Figure 3.

Failure of organ-specific memory T cell response. Following infection with Leishmania parasites, individuals develop VL, and generally antileishmanial treatment results in lifelong immunity due to the presence of systemic CM and EM T cells. In patients with self-limiting PKDL (e.g., in Sudan), an increased EM T cell response in the skin causes spontaneous resolution. However, in Indian PKDL, a weak skin-specific EM T cell response accounts for its non-self-healing nature. Abbreviations: CM T cells, central memory T cells; EM T cells, effector memory T cells; VL, visceral leishmaniasis; PKDL, post kala-azar dermal leishmaniasis.