Visceral leishmaniasis, hypertriglyceridemia and secondary hemophagocytic lymphohistiocytosis

Abstract

cytokines, an upregulation of adhesion molecules and MHC I and II molecules on mono/macrophages, and an expansion of inflammatory monocytes. This exaggerated inflammatory response is responsible for necrosis and organ failure and results in uncontrolled proliferation and phagocytic activity of histiocytes [2]. Hypertriglyceridemia (fasting, greater than or equal to 265 mg/100 ml) is one of the current diagnostic criteria for HLH [2]. Several studies link hypertriglyceridemia to inhibition of lipoprotein lipase (LPL) by tumor necrosis factor-α (TNF-α), and TNF-α is a powerful autocrine and paracrine regulator of adipose tissue [3]. Indeed, many different sources of intense and prolonged T-lymphocyte/macrophage activation may be associated with dyslipidemia (particularly with hypertriglyceridemia) through inappropriate release of TNF-a, IFN-g, GM-CSF and respectively, of IL-1/IL-6, leading to adipose tissue lipolysis with increased VLDL secretion, decreased VLDL clearance, increased hepatic fatty acid synthesis, and suppression of fatty acid oxidation with HIV infection being the wellknown paradigm of this mechanism (possibly enhanced by some antiretroviral drugs). In PubMed there are at least 70 papers in which the association leishmaniasis/(hemophagocytic or haemophagocytic) is present. Leishmania parasites have been found to be the most common protozoan trigger of acquired HLH. In a multicenter prospective study conducted to determine the frequency of HLH syndrome in children with VL, ten children out of 24 (41 %) with VL developed HLH syndrome [4]. HLH incidence in European adult population is about 1/800,000/year, with a reported prevalence of parasitic infections of 2.4 % (53 out of 2197 subjects), and of Leishmania spp. of 0.77 % (17 out of 2197) as a trigger. The clinical picture of VL with HLH initially can be indistinguishable from HLH of other etiology, potentially Dear Sir,