These abstract are a bit old, but nonetheless show a great need for more research into how the nervous system affects and controls the immune system of the body. Check it out:
Enhanced Phagocytic Cell Respiratory Burst Induced by
Spinal Manipulation: Potential Role of Substance P
Enhanced Neutrophil Respiratory
Burst as a Biological Marker for Manipulation Forces: Duration of the
Effect and Association with Substance P and Tumor Necrosis Factor
Now be careful with what is being said here. Chiropractors adjust the spine, thus affecting the nervous system. The nervous system has been found to have certain controlling influences on the immune system. By adjusting the spine, according to these studies, certain immune functions have been raised. So what does it mean? Quite frankly we don't know, but that is why we need more research. Instead of just dismissing it out of hand, and possibly losing a great opportunity, we must devote more time and resources to researching this.
Bottom line, don't just accept the status quo, especially when it comes to your health!