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Volume 31, Number 3—March 2025
Dispatch
Donor-Derived Ehrlichiosis Caused by Ehrlichia chaffeensis from Living Donor Kidney Transplant
Figure

Figure. Histopathologic and immunohistochemical staining of renal graft biopsy from donor-derived ehrlichiosis caused by Ehrlichia chaffeensis from living donor kidney transplant. We performed an immunohistochemical (IHC) assay using an immunoperoxidase technique, with naphthol fast-red substrate, light hematoxylin counterstaining, and an antibody raised against E. canis but known to cross-react with other Ehrlichia species, including E. chaffeensis and E. ewingii, among others. A) Interstitial peritubular mononuclear cell infiltrate (arrows). Hematoxylin and eosin (H&E) stain; original magnification ×400. B) Immunostaining of bacterial antigens from Ehrlichia species within 2 morulae in the cytoplasm of reactive endothelial cells of a renal venule (arrows). Original magnification ×630. C) Periglomerular focal interstitial mononuclear cell inflammation (arrows). H&E stain; original magnification ×400. D) Magnification of IHC assay of kidney biopsy indicating a granular immunostaining pattern within intracellular morulae (arrows). Original magnification ×1,000. E) Renal tubules displaying some features of acute tubular necrosis including epithelial cells with condensed chromatin and sloughing of cells into lumina. The tubular lumina are filled with sloughed off necrotic tubular epithelial cells (arrowheads). Some tubules show near complete luminal occlusion. Casts are not identified. H&E stain; original magnification ×630. F) Another intracellular morulae seen on kidney biopsy by IHC assay (arrow). Original magnification ×1,000.
1These first authors contributed equally to this article.
2These senior authors contributed equally to this article.