Syndrome

Features

SSc + PM (scleromyositis)

Serologic marker: Positive anti-PM/Scl antibodies in 24% of patients (nucleolar staining on immunofluorescence)

Clinical manifestations similar to antisynthetase syndrome; however, myositis and interstitial pneumonia are less frequent, the course is less severe, and the response to treatment is better

SLE + scleroderma

SLE with antibodies to histones and centromere: More frequent pulmonary, renal, and cardiac involvement

SLE with anti-Scl-70 antibodies: Higher disease activity, more frequent pulmonary hypertension and renal involvement

SLE with Raynaud phenomenon: More frequent anti-U1 RNP antibodies, dilated nail-fold capillaroscopy with “drop-outs” (typical for scleroderma)

SLE + RA (rhupus)

Destructive arthritis, rheumatoid nodules, positive RF and/or ACPAs; these most frequently precede features of SLE: leukopenia, thrombocytopenia, positive ANAs and anti-dsDNA, decreased levels of complement components