T helper cells1/ T helper cells2 conversion to T helper cells1 immune response switch: the case of post kala-azar dermal leishmaniasis

Abstract

The Leishmaniases are a group of diseases caused by the genus Leishmania of the family: Trypansomatidae. They are transmitted by the female sand flies of the genus phlebotomus in the Old World and lutzomyia in the New World. The clinical forms in man include visceral leishmaniasis (VL), post kala-azar dermal leshmaniasis (PKDL), diffuse cutaneous leishmaniasis (DCL), mucocutaneous (MCL), self-healing cutaneous (CL). VL is the most serious and is fatal if not treated (El- Hassan & El- Hassan, 1997; Zijlstra & El-Hassan, 2001a; Zijlstra et al., 2001b; Musa et al., 2002). VL is caused by Leishmania donovani in the Old World, L.infantum in the Mediterranean basin and L.chagasi in the New World. It is characterized by development of fever, splenomegaly, hepatomegaly, weight loss and pancytopenia. Often complications occur such as epistaxis or bleeding from other sites, and concurrent infections (Zijlstra & EL-Hassan, 2001a).