Tocilizumab for treatment of chronic active antibody-mediated rejection in kidney transplant recipients.

BACKGROUND: The optimal treatment for chronic active antibody-mediated rejection (ca-AMR) remains unclear. Tocilizumab (TCZ), a monoclonal antibody against IL-6, has been proposed as a therapeutic option. We reported our experience treating ca-AMR with TCZ either as the first line option or as a rescue therapy. METHODS: We studied 11 adult kidney transplant recipients with biopsy-proven ca-AMR and preserved kidney function (eGFR 57 ± 18) who were treated with TCZ (8 mg/kg IV monthly). All biopsies were prompted by abnormal surveillance biomarker testing with DSA and/or dd-cfDNA. Clinical monitoring included dd-cfDNA and DSA testing every 3 months during the treatment with TCZ. RESULTS: In this cohort, ca-AMR was diagnosed at a median of 90 months (range 14-224) post-transplant, and 4 of 11 patients had DSA negative ca-AMR. Patients received a minimum of 3 months of TCZ, with 6 patients receiving at least 12 months of TCZ. Dd-cfDNA was elevated in all patients, with a median 2.24% at the start of TCZ treatment. After 6 months of TCZ treatment, 8/11 patients had dd- cfDNA <1%, and 3/11 had values <0.5%. Among those who completed at least 12 months of TCZ, dd-cfDNA decreased by 29% at 6 months (p = .05) and 47% by 12 months (p = .04). DSA also stabilized and, by 12 months, was reduced by 29% (p = .047). Graft function remained stable with no graft loss during treatment. There was a nonsignificant trend towards proteinuria reduction. During the course of treatment with tocilizumab, two patients experienced moderate to severe infections. CONCLUSIONS: In our early short-term experience, TCZ appears to reduce graft injury as measured by dd-cfDNA and modulate the immune response as evident by a modest reduction in immunodominant DSA MFI. Allograft function and proteinuria also stabilized.

Multicenter Clinicopathologic Correlation of Kidney Biopsies Performed in COVID-19 Patients Presenting With Acute Kidney Injury or Proteinuria.

RATIONALE & OBJECTIVE: Kidney biopsy data inform us about pathologic processes associated with infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We conducted a multicenter evaluation of kidney biopsy findings in living patients to identify various kidney disease pathology findings in patients with coronavirus disease 2019 (COVID-19) and their association with SARS-CoV-2 infection. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: We identified 14 native and 3 transplant kidney biopsies performed for cause in patients with documented recent or concurrent SARS-CoV-2 infection treated at 7 large hospital systems in the United States. OBSERVATIONS: Men and women were equally represented in this case series, with a higher proportion of Black (n=8) and Hispanic (n=5) patients. All 17 patients had SARS-CoV-2 infection confirmed by reverse transcriptase-polymerase chain reaction, but only 3 presented with severe COVID-19 symptoms. Acute kidney injury (n=15) and proteinuria (n=11) were the most common indications for biopsy and these symptoms developed concurrently or within 1 week of COVID-19 symptoms in all patients. Acute tubular injury (n=14), collapsing glomerulopathy (n=7), and endothelial injury/thrombotic microangiopathy (n=6) were the most common histologic findings. 2 of the 3 transplant recipients developed active antibody-mediated rejection weeks after COVID-19. 8 patients required dialysis, but others improved with conservative management. LIMITATIONS: Small study size and short clinical follow-up. CONCLUSIONS: Cases of even symptomatically mild COVID-19 were accompanied by acute kidney injury and/or heavy proteinuria that prompted a diagnostic kidney biopsy. Although acute tubular injury was seen among most of them, uncommon pathology such as collapsing glomerulopathy and acute endothelial injury were detected, and most of these patients progressed to irreversible kidney injury and dialysis.

Contemporary patterns in kidney graft survival from donors after circulatory death in the United States.

BACKGROUND: Kidney transplants from donors after circulatory death (DCD) make up an increasing proportion of all deceased donor kidney transplants in the United States (US). However, DCD grafts are considered to be of lower quality than kidneys from donors after brain death (DBD). It is unclear whether graft survival is different for these two types of donor kidneys. MATERIALS AND METHODS: We conducted a retrospective cohort study of US deceased donor kidney recipients using data from the United Network of Organ Sharing from 12/4/2014 to 6/30/2018. We employed a Cox proportional hazard model with mixed effects to compare all-cause graft loss and death-censored graft loss for DCD versus DBD deceased donor kidney transplant recipients. We used transplant center as the random effects term to account for cluster-specific random effects. In the multivariable analysis, we adjusted for recipient characteristics, donor factors, and transplant logistics. RESULTS: Our cohort included 27,494 DBD and 7,770 DCD graft recipients transplanted from 2014 to 2018 who were followed over a median of 1.92 years (IQR 1.08-2.83). For DCD compared with DBD recipients, we did not find a significant difference in all-cause graft loss (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.87-1.05 in univariable and HR 1.03 [95% CI 0.95-1.13] in multivariable analysis) or for death-censored graft loss (HR 0.97 (95% CI 0.91-1.06) in univariable and 1.05 (95% CI 0.99-1.11) in multivariable analysis). CONCLUSIONS: For a contemporary cohort of deceased donor kidney transplant recipients, we did not find a difference in the likelihood of graft loss for DCD compared with DBD grafts. These findings signal a need for additional investigation into whether DCD status independently contributes to other important outcomes for current kidney transplant recipients and indices of graft quality.

Hyperammonemia syndrome due to Ureaplasma infection after liver-kidney transplant.

Hyperammonemia syndrome, with high levels of ammonia and neurologic dysfunction, is a syndrome with historically high mortality that may occur after solid organ transplantation. Recently, this has been associated with infection due to Ureaplasma, mostly following lung transplantation. We describe the first case of hyperammonemia syndrome due to Ureaplasma infection after liver-kidney transplantation. Our patient rapidly recovered after specific antibiotic treatment. It is important to consider these infections in the differential diagnosis for encephalopathy post-transplant, as these organisms often do not grow using routine culture methods and polymerase chain reaction testing is typically required for their detection. This is particularly critical after liver transplantation, where a number of other etiologies may be considered as a cause of hyperammonemia syndrome.

Cytokine Profile in Early Infection by Leptospira interrogans in A/J Mice.

Leptospirosis is considered a neglected disease with an estimated more than one million cases every year. Since rodents are at the same time the main reservoir and generally asymptomatic to Leptospira infection, understanding why some animal species are resistant and others are susceptible to this infection would shed some light in how to control this important zoonosis. The innate immune response against Leptospira is mainly dependent on phagocytosis and activation of the Complement System. In this context, cytokines may drive the early control of infection and the adaptive response. Since the Complement System is important to eliminate leptospires in vivo, we investigated if Complement C5 in A/J mice would modulate the cytokine production during infection by Leptospira interrogans serovar Kennewicki type Pomona Fromm (LPF). Thus, our aim was to investigate the systemic levels of pro- and anti-inflammatory cytokines during Leptospira infection in the blood, liver, lung, and kidney on the third and sixth days of infection in A/J C5+/+ and A/J C5-/- mice. Blood levels of TNF-α, IL-6, IFN-γ, and MCP-1 reached a peak on the third day. Although both mouse strains developed splenomegaly, similar histopathological alterations in the liver and the lung, levels of pro- and anti-inflammatory cytokines were different. A/J C5+/+ mice had higher levels of liver IL-10, IL-1ß, IL-12p40, and IL-12p70 and kidney IL-1ß, IL-12p40, and IL-12p70 on the sixth day of infection when compared to A/J C5-/- mice. Our results showed that in A/J genetic background, the Complement component C5 modulates a cytokine profile in the liver and kidney of infected mice, which may play a role in the control of disease progression.

Metformin exerts antitumor activity via induction of multiple death pathways in tumor cells and activation of a protective immune response.

The antitumor effect of metformin has been demonstrated in several types of cancer; however, the mechanisms involved are incompletely understood. In this study, we showed that metformin acts directly on melanoma cells as well as on the tumor microenvironment, particularly in the context of the immune response. In vitro, metformin induces a complex interplay between apoptosis and autophagy in melanoma cells. The anti-metastatic activity of metformin in vivo was assessed in several mouse models challenged with B16F10 cells. Metformin's activity was, in part, immune system-dependent, whereas its antitumor properties were abrogated in immunodeficient (NSG) mice. Metformin treatment increased the number of lung CD8-effector-memory T and CD4+Foxp3+IL-10+ T cells in B16F10-transplanted mice. It also decreased the levels of Gr-1+CD11b+ and RORγ+ IL17+CD4+ cells in B16F10-injected mice and the anti-metastatic effect was impaired in RAG-1-/- mice challenged with B16F10 cells, suggesting an important role for T cells in the protection induced by metformin. Finally, metformin in combination with the clinical metabolic agents rapamycin and sitagliptin showed a higher antitumor effect. The metformin/sitagliptin combination was effective in a BRAFV600E/PTEN tamoxifen-inducible murine melanoma model. Taken together, these results suggest that metformin has a pronounced effect on melanoma cells, including the induction of a strong protective immune response in the tumor microenvironment, leading to tumor growth control, and the combination with other metabolic agents may increase this effect.

Role of Murine Complement Component C5 in Acute in Vivo Infection by Pathogenic Leptospira interrogans.

Leptospirosis is considered one of the most important zoonosis worldwide. The activation of the Complement System is important to control dissemination of several pathogens in the host. Only a few studies have employed murine models to investigate leptospiral infection and our aim in this work was to investigate the role of murine C5 during in vivo infection, comparing wild type C57BL/6 (B6 C5+/+) and congenic C57BL/6 (B6 C5-/-, C5 deficient) mice during the first days of infection. All animals from both groups survived for at least 8 days post-infection with pathogenic Leptospira interrogans serovar Kennewicki strain Fromm (LPF). At the third day of infection, we observed greater numbers of LPF in the liver of B6 C5-/- mice when compared to B6 C5+/+ mice. Later, on the sixth day of infection, the LPF population fell to undetectable levels in the livers of both groups of mice. On the third day, the inflammatory score was higher in the liver of B6 C5+/+ mice than in B6 C5-/- mice, and returned to normal on the sixth day of infection in both groups. No significant histopathological differences were observed in the lung, kidney and spleen from both infected B6 C5+/+ than B6 C5-/- mice. Likewise, the total number of circulating leukocytes was not affected by the absence of C5. The liver levels of IL-10 on the sixth day of infection was lower in the absence of C5 when compared to wild type mice. No significant differences were observed in the levels of several inflammatory cytokines when B6 C5+/+ and B6 C5-/- were compared. In conclusion, C5 may contribute to the direct killing of LPF in the first days of infection in C57BL/6 mice. On the other hand, other effector immune mechanisms probably compensate Complement impairment since the mice survival was not affected by the absence of C5 and its activated fragments, at least in the early stage of this infection.

Nephrotic syndrome in pregnancy poses risks with both maternal and fetal complications.

In the absence of uncontrolled hypertension or renal insufficiency, many consider the perinatal outcomes in pregnant women with nephrotic syndrome to be good. To further investigate this we performed a retrospective chart review of women with biopsy-proven nephrotic syndrome due to primary glomerular disease during pregnancy at a single tertiary center. Our review determined characteristics, presentation, management, pathologic diagnoses, and associated renal and maternal-fetal outcomes of 19 individuals with 26 pregnancies and 26 offspring. The mean age was 27.6 years, the mean gestational age at the presentation of nephrotic syndrome was 18.6 weeks, the mean creatinine was 0.85 mg/dL, mean serum albumin was 1.98 g/dL, and the mean proteinuria was 8.33 g/24 hours. The mean cardiac output was 8.6 L/minute, which was elevated compared to normal pregnancy. A kidney biopsy was performed during pregnancy in 8 individuals (median gestational age at time of biopsy was 21 weeks), changing management in six. Of the 26 pregnancies, maternal complications included preeclampsia in seven, acute kidney injury in six, premature rupture of membranes in two, and cellulitis in three. The mean age of gestation at delivery was 35.5 weeks. Fetal complications included low birth weight (under 2,500 g) in 14, intra-uterine growth restriction in three, and neonatal intensive care unit admission in eight. Thus, pregnant women with nephrotic syndrome are at high risk for developing both maternal and fetal complications, even in the absence of significant renal impairment or uncontrolled hypertension at the time of presentation of nephrotic syndrome.

Complement C5 controls liver lipid profile, promotes liver homeostasis and inflammation in C57BL/6 genetic background.

Innate immunity contributes effectively to the development of alcoholic liver disease (ALD). In special, the activation of the complement system is involved in the pathogenesis of this disease. Here we investigated the contribution of complement C5 protein to the establishment and maintenance of ALD. Eight- to ten-week-old B6C5(+) and B6C5(-) male mice were fed with high fat diet (HFD) only or the same diet containing equicaloric supplements of ethanol (HFDE) or maltodextrin (HFDM) for 10 weeks. Serum parameters of liver function as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AP), albumin, glucose, triglycerides (TG) and cholesterol were evaluated. Liver tissue samples were collected for histopathological analysis, lipid extraction (TG and cholesterol), cytokines (TNF-α, IL-6, IL-1ß, IL-10, IL-12, IL-17, IFN-γ, TGF-ß) measurement and NO production. We observed that B6C5(-) mice HFDE-fed accumulated more liver cholesterol and TG, increased liver IL-17 and IL-10 levels and reduced liver TGF-ß levels when compared to HFD-fed mice. We also observed that serum AST, AP and albumin were increased in B6C5(-) mice. Liver IL-1ß, IL-6, IL-12 and IFN-γ were decreased in B6C5(-) mice independently of diet. We conclude that C5 acts in the control of serum TG and cholesterol, liver cholesterol deposition, liver homeostasis and C5 promotes a pro-inflammatory liver environment in our mouse model of ALD.

C57BL/6 and A/J Mice Have Different Inflammatory Response and Liver Lipid Profile in Experimental Alcoholic Liver Disease.

Alcoholic liver disease (ALD) is an important worldwide public health issue characterized by liver steatosis, inflammation, necrosis, and apoptosis of hepatocytes with eventual development of fibrosis and cirrhosis. Comparison of murine models with different inflammatory responses for ALD is important for an evaluation of the importance of genetic background in the interpretation of ethanol-induced phenotypes. Here, we investigated the role of inflammation and genetic background for the establishment of ALD using two different mouse strains: C57BL/6 (B6) and A/J. B6 and A/J mice were treated with a high fat diet containing ethanol (HFDE) and compared to the controls for 10 weeks. Hepatomegaly and steatohepatitis were similar in B6 and A/J mice, but only A/J mice were resistant to weight gain. On the other hand, HFDE-fed B6 accumulated more triglycerides (TG) and cholesterol and presented more intense cellular infiltrate in the liver when compared to HFDM-fed mice. Liver inflammatory environment was distinct in these two mouse strains. While HFDE-fed B6 produced more liver IL-12, A/J mice increased the TNF-α production. We concluded that mouse genetic background could dictate the intensity of the HFDE-induced liver injury.

Staphylococcus aureus manganese transport protein C (MntC) is an extracellular matrix- and plasminogen-binding protein.

Infections caused by Staphylococcus aureus--particularly nosocomial infections--represent a great concern. Usually, the early stage of pathogenesis consists on asymptomatic nasopharynx colonization, which could result in dissemination to other mucosal niches or invasion of sterile sites, such as blood. This pathogenic route depends on scavenging of nutrients as well as binding to and disrupting extracellular matrix (ECM). Manganese transport protein C (MntC), a conserved manganese-binding protein, takes part in this infectious scenario as an ion-scavenging factor and surprisingly as an ECM and coagulation cascade binding protein, as revealed in this work. This study showed a marked ability of MntC to bind to several ECM and coagulation cascade components, including laminin, collagen type IV, cellular and plasma fibronectin, plasminogen and fibrinogen by ELISA. The MntC binding to plasminogen appears to be related to the presence of surface-exposed lysines, since previous incubation with an analogue of lysine residue, ε-aminocaproic acid, or increasing ionic strength affected the interaction between MntC and plasminogen. MntC-bound plasminogen was converted to active plasmin in the presence of urokinase plasminogen activator (uPA). The newly released plasmin, in turn, acted in the cleavage of the α and ß chains of fibrinogen. In conclusion, we describe a novel function for MntC that may help staphylococcal mucosal colonization and establishment of invasive disease, through the interaction with ECM and coagulation cascade host proteins. These data suggest that this potential virulence factor could be an adequate candidate to compose an anti-staphylococcal human vaccine formulation.

Basal physiological parameters of two congenic mice strains: C5 deficient C57BL/6 and C5 sufficient A/J.

To investigate the in vivo role of complement component C5 it is common to compare the inflammatory response between C5-normal and C5-deficient inbred mice strains. Nevertheless, it should be expected that differences in the genetic backgrounds between those strains may affect several physiological parameters, complicating the correct interpretation of results. The use of congenic mice, developed by backcrossing, is therefore preferred. Still, several physiological parameters may be distinctive in the normal and deficient strains and therefore require careful analysis before animals are selected for investigation. We generated two congenic mouse strains: C57BL/6 (B6) C5(-), derived from the parental B6 C5(+) strain and A/J C5(+) mice derived from the parental A/J C5(-) strain. After confirmation by nucleotide sequencing, immunodiffusion and hemolytic activity analysis, several basal physiological parameters were analyzed in the congenic and parental strains before antigen exposition. Serum levels of liver alanine aminotransferase, alkaline phosphatase, albumin, triglycerides, cholesterol and uric acid were found to be different in C5-sufficient and C5-deficient mice from one or both genetic backgrounds (B6 and/or A/J). On the other hand, serum levels of liver aspartate aminotransferase, glucose and urea were not affected by the presence of C5 in either strain. Furthermore, in some cases, C5-dependent variations in these parameters were more evident in mice of the same gender. We conclude here that C5-deficient mice strains may present distinct systemic behaviors which should be taken in consideration before differences in the immune responses are attributed solely to the lack of circulating C5.