Sjögren syndrome and systemic lupus erythematosus are distinct conditions.

Sjogren syndrome (SS) and systemic lupus erythematosus (SLE) are both collagen vascular diseases that can be accompanied by Ro antibodies. Clinical evidence suggests that they are wholly distinct diseases. SS is strongly linked to lymphoma while lupus is not. SS patients do not commonly exhibit photosensitivity even though anti-Ro antibodies circulate in their blood; SLE patients generally exhibit photosensitivity. SS does not respond to hydroxychloroquine in a reproducible fashion whereas SLE does. SS has not been linked to parvovirus B19, but SLE has. However, SS and SLE do have similarities. Their autoantibody profiles are similar. They effect women more than men and have similar HLA haplotypes and autoantibodies; this is not likely coincidence but it may not clinically relevant.