Rheumo/gi want nerve biopsy. Check 4 inflammatory vasculitis. Have sjogrens, rsynauds, MS plus severe neuropathy. What does vasculitis mean w all this?

Vasculitis. Vascular involvement -- it might effect clotting and bleeding issues, and risks of heart attack and stroke if you had them.
Vasculitis. Vasculitis is an inflammatory condition of the the blood vessels. Because it is often systemic, meaning widespread throughout the body, it can affect any organ system including the nervous system. A biopsy of the nerve may help to determine what kind of inflammation is present and help to guide the best treatment.
Likely more than one. Issue. A nerve biopsy is not needed to diagnose vasculitis, skin biopsy is usually sufficient. However, given your medical history a nerve biopsy may be needed to ascertain the cause of neuropathy. Nerve biopsy can reveal vasculitis also. It would be prudent to discuss the matter with your doctor as s/he knows your medical issues better.
Sort this out. Do you truly have MS, & if so, why are you NOT on MS drug? Sjogren's can masquerade as primary progressive MS, and can cause small fibre peripheral neuropathy. Perhaps that is why your doctors want to look at nerve biopsy. Rather unlikely to expect vasculitis confirmation from a nerve biopsy, but vasculitis can occur in collagen vascular disease, especially lupus. You need a unitary diagnosis.