Reciprocal changes in complement activity and immune-complex levels during plasma infusion in a C2-deficient SLE...

Area of Science:

• Immunology
• Rheumatology

Background:

• Systemic lupus erythematosus (SLE) is frequently observed in individuals with complement deficiencies.
• Direct causal evidence linking specific complement deficiencies to SLE manifestations has been limited.

Purpose of the Study:

• To investigate the relationship between complement component C2 levels and clinical outcomes in a patient with C2 deficiency and SLE.
• To analyze changes in immune complexes, C2, and C3d during fresh frozen plasma (FFP) infusions.

Main Methods:

• A patient with C2 deficiency and SLE received 56 courses of FFP infusions over 8 years.
• Each infusion involved 12 units of FFP over 4 days, with monitoring of immune complexes, C2, and C3d levels.
• Clinical remission duration was recorded following each infusion cycle.

Main Results:

• FFP infusions consistently restored the classical pathway of complement, leading to clinical remission lasting 6-8 weeks.
• Four distinct peaks in C2 and C3d levels were observed during the 4-day infusion period.
• These C2 and C3d peaks correlated with reciprocal troughs in immune complex levels.

Conclusions:

• The consistent association between C2 restoration and clinical remission strongly indicates a causal relationship.
• This study provides compelling evidence for the role of complement component C2 in SLE pathogenesis and treatment response.
• FFP infusions represent a viable therapeutic strategy for managing SLE in C2-deficient individuals.