Can Taking Plaquenil For Lupus Affect The Immune System?

I am taking plaquenil for Lupus, diagnosed April 2014. THis winter I have had continuous colds including severe coughing . I have given medicines, steroids, and antibiotics and I still keep getting colds. This started in Nov. and has continued even to the present. Could plaquenil be hurting my immune system? I also have a low white blood cell count from the Lupus.