--is worth looking into, but your intake levels don't seem high enough for you to be suffering neuropathy from that; most reports of B6 overdose neuropathy involve doses WAY in excess of what you are reporting:

http://www.neuro.wustl.edu/neuromusc...yridoxineintox

While having an immunofixation electrophoresis (IFE) that is clear of rogue monoclonal antibodies (m-proteins) is a good thing, your immunoglobulin levels across the board are indeed a bit low for an adult. This can be due to a lot of things, most commonly Common Variable Immunodeficiency; more investigation into this would be a good idea, to see if you have particular deficits within certain immunoglobulin subclasses that are driving the overall numbers down. (Do you get a lot of bacterial infections?)

While the gliadin test was negative, an anti-transglutaminase assay should also be done if gluten sensitivity/celiac is supected (more specific, though less sensitive, test than than the anti-gliadin). Another important point here--these tests tend not to be as accurate in those who have low immunoglobulin levels (the anti-gliadin and anti-transglutaminase antibodies are IgG and IgA class). And--there have been plenty of people with "seronegative" gluten sensitivity; in fact, as Cara's Gluten File (you can find links to that in the gluten forum here) indicates, people with primarily neurolgoical symptoms of gluten intolerance are more likely to be seronegative.

It's similar with Sjogren's; there are plenty of people with symptoms who are seronegative for those characteristic antibodies. (Have you had anti-nuclear antibody/rheumatoid factor tests run, for connective tissue/vasculitic syndromes that may result in neuropathy?)

I agree that it often takes a 3-5 hour glucose tolerance test, with levels taken every half-hour, to show imminent or developing impaired glucose tolerance, which can certainly lead to neuropathy symptoms well before frank diabetes would be diagnosed. But, too many doctors will attribute neuropathic symptoms to that without a real thorough search for other possiblities.

The Liza Jane spreadsheets at www.lizajane.org are a great way to see just how comprehensive your work-ups have been, as well as to track the patterns of your test results over time.