The diversity of antibodies in patients with scleroderma, mixed connective tissue disease or "primary" Raynaud's phenomenon could be used as a laboratory aid in the clinical diagnosis. In serum samples of 75 patients we screened for antinuclear antibodies (HEp 2 cells), anti DNA, soluble nucleoprotein and extractable nuclear antigens (Sm, rRNP, U1-nRNP, SSA/Ro, SSB/La and Scl-70). Distinctive antinuclear antibodies pattern was identified in each group of patients. This immunologic profile is valuable for clinical diagnosis and the preferential association of certain autoantibodies with some diseases and not with others, suggest an antigen-driven stimulus for its production.