Anti - glucose regulated protein 78 [GRP78] antibody responses in Alum/ALM plus BCG vaccinee, visceral leishmaniasis, and Post Kala- azar Dermal leishmaniasis patients

The Glucose Regulated Protein 78 [GRP78] of Leishmania donovani is considered to be one of the potential Leishmania vaccine candidates. Using Enzyme-Linked Immunosorbent Assay [ELISA], we measured IgG antibody responses to GRP78 in 39 healthy Sudanese volunteers vaccinated with Leishmania Alum/ALM + BCG vaccine, 29 patients with visceral leishmaniasis [VL], and 26 patients with post kala-azar dermal leishmaniasis [PKDL]. There was, no significant statistical difference in plasma levels of GRP78 antibodies in immunized and control group [P=0.37]. Furthermore, no significant statistical difference in the levels of GRP78 antibodies in the pre and post vaccination plasma samples [P=0.60]. Plasma IgG levels to GRP78 was significantly higher in visceral leishmaniasis and PKDL patients compared with control group [P=0.00]. This study concludes that Alum/ALM vaccine does not induce a Th2 type of immune response. It also demonstrated clearly that VL and PKDL are associated with elevation of anti-GRP 78 antibodies and that GRP78 ELISA can be used to confirm diagnosis of Leishmania infections based on the clinical presentation