Clinical and Serological Correlates of Serum C1Q and Anti-C1Q Antibodies in South Africans With Systemic Lupus Erythematosus
(2025) In Journal of Clinical Laboratory Analysis 39(18).- Abstract
Objective: To investigate prevalence and clinical correlates of serum C1q and anti-C1q antibody titres in black South Africans with systemic lupus erythematosus (SLE). Methods: Cross-sectional study of 96 SLE patients, 49 with lupus nephritis (LN). Anti-C1q antibodies were tested by ELISA. Serum C1q was measured as a percentage of normal by immunoelectrophoresis. Disease activity was assessed using the SELENA-SLE disease activity index. Results: Most patients were female (90.7%), mean (SD) age and follow-up period diagnosis of 38.1 (13.0) and 4.2 (4.4) years, respectively. Low serum C1q and positive anti-C1q antibody test were detected in 17 (17.7%) and 12 (12.5%) patients, respectively, overall. There was an inverse correlation between... (More)
Objective: To investigate prevalence and clinical correlates of serum C1q and anti-C1q antibody titres in black South Africans with systemic lupus erythematosus (SLE). Methods: Cross-sectional study of 96 SLE patients, 49 with lupus nephritis (LN). Anti-C1q antibodies were tested by ELISA. Serum C1q was measured as a percentage of normal by immunoelectrophoresis. Disease activity was assessed using the SELENA-SLE disease activity index. Results: Most patients were female (90.7%), mean (SD) age and follow-up period diagnosis of 38.1 (13.0) and 4.2 (4.4) years, respectively. Low serum C1q and positive anti-C1q antibody test were detected in 17 (17.7%) and 12 (12.5%) patients, respectively, overall. There was an inverse correlation between serum C1q and anti-C1q antibodies titres (r = −0.22, p = 0.03) and a direct correlation of anti-C1q antibodies titres with SELENA-SLEDAI scores (r = 0.27, p = 0.008). Patients with an active urine sediment (n = 21) had higher anti-C1q antibodies titres (p = 0.007) and low serum C1q (OR = 4.51, p = 0.01), compared to the remainder of patients. Anti-C1q antibody titres were higher in patients with C3/C4 hypocomplementaemia (n = 14) than those with normal C3/C4 (p = 0.02). A positive Coombs test (without evidence of red cell haemolysis) (n = 17) was associated with a positive anti-C1q antibody test (OR = 4.29, p = 0.02), low serum C1q (OR = 3.37, p = 0.04) and C3/C4 hypocomplementaemia (OR = 4.84, p = 0.02). Conclusion: Our findings broadly confirm the clinical utility of the anti-C1q antibody test in SLE. Raised anti-C1q antibody titres were associated with active LN, as evidenced by an active urine sediment. The association of a positive anti-C1q antibody and low serum C1q with a positive Direct Coombs' test merits further study and confirmation.
(Less)
- author
- Tikly, Mohammed ; Skattum, Lillemor LU and Makda, Mohamed Amin
- organization
- publishing date
- 2025-09
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Africa, anti-C1q antibodies, direct coombs test, systemic lupus erythematosus
- in
- Journal of Clinical Laboratory Analysis
- volume
- 39
- issue
- 18
- article number
- e70087
- publisher
- John Wiley & Sons Inc.
- external identifiers
-
- pmid:40719289
- scopus:105011861637
- ISSN
- 0887-8013
- DOI
- 10.1002/jcla.70087
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2025 The Author(s). Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.
- id
- dcde74b4-6479-4b67-9f54-b69b1dd27e14
- date added to LUP
- 2026-01-08 15:02:38
- date last changed
- 2026-01-08 15:03:48
@article{dcde74b4-6479-4b67-9f54-b69b1dd27e14,
abstract = {{<p>Objective: To investigate prevalence and clinical correlates of serum C1q and anti-C1q antibody titres in black South Africans with systemic lupus erythematosus (SLE). Methods: Cross-sectional study of 96 SLE patients, 49 with lupus nephritis (LN). Anti-C1q antibodies were tested by ELISA. Serum C1q was measured as a percentage of normal by immunoelectrophoresis. Disease activity was assessed using the SELENA-SLE disease activity index. Results: Most patients were female (90.7%), mean (SD) age and follow-up period diagnosis of 38.1 (13.0) and 4.2 (4.4) years, respectively. Low serum C1q and positive anti-C1q antibody test were detected in 17 (17.7%) and 12 (12.5%) patients, respectively, overall. There was an inverse correlation between serum C1q and anti-C1q antibodies titres (r = −0.22, p = 0.03) and a direct correlation of anti-C1q antibodies titres with SELENA-SLEDAI scores (r = 0.27, p = 0.008). Patients with an active urine sediment (n = 21) had higher anti-C1q antibodies titres (p = 0.007) and low serum C1q (OR = 4.51, p = 0.01), compared to the remainder of patients. Anti-C1q antibody titres were higher in patients with C3/C4 hypocomplementaemia (n = 14) than those with normal C3/C4 (p = 0.02). A positive Coombs test (without evidence of red cell haemolysis) (n = 17) was associated with a positive anti-C1q antibody test (OR = 4.29, p = 0.02), low serum C1q (OR = 3.37, p = 0.04) and C3/C4 hypocomplementaemia (OR = 4.84, p = 0.02). Conclusion: Our findings broadly confirm the clinical utility of the anti-C1q antibody test in SLE. Raised anti-C1q antibody titres were associated with active LN, as evidenced by an active urine sediment. The association of a positive anti-C1q antibody and low serum C1q with a positive Direct Coombs' test merits further study and confirmation.</p>}},
author = {{Tikly, Mohammed and Skattum, Lillemor and Makda, Mohamed Amin}},
issn = {{0887-8013}},
keywords = {{Africa; anti-C1q antibodies; direct coombs test; systemic lupus erythematosus}},
language = {{eng}},
number = {{18}},
publisher = {{John Wiley & Sons Inc.}},
series = {{Journal of Clinical Laboratory Analysis}},
title = {{Clinical and Serological Correlates of Serum C1Q and Anti-C1Q Antibodies in South Africans With Systemic Lupus Erythematosus}},
url = {{http://dx.doi.org/10.1002/jcla.70087}},
doi = {{10.1002/jcla.70087}},
volume = {{39}},
year = {{2025}},
}