ANA (Anti Nuclear Antibodies) becomes + in autoimmune diseases like systemic lupus erythematosis or SLE,polymyositis and others.
Anti- sm/RNP positive means autoimmune disease including mixed connective tissue disorder, systemic sclerosis, scleroderma primary sjorgen,s syndrome etc.
It is positive in 90% of cases of mixed connective tissue disorders, 40% positive in SLE,and 30% cases of systemic sclerosis.
Now, if anti smith or Anti-sm antibodies are negative, it is almost certain that ANA positive is not because of SLE but because of other auto immune diseases.
Anti RNP is highly associated with mixed connective tissue disease and its absence almost excludes that option as well.
So it seems more like a case of either progressive systemic sclerosis, sjorgens syndrome, or scleroderma.
But you can not diagnose just on the basis of labortary tests. Clinical presentation and history is more important in order to know the underlying auto immune disorder.