Immunopathology of Leishmaniasis: An Update

Abstract

Leishmaniasis represents a severe, increasing, public health problem. The perspective of its control is highly dependent on research progress, on therapeutic manipulations of the immune system, and on vaccine development. There is a correlation between the clinical outcome of Leishmania infection and the cytokine response profile. While a protective immune response against Leishmania has been clearly identified to be related to the influence of a type-l response and IFN-y production, the precise role of T helper (TH) 2 cytokines in non-healing infections requires further exploration. IL-4 and IL-13 (TH2 cytokines) can promote disease progression in cutaneous leishmaniasis, whereas IL-4 would appear to enhance protective type-l responses in visceral leishmaniasis. Thus, the THlITH2 paradigm of resistance/ susceptibility to intracellular parasites is probably an oversimplification of a more complicated network of regulatory/counter regulatory interactions. Moreover, the presence of antigen specific regulatory T cell subsets may provide an environment that contributes to the balance between THI and T H2 cells. Finally, the involvement of CD8+ T cells has been described, but the modality of their function in this kind of infection has not been so far elucidated.Leishmaniasis represents a severe, increasing public health problem (1-2). Moreover, many of the 50 million people who travel from industrialized to developing countries each year report some infective illness associated with their travel, included leishmaniasis, which is endemic in the areas of tropics, subtropics, and southern Europe (3). The perspective of control is still highly dependent on research progresses, to obtain better tools and more cost-effective strategy for vector control and case management, through therapeutic manipulations of the immune system, and vaccine development (4).Leishmaniasis comprises a group of diseases caused by protozoan parasites of the Leishmania genus. Leishmaniasis is characterized by different clinical manifestations, which are dependent not only on host genetic control, but also on the infecting species, which to date are more than 20 (5).The parasites which cause the various forms of leishmaniasis in humans are classified in the subgenus Leishmania (L.) or Viannia (V. (V.) braziliensis, Leishmania (V.) guyanensis, Leishmania (V.) lainsoni, Leishmania (V.) naiffi, Leishmania (V.) panamensis, Leishmania (v.)

Immune response to Leishmania (Leishmania) chagasi infection is reduced in malnourished BALB/c mice

“…In fact, in BALB/c mice, the control of visceral infection is associated with the development of parasitespecific cell-mediated immune responses involving both CD4 + and CD8 + T cells (Carrión et al 2006). Although IL-10 is a cytokine with suppressive effects (Mansueto et al 2007, Nylén & Sacks 2007, no difference was detected in its level between control and malnutrition groups. No production of IL-4 and NO by spleen cells was detected in the experimental groups through the methods used.…”

Significance of persistence of antibodies against Leishmania infantum in sicilian patients affected by acute visceral leishmaniasis

“…Furthermore, Leishmania-specific polymerase chain reaction (PCR) of peripheral blood is used to confirm parasite infection [3]. It is commonly accepted that it is possible to detect only the presence of serum-specific IgG antibodies, given that the appearance and disappearance of serum-specific IgM antibodies occurs rapidly, always before a specific diagnosis of VL could be made [4][5][6].…”

Leishmania amazonensispromastigotes induce and are killed by neutrophil extracellular traps

“…Worldwide, Ͼ10 million people are affected by this disease that causes significant morbidity and mortality (8). Leishmania amazonensis is the causative agent of human cutaneous leishmaniasis in the New World, with a high proportion of cases evolving to the severe anergic diffuse cutaneous leishmaniasis (9).…”