A prospective cohort study identifies two types of HIV+ Kaposi Sarcoma lesions: proliferative and inflammatory.

Kaposi sarcoma (KS) is the most common cancer in people living with HIV (PLWH) in many countries where KS-associated herpesvirus is endemic. Treatment has changed little in 20 years, but the disease presentation has. This prospective cohort study enrolled 122 human immunodeficiency virus (HIV) positive KS patients between 2017 and 2019 in Malawi. Participants were treated with bleomycin, vincristine and combination antiretroviral therapy, the local standard of care. One-year overall survival was 61%, and progression-free survival was 58%. The 48-week complete response rate was 35%. RNAseq (n = 78) differentiated two types of KS lesions, those with marked endothelial characteristics and those enriched in inflammatory transcripts. This suggests that different KS lesions are in different disease states consistent with the known heterogeneous clinical response to treatment. In contrast to earlier cohorts, the plasma HIV viral load of KS patients in our study was highly variable. A total of 25% of participants had no detectable HIV; all had detectable KSHV viral load. Our study affirms that many KS cases today develop in PLWH with well-controlled HIV infection and that different KS lesions have differing molecular compositions. Further studies are needed to develop predictive biomarkers for this disease.

A Banff-based histologic chronicity index is associated with graft loss in patients with a kidney transplant and antibody-mediated rejection.

Antibody-mediated rejection (AMR) is the major cause of graft loss in kidney transplant recipients. The Banff classification defines two classes of AMR, active and chronic active but over time this classification has become increasingly complex. To simplify the approach to AMR, we developed activity and chronicity indices based on kidney transplant biopsy findings and examined their association with graft survival in 147 patients with active or chronic active AMR, all of whom had donor-specific antibodies and were treated for AMR. The activity index was determined as the sum of Banff glomerulitis (g), peritubular capillaritis (ptc), arteritis (v) and C4d scores, with a maximum score of 12. The chronicity index was the sum of interstitial fibrosis (ci), tubular atrophy (ct), chronic vasculopathy (cv), and chronic glomerulopathy (cg) scores, the latter doubled, with a maximum score of 15. While the activity index was generally not associated with graft loss, the chronicity index was significantly associated with graft loss with an optimal threshold value of 4 or greater for predicting graft loss. The association of the chronicity index of 4 or greater with graft loss was independent of other parameters associated with graft loss, including the estimated glomerular filtration rate at the time of biopsy, chronic active (versus active) AMR, AMR with de novo (versus persistent/rebound) donor-specific antibodies, Banff (g+ptc) scores, concurrent T cell-mediated rejection and donor-specific antibody reduction post-biopsy. The association of the chronicity index of 4 or greater with graft loss was confirmed in an independent cohort of 61 patients from Necker Hospital, Paris. Thus, our findings suggest that the chronicity index may be valuable as a simplified approach to decision-making in patients with AMR.

Clazakizumab for desensitization in highly sensitized patients awaiting transplantation.

Alloantibodies are a significant barrier to successful transplantation. While desensitization has emerged, efficacy is limited. Interleukin-6 (IL-6) is an important mediator of inflammation and immune cell activation. Persistent IL-6 production increases the risk for alloantibody production. Here we report our experience with clazakizumab (anti-IL-6) for desensitization of highly HLA-sensitized patients (HS). From March 2018 to September 2020, 20 HS patients were enrolled in an open label pilot study to assess safety and limited efficacy of clazakizumab desensitization. Patients received PLEX, IVIg, and clazakizumab 25 mg monthly X6. If transplanted, graft function, pathology, HLA antibodies and regulatory immune cells were monitored. Transplanted patients received standard immunosuppression and clazakizumab 25 mg monthly posttransplant. Clazakizumab was well tolerated and associated with significant reductions in class I and class II antibodies allowing 18 of 20 patients to receive transplants with no DSA rebound in most. Significant increases in Treg and Breg cells were seen posttransplant. Antibody-mediated rejection occurred in three patients. The mean estimated glomerular filtration rate at 12 months was 58 ± 29 ml/min/1.73 m2 . Clazakizumab was generally safe and associated with significant reductions in HLA alloantibodies and high transplant rates for highly-sensitized patients. However, confirmation of efficacy for desensitization requires assessment in randomized controlled trials.

Assessment of humoral and cellular immune responses to SARS CoV-2 vaccination (BNT162b2) in immunocompromised renal allograft recipients.

BACKGROUND: Assessing the composition of immune responses to SARS-CoV-2 vaccines is critical for our understanding of protective immunity, especially for immune compromised patients. The Pfizer (BNT162b2) vaccination showed >90% efficacy in protecting individuals from infection. However, these studies did not examine responses in immunocompromised kidney transplant patients (KT). Subsequent reports in KT have shown severe deficiencies in Spike-specific immunoglobin G (IgG) responses prompting booster vaccinations, but a broader understanding of T-cell immunity to vaccinating is lacking. METHODS: We examined SARS-CoV-2 Spike IgG and CD4+/CD8+ Spike-specific T-cell responses in 61 KT patients maintained on different immunosuppressive protocols (ISP) (Tac + mycophenolate mofetil + prednisone) versus (belatacept + MMF + prednisone) and compared to 41 healthy controls. We also examined cytomegalovirus-cytotoxic T-cell responses (CMV-Tc) in both groups to assess T-cell memory. RESULTS: Our data confirmed poor Spike IgG responses in vaccinated KT patients with both ISP (21% demonstrating Spike IgG 1M post-second dose of BNT162b2 vs. 93% in controls). However, 35% of Spike IgG (-) patients demonstrated CD4+ and/or CD8+ T-cell responses. All but one CMV-IgG+ patient demonstrated good CMV-Tc responses. No differences in T-cell immunity by ISP were seen. CONCLUSION: Immunocompromised KT recipients showed severe defects in humoral and T-cell immune response after vaccination. No differences in immune responses to SARS-CoV-2 Spike peptides were observed in KT patients by ISP post-vaccination. The detection of Spike-specific T-cell immunity in the absence of Spike IgG suggests that vaccination in immunocompromised KT patients may provide partial immunity, although not preventing infection, T-cell immunity may limit its severity.

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.

IgG Endopeptidase in Highly Sensitized Patients Undergoing Transplantation.

BACKGROUND: Donor-specific antibodies create an immunologic barrier to transplantation. Current therapies to modify donor-specific antibodies are limited and ineffective in the most highly HLA-sensitized patients. The IgG-degrading enzyme derived from Streptococcus pyogenes (IdeS), an endopeptidase, cleaves human IgG into F(ab')2 and Fc fragments inhibiting complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity, which suggests that IdeS might be useful for desensitization. We report on the combined experience of two independently performed open-label, phase 1-2 trials (conducted in Sweden and the United States) that assessed the efficacy of IdeS with regard to desensitization and transplantation of a kidney from an HLA-incompatible donor. METHODS: We administered IdeS to 25 highly HLA-sensitized patients (11 patients in Uppsala or Stockholm, Sweden, and 14 in Los Angeles) before the transplantation of a kidney from an HLA-incompatible donor. Frequent monitoring for adverse events, outcomes, donor-specific antibodies, and renal function was performed, as were renal biopsies. Immunosuppression after transplantation consisted of tacrolimus, mycophenolate mofetil, and glucocorticoids. Patients in the U.S. study also received intravenous immune globulin and rituximab after transplantation to prevent antibody rebound. RESULTS: Recipients in the U.S. study had a significantly longer cold ischemia time (the time elapsed between procurement of the organ and transplantation), a significantly higher rate of delayed graft function, and significantly higher levels of class I donor-specific antibodies than those in the Swedish study. A total of 38 serious adverse events occurred in 15 patients (5 events were adjudicated as being possibly related to IdeS). At transplantation, total IgG and HLA antibodies were eliminated. A total of 24 of 25 patients had perfusion of allografts after transplantation. Antibody-mediated rejection occurred in 10 patients (7 patients in the U.S. study and 3 in the Swedish study) at 2 weeks to 5 months after transplantation; all these patients had a response to treatment. One graft loss, mediated by non-HLA IgM and IgA antibodies, occurred. CONCLUSIONS: IdeS reduced or eliminated donor-specific antibodies and permitted HLA-incompatible transplantation in 24 of 25 patients. (Funded by Hansa Medical; ClinicalTrials.gov numbers, NCT02224820 , NCT02426684 , and NCT02475551 .).

Early clinical experience using donor-derived cell-free DNA to detect rejection in kidney transplant recipients.

Donor-derived cell-free DNA (dd-cfDNA) became Medicare reimbursable in the United States in October 2017 for the detection of rejection in kidney transplant recipients based on results from its pivotal validation trial, but it has not yet been externally validated. We assessed 63 adult kidney transplant recipients with suspicion of rejection with dd-cfDNA and allograft biopsy. Of these, 27 (43%) patients had donor-specific antibodies and 34 (54%) were found to have rejection by biopsy. The percentage of dd-cfDNA was higher among patients with antibody-mediated rejection (ABMR; median 1.35%; interquartile range [IQR]: 1.10%-1.90%) compared to those with no rejection (median 0.38%, IQR: 0.26%-1.10%; P < .001) and cell-mediated rejection (CMR; median: 0.27%, IQR: 0.19%-1.30%; P = .01). The dd-cfDNA test did not discriminate patients with CMR from those without rejection. The area under the ROC curve (AUC) for CMR was 0.42 (95% CI: 0.17-0.66). For ABMR, the AUC was 0.82 (95% CI: 0.71-0.93) and a dd-cfDNA ≥0.74% yielded a sensitivity of 100%, specificity 71.8%, PPV 68.6%, and NPV 100%. The dd-cfDNA test did not discriminate CMR from no rejection among kidney transplant recipients, although performance characteristics were stronger for the discrimination of ABMR.

Allocation of the Highest Quality Kidneys and Transplant Outcomes Under the New Kidney Allocation System.

RATIONALE & OBJECTIVE: Increased access to transplantation for highly sensitized candidates following implementation of the kidney allocation system (KAS) has been mostly due to higher use of organs with a lower kidney donor profile index (KDPI; a quality metric for donated kidneys), although changes in allocation of these organs was not intended. It is unclear whether clinical outcomes have changed in association with these changes. We investigated the use of kidneys with low and high KDPI scores over time and whether KDPI score affects patient and graft survival differently across varying levels of allosensitization. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: Adult (aged ≥18 years) recipients of a deceased donor kidney transplant between October 1, 2009, and September 30, 2017 (Organ Procurement and Transplantation Network/United Network for Organ Sharing database; n = 84,451). PREDICTORS: Calculated panel-reactive antibody (cPRA) level (0%, 1%-79%, 80%-89%, 90%-98%, and 99%-100%) and KDPI score (≤20%, 21%-85%, and >85%). OUTCOMES: Death, graft loss. ANALYTICAL APPROACH: Time to event. RESULTS: Allocation of kidneys with KDPI scores ≤ 20% and KDPI scores of 21% to 85% to recipients with cPRA levels ≥ 99% increased 4-fold following implementation of the KAS with little change in allocation of kidneys with KDPI scores > 85%. Patient survival and graft loss were strongly associated with KDPI score, whereas the association with cPRA level was minimal. There was no evidence of a differential effect of KDPI scores across the range of cPRA levels on patient survival (P for interaction=0.06-0.9) or graft loss (P for interaction=0.5-0.9). Patient survival at 5 years among the 5 cPRA groups ranged from 87.2% to 89.8% for recipients of kidneys with KDPI scores ≤ 20% (P=0.2), 82.8% to 85.5% for KDPI scores of 21% to 85% (P=0.04), and 70.2% to 79.2% for KDPI scores > 85% (P=0.2). Cumulative incidence of graft loss by cPRA level ranged from 7.7% to 10.6% for recipients of kidneys with KDPI scores ≤ 20% (P=0.2), 11.8% to 15.0% for KDPI scores of 21% to 85% (P < 0.001), and 19.8% to 29.7% for KDPI scores > 85% (P = 0.4). LIMITATIONS: Lack of data for crossmatches, donor-specific antibodies, and immunomodulation. CONCLUSIONS: Highly sensitized recipients received kidneys with lower KDPI scores following implementation of the KAS, reducing access to these kidneys by less-sensitized candidates. KDPI score has a stronger association with patient survival and graft loss than cPRA level. The association of KDPI score with these outcomes was not modified by the recipient's level of sensitization. The impact of the redistribution of kidneys with low KDPI scores on outcomes among less-sensitized recipients needs further evaluation.

A phase I/II, double-blind, placebo-controlled study assessing safety and efficacy of C1 esterase inhibitor for prevention of delayed graft function in deceased donor kidney transplant recipients.

Delayed graft function (DGF) is defined as need for dialysis early posttransplant. DGF is related to ischemia-reperfusion injury (IRI) that diminishes allograft function and may be complement dependent. Here, we investigate the ability of C1 esterase inhibitor (C1INH) to prevent IRI/DGF in kidney transplant recipients. Seventy patients receiving deceased donor kidney transplants at risk for DGF were randomized to receive C1INH 50 U/kg (#35) or placebo (#35) intraoperatively and at 24 hours. The primary end point was need for hemodialysis during the first week posttransplant. Assessments of glomerular filtration rate and dialysis dependence were accomplished. Complications and safety of therapy were recorded. Similar characteristics with no significant differences in cold-ischemia time or risk factors for DGF were seen. C1INH did not result in reduction of dialysis sessions at 1 week posttransplant, but significantly fewer dialysis sessions (P = .0232) were required 2 to 4 weeks posttransplant. Patients at highest risk for DGF (Kidney Donor Profile Index ≥85) benefited most from C1INH therapy. Significantly better renal function was seen at 1 year in C1INH patients (P = .006). No significant adverse events were noted with C1INH. Although the primary end point was not met, significant reductions in need for dialysis and improvements in long-term allograft function were seen with C1INH treatment.

Differences in pathologic features and graft outcomes in antibody-mediated rejection of renal allografts due to persistent/recurrent versus de novo donor-specific antibodies.

Antibody-mediated rejection (ABMR) of renal allografts occurs in two forms. Type 1 ABMR results from persistence and/or a rebound of preexisting donor-specific antibodies in sensitized patients and usually occurs early post-transplantation. Type 2 ABMR is associated with de novo donor-specific antibodies and usually occurs over one year post-transplantation. It is generally accepted that types 1 and 2 also differ with regard to certain pathologic features including the frequencies of C4d positivity and concurrent cell-mediated rejection. However, direct comparison of pathologic, serologic, and clinical features of types 1 and 2 ABMR is lacking. Here we compared these features in 80 cases of ABMR (37 type 1, 43 type 2) diagnosed at our center. Compared with type 1, type 2 ABMR occurred later post-transplantation, was more often associated with donor-specific antibodies against Class II HLA, and was associated with more interstitial fibrosis/tubular atrophy and more frequent cell-mediated rejection, although these did not differ with respect to C4d positivity. By univariate analysis, graft survival was lower with type 2 than type 1 ABMR with borderline significance. Still, among these 80 patients, all but one treated for ABMR following diagnosis, the only two independent predictors of graft failure were at least moderate interstitial fibrosis/tubular atrophy and failure of the donor-specific antibody relative intensity scale score, a measure of the combined strength of all donor-specific antibodies present, to decrease in response to therapy.

Six-year outcomes in broadly HLA-sensitized living donor transplant recipients desensitized with intravenous immunoglobulin and rituximab.

Desensitization with intravenous immunoglobulin (IVIG) and rituximab can improve transplantation rates in broadly sensitized kidney transplant recipients. However, long-term outcomes are lacking. Here we analyze long-term outcomes in living donor kidney transplant recipients desensitized with this regimen and compare them to low-risk recipients. Living donor kidney transplants that took place between July 2006 and December 2010 were considered retrospectively. The primary end point of the study was death-censored allograft survival at last follow-up. Secondary end points included patient survival, incidence of rejection, glomerular filtration rate (GFR), and proteinuria. There were 66 sensitized and 111 low-risk patients included. Average follow-up was 68 months. There was no difference in long-term patient or graft survival. The rate of rejection was similar in the groups with more early rejection in the sensitized group and more late rejection in the low-risk group. There was more antibody-mediated rejection in the sensitized group. Estimated GFR was similar during the follow-up period. Risk factors for rejection included a positive cross-match (HR: 2.4 CI: 1.35-4.40) and age (HR: 0.97 CI: 0.95-0.99). Desensitization with IVIG and rituximab has good long-term results with graft outcomes similar to non-HLA-sensitized patients despite higher immunologic risk.

Risk factors associated with the development of histocompatibility leukocyte antigen sensitization.

PURPOSE OF REVIEW: Despite excellent short-term kidney allograft survival rates, long-term outcomes have not improved. For years, the focus on improving these outcomes revolved around minimization or elimination of calcineurin toxicity. Despite our best efforts, approximately 5000 allografts are lost each year in the United States and results in a significant emotional burden for patients and financial burden for the healthcare system. RECENT FINDINGS: Advancements in detection of donor-specific histocompatibility leukocyte antigen antibodies (DSAs) and improved assessment of allograft biopsy tissue have shown that the most common cause for graft failures is DSA-related antibody-mediated rejection. Sensitization is directly related to human tissue exposure prior to transplant. We now know that sensitization can occur in patients who are non compliant or poorly compliant with their calcineurin inhibitors. They develop de-novo DSAs, which are responsible for numerous allograft losses around the world. SUMMARY: Given the current evidence, it is imperative that all transplant physicians recognize the importance of encouraging medication adherence to prevent the consequences of DSA-induced graft failure. However, little progress has been made in this area. Other potential therapeutic approaches based on B-cell depletion or modulation early posttransplant may help to reduce the risk for de-novo DSA development.

Histopathologic features of transplant glomerulopathy associated with response to therapy with intravenous immune globulin and rituximab.

Transplant glomerulopathy (TG) is associated with poor long-term allograft survival and is often accompanied by microcirculation inflammation. Histopathologic scoring may inform prognosis and help guide therapy. We retrospectively assessed 33 patients with biopsy-proven TG. All biopsies were given a glomerulitis (g) and peritubular capillaritis (ptc) score. We determined allograft survival and serum creatinine stability in three different score groups: g < 2 and ≥ 2, ptc < 2 and ≥ 2, and (g + ptc) < 4 and ≥ 4. We assessed the impact of treatment with intravenous immune globulin (IVIG) and rituximab on outcomes. Graft survival and serum creatinine stability did not differ in each of the histopathologic score groups. Higher-score groups were associated with the presence of concomitant antibody-mediated rejection and were more likely to receive IVIG and rituximab. Treatment with IVIG and rituximab resulted in stability of serum creatinine within the higher-score groups, but not in the lower-score groups. Stabilization of serum creatinine was associated with an improvement in donor-specific antibody. Histopathologic scoring in kidney allograft biopsies with TG may help guide treatment. The combination of IVIG and rituximab appears to be beneficial in patients whose biopsies have moderate or severe microvascular injury.

Design of a protease-activated PD-L1 inhibitor.

Immune checkpoint inhibitors that bind to the cell surface receptor PD-L1 are effective anti-cancer agents but suffer from immune-related adverse events as PD-L1 is expressed on both healthy and cancer cells. To mitigate toxicity, researchers are testing prodrugs that have low affinity for checkpoint targets until activated with proteases enriched in the tumor microenvironment. Here, we engineer a prodrug form of a PD-L1 inhibitor. The inhibitor is a soluble PD-1 mimetic that was previously engineered to have high affinity for PD-L1. In the basal state, the binding surface of the PD-1 mimetic is masked by fusing it to a soluble variant of its natural ligand, PD-L1. Proteolytic cleavage of the linker that connects the mask to the inhibitor activates the molecule. To optimize the mask so that it effectively blocks binding to PD-L1 but releases upon cleavage, we tested a set of mutants with varied affinity for the inhibitor. The top-performing mask reduces the affinity of the prodrug for PD-L1 120-fold, and binding is nearly fully recovered upon cleavage. In a cell-based assay measuring inhibition of the PD-1:PD-L1 interaction on the surface of cells, the IC50s of the masked inhibitors were up to 40-fold higher than their protease-treated counterparts. The changes in activity we observe upon protease treatment are comparable to systems currently tested in the clinic and provide evidence that natural binding partners are an excellent starting point for creating a prodrug.

An Assessment of the Value of Donor-derived Cell-free DNA Surveillance in Patients With Preserved Kidney Allograft Function.

BACKGROUND: Donor-derived cell-free DNA (dd-cfDNA) is a biomarker validated to detect rejection when measured to assess kidney allograft dysfunction. However, it remains unclear whether routine surveillance with dd-cfDNA provides additional information over standard monitoring of kidney allografts with creatinine and donor-specific antibodies (DSAs), particularly among those with little suspicion of rejection or injury. We investigated the value of measuring dd-cfDNA in patients with preserved allograft function and describe its association with future events. METHODS: Three-hundred seventeen kidney transplant recipients with a creatinine ≤1.5 mg/dL, no current DSA, and no prior rejection were assessed with dd-cfDNA and categorized into low (dd-cfDNA <0.5%; n = 239), moderate (dd-cfDNA 0.5% to <1.0%; n = 43), and high (dd-cfDNA ≥1.0%; n = 35) groups. The occurrence of rejection, DSA, graft loss, and change in estimated glomerular filtration rate over time after dd-cfDNA assessment was compared. RESULTS: Over follow-up, rejections were more commonly found among patients with high vs low dd-cfDNA (17% versus 5%; P = 0.01); a similar nonsignificant trend was observed among patients with moderate compared to low dd-cfDNA (12% versus 5%; P = 0.13). DSA development was uncommon and not different between groups (low: 4%; moderate: 3%; high: 0%; P = 0.52). There was only 1 graft loss in a patient with low dd-cfDNA, and dd-cfDNA was not associated with graft dysfunction over time. CONCLUSIONS: Most patients with elevated dd-cfDNA in conjunction with preserved allograft function remained stable over follow-up without deterioration in function or graft loss. Studies are needed to differentiate patients with elevated dd-cfDNA who will develop adverse outcomes from those who will remain clinically stable.

Large-scale heparin-based bind-and-elute chromatography identifies two biologically distinct populations of extracellular vesicles.

Purifying extracellular vesicles (EVs) has been challenging because EVs are heterogeneous in cargo yet share similar sizes and densities. Most surface marker-based affinity separation methods are limited to research or diagnostic scales. We report that heparin chromatography can separate purified EVs into two distinct subpopulations as ascertained by MS/MS: a non-heparin-binding (NHB) fraction that contains classical EV markers such as tetraspanins and a heparin-binding (HB) fraction enriched in fibronectins and histones. Both fractions were similarly fusogenic but induced different transcriptional responses in endothelial cells. While EVs that were purified by conventional, non-affinity methods alone induced ERK1/2 phosphorylation and Ki67, the NHB fraction did not. This result suggests heparin chromatography as an additional novel fractionation step that is inherently scalable, does not lead to loss of material, and separates inflammatory and pyrogenic EVs from unreactive EVs, which will improve clinical applications.

Pediatric HIV+ Kaposi sarcoma exhibits clinical, virological, and molecular features different from the adult disease.

BACKGROUNDKaposi sarcoma (KS) is among the most common childhood cancers in Eastern and Central Africa. Pediatric KS has a distinctive clinical presentation compared with adult KS, which includes a tendency for primary lymph node involvement, a considerable proportion of patients lacking cutaneous lesions, and a potential for fulminant disease. The molecular mechanisms or correlates for these disease features are unknown.METHODSThis was a cross-sectional study. All cases were confirmed by IHC for KS-associated herpesvirus (KSHV) LANA protein. Baseline blood samples were profiled for HIV and KSHV genome copy numbers by qPCR and secreted cytokines by ELISA. Biopsies were characterized for viral and human transcription, and KSHV genomes were determined when possible.RESULTSSeventy participants with pediatric KS were enrolled between June 2013 and August 2019 in Malawi and compared with adult patients with KS. They exhibited high KSHV genome copy numbers and IL-6/IL-10 levels. Four biopsies (16%) had a viral transcription pattern consistent with lytic viral replication.CONCLUSIONThe unique features of pediatric KS may contribute to the specific clinical manifestations and may direct future treatment options.FUNDINGUS National Institutes of Health U54-CA-254569, PO1-CA019014, U54-CA254564, RO1-CA23958.

Evaluation of Clazakizumab (Anti-Interleukin-6) in Patients With Treatment-Resistant Chronic Active Antibody-Mediated Rejection of Kidney Allografts.

Introduction: Interleukin-6 (IL-6) is an important mediator of inflammation and activation of T cells, B cells, and plasma cells. Excessive IL-6 production is linked to human diseases characterized by unregulated antibody production, including alloimmunity, where persistence of donor-specific antibodies (DSAs), chronic active antibody-mediated rejection (cAMR), and graft loss are noted. Here, we report our experience investigating clazakizumab, a novel IL-6 inhibitor, in treating human leukocyte antigen (HLA)-sensitized patients with cAMR. Methods: Between February 2018 and January 2019, 10 adults with biopsy-proven cAMR were enrolled in a phase 2, single-center, open-label study. Patients received clazakizumab 25 mg subcutaneously (s.c.) monthly for 12 months, with a 6-month protocol biopsy. Primary end points included patient survival, graft survival, estimated glomerular filtration rate (eGFR), and safety. Secondary end points assessed immune markers (DSAs, IgG, T-regulatory [Treg] cells). At 12 months, stable patients entered a long-term extension (LTE). Results: LTE patients received clazakizumab for >2.5 years. Mean eGFRs showed significant declines from -24 months to study initiation (0 months) (52.8 ± 14.6 to 38.11 ± 12.23 ml/min per 1.73 m2, P = 0.03). However, after initiation of clazakizumab, eGFR stabilized at (41.6 ± 14.2 and 38.1 ± 20.3 ml/min per 1.73 m2, at 12 and 24 months, respectively). Banff 2017 analysis of pre- and post-treatment biopsies showed reductions in g+ptc and C4d scores. DSA reductions were seen in most patients. Adverse events (AEs) were minimal, and 2 graft losses occurred, both in patients who discontinued clazakizumab therapy at 6 months and 12 months after study initiation. Conclusion: In this small cohort of patients with cAMR, clazakizumab treatment showed a trend toward stabilization of eGFR and reductions in DSA and graft inflammation. No significant safety issues were observed. A randomized, placebo-controlled clinical trial (IMAGINE) of clazakizumab in cAMR treatment is underway (NCT03744910).

Rituximab and intravenous immune globulin for desensitization during renal transplantation.

BACKGROUND: Few options for transplantation currently exist for patients highly sensitized to HLA. This exploratory, open-label, phase 1-2, single-center study examined whether intravenous immune globulin plus rituximab could reduce anti-HLA antibody levels and improve transplantation rates. METHODS: Between September 2005 and May 2007, a total of 20 highly sensitized patients (with a mean [+/-SD] T-cell panel-reactive antibody level, determined by use of the complement-dependent cytotoxicity assay, of 77+/-19% or with donor-specific antibodies) were enrolled and received treatment with intravenous immune globulin and rituximab. We recorded rates of transplantation, panel-reactive antibody levels, cross-matching results at the time of transplantation, survival of patients and grafts, acute rejection episodes, serum creatinine values, adverse events and serious adverse events, and immunologic factors. RESULTS: The mean panel-reactive antibody level was 44+/-30% after the second infusion of intravenous immune globulin (P<0.001 for the comparison with the pretreatment level). At study entry, the mean time on dialysis among recipients of a transplant from a deceased donor was 144+/-89 months (range, 60 to 324). However, the time to transplantation after desensitization was 5+/-6 months (range, 2 to 18). Sixteen of the 20 patients (80%) received a transplant. At 12 months, the mean serum creatinine level was 1.5+/-1.1 mg per deciliter (133+/-97 micromol per liter), and the mean survival rates of patients and grafts were 100% and 94%, respectively. There were no infusion-related adverse events or serious adverse events during the study. Long-term monitoring for infectious complications and neurologic problems revealed no unanticipated events. CONCLUSIONS: These findings suggest that the combination of intravenous immune globulin and rituximab may prove effective as a desensitization regimen for patients awaiting a transplant from either a living donor or a deceased donor. Larger and longer trials are needed to evaluate the clinical efficacy and safety of this approach. (ClinicalTrials.gov number, NCT00642655.)

Infectious Complications in Tocilizumab-treated Kidney Transplant Recipients.

BACKGROUND: Tocilizumab is an interleukin-6 receptor antagonist recently described as a promising treatment for antibody-mediated rejection. We compared infectious complications among tocilizumab-treated kidney transplant patients with those receiving intravenous immunoglobulin (IVIG)/rituximab. METHODS: Infections occurring among 148 kidney recipients treated with tocilizumab 8 mg/kg IV monthly (n = 83) or IVIG/rituximab (n = 65) for donor-specific antibodies and antibody-mediated rejection through 1 year after treatment cessation were reviewed. Incidence rates of infections were compared using Poisson regression. RESULTS: There were 106 infections observed over 190.1 person-years, yielding an incidence rate of 558 infections/1000 patient-years. A lower incidence rate of infections was observed among tocilizumab-treated compared with IVIG/rituximab-treated patients (463 infections/1000 patient-years versus 730 infections/1000 patient-years; P = 0.02). Twenty-five of 49 infections (51%) in the IVIG/rituximab group required hospitalization compared with 31 of 57 (54%; P = 0.85) in the tocilizumab group. There were no infection-related deaths in either group. Urinary tract infections and pneumonia were the most common types of infections, whereas gastrointestinal, blood, skin/soft tissue, viral, and fungal infections were less common. On multivariable Poisson regression, there was a lower incidence rate of infections associated with tocilizumab compared with IVIG/rituximab (incidence rate ratio, 0.63; 95% confidence interval, 0.43-0.93). CONCLUSIONS: Among kidney transplant patients treated with tocilizumab, there was no excess risk of infections compared with standard therapy with IVIG/rituximab.