Combination of Donor-Specific HLA Antibodies and Non-HLA Antibodies Associated with Higher Risk of Acute Cellular Rejection in Pediatric Liver Transplant Recipients

The presence of donor-specific Human Leukocyte Antigen (HLA) antibodies and non-HLA antibodies was associated with a higher risk of acute cellular rejection in pediatric liver transplant recipients, UPMC Children’s Hospital of Pittsburgh and University of Pittsburgh researchers reported in Human Immunology.

“This research begins to shed light on the complex interplay between the different parts of the immune system and how they could be potentially contributing to the development of rejection of liver transplants in pediatric patients,” says lead author James E. Squires, MD, MS, associate professor of pediatrics, associate director of hepatology, and director of the pediatric transplant hepatology fellowship at the University of Pittsburgh School of Medicine.

Study co-authors include Adriana Zeevi, PhD, ABHI (D), University of Pittsburgh Department of Pathology, George V. Mazariegos, MD, FACS, chief of pediatric transplantation at UPMC Children’s, Rakesh Sindhi, MD, director of pediatric transplantation research at UPMC Children’s, Carol Bentlejewski, University of Pittsburgh Department of Pathology, Sarah M. Bedoyan, MD, UPMC Children’s Department of Pediatrics, and Qingyong Xu, PhD, ABHI (D), F (ACHI), University of Pittsburgh Department of Pathology.

In posttransplant clinical management, acute cellular rejection is currently detected only when it is already in progress or has already occurred. It is usually detected through elevated liver enzymes in routine bloodwork and diagnosed through a follow-up liver biopsy.

Increased understanding of the interacting cellular and immune mechanisms that lead to rejection could contribute to improved posttransplant monitoring protocols and better graft loss risk stratification for pediatric liver transplant recipients.

This paper is a first step to illuminating the immune system dynamics that may contribute to graft rejection in pediatric liver transplant recipients.

Antibodies to Human Leukocyte Antigen (HLA) and non-HLA antigens have been shown to be associated with graft dysfunction and loss in adult kidney, heart, and lung transplant recipients. But, past research studies have not shown a clear association between HLA and non-HLA antigens and graft rejection in adult and pediatric liver transplant recipients. This study focuses on determining whether HLA and non-HLA antibodies were associated with acute cellular rejection in pediatric liver transplant recipients.

Methods

The researchers examined posttransplant liver biopsy and sera data from 101 pediatric transplant recipients who received liver transplants at UPMC Children’s Hospital of Pittsburgh in the time period from January 1, 2014 to October 1, 2020.

Biopsy were collected at least 1 month posttransplant, as part of five year-posttransplant surveillance or due to possible graft dysfunctions.

Sera was collected within three months of biopsy collection.

Sera was tested for the presence of donor-specific HLA antibodies (DSA) as part of routine patient care. Researchers used Luminex Single antigen beads assay to determine the presence of donor-specific HLA antibodies (DSA).

Sera was retrospectively tested for 60 non-HLA antibodies using a Luminex-based solid-phase assay.

“This is one of the first studies that used these large multiplex antibody antigen testing techniques, these novel, new ways to take one small blood sample and look at many different markers and apply it to the pediatric population,” Dr. Squires says.

Results

The presence of both HLA and non-HLA antibodies was significantly associated with an increased risk of graft rejection when compared to recipients who had neither HLA nor non-HLA antibodies. The presence of a single type of antibody (HLA or non-HLA) was not significantly associated with an increased risk of graft rejection.

Three of the 60 non-HLA antibodies were significantly associated with an increased risk of graft rejection:

• anti-SNRPB (small nuclear ribonucleoprotein polypeptides B)
• anti-GSTT1 (Glutathione S-transferase theta-1) antibodies
• anti-Actin antibodies

Future Directions of Research

Dr. Squires stresses that this study is preliminary. Future directions of research could repeat this assay-based testing in a prospective, multi-center study of pediatric liver transplant recipients.

“I think that’s the really exciting potential of this study is to say, ‘Are there markers we could be checking at a regular interval that we could then monitor for potential rejection risk?’ It is potentially a way to think about monitoring for patients who may be at risk for the development of future rejections down the road.”

Reference

Xu Q, Bedoyan SM, Bentlejewski C, Sindhi R, Mazariegos GV, Zeevi A, Squires JE. The impact of donor-specific antibody and non-HLA antibodies on acute cellular rejection in pediatric liver transplantation. Hum Immunol. 2025 May 28;86(3):111289