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Difficulty: HardRheumatology and Immunology

Match each patient's clinical presentation with the autoantibody or immunologic marker most strongly associated with their underlying disease process.

  • A 48-year-old woman presenting with proximal muscle weakness, hyperkeratotic cracking on the lateral aspects of her fingers, and new-onset interstitial lung disease.Anti-Jo-1 (anti-histidyl-tRNA synthetase) antibodies
  • A 32-year-old woman with a history of unprovoked pulmonary embolism presenting with recurrent mid-trimester pregnancy losses and an isolated prolonged PTT.Anti-beta-2-glycoprotein I antibodies
  • A 55-year-old man with palpable purpura, arthralgias, peripheral neuropathy, and hypocomplementemia (low C4), who recently tested positive for Hepatitis C.Rheumatoid factor
  • A 60-year-old woman with severe xerophthalmia, xerostomia, and bilateral parotid gland enlargement who recently noticed a rapidly enlarging cervical lymph node.Anti-Ro/SSA antibodies

Answer

Antisynthetase syndrome matches with Anti-Jo-1; Antiphospholipid syndrome matches with Anti-beta-2-glycoprotein I; Mixed cryoglobulinemia matches with Rheumatoid factor; Sjögren syndrome matches with Anti-Ro/SSA.
Each left item provides a high-yield, specific clinical vignette for a systemic autoimmune disease. Antisynthetase syndrome is driven by anti-Jo-1; antiphospholipid syndrome relies on markers like anti-beta-2-glycoprotein I; Hepatitis C-associated mixed cryoglobulinemia features IgM rheumatoid factor; and Sjögren syndrome is characterized by anti-Ro/SSA antibodies.

Step-by-Step Solution

1
Analyze the first patient's symptoms (myositis, mechanic's hands, interstitial lung disease) to diagnose antisynthetase syndrome.
Identify Anti-Jo-1 as the highly specific antibody for this condition.
Anti-Jo-1 targets histidyl-tRNA synthetase and defines this distinct subset of inflammatory myopathies.
2
Evaluate the second patient's history of thrombosis, pregnancy loss, and isolated prolonged PTT to diagnose antiphospholipid syndrome.
Identify Anti-beta-2-glycoprotein I as one of the defining diagnostic autoantibodies.
The prolonged PTT is an in vitro artifact of the lupus anticoagulant; the syndrome is mediated by antibodies against phospholipid-binding proteins.
3
Correlate the third patient's palpable purpura, neuropathy, low C4, and Hepatitis C with mixed cryoglobulinemia.
Identify Rheumatoid factor as the key immunologic marker.
Type II mixed cryoglobulins are immune complexes composed of polyclonal IgG and monoclonal IgM; the IgM component possesses rheumatoid factor activity (affinity for the Fc portion of IgG), which consumes complement C4.
4
Recognize the fourth patient's sicca symptoms, parotid swelling, and new lymphadenopathy as Sjögren syndrome with likely lymphomatous transformation.
Identify Anti-Ro/SSA antibodies as the classic serologic marker.
Sjögren syndrome carries a significantly elevated risk for B-cell non-Hodgkin lymphoma, and is diagnosed using Anti-Ro/SSA and Anti-La/SSB antibodies.

Key Concept

Clinical and serologic correlations in systemic autoimmune and rheumatic diseases
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Topics

Rheumatology and Immunology

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