The phenotype of SLE associated with complete deficiency of complement isotype C4A

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Published on: November 1, 2015

T R Welch1, C Brickman, N Bishof

  • 1Division of Nephrology, Children's Hospital Research Foundation, Cincinnati, Ohio 45229-3039, USA.

Journal of Clinical Immunology
|February 25, 1998
PubMed

Insights

Complete deficiency of complement C4A isotype is linked to systemic lupus erythematosus (SLE). C4A-deficient SLE patients showed significantly less renal disease and lower C3 levels, suggesting a milder disease course.

Area of Science:

  • Immunogenetics
  • Rheumatology
  • Complement System Biology

Background:

  • Complete deficiency of the complement C4A isotype is a recognized genetic risk factor for systemic lupus erythematosus (SLE).
  • The specific clinical and serological disease phenotype associated with C4A deficiency in SLE patients has not been previously defined.

Purpose of the Study:

  • To define the disease phenotype of patients with SLE and C4A deficiency.
  • To compare the clinical and serological features of C4A-deficient SLE patients with those who are C4A replete.

Main Methods:

  • Identification of 18 (9%) C4A-deficient individuals among 200 SLE patients from five centers.
  • Comparative analysis of clinical and serological features between C4A-deficient and C4A-replete SLE patient groups.

Main Results:

  • C4A-deficient SLE patients exhibited significantly lower rates of renal disease (11% vs. 46%, P < 0.006).
  • Lower serum concentrations of complement C3 were observed in C4A-deficient patients (11% vs. 35%, P < 0.04).
  • A trend towards milder disease was noted in the C4A-deficient cohort.

Conclusions:

  • C4A deficiency in SLE is associated with a distinct phenotype characterized by reduced renal involvement and lower C3 levels.
  • The findings suggest that C4A-deficient individuals may experience a milder form of SLE.
  • Clinicians should be cautious about aggressive C4 level normalization in these patients due to their inherent deficiency.

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