# Cannabidiol exerts antiinflammatory effects but maintains T effector memory cell differentiation in humans

## TL;DR

CBD reduces immune cell proliferation and inflammation but increases memory T cells in humans, suggesting complex immune effects.

## Contribution

First detailed single-cell analysis of CBD's immunomodulatory effects in humans at steady state with tacrolimus.

## Key findings

- CBD increased T effector memory cells by 22% and reduced T and B cell proliferation.
- CBD altered cytokine levels, increasing IL-6 and IL-10 while decreasing TNF-α and IL-2.
- Single-cell RNA sequencing showed reduced IL2 and TNF signaling in T effector memory cells.

## Abstract

Cannabidiol (CBD) is increasingly used for pain management, including in transplant recipients with limited analgesic options. Its immunomodulatory effects in humans are not well defined at a single-cell level at CBD steady state with concomitant tacrolimus treatment.

In a phase I ex vivo study, peripheral blood mononuclear cells from 23 participants who received oral CBD (Epidiolex) up to 5 mg/kg twice daily for 11 days were collected before CBD (pre-CBD) and at steady state (post-CBD). Lymphocytes were isolated and stimulated with anti-CD3/CD28 antibodies, with or without tacrolimus (5 ng/mL). Pharmacodynamic responses were assessed using CellTiter-Glo proliferation, single-cell and single-nucleus RNA sequencing, cytokine assays, and flow cytometry. Steady-state plasma concentrations of CBD were quantified via tandem mass spectrometry.

We identified an increased proportion of T effector memory (TEM) cells post-CBD (22% increase), which correlated with CBD plasma concentrations (R = 0.77, P = 0.01). CBD reduced proliferation of T (37% decrease) and CD70hi B (17% decrease) lymphocytes with additive immunosuppressive effects to tacrolimus. Single-cell RNA sequencing revealed reduced IL2 and TNF signaling and altered receptor-ligand networks in TEM cells. Post-CBD cytokine assays revealed elevated proinflammatory IL-6 protein levels and antiinflammatory IL-10 levels, with reduced TNF-α, LTA, and IL-2. In flow cytometry, the proportion of TEM and TEMRA cells increased post-CBD with tacrolimus.

CBD exerts mixed immunomodulatory effects in humans, combining antiproliferative and pro- and antiinflammatory responses. Understanding the clinical safety of CBD use is important given the paucity of pain control options available for immunocompromised transplant populations.

ClinicalTrials.gov NCT05490511

NIH/National Center for Complementary and Integrative Health (R01AT011463); NIH/National Institute of General Medical Sciences (NIGMS) (R35GM145383); Intramural Research Program of the NIH; NIH/NIGMS (T32GM008425).

<span>We determine the effects of cannabidiol on lymphocyte populations in a clinical study of participants taking oral cannabidiol for 11 days with deep phenotyping: pharmacokinetic sampling, cell proliferation assays, cytokine measurement, flow cytometry, and scRNA sequencing of lymphocytes. </span>