Hemophagocytic Lymphohistiocytosis due to Brucellosis in a Xeroderma Pigmentosum Pediatric Patient: A Case Report and Review of the Literature.

We report a pediatric patient with xeroderma pigmentosum (XP) who developed hemophagocytic lymphohistiocytosis (HLH) secondary to Brucella infection-an exceedingly rare occurrence. XP is a rare autosomal recessive genetic disorder characterized by extreme ultraviolet radiation (UVR) sensitivity due to the inability to repair DNA pyrimidine dimers caused by UV exposure. This defect leads to a markedly increased risk of skin cancer and progressive neurological degeneration (Leung, 2022). HLH is a rare, potentially fatal hypersensitivity syndrome characterized by excessive activation and impaired downregulation of T-lymphocytes and macrophages. This dysregulation results in an overproduction of proinflammatory cytokines, destruction of blood cells, and subsequent tissue and organ damage (Fisman, 2000). While secondary HLH may follow various infections, Brucella-induced HLH is rare (Wolska, 2006), and to our knowledge, this is the first reported case in a patient with XP.