CD40LG and infection: Our previous report identified an inverse relationship between sCD40L levels in the sera of VL patients and cure in response to treatment, implicating a role for sCD40L in protection against L. infantum. To determine if sCD40L could have a protective role against L. infantum infection, we added recombinant human CD40L (rCD40L) in combination with anti-CD40L to human macrophages infected with L. infantum. Firstly, we demonstrated that a wide range of rCD40L concentrations could reduce the infection (Fig 1A and 1B) and determined to use 2 μg/ml of rCD40L in further experiments.