INDIVIDUAL TEST 890
C1q Antibodies
Indication
Suspicion of Hypocomplementemic urticarial vasculitis syndrome or SLE with renal involvement
Sample material
Serum
- Minim. volume: 0,5 mL
EDTA-plasma
- Minim. volume: 0,5 mL
Transport
- Within Sweden: frozen
- International: frozen
Method
ELISA
Reference interval
<10 negative, 10-15 borderline
Result
Results are reported as negative, borderline, or positive with a ratio.
Interpretation
Autoantibodies against C1q are often seen in severe SLE in combination with low levels of C1q and are associated with lupus nephritis. In hypocomplementemic urticarial vasculitis syndrome (HUVS), antibodies against C1q are found in almost all cases (>95%). The antibodies recognize different epitopes of C1q in SLE and HUVS, respectively, but, at higher levels, can usually be distinguished by Western blot.
In SLE, the antibody level usually decreases following immunomodulatory treatment.
References
- Chao C et al. BMJ Case Rep. 2025. Rare presentation of hypocomplementaemic urticarial vasculitis syndrome (HUVS) overlapping with systemic erythematosus lupus (SLE) and small lymphocytic lymphoma (SLL). PMID: 39933844
- Marzano AV et al. J Allergy Clin Immunol. 2022. Urticarial vasculitis: Clinical and laboratory findings with a particular emphasis on differential diagnosis. PMID: 35396080
Last updated: 2025-12-05
Can't find what you're looking for? We are here to help
ENSKILD ANALYS 890
C1q-antikroppar
Indikation
Misstanke om hypokomplementemiskt urtikariavaskulit-syndrom (HUVS) eller SLE med njurengagemang
Provmaterial
Serum
- Minim. volym: 0,5 mL
EDTA-plasma
- Minim. volym: 0,5 mL
Transport
- Inom Sverige: fryst
- Internationellt: fryst
Metod
ELISA
Referensintervall
<10 negativt, 10-15 gränsvärde
Resultat
Resultat anges som positivt, gränsvärde eller negativt med kvot.
Tolkning
Antikroppar mot C1q ses oftast vid svår SLE i kombination med låg C1q-nivå och är associerat med lupusnefrit. Vid hypokomplementemisk urtikaria-vaskulitsyndrom (HUVS) förekommer antikroppar mot C1q i nästan alla fall (>95%). Antikroppar mot C1q vid SLE respektive HUVS binder till olika epitoper på C1q och kan, vid högre nivåer, särskiljas med Western blot.
Vid SLE brukar antikroppsnivån sjunka som svar på behandling.
Referenser
- Chao C et al. BMJ Case Rep. 2025. Rare presentation of hypocomplementaemic urticarial vasculitis syndrome (HUVS) overlapping with systemic erythematosus lupus (SLE) and small lymphocytic lymphoma (SLL). PMID: 39933844
- Marzano AV et al. J Allergy Clin Immunol. 2022. Urticarial vasculitis: Clinical and laboratory findings with a particular emphasis on differential diagnosis. PMID: 35396080
Senast uppdaterat: 2025-12-05