Intravenous immunoglobulin a natural regulator of immunity and inflammation

Intravenous Immunoglobulins Alone for the Desensitization of Lung Transplant Recipients with Preformed Donor Specific Antibodies and Negative Flow Cytometry Crossmatch

BACKGROUND

The lack of evidence regarding optimal desensitization strategies for lung transplant candidates with preformed donor specific anti-human leukocyte antigen antibodies (DSAs) has led to varying approaches among centers towards this patient group. Our institution's desensitization protocol for recipients with preformed DSAs and negative flow cytometry crossmatch (FCXM) consists of intravenous immunoglobulin (IVIG) as the sole therapy. The study aimed to determine outcomes using this approach.

METHODS

This retrospective study included adults who underwent lung-only transplantation for the first time between January 2015 and March 2022 at a single center. We excluded patients with positive or missing FCXM results. Transplant recipients with any DSA ≥ 1000 MFI on latest testing within three months of transplant were considered DSA-positive, while recipients with DSAs <1000 MFI and those without DSAs were assigned to the low-level/negative group. Graft survival (time to death/retransplantation) and chronic lung allograft dysfunction (CLAD)-free times were compared between groups using Cox proportional hazards models.

RESULTS

Thirty-six out of 167 eligible patients (22%) were DSA-positive. At least 50% of preformed DSAs had documented clearance (decrease to <1000 MFI) within the first 6 months of transplant. Multivariable Cox regression analyses did not detect a significantly increased risk of graft failure (aHR 1.04 95%CI 0.55-1.97) or chronic lung allograft dysfunction (aHR 0.71 95%CI 0.34-1.52) in DSA-positive patients compared to patients with low-level/negative DSAs. Incidences of antibody-mediated rejection (p = 1.00) and serious thromboembolic events (p = 0.63) did not differ between study groups.

CONCLUSION

We describe a single-center experience of administering IVIG alone to lung transplant recipients with preformed DSAs and negative FCXM. Further studies are required to confirm the efficacy of this strategy against other protocols.

Etiology, pathology, and host-impaired immunity in medical implant-associated infections

Host impaired immunity and pathogens adhesion factors are the key elements in analyzing medical implant-associated infections (MIAI). The infection chances are further influenced by surface properties of implants. This review addresses the medical implant-associated pathogens and summarizes the etiology, pathology, and host-impaired immunity in MIAI. Several bacterial and fungal pathogens have been isolated from MIAI; together, they form cross-kingdom species biofilms and support each other in different ways. The adhesion factors initiate the pathogen's adherence on the implant's surface; however, implant-induced impaired immunity promotes the pathogen's colonization and biofilm formation. Depending on the implant's surface properties, immune cell functions get slow or get exaggerated and cause immunity-induced secondary complications resulting in resistant depression and immuno-incompetent fibro-inflammatory zone that compromise implant's performance. Such consequences lead to the unavoidable and straightforward conclusion for the downstream transformation of new ideas, such as the development of multifunctional implant coatings.

De Novo Donor-Specific Antibodies after Heart Transplantation: A Comprehensive Guide for Clinicians

Antibodies directed against donor-specific human leukocyte antigens (HLAs) can be detected de novo after heart transplantation and play a key role in long-term survival. De novo donor-specific antibodies (dnDSAs) have been associated with cardiac allograft vasculopathy, antibody-mediated rejection, and mortality. Advances in detection methods and international guideline recommendations have encouraged the adoption of screening protocols among heart transplant units. However, there is still a lack of consensus about the correct course of action after dnDSA detection. Treatment is usually started when antibody-mediated rejection is present; however, some dnDSAs appear years before graft failure is detected, and at this point, damage may be irreversible. In particular, class II, anti-HLA-DQ, complement binding, and persistent dnDSAs have been associated with worse outcomes. Growing evidence points towards a more aggressive management of dnDSA. For that purpose, better diagnostic tools are needed in order to identify subclinical graft injury. Cardiac magnetic resonance, strain techniques, or coronary physiology parameters could provide valuable information to identify patients at risk. Treatment of dnDSA usually involves plasmapheresis, intravenous immunoglobulin, immunoadsorption, and ritxumab, but the benefit of these therapies is still controversial. Future efforts should focus on establishing effective treatment protocols in order to improve long-term survival of heart transplant recipients.

A modified perioperative regimen for deceased donor kidney transplantation in presensitized recipients without prior desensitization therapy

Background

Renal transplantation in HLA-presensitized recipients entails an increased risk of antibody-mediated rejection (AMR) and graft loss. There is currently no accepted standard treatment protocol that can help transplant surgeons safely perform deceased donor (DD) kidney transplantation in presensitized patients without pretransplant desensitization.

Methods

Fifty-one panel-reactive antibody (PRA)-positive recipients and 62 PRA-negative retransplant recipients (control) who received DD renal transplantation were included. Patients in the presensitized group (donor-specific antibody [DSA]-positive, n=25; DSA-negative, n=26) without desensitization received a modified perioperative treatment starting on day 0 or -1 with rituximab, thymoglobulin, and low daily doses of intravenous immunoglobulin (IVIG, 10-20 g/d, for 14 days). Plasmapheresis was performed once before surgery in DSA-positive recipients.

Results

The median follow-up time was 51 months in the presensitized group and 41 months in the control group. The incidence of early acute rejection (AR) and AMR (including mixed rejection) was 35.3% and 13.7% in the presensitized group, respectively, significantly higher than in the control group (14.5% and 1.6%, respectively). Within the presensitized group, the DSA-positive subgroup had more AMR than the DSA-negative subgroup (24.0% vs. 3.8%), but the incidence of T cell-mediated rejection was comparable (20.0% vs. 23.4%). In the presensitized group, all rejections were successfully reversed, and graft function remained stable during follow-up. The 1-year and 3-year survival rates of the grafts and recipients in this group were 98.0%.

Conclusion

With a modified IVIG-based perioperative regimen, excellent intermediate-term graft and recipient survival outcomes can be achieved in presensitized patients who received DD kidney transplantation without prior desensitization.

Refractory Keratolimbal Allograft Rejection in Autoimmune Polyglandular Syndrome-Associated Keratopathy Treated With Intravenous Immunoglobulin

PURPOSE

The aim of this study was to describe the use of intravenous immunoglobulin (IVIG) in the management of a 20-year-old woman with autoimmune polyglandular syndrome-associated keratopathy who developed acute transplant rejection after keratolimbal allograft (KLAL) surgery.

CASE

Nine weeks after KLAL surgery, a 20-year-old woman with autoimmune polyglandular syndrome-related limbal stem cell deficiency presented with graft injection, hemorrhage, and an epithelial rejection line. This was concerning for acute rejection in the setting of triple-agent systemic immunosuppression (albeit nonadherence at times). There was initial reversal of the rejection process with a sub-Tenon's injection of triamcinolone, frequent topical corticosteroids, increase in oral prednisone, and optimization of systemic immunosuppression medications; however, recurrence of the epithelial rejection line and symptoms were noted whenever the prednisone dose was tapered. This was accompanied by ocular surface decompensation (late staining, neovascularization, and persistent epithelial defects). She was found to have weakly positive HLA Class 1 antibodies. The patient was treated with a pulsed corticosteroid infusion and 2 monthly IVIG infusions. This led to resolution of the acute rejection. However, there was a subsequent rejection episode 4 months later after tapering the prednisone. Monthly IVIG for 6 more months led to final resolution with successful prednisone tapering and no further rejection.

CONCLUSIONS

Treatment with prolonged IVIG showed better improvement in a case of acute rejection refractory to traditional treatments, especially in the setting of HLA antibodies. The case demonstrates that close follow-up with a corneal specialist and collaboration with a transplant specialist is important to monitor for postoperative KLAL rejection.

Effects of glucose oxidase on growth performance, clinical symptoms, serum parameters, and intestinal health in piglets challenged by enterotoxigenic Escherichia coli

Glucose oxidase (GOD) could benefit intestinal health and growth performance in animals. However, it is unknown whether GOD can protect piglets against bacterial challenge. This study aimed to evaluate the protective effects of GOD on growth performance, clinical symptoms, serum parameters, and intestinal health in piglets challenged by enterotoxigenic Escherichia coli (ETEC). A total of 44 male weaned piglets around 38 days old were divided into four groups (11 replicates/group): negative control (NC), positive control (PC), CS group (PC piglets +40 g/t colistin sulfate), and GOD group (PC piglets +200 g/t GOD). All piglets except those in NC were challenged with ETEC (E. coli K88) on the 11th day of the experiment. Parameter analysis was performed on the 21st day of the experiment. The results showed that the ETEC challenge elevated (p < 0.05) the rectal temperature and fecal score of piglets at certain time-points post-challenge, reduced (p < 0.05) serum glucose and IgG levels but increased (p < 0.05) serum alanine aminotransferase activity, as well as caused (p < 0.05) intestinal morphology impairment and inflammation. Supplemental GOD could replace CS to reverse (p < 0.05) the above changes and tended to increase (p = 0.099) average daily gain during the ETEC challenge. Besides, GOD addition reversed ETEC-induced losses (p < 0.05) in several beneficial bacteria (e.g., Lactobacillus salivarius) along with increases (p < 0.05) in certain harmful bacteria (e.g., Enterobacteriaceae and Escherichia/Shigella). Functional prediction of gut microbiota revealed that ETEC-induced upregulations (p < 0.05) of certain pathogenicity-related pathways (e.g., bacterial invasion of epithelial cells and shigellosis) were blocked by GOD addition, which also normalized the observed downregulations (p < 0.05) of bacterial pathways related to the metabolism of sugars, functional amino acids, nucleobases, and bile acids in challenged piglets. Collectively, GOD could be used as a potential antibiotic alternative to improve growth and serum parameters, as well as attenuate clinical symptoms and intestinal disruption in ETEC-challenged piglets, which could be associated with its ability to mitigate gut microbiota dysbiosis. Our findings provided evidence for the usage of GOD as an approach to restrict ETEC infection in pigs.

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.

Heart transplantation: focus on donor recovery strategies, left ventricular assist devices, and novel therapies

Heart transplantation is advocated in selected patients with advanced heart failure in the absence of contraindications. Principal challenges in heart transplantation centre around an insufficient and underutilized donor organ pool, the need to individualize titration of immunosuppressive therapy, and to minimize late complications such as cardiac allograft vasculopathy, malignancy, and renal dysfunction. Advances have served to increase the organ donor pool by advocating the use of donors with underlying hepatitis C virus infection and by expanding the donor source to use hearts donated after circulatory death. New techniques to preserve the donor heart over prolonged ischaemic times, and enabling longer transport times in a safe manner, have been introduced. Mechanical circulatory support as a bridge to transplantation has allowed patients with advanced heart failure to avoid progressive deterioration in hepato-renal function while awaiting an optimal donor organ match. The management of the heart transplantation recipient remains a challenge despite advances in immunosuppression, which provide early gains in rejection avoidance but are associated with infections and late-outcome challenges. In this article, we review contemporary advances and challenges in this field to focus on donor recovery strategies, left ventricular assist devices, and immunosuppressive monitoring therapies with the potential to enhance outcomes. We also describe opportunities for future discovery to include a renewed focus on long-term survival, which continues to be an area that is under-studied and poorly characterized, non-human sources of organs for transplantation including xenotransplantation as well as chimeric transplantation, and technology competitive to human heart transplantation, such as tissue engineering.

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome in liver transplantation

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a rare delayed-type hypersensitivity reaction that causes skin abnormalities and mucosal involvement of the entire body. This is a case report of DRESS occurring in a liver transplantation recipient after taking drugs. A 57-year-old female patient with hepatocellular carcinoma underwent living donor liver transplantation in April 2019. She had no previous medical histories relevant to allergic diseases. There were no adverse events during hospitalization. She was admitted to evaluate and treat a headache occurring at one month after transplantation. However, she suffered from adverse drug reactions after taking anticonvulsants, showing skin rash, itching sense, and fever with eosinophilia. Piperacillin/Tazoperan was administered for ten days as an empirical antibiotic. Skin biopsy was performed on postoperative day 106 for erythematous maculopapular rash in the arms, legs, and torso. Her symptoms improved after discontinuation of the suspected medication with conservative skin treatment and high-dose steroid treatment. This case suggests that suspicion of drug history is essential for early diagnosis and management of DRESS.

Plasma cell biology: Foundations for targeted therapeutic development in transplantation

Solid organ transplantation is a life-saving procedure for patients with end-stage organ disease. Over the past 70 years, tremendous progress has been made in solid organ transplantation, particularly in T-cell-targeted immunosuppression and organ allocation systems. However, humoral alloimmune responses remain a major challenge to progress. Patients with preexisting antibodies to human leukocyte antigen (HLA) are at significant disadvantages in regard to receiving a well-matched organ, moreover, those who develop anti-HLA antibodies after transplantation face a significant foreshortening of renal allograft survival. Historical therapies to desensitize patients prior to transplantation or to treat posttransplant AMR have had limited effectiveness, likely because they do not significantly reduce antibody levels, as plasma cells, the source of antibody production, remain largely unaffected. Herein, we will discuss the significance of plasma cells in transplantation, aspects of their biology as potential therapeutic targets, clinical challenges in developing strategies to target plasma cells in transplantation, and lastly, novel approaches that have potential to advance the field.

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.

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.

SARS-CoV-2 infection in kidney transplant recipients: Experience of the italian marche region

Background

Infection related to Coronavirus‐19 (CoV‐2) is pandemic affecting more than 4 million people in 187 countries worldwide. By May 10, 2020, it caused more than 280 000 deaths all over the world. Preliminary data reported a high prevalence of CoV‐2 infection and mortality due to severe acute respiratory syndrome related CoV‐2 (SARS‐CoV‐2) in kidney‐transplanted patients (KTRs). Nevertheless, the outcomes and the best treatments for SARS‐CoV‐2‐affected KTRs remain unclear.

Methods

In this report, we describe the clinical data, the treatments, and the outcomes of 5 KTRs with SARS‐CoV‐2 admitted to our hospital in Ancona, Marche region, Italy, from March 17 to present. Due to the severity of SARS‐CoV‐2, immunosuppression with calcineurin inhibitors, antimetabolites, and mTOR‐inhibitors were stopped at the admission. All KTRs were treated with low‐dose steroids. 4/5 KTRs were treated with hydroxychloroquine. All KTRs received tocilizumab up to one dose.

Results

Overall, the incidence of SARS‐CoV‐2 in KTRs in the Marche region was 0.85%. 3/5 were admitted in ICU and intubated. One developed AKI with the need of CRRT with Cytosorb. At present, two patients died, two patients were discharged, and one is still inpatient in ICU.

Conclusions

The critical evaluation of all cases suggests that the timing of the administration of tocilizumab, an interleukin‐6 receptor antagonist, could be associated with a better efficacy when administered in concomitance to the drop of the oxygen saturation. Thus, in SARS‐CoV‐2‐affected KTRs, a close biochemical and clinical monitoring should be set up to allow physicians to hit the virus in the right moment such as a sudden reduction of the oxygen saturation and/or a significant increase in the laboratory values such as D‐dimer.

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.

Currently available intravenous immunoglobulin contains antibodies reacting against severe acute respiratory syndrome coronavirus 2 antigens

Aim: There is a critical need for effective therapies that are immediately available to control the spread of COVID-19 disease. Material & methods: Gamunex®-C and Flebogamma® DIF (Grifols) intravenous immunoglobulin (IVIG) products were tested using ELISA techniques for antibodies against several antigens of human common betacoronaviruses that may crossreact with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. Results: Both IVIGs showed consistent reactivity to components of the tested viruses. Positive crossreactivity was seen in SARS-CoV, middle east respiratory syndrome-CoV and SARS-CoV-2. For SARS-CoV-2, positive reactivity was observed at IVIG concentrations ranging from 100 μg/ml with Gamunex-C to 1 mg/ml with Flebogamma 5% DIF. Conclusion: Gamunex-C and Flebogamma DIF contain antibodies reacting against SARS-CoV-2 antigens. Studies to confirm the utility of IVIG preparations for COVID-19 management may be warranted.

Role of Immunoglobulin Therapy to Prevent and Treat Infections

Immunoglobulins have been used widely in medicine for a variety of diseases including infectious diseases. While the main clinical applications of immunoglobulin therapy concern their use as replacement for patients with primary immunodeficiencies, or as treatment for autoimmune and inflammatory disorders, their role in infectious disease is limited largely to viral and toxin neutralization and replacement therapy in patients with immunoglobulin deficiencies. Many aspects of the therapeutic regimen of immunoglobulins even in the established indications remain open. Recently, due to the worldwide surge of immunosuppression caused by AIDS, organ transplantation, cancer, and autoimmune therapies, as well as the emergence of multidrug-resistant bacteria, there has been renewed interest in the use of antibody preparation to prevent infections in high-risk groups.

Knowing the limitations of the current anti-infective armamentarium, approaches that target the host through manipulations to augment the host immune response provide a helpful aid to conventional treatment options. A substantial body of evidence has demonstrated that strategies aiming to support or stimulate immune response could be feasible approaches that would benefit immunocompromised patients. In the present chapter, we present contemporary indications of immunoglobulin administration for therapy and prophylaxis of infections in the immunocompromised population.

Case Report: Renal Transplantation in Patients with Pre-existing Hypogammaglobulinemia

Hypogammaglobulinemia (HGG) is well-characterized as a common phenomenon after kidney transplantation. However, no reports of pre-existing HGG from kidney transplantation seem to be available. We have reviewed three patients who developed HGG prior to kidney transplantation, and all three were treated successfully with immunoglobulin replacement therapy before and after kidney transplantation. The kidney grafts were functioning at follow-up 1.5-8 years (mean: 3.6 years) after transplantation, and there were no diagnosed episodes of clinical rejections and no severe infection complications post-transplantation.

Neuroprotective strategies following intraparenchymal hemorrhage

Intracerebral hemorrhage and, more specifically, intraparenchymal hemorrhage, are devastating disease processes with poor clinical outcomes. Primary injury to the brain results from initial hematoma expansion while secondary hemorrhagic injury occurs from blood-derived products such as hemoglobin, heme, iron, and coagulation factors that overwhelm the brains natural defenses. Novel neuroprotective treatments have emerged that target primary and secondary mechanisms of injury. Nonetheless, translational application of neuroprotectants from preclinical to clinical studies has yet to show beneficial clinical outcomes. This review summarizes therapeutic agents and neuroprotectants in ongoing clinical trials aimed at targeting primary and secondary mechanisms of injury after intraparenchymal hemorrhage.

Desensitization: Overcoming the Immunologic Barriers to Transplantation

HLA (Human Leucocyte Antigen) sensitization is a significant barrier to successful kidney transplantation. It often translates into difficult crossmatch before transplant and increased risk of acute and chronic antibody mediated rejection after transplant. Over the last decade, several immunomodulatory therapies have emerged allowing for increased access to kidney transplantation for the immunologically disadvantaged group of HLA sensitized end stage kidney disease patients. These include IgG inactivating agents, anti-cytokine antibodies, costimulatory molecule blockers, complement inhibitors, and agents targeting plasma cells. In this review, we discuss currently available agents for desensitization and provide a brief analysis of data on novel biologics, which will likely improve desensitization outcomes, and have potential implications in treatment of antibody mediated rejection.

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

Renal safety of high-dose, sucrose-free intravenous immunoglobulin in kidney transplant recipients: an observational study

High-dose intravenous immunoglobulin (IVIg) is commonly used during kidney transplantation. Its nephrotoxicity has been attributed to sucrose stabilizers. We evaluated the renal safety of newer formulations of sucrose-free IVIg. We retrospectively studied clinical and histological data from 75 kidney recipients receiving high-dose, sucrose-free IVIg courses. This group was compared with 75 matched kidney recipients not treated with IVIg. Sucrose-free IVIg treatment was not associated with any acute kidney injury episode at 3 months, but an increased frequency of tubular macrovacuoles (28% vs. 2.8%, P < 0.001) was observed. Among IVIg-treated patients, the presence of macrovacuoles at 3 months was associated with increased IF/TA scores at 3 months (1.7 ± 1 vs. 1 ± 1, P = 0.005) and was more often observed in kidneys with higher IF/TA scores on day 0 (0.6 ± 0.9 vs. 0.3 ± 0.8, P = 0.03) at 3 months. Finally, patients treated with amino-acid-stabilized formulations developed fewer macrovacuoles at 3 months (12% vs. 60%; P < 0.001) than those treated with carbohydrate-stabilized IVIg. Our study shows that high-dose, sucrose-free IVIg use in early kidney recipients is clinically well tolerated. Among sucrose-free IVIg, amino-acid-stabilized formulations are associated with less tubular toxicity than carbohydrate-stabilized IVIg.

Treatment and prevention of cytomegalovirus infection in heart and lung transplantation: an update

INTRODUCTION

Heart and lung transplantation are standard therapeutic strategies to improve survival and quality of life in selected patients with end-stage heart or lung diseases. Cytomegalovirus (CMV) is one the most clinically relevant and frequent post-transplant infectious agents, which may cause direct acute syndromes, and chronic indirect graft-related injury. Despite effective antiviral drugs being available to prevent and treat CMV infection, due to the immunosuppression burden and the specific characteristics of thoracic grafts, CMV infection remains a major clinical problem in heart and lung transplant recipients.

AREAS COVERED

We performed an extensive literature search focused on studies specifically including heart or lung transplantation, when available, or kidney transplant recipients when data on thoracic transplants were not available. We discuss the pros and cons supporting the use of currently available drugs and strategies for CMV prevention and treatment, highlighting current unmet needs.

EXPERT OPINION

While (Val)Ganciclovir remains the cornerstone of anti-CMV therapy, prolonged universal prophylaxis may expose a large number of patients to an excess of drug toxicity. Additional drugs with lower toxicity may be available in the context of anti-CMV prophylaxis, and effective CMV-risk stratification, by means of novel immune monitoring assays, which may help to customize the therapeutic approach.

Low incidence of acute rejection in hepatitis B virus positive liver transplant recipients and the impact of hepatitis B immunoglobulin

Historically, hepatitis B virus (HBV) liver transplantation (LT) recipients have less acute cellular rejection (ACR) than those without HBV. We questioned whether this has persisted in an era of decreased Hepatitis B immunoglobulin use (HBIG) given its in vitro immunoregulatory effects. We compared the incidence, risk factors and outcomes of ACR among 40,593 primary LT recipients with HBV, hepatitis C, steatohepatitis, and immune liver disease (OPTN 2000-2011). We also assessed the in vitro effect of HBIG on alloimmune lymphoproliferation and regulatory T cell generation using mixed lymphocyte reactions. In multivariate analysis, HBV status remained a strong independent predictor of freedom from ACR (OR 0.58, 95% CI: 1.5-2.1). Patient (67.7% vs 72.3%) and graft (60.8% vs 69.1%) survival were significantly lower in patients with ACR versus no ACR for all causes except HBV. HBIG use had no statistical association with ACR. In vitro, HBIG at concentrations equivalent to clinical dosing did not inhibit lymphoproliferation or promote regulatory T cell development. In summary, the incidence and impact of ACR is lower now for HBV LT and does not appear to be secondary to HBIG by our in vitro and in vivo analyses. Rather, it may be due to the innate immunosuppressive properties of chronic HBV infection.

Heme oxygenase-1 is dispensable for the anti-inflammatory activity of intravenous immunoglobulin

Intravenous immunoglobulin G (IVIG) is used in the therapy of various autoimmune and inflammatory conditions. The mechanisms by which IVIG exerts anti-inflammatory effects are not completely understood. IVIG interacts with numerous components of the immune system including dendritic cells, macrophages, T and B cells and modulate their functions. Recent studies have reported that heme oxygenase-1 (HO-1) pathway plays an important role in the regulation of inflammatory response in several pathologies. Several therapeutic agents exert anti-inflammatory effects via induction of HO-1. Therefore, we aimed at exploring if anti-inflammatory effects of IVIG are mediated via HO-1 pathway. Confirming the previous reports, we report that IVIG exerts anti-inflammatory effects on innate cells as shown by the inhibitory effects on IL-6 and nitric oxide production and confers protection in experimental autoimmune encephalomyelitis (EAE) model. However, these effects were not associated with an induction of HO-1 either in innate cells such as monocytes, dendritic cells and macrophages or in the kidneys and liver of IVIG-treated EAE mice. Also, inhibition of endogenous HO-1 did not modify anti-inflammatory effects of IVIG. These results thus indicate that IVIG exerts anti-inflammatory effects independent of HO-1 pathway.

Efficacy of intravenous immunoglobulin in the treatment of persistent BK viremia and BK virus nephropathy in renal transplant recipients

BK virus-associated nephropathy (BKVN) can cause clinically significant viral infection in renal transplant recipients, leading to allograft dysfunction and loss. The usual management of BKVN involves the reduction of immunosuppression and the addition of leflunomide, quinolones, and cidofovir, but the rate of graft loss remains high. The aim of this study was to assess the impact of treatment with intravenous human immunoglobulin (IVIG) on the outcome of BKVN in renal transplant recipients. Upon diagnosis of BKVN, patients remained on anti-polyomavirus treatment, consisting of the reduction of immunosuppression and the use of leflunomide therapy. Treatment with IVIG was given only to patients who did not respond to 8 weeks of the adjustment of immunosuppression and leflunomide. All 30 patients had persistent BKV viremia and BKVN with their mean BK viral loads higher than the baseline (range, 15,000-2 million copies/mL). Mean peak BK load was 205,314 copies/mL compared with 697 copies/mL after 1 year of follow-up. Twenty-seven patients (90%) had a positive response in clearing viremia. The actuarial patient and graft survival rates after 12 months were 100% and 96.7%, respectively. IVIG administration appeared to be safe and effective in treating BKV viremia and BKVN and preventing graft loss in patients who had inadequate response to immunosuppression reduction and leflunomide therapy.

Intravenous immunoglobulin for antibody-mediated keratolimbal allograft rejection

A 33-year-old woman with congenital aniridia presented with decreased vision in her right eye. Slit lamp examination revealed diffuse conjunctivalisation of the ocular surface with mild subepithelial fibrosis consistent with aniridic keratopathy secondary to limbal stem cell deficiency. She underwent limbal stem cell transplantation with cadaver donor tissue (keratolimbal allograft (KLAL) surgery) and received systemic immunosuppression. Despite optimal combination immunosuppressive therapy managed by a renal transplant specialist, 2 weeks after the KLAL, the patient developed intractable eye pain, conjunctival injection, dilation of the KLAL graft blood vessels and limbal haemorrhages. There were no epithelial defects noted. Donor-specific antibody testing was positive, and intravenous immunoglobulin therapy was initiated. There was immediate symptomatic and objective improvement. Fifteen months postoperatively, the patient's vision was 20/400 with a stable corneal epithelium and no evidence of inflammation.

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.

Achieving incompatible transplantation through desensitization: current perspectives and future directions

The application of life-saving transplantation is severely limited by the shortage of organs, and histoincompatibility. To increase transplant rates in sensitized patients, new protocols for HLA and blood type incompatible (ABOi) desensitization have emerged. These approaches require significant desensitization using intravenous immunoglobulin, rituximab and plasma exchange. In addition, the development of donor-specific antibody responses post transplant is the major cause of allograft failure with return to dialysis. This increases patient morbidity/mortality and cost. Immunotherapeutic agents used for desensitization evolved from drug development in oncology and autoimmune diseases. Currently, there is a renaissance in development of novel drugs likely to improve antibody reduction in transplantation. These include agents that inactivate IgG molecules, anticytokine antibodies, costimulatory molecule blockade, anticomplement agents and therapies aimed at the plasma cell.

Establishment of HSV1 latency in immunodeficient mice facilitates efficient in vivo reactivation

The establishment of latent infections in sensory neurons is a remarkably effective immune evasion strategy that accounts for the widespread dissemination of life long Herpes Simplex Virus type 1 (HSV1) infections in humans. Periodic reactivation of latent virus results in asymptomatic shedding and transmission of HSV1 or recurrent disease that is usually mild but can be severe. An in-depth understanding of the mechanisms regulating the maintenance of latency and reactivation are essential for developing new approaches to block reactivation. However, the lack of a reliable mouse model that supports efficient in vivo reactivation (IVR) resulting in production of infectious HSV1 and/or disease has hampered progress. Since HSV1 reactivation is enhanced in immunosuppressed hosts, we exploited the antiviral and immunomodulatory activities of IVIG (intravenous immunoglobulins) to promote survival of latently infected immunodeficient Rag mice. Latently infected Rag mice derived by high dose (HD), but not low dose (LD), HSV1 inoculation exhibited spontaneous reactivation. Following hyperthermia stress (HS), the majority of HD inoculated mice developed HSV1 encephalitis (HSE) rapidly and synchronously, whereas for LD inoculated mice reactivated HSV1 persisted only transiently in trigeminal ganglia (Tg). T cells, but not B cells, were required to suppress spontaneous reactivation in HD inoculated latently infected mice. Transfer of HSV1 memory but not OVA specific or naïve T cells prior to HS blocked IVR, revealing the utility of this powerful Rag latency model for studying immune mechanisms involved in control of reactivation. Crossing Rag mice to various knockout strains and infecting them with wild type or mutant HSV1 strains is expected to provide novel insights into the role of specific cellular and viral genes in reactivation, thereby facilitating identification of new targets with the potential to block reactivation.

Although mouse models have been very useful in studies of HSV1 latency, the inability to efficiently reactivate latent HSV1 in vivo has impeded studies of reactivation. Reasoning that reactivation would be much more efficient in the absence of T cells, we exploited IVIG to promote survival of latently infected Rag mice lacking B and T cells. We established a threshold inoculum dose that was higher for B6- compared to 129-Rag mice, which determined whether HSV1 could be efficiently reactivated in vivo resulting in encephalitis. We showed directly that memory T cells are required to control spontaneous and induced reactivation in mice inoculated at high dose but are dispensable for maintaining latency in low dose inoculated mice. Incorporating different knockout strains into the Rag latency model by adoptive transfer of cells or crossbreeding will facilitate studying the role of various cellular genes involved in regulating neuronal gene expression and innate and adaptive immunity in the control of HSV1 reactivation. The potential of this powerful latency model to unravel the molecular and immune mechanisms regulating latency will be realized only after it is adopted and refined by researchers in the field.

Intravenous immunoglobulin-induced IL-33 is insufficient to mediate basophil expansion in autoimmune patients

Intravenous immunoglobulin (IVIg) is used in the therapy of various autoimmune and inflammatory diseases. Recent studies in experimental models propose that anti-inflammatory effects of IVIg are mainly mediated by α2,6-sialylated Fc fragments. These reports further suggest that α2,6-sialylated Fc fragments interact with DC-SIGN⁺ cells to release IL-33 that subsequently expands IL-4-producing basophils. However, translational insights on these observations are lacking. Here we show that IVIg therapy in rheumatic patients leads to significant raise in plasma IL-33. However, IL-33 was not contributed by human DC-SIGN⁺ dendritic cells and splenocytes. As IL-33 has been shown to expand basophils, we analyzed the proportion of circulating basophils in these patients following IVIg therapy. In contrast to mice data, IVIg therapy led to basophil expansion only in two patients who also showed increased plasma levels of IL-33. Importantly, the fold-changes in IL-33 and basophils were not correlated and we could hardly detect IL-4 in the plasma following IVIg therapy. Thus, our results indicate that IVIg-induced IL-33 is insufficient to mediate basophil expansion in autoimmune patients. Hence, IL-33 and basophil-mediated anti-inflammatory mechanism proposed for IVIg might not be pertinent in humans.

Targeting B cells in sensitized kidney transplant patients: state of the art and future perspectives

PURPOSE OF REVIEW

In sensitized kidney transplant recipients, whose number is continuously growing, the negative impact of antibody-mediated rejection is being increasingly recognized. The purpose of this review is to summarize the state of knowledge about the mechanisms of alloantibody production. We will also report the most recent clinical results of current immunosuppressive protocols - either preventive or curative - in this population.

RECENT FINDINGS

Even if progress in access to transplantation and short-term graft survival has been made in sensitized patients using therapeutic strategies targeting both alloantibodies (plasmapheresis and/or intravenous globulins) and B cells (CD20 antibodies), antibody-mediated rejection remains a critical issue frequently compromising renal function and middle-term graft survival. The partial efficacy of such strategies and the presence in sensitized patients of both peripheral memory B cells and bone marrow plasma cells capable of alloantibody synthesis in vitro suggest that, in vivo, alloantibody production most likely involves both cell types, not equally targeted by CD20 antibody-based therapies.

SUMMARY

The need for improved strategies of prevention/treatment of antibody-mediated rejection, have led, based on the actual understanding of alloantibody synthesis, to the use of drugs targeting plasma cells, that is proteasome inhibitors. Preliminary results are contrasted and highlight the necessity for controlled studies in the field of antihumoral therapies.

Therapeutic effect of IVIG on inflammatory arthritis in mice is dependent on the Fc portion and independent of sialylation or basophils

High-dose i.v. Ig (IVIG) is used to treat various autoimmune and inflammatory diseases; however, the mechanism of action remains unclear. Based on the K/BxN serum transfer arthritis model in mice, IVIG suppression of inflammation has been attributed to a mechanism involving basophils and the binding of highly sialylated IgG Fc to DC-SIGN-expressing myeloid cells. The requirement for sialylation was examined in the collagen Ab-induced arthritis (CAbIA) and K/BxN serum transfer arthritis models in mice. High-dose IVIG (1-2 g/kg body weight) suppressed inflammatory arthritis when given prophylactically. The same doses were also effective in the CAbIA model when given subsequent to disease induction. In this therapeutic CAbIA model, the anti-inflammatory effect of IVIG was dependent on IgG Fc but not F(ab')2 fragments. Removal of sialic acid residues by neuraminidase had no impact on the anti-inflammatory activity of IVIG or Fc fragments. Treatment of mice with basophil-depleting mAbs did not abrogate the suppression of either CAbIA or K/BxN arthritis by IVIG. Our data confirm the therapeutic benefit of IVIG and IgG Fc in Ab-induced arthritis but fail to support the significance of sialylation and basophil involvement in the mechanism of action of IVIG therapy.

Plasmapheresis-resistant acute humoral rejection successfully treated with anti-C5 antibody

Even if kidney graft survival has improved during the last decades, sensitized pediatric patients are an emerging problem. We describe a 17-yr-old male who lost his first graft due to chronic rejection becoming hyperimmunized (CDC PRA 99.61%). A desensitization protocol based on high-dose IVIG, PP, and two Mabthera(®) infusions was performed with minor response (CDC PRA post-desensitization 80%). One month after his second non-living transplant, he developed a biopsy-proven AMR; post-transplant immunological monitoring showed the presence of donor-specific anti-DQ5 antibodies (DSA, MFI 20.000). He received methylprednisolone pulses and 45 PP sessions without clinical response; eculizumab was then used to salvage a kidney undergoing severe PP-resistant rejection. A biopsy performed after the fourth eculizumab infusion showed complete resolution of AMR. Eculizumab infusions were then continued for the first year post-transplantation. Two yr after transplantation, graft function is stable. Anti-C5 therapy may represent an effective therapeutic option in pediatric patients with PP-resistant AMR.

IVIG Effects on Erythrocyte Sedimentation Rate in Children

Background. Erythrocyte sedimentation rate (ESR) is a valuable laboratory tool in evaluation of infectious, inflammatory, and malignant diseases. Red blood cells in outside from the body precipitate due to their higher density than the plasma. In this study we discuss the IVIG effect on ESR in different diseases and different ages. Methods and Materials. Fifty patients under 12 years old who had indication to receive IVIG enrolled in this study. Total dose of IVIG was 2 gr/kg (400 mg/kg in five days or 2 gr/kg in single dose). ESR before infusion of IVIG and within 24 hours after administration of the last dose of IVIG was checked. Results. 23 (46%) patients were males and 27 (54%) were females. The mean of ESR before IVIG was 31.8 ± 29.04 and after IVIG it was 47.2 ± 36.9; this difference was meaningful (P = 0.05). Results of ESR changes in different age groups, 6 patients less than 28 days, 13 patients from 1 month to 1 year, 20 patients from 1 to 6 years old, and 11 patients from 6 to 12 years have been meaningful (P = 0.001, P = 0.025, and P = 0.006, resp.). Conclusion. In patients who are receiving IVIG as a therapy, ESR increased falsely (noninflammatory rising); therefore use of ESR for monitoring of response to treatment may be unreliable. Although these results do not apply to neonatal group, we suggest that, in patients who received IVIG, interpretation of ESR should be used cautiously on followup.

Intravenous immunoglobulin expands regulatory T cells via induction of cyclooxygenase-2-dependent prostaglandin E2 in human dendritic cells

CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) play a critical role in the maintenance of immune tolerance. Intravenous immunoglobulin (IVIg), a therapeutic preparation of normal pooled human IgG, expands Tregs in various experimental models and in patients. However, the cellular and molecular mechanisms by which IVIg expands Tregs are relatively unknown. As Treg expansion in the periphery requires signaling by antigen-presenting cells such as dendritic cells (DCs) and IVIg has been demonstrated to modulate DC functions, we hypothesized that IVIg induces distinct signaling events in DCs that subsequently mediate Treg expansion. We demonstrate that IVIg expands Tregs via induction of cyclooxygenase (COX)-2-dependent prostaglandin E2 (PGE2) in human DCs. However, costimulatory molecules of DCs such as programmed death ligands, OX40 ligand, and inducible T-cell costimulator ligands were not implicated. Inhibition of PGE2 synthesis by COX-2 inhibitors prevented IVIg-mediated Treg expansion in vitro and significantly diminished IVIg-mediated Treg expansion in vivo and protection from disease in experimental autoimmune encephalomyelitis model. IVIg-mediated COX-2 expression, PGE2 production, and Treg expansion were mediated in part via interaction of IVIg and F(ab')2 fragments of IVIg with DC-specific intercellular adhesion molecule-3-grabbing nonintegrin. Our results thus uncover novel cellular and molecular mechanism by which IVIg expands Tregs.

Severe antibody-mediated rejection following IVIG infusion in a kidney transplant recipient with BK-virus nephropathy

Intravenous immune-globulin (IVIG) use in renal transplantation has increased, with common uses including desensitization, treatment of antibody mediated rejection and adjunctive therapy for BK virus nephropathy. Although considered generally safe, potential side effects can occur in up to 23% of patients including acute kidney injury. We present a case of an unexpected cause of acute kidney injury in a renal transplant recipient following IVIG infusion. A 48-year-old nonsensitized female with end stage renal disease secondary to polycystic kidney disease received a deceased donor kidney transplant. The initial post-transplant period was unremarkable however at three years post-transplant the patient develops BK virus nephropathy. Despite a reduction in immunosuppression, graft function worsened and IVIG infusion was commenced. Immediately following the IVIG infusion, the patient develops anuric acute kidney injury necessitating hemodialysis. Renal transplant biopsy performed before and after the IVIG infusion revealed the de novo development of acute antibody mediated rejection and donor specific antibodies in the serum. Anti-HLA and donor-specific antibodies were also confirmed in a diluted sample of the IVIG preparation. We argue that the anti-HLA antibodies present in the IVIG caused an acute antibody mediated rejection in this previously nonsensitized female.

Autoantibodies targeting tumor-associated antigens in metastatic cancer: Sialylated IgGs as candidate anti-inflammatory antibodies

In addition to the well-established effector functions of IgGs, including direct cytotoxicity and antibody-dependent cellular cytotoxicity, some populations of IgGs may exert anti-inflammatory effects. Here, we describe a population of antibodies that form in the natural course of metastatic cancer and contain glycans that terminate with sialic acid. We demonstrate that both the titer of these antibodies and their level of sialylation are relatively stable throughout the progression of metastatic melanoma. The sialylation pattern of these antibodies somehow correlates with their specificity for tumor-associated antigens, as IgGs targeting several antigens associated with infectious agents are relatively poor of sialic acid. We also show that some antibodies targeting the melanoma-associated antigen NY-ESO-1 bind to the human C-type lectin CD209 (DC-SIGN). We propose that these antibodies are candidate anti-inflammatory antibodies. The presence of anti-inflammatory antibodies in cancer patients may explain, at least in part, why tumors persist and spread in the host despite strong tumor-specific humoral responses. The elucidation of the cellular and molecular pathways involved in the induction of anti-inflammatory antibodies specific for tumor-associated antigens and their function may yield important insights into how tumors evade immune detection and progress.

Effect of high-dose intravenous immunoglobulin on anti-HLA antibodies in sensitized kidney transplant candidates

Limited data exist on the effect of intravenous immunoglobulin (IVIg) on anti-HLA antibodies as determined by solid-phase assays. We reviewed our experience treating sensitized wait-listed kidney transplant recipients with IVIg as a method for desensitization and report our results utilizing Luminex single antigen (LSA) bead assay to quantify antibody reactivity (MFI). Fifteen patients with a cPRA > 40% received 2 g/kg IVIg per month for four months or until transplanted. LSA testing was performed before and after IVIg. Median MFI for anti-class I antibodies fell in 11 (73%) and increased in 4 (27%) patients after IVIg. Similar significant changes in MFI for anti-class II antibodies were observed in 10 patients (66%). Administration of IVIg was associated with a modest decrease in reactivity to both class I and II HLA antigens (median MFI change 493 and 1110, respectively; p < 0.0001) but did not significantly alter mean cPRA (85% before IVIg vs. 80% after IVIg; p = 0.1). Our data suggest a smaller effect of IVIg on HLA antibody reactivity than previously described, leading us to question how best to measure the efficacy of a desensitization protocol in current practice.

The safety profile of home infusion of intravenous immunoglobulin in patients with neuroimmunologic disorders

OBJECTIVES

To assess the overall safety of high-dose intravenous immunoglobulin (IG) products used to treat patients with neuroimmunological disorders in a supervised home-based setting.

METHODS

The incidence of adverse reactions was assessed in a retrospective chart review of 420 patients who consecutively received 4076, home-based, individual, intravenous immunoglobulin (IVIG) infusions between January 2009 and December 2009.

RESULTS

A total of 90 patients (21.4%) developed adverse reactions related to IVIG administration (2.6% per individual infusion). A total of 95.5% of adverse reactions were mild, and no serious side effects were observed. The incidence of adverse reactions was significantly lower in the subgroup of patients with neuroimmunological disorders who received premedication (18.2% compared with 29.3%, P = 0.02). There was no significant statistical difference in the incidence of side effects among the different brands of IVIG used in this study.

CONCLUSIONS

The combination of premedication and well-defined clinical, IVIG infusion policies may reduce the incidence of high-dose IVIG adverse reactions administered in a home-based setting in patients with neuroimmunological disorders.

Role of complement and perspectives for intervention in transplantation

The complement cascade is a major contributor to the innate immune response. It has now been well accepted that complement plays a critical role in hyperacute rejection and acute antibody-mediated rejection of transplanted organ. There is also increasing evidence that complement proteins contribute to the pathogenesis of organ ischemia-reperfusion injury, and even to cell-mediated rejection. Furthermore, the chemoattractants C3a and C5a and the terminal membrane attack complex that are generated by complement activation can directly or indirectly mediate tissue injury and trigger adaptive immune responses. Here, we review recent findings concerning the role of complement in graft ischemia-reperfusion injury, antibody-mediated rejection and accommodation, and cell-mediated rejection. We also discuss the current status of complement intervention therapies in clinical transplantation and describe potential new therapeutic strategies for clinical application.