Visceral leishmaniasis in immunocompromised: Diagnostic and therapeutic approach and evaluation of the recently released IDSA guidelines

Visceral Leishmaniasis (VL) is a chronic infectious disease endemic in tropical and sub-tropical areas including the Mediterranean basin, caused by a group of protozoan parasites of the genus Leishmania and transmitted by phlebotomine sandflies. Typically, VL is classified as a zoonotic infection when Leishmania infantum is the causative agent and as an anthroponotic one when L. donovani is the causative agent. Immunocompromised patients, in particular HIV positive, are considered at risk of VL. They may present atypical signs and poor response to the treatment due to a compromission of T-helper and regulatory cells activity. Also pregnancy can be considered a condition predisposing to Leishmania reactivation and to the changes in immune response, due to a switch toward a Th2 response reported in this condition of the life. Laboratory diagnosis is based on microscopy for parasites detection on bone-marrow or spleen aspirates. Value of serology remains high in term of sensibility, but a positive test has to be confirmed by microscopy or molecular tests. Hypergammaglobulinemia and pancytopenia are the main alteration identified by blood examination. Treatment is based on use of liposomal amphotericin B (L-AmB) whose administration is associated to lower incidence of side effects, in respect to antimonials and other formulations of AmB. Use of Miltefosine needs further investigation when L. infantum is the causative agent. Relapses to treatment are observed in coinfected HIV patients. They can benefit of a second cycle, but cumulative efficacy of the treatment can be low.