Human kidney damage in fatal dengue hemorrhagic fever results of glomeruli injury mainly induced by IL17

• Lymphocytes CD4+ predominated over CD8+ T cells, B cells and natural killer cells.
• An expressive number of macrophagic CD68+ cells were present in dengue kidney tissues.
• Cells expressing IL17 and IL18+ cytokines predominated in the renal tissues.
• Cells showing IL17 and IL18+ reflect the acute inflammatory response and local lesion.
• Human kidney damage in fatal severe dengue results of glomeruli injury induced by IL17.

Acute kidney injury is an unusual complication during dengue infection. The objective of this study was to better identify the characteristics of glomerular changes focusing on in situ immune cells and cytokines. An immunohistochemical assay was performed on 20 kidney specimens from fatal human cases of dengue hemorrhagic fever (DHF). It was observed a lymphomononuclear infiltrate, neutrophils and nuclear fragmentation in the glomeruli, hydropic degeneration, nuclear retraction, eosinophilic tubules and intense acute congestion. Sickle erythrocytes were frequent in glomeruli and inflammatory infiltrate. The glomeruli presented endothelial swelling and mesangial proliferation. Lymphocytes CD4+ predominated over CD8+ T cells, B cells and natural killer cells. There were also an expressive number of macrophagic CD68+ cells. S100, Foxp3 and CD123 cells were not identified. Cells expressing IL17 and IL18+ cytokines predominated in the renal tissues, while IL4, IL6, IL10, IL13, TNF-alpha and IFN-gamma were rarely visualized. The high number of cells expressing IL17 and IL18+ could reflect the acute inflammatory response and possibly contribute to the local lesion. CD8+ T cells could play a role in the cytotoxic response. DHF is a multifactorial disease of capillary leakage associated with a “Tsunami of cytokines expression”. The large numbers of cells expressing IL17 seems to play a role favoring the increased permeability.