Peripheral Blood Eosinophilia as a Marker of Acute Cellular Rejection in Liver Transplant Recipients: A Retrospective...

Although liver biopsy in patients with acute cellular rejection (ACR) is the gold standard for diagnosis, its invasive nature highlights the need for reliable noninvasive biomarkers. With evidence suggesting that peripheral blood eosinophil levels may be associated with rejection, we evaluated the relationship between eosinophil levels and ACR to determine whether eosinophil dynamics reflect rejection severity.

We retrospectively analyzed 151 liver transplant recipients who underwent 398 liver biopsies between 2012 and 2022. To analyze eosinophil changes, we collected data on eosinophil counts, eosinophil percentages, liver enzymes, bilirubin, international normalized ratio, and rejection activity index (RAI) scores from biopsy day (day 0) and day 5 after treatment; patients with and without rejection (established histopathologically with RAI) were compared. We analyzed correlations between RAI severity and eosinophil levels.

Liver enzyme levels were significantly higher in patients with versus without ACR (P < .05). In the rejection group, eosinophil count and percentage decreased markedly after treatment (P < .001), whereas no significant change was observed in the non-rejection group. Higher RAI scores were associated with increased eosinophil count (P = .029) and percentage (P = .021) on day 0 and a more pronounced decline on day 5 (both P < .001).

Peripheral blood eosinophil levels were associated with ACR and exhibited characteristic changes that reflected rejection severity and therapeutic response. Eosinophil monitoring may be a useful noninvasive adjunct in the early detection and follow-up of ACR. Larger prospective multicenter studies are needed to validate these findings.