During solid organ transplantation, donor leukocytes, including myeloid cells, are transferred within the organ to the recipient. Both tolerogenic and alloreactive roles have been attributed to donor myeloid cells; however, their subset-specific retention posttransplantation has not been investigated in detail.

Major histocompatibility complex (MHC)-matched and mismatched liver transplants were performed in mice, and the fate of donor and recipient myeloid cells was assessed.

Following MHC-matched transplantation, a proportion of donor myeloid cells was retained in the graft, whereas others egressed and persisted in the blood, spleen, and bone marrow but not the lymph nodes. In contrast, after MHC-mismatched transplantation, all donor myeloid cells, except Kupffer cells, were depleted. This depletion was caused by recipient T and B cells because all donor myeloid subsets were retained in MHC-mismatched grafts when recipients lacked T and B cells. Recipient myeloid cells rapidly infiltrated MHC-matched and, to a greater extent, MHC-mismatched liver grafts. MHC-mismatched grafts underwent a transient rejection episode on day 7, coinciding with a transition in macrophages to a regulatory phenotype, after which rejection resolved.

Phenotypic and kinetic differences in the myeloid cell responses between MHC-matched and mismatched grafts were identified. A detailed understanding of the dynamics of immune responses to transplantation is critical to improving graft outcomes.

A polyherbal formulation with hepatoprotective and choleretic properties combining pharmacological potential of eight medicinal plants was developed in Nargiz Medical center (Republic of Azerbaijan) for the use as herbal tea. To explore the effect of polyherbal composition on the metabolism of LPS-stimulated macrophages in vitro.

The qualitative and quantitative phytochemical analysis was conducted using specific color reactions and gas chromatography-mass spectrometry (GC-MS). Nitric oxide (NO) assay was determined using the Griess reaction. Reactive oxygen species (ROS) generation was measured using ROS-sensitive fluorescence indicator, H2DCFDA, by flow cytometry. Arginase activity was examined by colorimetric method.

The studied polyherbal formulation exerted anti-inflammatory activity in LPS-stimulated macrophages which was evidenced by dose-dependent decrease of ROS generation and by shift of arginine metabolism to the increase of arginase activity and decrease of NO release.

Our findings suggest that the herbal tea reduces macrophage inflammatory activity, that provide an important rationale to utilize it for the attenuation of chronic inflammation typical of hepatobiliary disorders.

Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is an innovative surgical approach for the treatment of massive hepatocellular carcinoma (HCC), the key to successful planned stage 2 ALPPS is future liver remnant (FLR) volume growth, but the exact mechanism has not been elucidated. The correlation between regulatory T cells (Tregs) and postoperative FLR regeneration has not been reported.

To investigate the effect of CD4+CD25+ Tregs on FLR regeneration after ALPPS.

Clinical data and specimens were collected from 37 patients who developed massive HCC treated with ALPPS. Flow cytometry was performed to detect changes in the proportion of CD4+CD25+ Tregs to CD4+ T cells in peripheral blood before and after ALPPS. To analyze the relationship between peripheral blood CD4+CD25+ Treg proportion and clinicopathological information and liver volume.

The postoperative CD4+CD25+ Treg proportion in stage 1 ALPPS was negatively correlated with the amount of proliferation volume, proliferation rate, and kinetic growth rate (KGR) of the FLR after stage 1 ALPPS. Patients with low Treg proportion had significantly higher KGR than those with high Treg proportion (P = 0.006); patients with high Treg proportion had more severe postoperative pathological liver fibrosis than those with low Treg proportion (P = 0.043). The area under the receiver operating characteristic curve between the percentage of Tregs and proliferation volume, proliferation rate, and KGR were all greater than 0.70.

CD4+CD25+ Tregs in the peripheral blood of patients with massive HCC at stage 1 ALPPS were negatively correlated with indicators of FLR regeneration after stage 1 ALPPS and may influence the degree of fibrosis in patients' livers. Treg percentage was highly accurate in predicting the FLR regeneration after stage 1 ALPPS.

More than 90% of cases of hepatocellular carcinoma (HCC) occurs in patients with cirrhosis, of which hepatitis B virus and hepatitis C virus are the leading causes, while the tumor less frequently arises in autoimmune liver diseases. Advances in understanding tumor immunity have led to a major shift in the treatment of HCC, with the emergence of immunotherapy where therapeutic agents are used to target immune cells rather than cancer cells. Regulatory T cells (Tregs) are the most abundant suppressive cells in the tumor microenvironment and their presence has been correlated with tumor progression, invasiveness, as well as metastasis. Tregs are characterized by the expression of the transcription factor Foxp3 and various mechanisms ranging from cell-to-cell contact to secretion of inhibitory molecules have been implicated in their function. Notably, Tregs amply express checkpoint molecules such as cytotoxic T lymphocyte-associated antigen 4 and programmed cell-death 1 receptor and therefore represent a direct target of immune checkpoint inhibitor (ICI) immunotherapy. Taking into consideration the critical role of Tregs in maintenance of immune homeostasis as well as avoidance of autoimmunity, it is plausible that targeting of Tregs by ICI immunotherapy results in the development of immune-related adverse events (irAEs). Since the use of ICI becomes common in oncology, with an increasing number of new ICI currently under clinical trials for cancer treatment, the occurrence of irAEs is expected to dramatically rise. Herein, we review the current literature focusing on the role of Tregs in HCC evolution taking into account their opposite etiological function in viral and autoimmune chronic liver disease, and we discuss their involvement in irAEs due to the new immunotherapies.