Can some viruses & infections cause non specific rises in autoantibodies like rnp and contribute to having positive anas? help

Depends on titer: The higher the titer of anti-U1RNP and its relatives, the more likely it is that it's actually related to a real autoimmune disease. Low titers can often be detected and I suspect you are right -- and very serious infections (such as bacterial infections of the heart valves) are infamous for causing anti-nuclear antibodies to appear. These labs are adjuncts to the history & physical exam.