG infusion and ACR because of reduction of immunosuppression.

Hypogammaglobulinemia in pediatric kidney transplant recipients

Infections remain the most common cause of hospitalization after kidney transplantation, contributing to significant post-transplant morbidity and mortality. There is a growing body of literature that suggests that immunoglobulins may have a significant protective role against post-transplant infections, although the literature remains sparse, inconsistent, and not well publicized among pediatric nephrologists. Of great concern are data indicating a high prevalence of immunoglobulin abnormalities following transplantation and a possible link between these abnormalities and poorer outcomes. Our educational review focuses on the epidemiology and risk factors for the development of immunoglobulin abnormalities after kidney transplantation, the outcomes in patients with low immunoglobulin levels, and studies evaluating possible interventions to correct these immunoglobulin abnormalities.

The first clinical pig heart transplant: Was IVIg or pig cytomegalovirus detrimental to the outcome?

The clinical course of the first patient to receive a gene-edited pig heart transplant was recently reported by the University of Maryland team. Although the pig heart functioned well for >40 days, serum anti-pig antibodies then increased, and the patient sadly died after 60 days. Because of his debilitated pre-transplant state, the patient never thrived despite excellent graft function for several weeks, and the cause of his demise continues to be uncertain. A few days before an increase in anti-pig antibodies was observed, the patient had received intravenous human immunoglobulin (IVIg), and whether this played a role in his cardiac deterioration has been discussed. Furthermore, mcfDNA testing indicated an increase in pig cytomegalovirus (CMV), and its possible role in the development of cardiac dysfunction has also been considered. On the basis of the limited data provided in the publication and on our previous investigations into whether IVIg contains anti-TKO pig antibodies and therefore might be deleterious to TKO pig organ xenografts, we suggest that the steady rise in anti-pig antibody titer was more consistent with the failure of the immunosuppressive regimen to prevent elicited anti-TKO pig antibody production, rather than from the passive transfusion of IVIg or the presence of pig CMV in the graft. Although the outcome of the Maryland experience was disappointing, valuable lessons were learned. Our attention was drawn to the potential risks of heart transplantation in a "deconditioned" patient, the administration of IVIg, the transmission of pig CMV, and of the difficulties in interpreting myocardial biopsy findings.

Recent Improvement in Survival Outcomes and Reappraisal of Prognostic Factors in Pediatric Living Donor Liver Transplantation

Living donor liver transplantation (LDLT) is a significant advancement for the treatment of children with end-stage liver disease given the shortage of deceased donors. The ultimate goal of pediatric LDLT is to achieve complete donor safety and zero recipient mortality. We conducted a retrospective, single-center assessment of the outcomes as well as the clinical factors that may influence graft and patient survival after primary LDLTs performed between 1994 and 2020. A Cox proportional hazards model was used for multivariate analyses. The trends for independent prognostic factors were analyzed according to the following treatment eras: 1, 1994 to 2002; 2, 2003 to 2011; and 3, 2012 to 2020. Primary LDLTs were performed on 287 children during the study period. Biliary atresia (BA; 52%), acute liver failure (ALF; 26%), and monogenic liver disease (11%) were the leading indications. There were 45 graft losses (16%) and 27 patient deaths (7%) in this population during the study period. During era 1 (n = 81), the cumulative survival rates at 1 and 5 years after LDLT were 90.1% and 81.5% for patients and 86.4% and 77.8% for grafts, respectively. During era 2 (n = 113), the corresponding rates were 92.9% and 92% for patients and 89.4% and 86.7% for grafts, respectively. During era 3 (n = 93), the corresponding rates were 100% and 98.6% for patients and 98.9% and 95.4% for grafts, respectively. In the multivariate analyses, primary diagnosis ALF, bloodstream infection, posttransplant lymphoproliferative disease, and chronic rejection were found to be negative prognostic indicators for patient survival. Based on generalized care guidelines and center-oriented experiences, comprehensive advances in appropriate donor selection, refinement of surgical techniques, and meticulous medical management may eventually realize a zero-mortality rate in pediatric LDLT.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Case Report: Pure Red Cell Aplasia Caused by Refractory Parvovirus B19 Infection After Pancreas Transplantation Alone

A multidisciplinary team of doctors is in charge or is involved in the follow-up of patients who undergo solid organ transplantation (SOT). Immunosuppressive drugs are required after SOT, some potential unwanted side effects can be difficult to detect, and physicians must be aware of potential pitfalls. We report a case of a recipient with brittle type 1 diabetes who experienced severe and refractory anemia after pancreas transplantation alone (PTA). Despite a broad diagnostic approach for anemia, the diagnosis was delayed. The patient had normocytic normochromic anemia with severe reticulocytopenia and marked reduction or absence of erythroid precursors in the bone marrow, compatible with pure red cell aplasia (PRCA). Analyses of serological parvovirus B19 anti-IgM and anti-IgG antibodies, including PCR, were initially inconclusive/negative. The diagnosis of parvovirus B19 infection was confirmed after bone marrow biopsy with immunohistochemical staining for parvovirus B19. A retrospective analysis revealed an early post-transplant primary parvovirus B19 infection. The patient was successfully treated with intravenous immunoglobulin (IVIg) therapy. There is a risk of diagnostic delay for the less common types of anemia following SOT. Parvovirus B19 infection-associated PRCA is curable in SOT recipients and should be actively considered in patients with persistent anemia and low reticulocytes.

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.

Innovations in Heart Transplantation: A Review

Advanced heart failure affects tens of thousands of people in the United States alone with high morbidity and mortality. Cardiac transplantation offers the best treatment strategy but has been historically limited by donor availability. Recently, there have been significant advances in organ allocation, donor-recipient matching, organ preservation and expansion of the donor pool. The current heart allocation system prioritizes the sickest patients to minimize waitlist mortality. Advances in donor organ selection including predicted heart mass calculations and more sophisticated antibody detection methods for allosensitized patients offer more effective matching of donors and recipients. Innovations in organ preservation such as with organ preservation systems have geographically widened the donor pool. The use of hepatitis C donors is possible with the advent of effective direct-acting antiviral agents to cure donor-transmitted hepatitis C. Finally, further expansion of the donor pool is occurring with the utilization of higher-risk donors with advanced age, medical comorbidities, and left ventricular dysfunction and advances in donation after circulatory death. This review provides an update on the new technologies and transplantation strategies that serve to widen the donor pool and more effectively match donors and recipients so that heart transplant candidates may derive the best outcomes from heart transplantation.

Donor-Derived Human Parvovirus B19 Infection in Kidney Transplantation

Background

Donor-derived human parvovirus B19 (B19V) infections are rarely reported. Thus, its incidence in kidney transplantation is still unknown due to lack of surveillance studies. Similarly, whether the donor needs to be routinely screened for B19V and whether the kidneys from those with B19V DNAemia could be accepted also remain unknown.

Methods

This retrospective study aims to evaluate the donor-derived B19V infections occurring in 823 living and 1,225 deceased donor kidney transplantations from January 2016 to December 2020. The serum viral load of living donors and their corresponding recipients was evaluated before and after transplantation. Meanwhile, for the deceased donor kidney transplantation, the serum viral load of recipients was only tested after transplantation; if recipients of a deceased donor subsequently developed B19V infection, the serum viral load of recipients and their corresponding donors before transplantation would then be further traced.

Results

A total of 15 living donors were B19V DNAemia positive before the donation, of which B19V DNAemia occurred in three corresponding recipients. In deceased donor kidney transplantation, DNAemia occurred simultaneously in 18 recipients and their corresponding nine donors. A progressive decline in hemoglobin and reticulocyte count could be observed in one living donor recipient and other 11 deceased donor recipients, which were all well controlled by treatment eventually.

Conclusion

The incidence of donor-derived B19V infection was 0.4% and 1.5% in living and deceased kidney transplantations, respectively. B19V was seemingly unnecessary to be routinely screened for the donor. Moreover, kidneys of the donors with B19V infection were acceptable.

Antibody-mediated rejection of the liver allograft: An update and a clinico-pathological perspective

Antibody-mediated rejection after liver transplantation is an under-recognised cause of allograft injury. While definitions of acute and chronic antibody-mediated rejection have increased clinical awareness, timely identification and management of antibody-mediated rejection remain difficult because of complexities in diagnosis and histopathology, lack of treatment protocols, and unclear long-term outcomes. While recent cohort studies assessing the importance of donor-specific antibodies have aided in its diagnosis, literature on the treatment of antibody-mediated rejection in liver transplantation remain limited to case reports and small series. Further increasing the awareness and timely recognition of antibody-mediated rejection post-liver transplantation is crucial in order to stimulate future research and the development of protocols for its diagnosis and treatment. This review will summarise recent advances in the clinical diagnosis and treatment of antibody-mediated rejection in liver transplantation, as well as some of the histopathologic features (on liver biopsy tissue) of acute and chronic antibody-mediated rejection.

Current Desensitization Strategies in Heart Transplantation

Heart transplant candidates sensitized to HLA antigens wait longer for transplant, are at increased risk of dying while waiting, and may not be listed at all. The increasing prevalence of HLA sensitization and limitations of current desensitization strategies underscore the urgent need for a more effective approach. In addition to pregnancy, prior transplant, and transfusions, patients with end-stage heart failure are burdened with unique factors placing them at risk for HLA sensitization. These include homograft material used for congenital heart disease repair and left ventricular assist devices (LVADs). Moreover, these risks are often stacked, forming a seemingly insurmountable barrier in some cases. While desensitization protocols are typically implemented uniformly, irrespective of the mode of sensitization, the heterogeneity in success and post-transplant outcomes argues for a more tailored approach. Achieving this will require progress in our understanding of the immunobiology underlying the innate and adaptive immune response to these varied allosensitizing exposures. Further attention to B cell activation, memory, and plasma cell differentiation is required to establish methods that durably abrogate the anti-HLA antibody response before and after transplant. The contribution of non-HLA antibodies to the net state of sensitization and the potential implications for graft longevity also remain to be comprehensively defined. The aim of this review is to first bring forth select issues unique to the sensitized heart transplant candidate. The current literature on desensitization in heart transplantation will then be summarized providing context within the immune response. Building on this, newer approaches with therapeutic potential will be discussed emphasizing the importance of not only addressing the short-term pathogenic consequences of circulating HLA antibodies, but also the need to modulate alloimmune memory.

Parvovirus: Uncommon Causes of Anemia and Kidney Failure in a Kidney Transplant Patient

: Parvovirus is one of the uncommon causes of anemia in a kidney transplant patient. We reported a kidney transplant patient with parvovirus infection who developed severe anemia three weeks after kidney transplantation. Suspicion of infections increased due to the decrease in erythrocyte level. The patient's anemia became normal with a decrease in the amount of immunosuppressant and treatment with intravenous immunoglobulin (IVIG). Parvovirus B19 infection should be considered in all patients with persistent anemia with or without graft failure after renal transplant.

Intravenous immunoglobulins do not prove beneficial to reduce alloimmunity among kidney transplant recipients with BKV-associated nephropathy

Reduced immunosuppression during BKV-DNAemia has been associated with T-cell mediated rejection (TCMR), de novo donor-specific antibodies (DSA) and antibody-mediated rejection (ABMR). Intravenous immunoglobulins (IVIG) may reduce alloimmunity. We studied 860 kidney transplant recipients (KTRs) for the development of BKV-DNAuria and BKV-DNAemia (low-level <10 000 IE/ml, high-level >10 000 IE/ml). 52/131 KTRs with high-level BKV-DNAemia received IVIG. The HLA-related immunological risk was stratified by the Predicted Indirectly Recognizable HLA Epitopes (PIRCHE) algorithm. BKV-DNAuria only was observed in 86 KTRs (10.0%), low-level BKV-DNAemia in 180 KTRs (20.9%) and high-level BKV-DNAemia in 131 KTRs (15.2%). KTRs with low-level BKV-DNAemia showed significantly less TCMR compared to KTRs with high-level BKV-DNAemia (5.2% vs. 25.5%; P < 0.001) and no BKV-replication (13.2%; P = 0.014), lowest rates of de novo DSA (21.3%), ABMR (9.2%) and flattest glomerular filtration rate (GFR) slope (-0.8 ml/min). KTRs with low-level BKV-DNAemia showed significantly higher median (interquartile range) total PIRCHE if they developed TCMR [100.22 (72.6) vs. 69.52 (49.97); P = 0.020] or ABMR [128.86 (52.99) vs. 69.52 (49.96); P = 0.005]. Administration of IVIG did not shorten duration of BKV-DNAemia (P = 0.798) or reduce TCMR, de novo DSA and ABMR (P > 0.05). KTRs with low-level BKV-DNAemia showed best protection against alloimmunity, with a high number of PIRCHE co-determining the remaining risk. The administration of IVIG, however, was not beneficial in reducing alloimmunity.

Immunosuppressive drugs modes of action

The innate and adaptive immune systems work as a complex interplay between different cell types, involving cytokines and chemokines mediating extracellular and paracrine effects. At the intracellular level, the inflammatory cascade is mediated by multifaceted processes that have been better described in the last 10 years. Immunosuppressive agents available in clinical practice act at different points of those cascades at the intracellular or extracellular level. Those drugs can mediate their effects on one or more cell types finally limiting inflammation and immune responses to antigens. Every immunosuppressive agent is characterized by intrinsic toxicity and side effects that may be due to the same therapeutic pathways or to off-target secondary effect of each molecule. We will here review the mechanisms of action of the most widely used immunosuppressive agents in the field of solid organ transplantation and autoimmune disorders, describing the mechanisms underlying both the therapeutic and secondary effects.

COVID-19 pneumonia in kidney transplant recipients: A promising treatment algorithm in the absence of a disease-specific drug

There is no consensus on the management of coronavirus disease 2019 (COVID‐19) and modification of immunosuppressive therapy in kidney transplant recipients (KTRs). In this study, we examined the clinical outcome of our KTRs with COVID‐19 disease, who were treated with a broad‐spectrum anti‐inflammatory protocol. This protocol is essentially composed of intravenous immunoglobulin +/‐ tocilizumab in KTRs with severe COVID‐19 pneumonia. Among 809 KTRs, 64 patients diagnosed with COVID‐19 disease between April 2020 and February 2021, were evaluated. Twenty‐nine patients with pneumonia confirmed by chest computed tomography (CCT) were hospitalized. The treatment protocol included high‐dose intravenous methylprednisolone, favipiravir, enoxaparin, and empirical antibiotics. Patients with pneumonic involvement of more than 25% on CCT with or without respiratory failure were given a total of 2 g/kg intravenous immunoglobulin (IVIg) therapy. Nonresponders received tocilizumab, an interleukin‐6 receptor antibody. Of the 29 patients with pneumonia, 6 were treated in other hospitals. These six patients did not receive IVIg and 5 of them deceased. In our center, IVIg treatment was applied to 15 of 23 patients. Seven of them required tocilizumab. Respiratory parameters improved significantly in all but one patient after IVIg ± tocilizumab treatment. The mortality rate was 6.6% in patients who received IVIg therapy and 35.7% in those who did not (p = 0.08). The mortality rate was higher in patients who received treatment in external centers (2.2% vs. 26.3%; p = 0.0073). The treatment of KTRs with severe COVID‐19 pneumonia in organ transplant centers with significant experience yields better results. The administration of broad‐spectrum anti‐inflammatory treatment in this patient group was safe and provided excellent outcomes.

Antibody-Mediated Rejection and Lung Transplantation

Antibody-mediated rejection (AMR) is now a widely recognized form of lung allograft rejection, with mounting evidence for AMR as an important risk factor for the development of chronic lung allograft dysfunction and markedly decreased long-term survival. Despite the recent development of the consensus diagnostic criteria, it remains a challenging diagnosis of exclusion. Furthermore, even after diagnosis, treatment directed at pulmonary AMR has been nearly exclusively derived from practices with other solid-organ transplants and other areas of medicine, such that there is a significant lack of data regarding the efficacy for these in pulmonary AMR. Lastly, outcomes after AMR remain quite poor despite aggressive treatment. In this review, we revisit the history of AMR in lung transplantation, describe our current understanding of its pathophysiology, discuss the use and limitations of the consensus diagnostic criteria, review current treatment strategies, and summarize long-term outcomes. We conclude with a synopsis of our most pressing gaps in knowledge, introduce recommendations for future directions, and highlight promising areas of active research.

HLA Desensitization in Solid Organ Transplantation: Anti-CD38 to Across the Immunological Barriers

The presence of anti-human leucocyte antigen (HLA) antibodies in the potential solid organ transplant recipient's blood is one of the main barriers to access to a transplantation. The HLA sensitization is associated with longer waitlist time, antibody mediated rejection and transplant lost leading to increased recipient's morbidity and mortality. However, solid organ transplantation across the HLA immunological barriers have been reported in recipients who were highly sensitized to HLA using desensitization protocols. These desensitization regimens are focused on the reduction of circulating HLA antibodies. Despite those strategies improve rates of transplantation, it remains several limitations including persistent high rejection rate and worse long-term outcomes when compare with non-sensitized recipient population. Currently, interest is growing in the development of new desensitization approaches which, beyond targeting antibodies, would be based on the modulation of alloimmune pathways. Plasma cells appears as an interesting target given their critical role in antibody production. In the last decade, CD38-targeting immunotherapies, such as daratumumab, have been recognized as a key component in the treatment of myeloma by inducing an important plasma cell depletion. This review focuses on an emerging concept based on targeting CD38 to desensitize in the field of transplantation.

Immunoglobulin levels in systemic lupus erythematosus: A narrative review

Immunoglobulins play a fundamental role in the protection of the human body against internal and external threats. They also contribute to the immune system homeostasis and maintenance of self-tolerance. Hypogammaglobulinemia is occasionally encountered in routine clinical practice by rheumatologists. Low levels of immunoglobulins can occur as primary or secondary issues and may predispose patients to various forms of infection. However, the impact of the low immunoglobulin level abnormality varies with the underlying condition. In this narrative review, we shed light on the overall types and functions of immunoglobulins for clinicians. We discuss important principles of immunoglobulin measurements. We then consider the primary and secondary causes of low immunoglobulins with a special focus on hypogammaglobulinemia in patients with systemic lupus erythematosus (SLE).

Case Report: Kidney Transplantation in a Patient With Acquired Agammaglobulinemia and SLE. Issues and Challenges

Lupus nephritis in the context of Systemic Lupus Erythematosus (SLE) is characterized by an unpredicted course with remissions and flare-ups. Among others, it remains a significant cause of end-stage kidney disease (ESKD) in relatively young patients. Therapeutic regimens with newer immunosuppressive agents have been introduced in order to control SLE clinical manifestations more efficiently and limit organ damage induced by immune complex formation and sustained inflammation. Treatment is usually long-term, and the cumulative impact of immunosuppression is expressed through the increased frequency of infections and neoplasms. However, if the observed immunity dysregulation is secondary and pharmaceutically induced or there is a pre-existing, primary immunodeficiency that shares common pathogenetic pathways with SLE's autoimmunity is not always clear. Herein, we present the case of a 39-year-old woman, that reached ESKD due to lupus nephritis. After an upper respiratory cytomegalovirus (CMV) infection and concomitant CMV reactivations the investigation revealed significant immunodeficiency. Not long after the initiation of intravenous immunoglobulin (IVIG) administration, patient received a cadaveric kidney transplant. IVIG was continued along with standard immunosuppression so that both recurrent infections and allograft rejection are avoided. Patient is closely monitored, and her post-transplant course is remarkably satisfying so far. ESKD patients with immunodeficiency syndromes should not be excluded by definition from kidney transplantation.

Intravenous Immunoglobulins at the Crossroad of Autoimmunity and Viral Infections

Intravenous immunoglobulins (IVIG) are blood preparations pooled from the plasma of donors that have been first employed as replacement therapy in immunodeficiency. IVIG interact at multiple levels with the different components of the immune system and exert their activity against infections. Passive immunotherapy includes convalescent plasma from subjects who have recovered from infection, hyperimmune globulin formulations with a high titer of neutralizing antibodies, and monoclonal antibodies (mAbs). IVIG are used for the prevention and treatment of several infections, especially in immunocompromised patients, or in case of a poorly responsive immune system. The evolution of IVIG from a source of passive immunity to a powerful immunomodulatory/anti-inflammatory agent results in extensive applications in autoimmune diseases. IVIG composition depends on the antibodies of the donor population and the alterations of protein structure due to the processing of plasma. The anti-viral and anti-inflammatory activity of IVIG has led us to think that they may represent a useful therapeutic tool even in COVID-19. The human origin of IVIG carries specific criticalities including risks of blood products, supply, and elevated costs. IVIG can be useful in critically ill patients, as well as early empirical treatment. To date, the need for further well-designed studies stating protocols and the efficacy/tolerability profile of IVIG and convalescent plasma in selected situations are awaited.

Corneal xenotransplantation: Where are we standing?

The search for alternatives to allotransplants is driven by the shortage of corneal donors and is demanding because of the limitations of the alternatives. Indeed, current progress in genetically engineered (GE) pigs, the introduction of gene-editing technology by clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9, and advanced immunosuppressants have made xenotransplantation a possible option for a human trial. Porcine corneal xenotransplantation is considered applicable because the eye is regarded as an immune-privileged site. Furthermore, recent non-human primate studies have shown long-term survival of porcine xenotransplants in keratoplasty. Herein, corneal immune privilege is briefly introduced, and xenogeneic reactions are compared with allogeneic reactions in corneal transplantation. This review describes the current knowledge on special issues of xenotransplantation, xenogeneic rejection mechanisms, current immunosuppressive regimens of corneal xenotransplantation, preclinical efficacy and safety data of corneal xenotransplantation, and updates of the regulatory framework to conduct a clinical trial on corneal xenotransplantation. We also discuss barriers that might prevent xenotransplantation from becoming common practice, such as ethical dilemmas, public concerns on xenotransplantation, and the possible risk of xenozoonosis. Given that the legal definition of decellularized porcine cornea (DPC) lies somewhere between a medical device and a xenotransplant, the preclinical efficacy and clinical trial data using DPC are included. The review finally provides perspectives on the current standpoint of corneal xenotransplantation in the fields of regenerative medicine.

Changing patterns of clinical decision making: are falling numbers of antibody incompatible transplants related to the increasing success of the UK Living Kidney Sharing Scheme? A national cohort study

Antibody incompatibility is a barrier to living kidney transplantation; antibody incompatible transplantation (AIT) is an accepted treatment modality, albeit higher risk. This study aims to determine changes to clinical decision making and access to AIT in the UK. An electronic survey was sent to all UK renal transplant centres (n = 24), in 2014, and again in 2018. Questions focused on entry & duration in the UKLKSS for HLA and ABO-incompatible pairs, Can and provision of direct AIT transplantation within those centres. Between 2014 & 2018, the duration recommended for patients in the UKLKSS increased. In 2014, 34.8% of centres reported leaving HLA-i pairs in the UKLKSS indefinitely, or reviewing on a case by case basis, by 2018 this increased to 61%. Centres offering direct HLA-i transplantation reduced from 58% to 37%. For low titre (1:8) ABO-i recipients, 66% of centres recommended at least 9 months (3 matching runs) in the UKLKSS scheme in 2018, compared to 47% in 2014, 50% fewer units consider direct ABO-i transplantation for unsuccessful pairs with high ABO titres (>1:512). Over time, clinicians appear to be facilitating more conservative management of AIT patients, potentially limiting access to living donor transplantation.

Implications of Fc Neonatal Receptor (FcRn) Manipulations for Transplant Immunotherapeutics

Alloimmune injury to allografts is mediated by pathogenic donor-specific alloantibodies, usually of the IgG isotype. Currently, strategies used to reduce donor-specific alloantibodies are collectively called desensitization. Despite successes, these treatments have limited efficacy and can be associated with adverse events, infectious complications, and high cost. Fc neonatal receptor (FcRn) was originally discovered as a transport mechanism for IgG from maternal circulation to fetus. FcRn receptors are now known to be widely distributed in virtually all tissues. IgG and albumin binding to FcRn is pH-dependent, which results in a significant prolongation their half-life. Structural analysis shows FcRn is a nonclassical major histocompatibility complex Class I receptor, which is emerging as a novel target to significantly reduce the half-life of pathogenic antibodies or extend the half-life of therapeutic monoclonals. Manipulation of IgG-Fc/FcRn interactions has implications for treatment of virtually all IgG-mediated diseases. The use of monoclonals directed at the FcRn can rapidly enhance the turnover of total IgG, including pathogenic IgG. In this review, we highlight the aspects of FcRn biology responsible for development of FcRn targeted therapeutics aimed at pathogenic autoantibodies and alloantibodies. We also explore the novel modifications of therapeutic monoclonals that exploit FcRn functions to enhance therapeutic efficacy.

Intravenous immunoglobulin as adjunctive therapy in kidney transplant recipients with severe pneumocystis pneumonia

Pneumocystis jirovecii is an opportunistic pathogen that may cause severe, life-threatening respiratory infections in immunocompromised patients such as those with kidney transplants. Although antimicrobial prophylaxis is now universally recommended in the early post-transplant period, Pneumocystis pneumonia (PCP) can occur later. If such infection occurs, mortality rates are high. Beyond standard therapy with trimethoprim-sulfamethoxazole, there is a lack of evidence-based options for intensifying treatment when initial therapy fails to show improvement. Moreover, it is usual to minimize immunosuppression in life-threatening infection, but graft damage may occur, particularly in kidney transplant recipients at above-average immunological risk. Here we present two cases of severe PCP in high immunological risk recipients who were managed with adjunctive intravenous immunoglobulin and withdrawal of immunosuppression. Both patients recovered and were discharged from hospital with functioning grafts.

Effect of intravenous immunoglobulin (IVIg) on primate complement-dependent cytotoxicity of genetically engineered pig cells: relevance to clinical xenotransplantation

Triple-knockout (TKO) pigs may be ideal sources of organs for clinical xenotransplantation because many humans have no preformed antibody to TKO pig cells. Intravenous immunoglobulin (IVIg) is widely used for severe infection or the treatment/prevention of antibody-mediated rejection in allotransplantation. Anti-pig antibodies in IVIg could be harmful in clinical xenotransplantation. It is unknown whether anti-TKO pig antibodies are present in IVIg. The main aim of this study was to investigate in vitro whether IVIg contains anti-TKO pig antibodies with cytotoxic effect to pig cells. Undiluted pooled human serum (HS) and five different commercial preparations of IVIg were tested for IgM and IgG binding to red blood cells (RBCs) from wild-type (WT), α1,3-galactosyltransferase gene-knockout (GTKO), and TKO pigs by flow cytometry. Complement-dependent lysis of IVIg against these pig pRBCs was measured by hemolytic assay. Pooled HS and 4 of 5 IVIg commercial preparations contained anti-pig IgG that bound to WT and GTKO pRBCs, but not to TKO pRBCs. One preparation of IVIg contained antibodies that bound to TKO pRBCs, but there was no cytotoxicity of IVIg to TKO pRBCs. The results suggest that IVIg administration to human recipients of TKO pig grafts would be safe. However, the specific preparation of IVIg would need to be screened before its administration.

B cell modulation strategies in the improvement of transplantation outcomes

Successful transplantation outcome is the final goal in most end stage and nonfunctional organs; however, despite using different therapeutic strategies, antibody-mediated rejection is still a big obstacle. B cells have a key role in transplant rejection by several functions, such as antibody production, antigen presenting, contribution in T cell activation, forming the germinal center, and tertiary lymphoid organs. Therefore, B cells modulation seems to be very crucial in transplant outcome. A double-edged sword function is considered for B cells during transplantation; On the one hand, antibody production against the transplanted organ induces antibody-mediated rejection. On the other hand, IL10 production by regulatory B (Breg) cells induces graft tolerance. Nowadays, several monoclonal antibodies (mAb) are available for B cell modulation that are routinely used in transplant recipients, among which rituximab (anti-CD20 mAb) act in eliminating B cells. However, there are some other monoclonal antibodies, such as epratuzumab and Inotuzumab ozogamicin (IO), which exert anti-CD22 activity, resulting in disruption of B cell functions and induction of tolerance in autoimmune disease or B cell malignancies; that notwithstanding, these mAbs have not yet been tried in transplantation. In this review, we focus on different methods for modulating the activity of B cells as well as induction of Breg cells, aiming to prevent the allograft rejection.

Epidemiology of parvovirus B19 and anemia among kidney transplant recipients: A meta-analysis

Background

Persistent anemia has been described in kidney transplant (KTx) recipients with parvovirus B19 virus infection. However, the epidemiology of parvovirus B19 and parvovirus B19-related anemia after KTx remains unclear. We conducted this systematic review (1) to investigate the incidence of parvovirus B19 infection after KTx and (2) to assess the incidence of parvovirus B19 among KTx patients with anemia.

Materials and Methods

A systematic review was conducted in EMBASE, MEDLINE, and Cochrane databases from inception to March 2019 to identify studies that reported the incidence rate of parvovirus B19 infection and/or seroprevalence of parvovirus B19 in KTx recipients. Effect estimates from the individual studies were extracted and combined using random-effects, generic inverse variance method of DerSimonian and Laird. The protocol for this systematic review is registered with PROSPERO (no. CRD42019125716).

Results

Nineteen observational studies with a total of 2108 KTx patients were enrolled. Overall, the pooled estimated seroprevalence of parvovirus B19 immunoglobulin G was 62.2% (95% confidence interval [CI]: 45.8%-76.1%). The pooled estimated incidence rate of positive parvovirus B19 DNA in the 1^st year after KTx was 10.3% (95% CI: 5.5%-18.4%). After sensitivity analysis excluded a study that solely included KTx patients with anemia, the pooled estimated incidence rate of positive parvovirus B19 DNA after KTx was 7.6% (95% CI: 3.7%-15.0%). Among KTx with anemia, the pooled estimated incidence rate of positive parvovirus B19 DNA was 27.4% (95% CI: 16.6%-41.7%). Meta-regression analysis demonstrated no significant correlations between the year of study and the incidence rate of positive parvovirus B19 DNA (P = 0.33). Egger's regression asymmetry test was performed and demonstrated no publication bias in all analyses.

Conclusion

The overall estimated incidence of positive parvovirus B19 DNA after KTX is 10.3%. Among KTx with anemia, the incidence rate of positive parvovirus B19 DNA is 27.4%. The incidence of positive parvovirus B19 DNA does not seem to decrease overtime.

The role of novel therapeutic approaches for prevention of allosensitization and antibody-mediated rejection

Modification of pathogenic antibodies and their effector functions in autoimmune diseases or use of B cell/plasma cell-directed anticancer therapies have illuminated the biologic relevance of B cells, plasma cells (PCs), and pathogenic antibodies and complement in alloimmunity. They have also rejuvenated interest in how B cells mediate multiple effector functions that include antibody production, antigen presentation to T cells, costimulation, and the production of immune stimulating and immune modulatory cytokines that drive dysfunctional immune responses. Current methods to reduce alloantibodies are only modestly successful. Rituximab is used for desensitization and antibody-mediated rejection (AMR) treatment by targeting CD20 found on B-lymphocytes. However, PCs do not express CD20, likely explaining the limited success of this approach. Intravenous immunoglobulin and plasmapheresis (PLEX) have limited success due to antibody rebound. Despite attempts to develop tolerable therapeutics for management of AMR, none, to date, have been universally accepted or obtained Food and Drug Administration approval. Lack of approved therapeutics often results in patients having a much shorter graft survival due to AMR. Repurposing drugs from autoimmunity and cancer immunotherapy has rapidly yielded important advancements in the care of AMR patients. Here we discuss emerging therapeutics aimed at prevention and treatment of AMR.

Effects of intravenous immunoglobulin therapy and Fc gamma receptor polymorphisms on BK virus nephropathy in kidney transplant recipients

BACKGROUND

BK virus nephropathy (BKVN) is a major complication in kidney transplant patients. This study aimed to investigate the efficacy of intravenous immunoglobulin (IVIG) therapy against persistent BKVN and to evaluate the association between persistent BKVN and Fc gamma receptor (FcγR) single nucleotide polymorphisms (SNPs).

METHODS

A total of 86 patients out of 279 kidney recipients with BKVN were investigated in a single-center retrospective study. The majority of 86 patients were Hispanic and Asian (69.8% and 17.4%). Patients were treated with adjunctive IVIG or standard therapy (controls). Subgroup analysis was performed between IVIG responders and non-responders. BK virus copy number and serum creatinine (SCr) were measured to evaluate the impact of IVIG. We analyzed the association between the response to IVIG and genotype at FcγR3A (rs396991) and FcγR2A (rs1801274) SNPs.

RESULTS

Viral load in IVIG non-responders was significantly higher than in responders at the time of diagnosis (219 271.8 vs 29 816.3 copies/mL, P = .015) and after 6 months of IVIG use (12 789.5 vs 1369.5 copies/mL, P < .001). However, analyses SNP of FcγR2A (OR = 0.807, CI = 0.435-1.496 P = .495) and FcγR3A (OR = 0.997, CI = 0.505-1.970, P = .993) SNPs showed no significant differences between the 2 groups.

CONCLUSION

IVIG appears to lower BK DNA viral load significantly in patients with persistent BKVN. However, no associations were identified between BKVN and FcγR2A or FcγR3A SNPs.

SARS-CoV-2 Inflammatory Syndrome. Clinical Features and Rationale for Immunological Treatment

The current pandemic coronavirus, SARS-CoV-2, is a global health emergency because of its highly contagious nature, the great number of patients requiring intensive care therapy, and the high fatality rate. In the absence of specific antiviral drugs, passive prophylaxis, or a vaccine, the treatment aim in these patients is to prevent the potent virus-induced inflammatory stimuli from leading to the acute respiratory distress syndrome (ARDS), which has a severe prognosis. Here, the mechanism of action and the rationale for employing immunological strategies, which range from traditional chemically synthesized drugs, anti-cytokine antibodies, human immunoglobulin for intravenous use, to vaccines, are reviewed.

SARS-CoV-2 Inflammatory Syndrome. Clinical Features and Rationale for Immunological Treatment

The current pandemic coronavirus, SARS-CoV-2, is a global health emergency because of its highly contagious nature, the great number of patients requiring intensive care therapy, and the high fatality rate. In the absence of specific antiviral drugs, passive prophylaxis, or a vaccine, the treatment aim in these patients is to prevent the potent virus-induced inflammatory stimuli from leading to the acute respiratory distress syndrome (ARDS), which has a severe prognosis. Here, the mechanism of action and the rationale for employing immunological strategies, which range from traditional chemically synthesized drugs, anti-cytokine antibodies, human immunoglobulin for intravenous use, to vaccines, are reviewed.

Cyclosporine a directly affects human and mouse b cell migration in vitro by disrupting a hIF-1 αdependent, o2 sensing, molecular switch

BACKGROUND

Hypoxia is a potent molecular signal for cellular metabolism, mitochondrial function, and migration. Conditions of low oxygen tension trigger regulatory cascades mediated via the highly conserved HIF-1 α post-translational modification system. In the adaptive immune response, B cells (Bc) are activated and differentiate under hypoxic conditions within lymph node germinal centers, and subsequently migrate to other compartments. During migration, they traverse through changing oxygen levels, ranging from 1-5% in the lymph node to 5-13% in the peripheral blood. Interestingly, the calcineurin inhibitor cyclosporine A is known to stimulate prolyl hydroxylase activity, resulting in HIF-1 α destabilization and may alter Bc responses directly. Over 60% of patients taking calcineurin immunosuppressant medications have hypo-gammaglobulinemia and poor vaccine responses, putting them at high risk of infection with significantly increased morbidity and mortality.

RESULTS

We demonstrate that O 2 tension is a previously unrecognized Bc regulatory switch, altering CXCR4 and CXCR5 chemokine receptor signaling in activated Bc through HIF-1 α expression, and controlling critical aspects of Bc migration. Our data demonstrate that calcineurin inhibition hinders this O 2 regulatory switch in primary human Bc.

CONCLUSION

This previously unrecognized effect of calcineurin inhibition directly on human Bc has significant and direct clinical implications.

Antibody-mediated rejection after lung transplantation

Antibody-mediated rejection (AMR) has been identified as a significant form of acute allograft dysfunction in lung transplantation. The development of consensus diagnostic criteria has created a uniform definition of AMR; however, significant limitations of these criteria have been identified. Treatment modalities for AMR have been adapted from other areas of medicine and data on the effectiveness of these therapies in AMR are limited. AMR is often refractory to these therapies, and graft failure and death are common. AMR is associated with increased rates of chronic lung allograft dysfunction (CLAD) and poor long-term survival. In this review, we discuss the history of AMR and describe known mechanisms, application of the consensus diagnostic criteria, data for current treatment strategies, and long-term outcomes. In addition, we highlight current gaps in knowledge, ongoing research, and future directions to address these gaps. Promising diagnostic techniques are actively being investigated that may allow for early detection and treatment of AMR. We conclude that further investigation is required to identify and define chronic and subclinical AMR, and head-to-head comparisons of currently used treatment protocols are necessary to identify an optimal treatment approach. Gaps in knowledge regarding the epidemiology, mechanisms, diagnosis, and treatment of AMR continue to exist and future research should focus on these aspects.

Six-year experience with treatment of early donor-specific anti-HLA antibodies in pediatric lung transplantation using a human immunoglobulin-based protocol

OBJECTIVES

Experience with the treatment of early donor-specific anti-HLA antibodies (eDSA) after lung transplantation in children is very limited. At our institution, we have treated patients with eDSA since 2013 with successive infusions of intravenous human immunoglobulins (IVIG), combined in some cases with a single dose of Rituximab and plasmapheresis (therapeutic plasma exchange [tPE]) or immunoabsorption. The aim of this study was to present the 6-year results of IVIG-based therapy in pediatric lung recipients.

METHODS

Records of pediatric (<18 years old) patients transplanted at our institution between 01/2013 and 03/2019 were reviewed. Outcomes were compared between patients with eDSA treated with IVIG (IVIG group) and without eDSA (control group). Median (interquartile range [IQR]) follow-up amounted to 28 (12-52) months.

RESULTS

During the study period, 66 lung-transplanted pediatric patients were included, of which 27 (41%) formed the IVIG group and 38 (57%) the control group. Among the IVIG patients, 14 (52%) patients showed concomitant graft dysfunction (possible clinical antibody-mediated rejection). The median time to eDSA detection was 24 (14-63) days after transplantation. eDSA were cleared in 25 (96%) of the 26 patients which completed treatment. At 3 years, graft survival (%) was 73 vs 85 (P = .65); freedom (%) from chronic lung allograft rejection (CLAD) was 89 vs 78 (P = .82); and from infection 47 vs 31 (P = .15), in IVIG vs control patients, respectively.

CONCLUSIONS

After lung transplantation, an IVIG-based treatment for eDSA yielded high eDSA clearance. IVIG and control patients showed similar CLAD-free and graft survival.

Pathogenicity of BK virus on the urinary system

Introduction

The polyomaviruses are omnipresent in nature. The major sites of BK virus appearance are the kidney tubular epithelial cells and urinary bladder surface transitional cells.

Material and methods

A literature search according to PRISMA guidelines within the Medline database was conducted in July 2019 for articles presenting data about BK virus in urologic aspect without setting time limits, using the terms ‘BK virus’ in conjunction with transplantation, nephropathy, stenosis, cancer, bladder, prostate, kidney.

Results

The BK virus usually stays latent, however, its replication may become active in various clinical situations of impaired immunocompetence such as solid organ transplantation, bone marrow transplantation, AIDS, pregnancy, multiple sclerosis, administration of chemotherapy or biologic therapy. BK virus is associated with two main complications after transplantation: polyomavirus-associated nephropathy in kidney transplant patients and polyomavirus-associated hemorrhagic cystitis in allogeneic hematopoietic stem cell transplant patients.

Conclusions

The aim of this article was to present available data on urologic aspects of BK virus infection, its detection methods and available treatment.

Parvovirus Infection-Related Anemia after Kidney Transplantation

Anemia postkidney transplantation is an important issue which has been correlated with increased hospitalizations and higher mortality. Infections, including those due to parvovirus B19, CMV, and BK virus (polyomavirus), have also been associated with an increased risk of anemia. Here, we present a case of new-onset anemia in a kidney transplant recipient within 3 months of transplant. The patient was found to have multiple viral infections from parvo B19, BK virus, and rhinovirus. The anemia resolved completely after successful reduction in the parvo B19 and BK viral load. Workup for viral infections must be considered in the differential diagnosis of postkidney transplant anemia.

Specificity, strength, and evolution of pretransplant donor-specific HLA antibodies determine outcome after kidney transplantation

In this cohort study (N = 924), we investigated the evolution and clinical significance of pretransplant donor-specific HLA antibodies (preDSA), detected in the single-antigen beads assay but complement-dependent cytotoxicity crossmatch-negative. Donor specificity of the preDSA (N = 107) was determined by high-resolution genotyping of donor-recipient pairs. We found that in 52% of the patients with preDSA, preDSA spontaneously resolved within the first 3 months posttransplant. PreDSA that persisted posttransplant had higher pretransplant median fluorescence intensity values and more specificity against DQ. Patients with both resolved and persistent DSA had a high incidence of histological picture of antibody-mediated rejection (ABMR_h ; 54% and 59% respectively). Patients with preDSA that persisted posttransplant had worse 10-year graft survival compared to resolved DSA and preDSA-negative patients. Compared to cases without preDSA, Cox modeling revealed an increased risk of graft failure only in the patients with persistent DSA, in the presence (hazard ratio [HR] = 8.3) but also in the absence (HR = 4.3) of ABMR_h . In contrast, no increased risk of graft failure was seen in patients with resolved DSA. We conclude that persistence of preDSA posttransplant has a negative impact on graft survival, beyond ABMR_h . Even in the absence of antibody-targeting therapy, low median fluorescence intensity DSA and non-DQ preDSA often disappear early posttransplantation and are not deleterious for graft outcome.

Parvovirus B19-Associated Anemia in Kidney Transplant Recipients: A Single-Center Experience

Parvovirus B19 (PVB19) has tropism to red blood cell progenitors and can be reactivated after organ transplantation. The aim of study was to describe clinical manifestations, laboratory findings, treatments used, and effectiveness in kidney recipients at Viet Duc hospital. A retrospective descriptive study was performed on 663 kidney recipients who were on regular follow-up from 2000 to 2018. PVB19 was detected by polymerase chain reaction PVB19-DNA. Effectiveness of therapy was assessed by Hemoglobin level. Nine out of 663 kidney recipients (1.4%) were diagnosed with PVB19-associated anemia. Eight of these 9 (89%) were diagnosed within the first 3 months following transplantation. All patients had normoscopic anemia; the average reticulocyte proportion and count were 0.15 ± 0.04% and 0.0039 ± 0.0011T/L, respectively. Graft dysfunction was observed in 4/9 (45%) patients. Treatment included reduction of immunosuppression, intravenous immunoglobulin (IVIG), and blood transfusion. All patients responded well to treatment except 1 (11%), who experienced relapse after using low dose of IVIG. PVB19-associated anemia usually occurred early after transplantation and was associated with very low reticulocyte proportion and count. Actual treatment was effective, but the risk of relapse was present.

Therapeutic Human IgG Preparations Contain Mixture of HLA Antibodies to Native HLA Antigens and Cryptic Epitopes With Little Clinical Significance

BACKGROUND

Human immunoglobulins (H-Ig) are widely used in solid organ transplantation for immunoglobulin G (IgG) replacement and for desensitization and treatment of antibody-mediated rejection. They are obtained from plasma pools and may contain HLA antibodies that can be detrimental to transplant recipients. The goal of this study was to evaluate HLA antibodies in multiple lots of 2 commercial H-Ig preparations by Luminex single-antigen bead (SAB) and cell-based crossmatch assays.

METHODS

Thirty lots of 2 commercial H-Ig products (CSL Behring, King of Prussia, PA) were evaluated: 6 Hizentra and 24 Privigen. All were adsorbed and diluted 1:10 before testing. HLA IgG antibodies were determined by 2 Luminex SAB kits and C1q screen for complement-binding capability. Lots were tested for the presence of antibody to denatured vs. intact class I HLA alleles using acid-treated SAB. Surrogate T and B-cell flow cytometry crossmatches (FCXM) were performed with peripheral blood lymphocytes from 2 healthy donors.

RESULTS

Twenty-two (73%) lots at 1:10 showed SAB reactivity with mean fluorescent intensity of 2000 or greater for HLA class I, 67% (20/30 lots) for class II. The reactivity pattern was similar using both SAB kits. Acid treatment revealed antibodies to denatured class I: the majority of HLA-C, half of HLA-B and few HLA-A alleles. No C1q reactivity was observed. Surrogate flow cytometry crossmatch results were positive (>150 median channel shift), but were fourfold to eightfold lower than expected.

CONCLUSIONS

The H-Ig products tested consisted of low titer, non-complement-binding HLA class I and class II antibodies; most of the observed class I HLA reactivity was toward denatured HLA antigens.

Human parvovirus B19 in solid organ transplantation: Guidelines from the American society of transplantation infectious diseases community of practice

Clinical manifestations of human parvovirus B19 infection can vary widely and may be atypical in solid organ transplant (SOT) recipients. However, disease is apparent when there is destruction of erythrocyte progenitor cells leading to severe acute or chronic anemia with lack of an appropriate reticulocyte response in the setting of active parvovirus B19 infection. Serology may not reliably establish the diagnosis. High-level viremia is more likely to be associated with symptomatic disease. Conversely, ongoing DNAemia after infection may not be clinically significant, if detected at low levels. Despite lack of robust data, intravenous immunoglobulin (IVIG) is frequently used for the treatment of SOT recipients with symptomatic parvovirus B19 infection. Although the optimal dosage and duration of IVIG is not known, most patients receive a total of 2 g/kg over a period of 2-5 days. A daily dose of 1 g/kg or more seems to be associated with higher incidence of toxicity. Application of standard and droplet isolation precautions remains the cornerstone for preventing human parvovirus B19 transmission. Additional research is needed to assess the efficacy of current and novel therapies and to develop a safe and effective parvovirus B19 vaccine.

Small-Molecule Immunosuppressive Drugs and Therapeutic Immunoglobulins Differentially Inhibit NK Cell Effector Functions in vitro

Small-molecule immunosuppressive drugs (ISD) prevent graft rejection mainly by inhibiting T lymphocytes. Therapeutic immunoglobulins (IVIg) are used for substitution, antibody-mediated rejection (AbMR) and HLA-sensitized recipients by targeting distinct cell types. Since the effect of ISD and IVIg on natural killer (NK) cells remains somewhat controversial in the current literature, the aim of this comparative study was to investigate healthy donor's human NK cell functions after exposure to ISD and IVIg, and to comprehensively review the current literature. NK cells were incubated overnight with IL2/IL12 and different doses and combinations of ISD and IVIg. Proliferation was evaluated by ³[H]-thymidine incorporation; phenotype, degranulation and interferon gamma (IFNγ) production by flow cytometry and ELISA; direct NK cytotoxicity by standard ⁵¹[Cr]-release and non-radioactive DELFIA assays using K562 as stimulator and target cells; porcine endothelial cells coated with human anti-pig antibodies were used as targets in antibody-dependent cellular cytotoxicity (ADCC) assays. We found that CD69, CD25, CD54, and NKG2D were downregulated by ISD. Proliferation was inhibited by methylprednisolone (MePRD), mycophenolic acid (MPA), and everolimus (EVE). MePRD and MPA reduced degranulation, MPA only of CD56^bright NK cells. MePRD and IVIg inhibited direct cytotoxicity and ADCC. Combinations of ISD demonstrated cumulative inhibitory effects. IFNγ production was inhibited by MePRD and ISD combinations, but not by IVIg. In conclusion, IVIg, ISD and combinations thereof differentially inhibit NK cell functions. The most potent drug with an effect on all NK functions was MePRD. The fact that MePRD and IVIg significantly block NK cytotoxicity, especially ADCC, has major implications for AbMR as well as therapeutic strategies targeting cancer and immune cells with monoclonal antibodies.

Pulse corticosteroids in treatment of rheumatic disease concomitant with cytomegalovirus infection

AIM

To investigate the impact of corticosteroids on the outcome of antiviral therapy in rheumatic patients with cytomegalovirus (CMV)-emia.

METHOD

Sixty-two patients with rheumatic disease complicated by CMV infection from 2011 to 2014 were retrospectively analyzed.

RESULTS

Fifty-five of 62 patients were diagnosed with CMV-DNAemia. Most patients (43/55, 78.2%) achieved viral clearance within 5 weeks. It was shown that, while undergoing active antiviral therapy, there was no significant difference in the CMV-DNAemia clearance rate between the pulse methylprednisolone (MPSL) therapy group and non-pulse group (8/9, 88.9% vs 30/36, 83.3%; OR = 1.600, 95% CI 0.168-15.273, P > 0.05) at the end of the 5-week follow-up. However, pulse MPSL might slightly prolong duration of CMV-DNAemia than non-pulse MPSL patients (20.78 ± 19.18 days vs 14.33 ± 9.01 days, P = 0.1430), especially in the high baseline titer group (33.7 ± 29.1 days in pulse MPSL group vs 18.3 ± 13.1 days in non-pulse group, P = 0.457). But in the low baseline titer group, CMVemia duration in the pulse MPSL group (14.3 ± 10.0 days) was about the same as that in the non-pulse MPSL group (13.4 ± 7.8 days).

CONCLUSION

With effective antiviral therapy, pulse MPSL is acceptable in rheumatic disease patients with CMV-DNAemia, without significant impact on final clearance of virus. However, duration of CMV-DNAemia may be prolonged, especially in patients with high CMV-DNA titer at baseline.

ABO-Incompatible Kidney Transplantation: Low Rates of Infectious Complications and Excellent Patient Survival

BACKGROUND

A significant gap exists between demand and supply of organs for patients with end-stage renal disease. To increase the donor pool, kidney transplantation is performed across ABO- and HLA-incompatible barriers. ABO-incompatible kidney transplant (ABOi-KT) recipients are at increased risk of antibody-mediated rejection, infection, and mortality. Hypogammaglobulinemia secondary to immunosuppression is highly prevalent after solid organ transplantation, and intravenous immunoglobulin (IVIG) has been reported to reduce the risks of infections in various settings. We use high-dose IVIG in ABOi-KT recipients perioperatively. We aimed to determine the rate of infectious complications along with graft and patient survival in our ABOi-KT recipients.

METHODS

We included all adult patients who underwent ABOi-KT from the year 2007 to 2016. Patients received rituximab, plasma exchange, and IVIG (2 g/kg body weight). Thymoglobulin and intravenous methylprednisolone were used as induction treatment. Oral prednisone, mycophenolate mofetil, and tacrolimus were used as maintenance therapy.

RESULTS

A total of 77 ABOi-KTs were performed, and the recipients were followed up for a median of 1557 days. Two patients were diagnosed as having BK nephropathy. No patients were diagnosed as having pneumocystis infection, cytomegalovirus disease, herpes simplex, varicella zoster, or fungal infection. One-year graft and patient survival was 94.8% and 100%, respectively.

CONCLUSIONS

In our series of ABOi-KTs, we observed a low risk of infectious complications and excellent patient survival. High-dose IVIG might have reduced infections.