And now for the number one yoga pose for boosting immunity: supported setu bandha sarvangasana. That’s a mouthful. It is also called supported bridge pose, or setu bandhasana. When I went through my yoga teacher certification program, I learned that there are hospitals in India that use yoga as medicine, prescribing various sequences depending upon the ailment and constitution of the individual receiving treatment. Regardless of the ailment, setu bandha sarvangasana is invariably a component of the healing regimen. Here is a great article that presents a simple sequence for boosting immunity, appropriate for all levels http://www.yogagroup.org/schatz.html.
Another tip for using yoga to keep the immune system strong is to alternate forward bends and back bends. A perfect example of how to do this is the sun salutation. This sequence wrings out the internal organs and lymphatic fluids throughout the body. Even a few sun salutations a day will help!