The complement system and systemic sclerosis

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C Benbassat1, M Schlesinger, C Luderschmidt

  • 1Department of Medicine B, Sheba Medical Center, Tel Hashomer, Israel.

Immunologic Research
|January 1, 1993
PubMed

Insights

Serum complement levels are altered in systemic sclerosis (SSC). Many complement components were elevated, but C4 levels were decreased in SSC patients, similar to primary biliary cirrhosis patterns.

Area of Science:

  • Immunology
  • Biochemistry

Background:

  • Systemic sclerosis (SSC) is an autoimmune disease characterized by fibrosis.
  • Complement system dysregulation may play a role in autoimmune pathogenesis.
  • Previous studies suggest an association between SSC and primary biliary cirrhosis (PBC).

Purpose of the Study:

  • To investigate serum complement component concentrations in patients with systemic sclerosis (SSC).
  • To compare complement profiles in SSC patients with healthy controls.
  • To explore similarities in complement patterns between SSC and primary biliary cirrhosis (PBC).

Main Methods:

  • Serum samples were collected from 80 patients with SSC and 58 healthy controls.
  • Concentrations of various complement components, including C1q, C2, C3, C4, C5, C6, C7, C8, C9, factor B, and properdin, were measured.
  • Statistical analysis was performed to compare component levels between groups.

Main Results:

  • Mean concentrations of C1q, C2, C5, C6, C7, C9, and factor B were significantly increased in SSC patients compared to controls.
  • Mean concentrations of C3 and C8 showed non-significant increases.
  • Mean C4 levels were significantly decreased in SSC patients, with 18 patients below 65% of the mean normal value. Properdin levels were also decreased but not significantly.

Conclusions:

  • Systemic sclerosis is associated with significant alterations in serum complement component concentrations.
  • The observed complement profile in SSC, particularly decreased C4, resembles that seen in primary biliary cirrhosis.
  • These findings suggest a potential link between complement dysregulation and the co-occurrence of SSC and PBC.

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