Antibody-Mediated Rejection and Recurrent Primary Disease: Two Main Obstacles in Abdominal Kidney, Liver, and Pancreas Transplants

Defining an NK Cell-enriched Rejection-like Phenotype in Liver Transplant Biopsies From the INTERLIVER Study

BACKGROUND

Initial analysis of liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov; unique identifier NCT03193151) using rejection-associated transcripts failed to find an antibody-mediated rejection state (ie, rich in natural killer [NK] cells and with interferon-gamma effects). We recently developed an optimization strategy in lung transplants that isolated an NK cell-enriched rejection-like (NKRL) state that was molecularly distinct from T cell-mediated rejection (TCMR). Here we apply the same strategy to a liver transplant biopsy population.

METHODS

We used this strategy to search for a molecular NKRL state in 765 consented liver transplant biopsies collected at participating international centers for gold-standard histology and molecular assessment by genome-wide microarrays. Validation through a training set-test set approach of an optimized selection of variables as inputs into unsupervised rejection classification identified an NKRL state in livers.

RESULTS

The full model classified 765 biopsies into the following molecular phenotypes, characterized by their gene expression: no-rejection 54%, TCMR 16%, NKRL 13%, and injury 16%. Top TCMR transcripts were expressed in effector T cells; top NKRL transcripts were almost exclusively expressed in NK cells; and both had increased interferon-γ-inducible transcripts, which were more pronounced in TCMR. Most TCMR biopsies had significant parenchymal injury, molecular fibrosis, and abnormal biochemistry. NKRL biopsies had no excess of injury, fibrosis, or biochemistry abnormalities.

CONCLUSIONS

Optimized rejection algorithms indicate that some liver transplants manifest an NKRL state that is well tolerated in the short term postbiopsy and with minimal injury and relatively normal biochemistry, while also underscoring the potential of TCMR to produce extensive parenchymal injury.

BSHI and BTS UK guideline on the detection of alloantibodies in solid organ (and islet) transplantation

Solid organ transplantation represents the best (and in many cases only) treatment option for patients with end-stage organ failure. The effectiveness and functioning life of these transplants has improved each decade due to surgical and clinical advances, and accurate histocompatibility assessment. Patient exposure to alloantigen from another individual is a common occurrence and takes place through pregnancies, blood transfusions or previous transplantation. Such exposure to alloantigen's can lead to the formation of circulating alloreactive antibodies which can be deleterious to solid organ transplant outcome. The purpose of these guidelines is to update to the previous BSHI/BTS guidelines 2016 on the relevance, assessment, and management of alloantibodies within solid organ transplantation.

Research priorities for therapeutic plasma exchange in critically ill patients

Therapeutic plasma exchange (TPE) is a therapeutic intervention that separates plasma from blood cells to remove pathological factors or to replenish deficient factors. The use of TPE is increasing over the last decades. However, despite a good theoretical rationale and biological plausibility for TPE as a therapy for numerous diseases or syndromes associated with critical illness, TPE in the intensive care unit (ICU) setting has not been studied extensively. A group of eighteen experts around the globe from different clinical backgrounds used a modified Delphi method to phrase key research questions related to "TPE in the critically ill patient". These questions focused on: (1) the pathophysiological role of the removal and replacement process, (2) optimal timing of treatment, (3) dosing and treatment regimes, (4) risk-benefit assumptions and (5) novel indications in need of exploration. For all five topics, the current understanding as well as gaps in knowledge and future directions were assessed. The content should stimulate future research in the field and novel clinical applications.

Chronic Active T-Cell Mediated Kidney Rejection as a Clinically Significant Type of Allograft Loss?

The purpose of this article is to assess the present knowledge about chronic active (CA) T-cell mediated rejection (TCMR) of a kidney. In the research authors review current Banff diagnostic criteria used in kidney rejection, focus on their possible future evolution, and investigate the role of currently available molecular methods that could be implemented into the diagnostic scheme. Research also points out previously and currently available treatment methods applied to CA TCMR and takes into account possible side effects consequent upon the therapy. Moreover, attention is being paid to the CA TCMR coincidence with other kidney rejection types such as antibody-mediated rejection (ABMR) and its influence on the treatment approach. Authors also mark the possibility of non-HLA antibodies coexistence in patients with CA TCMR and describe its possible resonance on kidney allograft function. Nonetheless, it seems that current knowledge about CA TCMR is not sufficient and requires further investigation.