Use of immune function test in monitoring immunosuppression in liver transplant recipients.

Immune function test (Immuknow™) is a measure of cell-mediated immunity based on peripheral CD4+ T cell adenosine triphosphate activity (desired range, 225-525 ng/mL). We evaluated the role of immune function test (IFT) in monitoring and adjustment of immunosuppression in orthotopic liver transplant (OLT) recipients. A total of 289 IFTs were obtained from 171 patients from March 2007 to June 2008. Graft/patient status was classified as stable, serious infection, or malignancy. IFT levels were analyzed with duration of follow-up after OLT, graft/patient status, and the presence of hepatitis C (HCV) infection. The mean age was 54±14 yr, with 62% men. The median follow-up was 65 (2-249) months. Mean IFT levels were significantly lower in patients who were <24 months than in those≥24 months post-OLT (220±19.5 vs. 257±11.3 ng/mL, p=0.03). Clinically stable patients had higher IFT levels than those with serious infection or malignancy (254±11.1 vs. 162.5±23.9, p<0.001). HCV-infected patients had lower IFT levels than uninfected patients (206.7±15.7 vs. 273±12.0 ng/mL, p<0.001). Immunosuppression was reduced in 58 patients with IFT levels<225 ng/mL, and 90% maintained stable graft function after a median follow-up of 22 (1-39) months. IFT may be a useful tool in monitoring and lowering of immunosuppression in long-term OLT recipients.

The Effect of Normothermic Machine Perfusion on the Immune Profile of Donor Liver.

Background: Normothermic machine perfusion (NMP) allows viability assessment and potential resuscitation of donor livers prior to transplantation. The immunological effect of NMP on liver allografts is undetermined, with potential implications on allograft function, rejection outcomes and overall survival. In this study we define the changes in immune profile of human livers during NMP. Methods: Six human livers were placed on a NMP device. Tissue and perfusate samples were obtained during cold storage prior to perfusion and at 1, 3, and 6 hours of perfusion. Flow cytometry, immunohistochemistry, and bead-based immunoassays were used to measure leukocyte composition and cytokines in the perfusate and within the liver tissue. Mean values between baseline and time points were compared by Student's t-test. Results: Within circulating perfusate, significantly increased frequencies of CD4 T cells, B cells and eosinophils were detectable by 1 hour of NMP and continued to increase at 6 hours of perfusion. On the other hand, NK cell frequency significantly decreased by 1 hour of NMP and remained decreased for the duration of perfusion. Within the liver tissue there was significantly increased B cell frequency but decreased neutrophils detectable at 6 hours of NMP. A transient decrease in intermediate monocyte frequency was detectable in liver tissue during the middle of the perfusion run. Overall, no significant differences were detectable in tissue resident T regulatory cells during NMP. Significantly increased levels of pro-inflammatory and anti-inflammatory cytokines were seen following initiation of NMP that continued to rise throughout duration of perfusion. Conclusions: Time-dependent dynamic changes are seen in individual leukocyte cell-types within both perfusate and tissue compartments of donor livers during NMP. This suggests a potential role of NMP in altering the immunogenicity of donor livers prior to transplant. These data also provide insights for future work to recondition the intrinsic immune profile of donor livers during NMP prior to transplantation.

Cannabidiol inhibits SARS-CoV-2 replication through induction of the host ER stress and innate immune responses.

The spread of SARS-CoV-2 and ongoing COVID-19 pandemic underscores the need for new treatments. Here we report that cannabidiol (CBD) inhibits infection of SARS-CoV-2 in cells and mice. CBD and its metabolite 7-OH-CBD, but not THC or other congeneric cannabinoids tested, potently block SARS-CoV-2 replication in lung epithelial cells. CBD acts after viral entry, inhibiting viral gene expression and reversing many effects of SARS-CoV-2 on host gene transcription. CBD inhibits SARS-CoV-2 replication in part by up-regulating the host IRE1α RNase endoplasmic reticulum (ER) stress response and interferon signaling pathways. In matched groups of human patients from the National COVID Cohort Collaborative, CBD (100 mg/ml oral solution per medical records) had a significant negative association with positive SARS-CoV-2 tests. This study highlights CBD as a potential preventative agent for early-stage SARS-CoV-2 infection and merits future clinical trials. We caution against use of non-medical formulations including edibles, inhalants or topicals as a preventative or treatment therapy at the present time.