This is a bit outside the stuff that I know about professionally but my impressions are:

ANA staining patterns can be suggestive of one or more auto-immune diseases but they are not diagnostic.

Sero-negative (ie, there are no detectable antibodies specific for the various nuclear antigens, Ro52 and others) scleroderma is known. My guess is that this is because it arises from over-production of collagen (for reasons which are poorly understood), sometimes but not always with an auto-immune aspect.

I think that your idea of getting a referral to a clinical immunologist is a good one. You could collect all of the clinical paperwork from your GP, show it to the clinical immunologist and see what s/he thinks.