Acquired factor XI deficiency in systemic lupus erythematosus

Area of Science:

• Hematology
• Immunology
• Rheumatology

Background:

• Systemic lupus erythematosus (SLE) is an autoimmune disease associated with diverse clinical manifestations.
• Coagulation abnormalities are recognized complications in SLE patients, though specific mechanisms remain under investigation.

Observation:

• A patient with SLE presented with a rare acquired factor XI deficiency.
• The deficiency was not caused by a typical inhibitor but by a plasma factor, likely an immunoglobulin, that specifically bound to factor XI.

Findings:

• The acquired factor XI deficiency in this SLE patient was attributed to a novel mechanism involving an immunoglobulin.
• Factor XI levels normalized following treatment with corticosteroids, suggesting an immune-mediated process.

Implications:

• This case suggests that immune complexes in SLE may sequester clotting factors, impacting coagulation.
• Understanding these immune-mediated coagulation defects can inform therapeutic strategies for SLE patients.