Factor XII deficiency with systemic lupus erythematosus. Biological implications

Area of Science:

• Hematology
• Immunology
• Rheumatology

Background:

• Factor XII (Hageman) deficiency is a rare inherited bleeding disorder.
• Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with diverse clinical manifestations.

Observation:

• A patient presented with concurrent Factor XII deficiency and fulminant SLE.
• The Factor XII deficiency predated SLE onset and persisted without bleeding complications.
• The patient exhibited a rapid, fatal disease course unresponsive to corticosteroid treatment.

Findings:

• Despite absent Factor XII, classic complement pathway activation and thromboembolic phenomena were observed.
• Factor XII levels remained unchanged during corticosteroid therapy.
• No circulating anticoagulant was detected.

Implications:

• This case challenges the traditional understanding of Factor XII's role in thrombosis.
• It suggests alternative pathways for complement activation and thrombosis in SLE patients with Factor XII deficiency.
• Further research is needed to elucidate the complex interplay between Factor XII, coagulation, inflammation, and SLE pathogenesis.