Two-dimensional difference gel electrophoresis (DIGE) analysis of sera from visceral leishmaniasis patients

Sera from six visceral leishmaniasis patients and six healthy controls were depleted of high abundant proteins by immunodepletion. The depleted sera were compared by 2-D Difference in gel electrophoresis (DIGE). Differentially expressed proteins were identified the by tandem mass spectrometry. Three of the identified proteins were further validated by western blotting.This is the first report of serum proteomics study using quantitative Difference in gel electrophoresis (DIGE) in visceral leishmaniasis. We identified alpha-1-acidglycoprotein and C1 inhibitor as up regulated and transthyretin, retinol binding protein and apolipoprotein A-I as down regulated proteins in visceral leishmaniasis sera in comparison with healthy controls. Western blot validation of C1 inhibitor, transthyretin and apolipoprotein A-I in a larger cohort (n = 29) confirmed significant difference in the expression levels (p < 0.05).In conclusion, DIGE based proteomic analysis showed that several proteins are differentially expressed in the sera of visceral leishmaniasis. The five proteins identified here have potential, either independently or in combination, as prognostic biomarkers.Leishmaniasis is a vector borne infection caused by the obligate intracellular protozoa belonging to the genus Leishmania. It is endemic disease affecting people in the large parts of tropical counties and the Mediterranean basin. Clinically, there are mainly four subtypes, namely cutaneous, muco-cutaneous, visceral (kala azar) and post kala azar dermal leishmaniasis. Visceral leishmaniasis is caused by the L. donovani group of organisms and transmitted by the bite of the phlebotomine sand fly. There are an estimated 500,000 new cases every year and more than 90% of these cases occur mainly in Bangladesh, India, Nepal, Sudan, Ethiopia and Brazil [1]. The disease has an incubation period between 2 to 6 months and presents with fever, anaemia and enlargement of liver, spleen and lymph nodes. It is almost always fatal