A dermatomyositis and scleroderma overlap syndrome with a remarkable high titer of anti-exosome antibodies

rheumatoid arthritis without a particular serologic profile, others like the sclerodermatomyositis are associated to specific antibodies such as anti-PM/Scl antibodies (2), this serologic system was described more than two decades ago, PM/Scl antigen was immunochemically characterized by the serum from a patient with sclerodermatomyositis, that reacted against a moiety present in a calf thymus extract and was named PM/Scl antigen.This moiety is located in the nucleolus of HEp-2 cells (3), the prevalence of anti-PM/Scl in sclerodermatomyositis overlap syndrome is ~24%; however anti-PM/Scl antibody is not exclusive, because it was reported in 8% of patients with polymyositis and in 3% of patients with scleroderma (3, 4).In summary, overlap syndromes are now clinically and serologically well characterized, and have been included as separate entities in the inflammatory myopathies new classification (5).We report a clinical case of scleroderma-dermatomyositis overlap syndrome with exceptional high titers of antinuclear antibodies with fine specificity to anti-PM/Scl-100. SUMMARYAn overlap syndrome of dermatomyositis and scleroderma is reported.The case corresponded to a 27-year-old female with a clinical picture of 14 months evolution, characterized by proximal muscles weakness, erythematous rash in wrists, knees, ankles, Gottron sign, heliotrope periorbital rash and dysphagia.A muscle biopsy was compatible with dermatomyositis; meanwhile the skin biopsy was compatible with scleroderma.Muscle enzymes were increased.Interestingly, the antinuclear antibody determination in HEp-2 cells was positive with a remarkable titer of 81,920 exhibiting a nucleolar pattern.Anti-Jo1 antibody was negative, but anti-PM/Scl-100 positive.The patient received methylprednisolone and cyclophosphamide pulses, with gradual improvement.Present report constitutes a case of overlap dermatomyositis-scleroderma syndrome, with anti-PM/Scl autoantibodies (anti-exosome).The remarkable of this case was the exceptional high antinucleolar antibody titer.Parole chiave -Sclerodermatomiosite, anticorpi antinucleo, anticorpi anti-PM/Scl, sindrome da sovrapposizione, esosoma.