In an active viral or bacterial infection it could

In an active viral or bacterial infection it could be counterproductive. Studies have shown a slight uptick in B and T cell production and moderate downregulation of some of the same cytokines that leronlimab effects in vitro. It would have some positive effect in symptomology of mild infections that the immune system can already keep under control. With the ability of Covid-19 to break out to an uncontrolled infection I wouldn't recommend anything that could suppress immune response early.