Hypereosinophilia in a Home HD Patient

Dufour, Inès [UCL]

Parallel Session 17: Clinical Case Discussions: Home HD Wednesday, November 29, 2023, 02:00PM-02:20PM, Level 4 ‘Hypereosinophilia in a Home HD Patient’ Inès Dufour Fellow in Nephrology UCLouvain Abstract: We described the case of a 55-year-old woman with kidney failure due to primary focal segmental glomerulosclerosis (FSGS) who received a kidney transplant in 1989. Chronic allograft dysfunction required kidney replacement therapy and the patient was started on home hemodialysis in October 2020. In February 2022, she presented with isolated total macroscopic hematuria for three consecutive days. Urinalysis ruled out urinary tract infection. Computed tomography scan of the abdomen showed uncomplicated kidney allograft atrophy. Cystoscopy and gynecologic examination were normal. In April 2022, routine monthly biology revealed severe hypereosinophilia (peak eosinophil count: 3,33× 109/L (normal, <0.5 × 109/L)), total white blood cells: 12,1 x 109/L (normal, 4-10× 109/L) and systemic inflammation (C-reactive protein: 41 mg/L, normal <5 mg/L). No new medication had recently been introduced. Stool ova and parasite test, and anti-neutrophil cytoplasmic antibody were both negative; and lymphocyte immunophenotyping and IgE concentration were normal. A18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) was performed and showed intense hyperactivity of the kidney allograft cortex. Graft nephrectomy was subsequently performed. Histopathology showed significant interstitial inflammation with lymphocytes and eosinophils infiltration, signs of glomerulitis (g3), peritubular capillaritis (ptc3) and glomerular basement membrane double contours (cg1). The C4d staining was positive in peritubular capillaries. These findings were all consistent with the diagnosis of eosinophil-rich acute antibody mediated rejection (ABMR) on chronic allograft nephropathy. Blood eosinophils count normalized two weeks after surgery. Association between peripheral blood eosinophilia and episodes of graft rejection were initially reported in the 1980s. More recent studies have confirmed those findings, proposing eosinophilia as a biomarker for acute rejection1. Rise of blood eosinophils in early post-transplant months has even been proposed as a hallmark of graft rejection2. Eosinophils are now considered true immunoregulatory cells having some roles in antigen presentation, T-cell regulation, B-cell priming, as well as regulation of dendritic and mast cells, basophils and neutrophils. Eosinophils have been linked to acute allograft rejection induced by Th2-type CD4+ cells, which are effector cells in the alternative pathway implicated in acute rejection3. Cytokines, like IL-5, released by activated T lymphocytes are responsible for the eosinophils recruitment in acute rejection. In experimental mouse heart transplant, acute rejection mediated by Th2 cells was characterized by a marked eosinophils infiltrate in the allograft.In summary, this case reminds that antibody-mediated rejection should be considered in the differential diagnosis of hypereosinophilia in a transplanted patient, even after kidney graft failure and hemodialysis resumption. References: 1. Wang GY, Li H, Liu W, Zhang J, Zhu HB, Wang GS, Zhang Q, Yang Y, Chen GH. Elevated blood eosinophil count is a valuable biomarker for predicting late acute cellular rejection after liver transplantation. Transplant Proc. 2013 Apr;45(3):1198-200. 2. Almirall J, Campistol JM, Sole M, Andreu J, Revert L. Blood and graft eosinophilia as a rejection index in kidney transplant. Nephron. 1993;65(2):304-9. 3. Goldman M, Le Moine A, Braun M, Flamand V, Abramowicz D. A role for eosinophils in transplant rejection. Trends Immunol. 2001 May;22(5):247-51.