{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,25]],"date-time":"2025-09-25T00:15:40Z","timestamp":1758759340698,"version":"3.44.0"},"reference-count":32,"publisher":"Wiley","issue":"18","license":[{"start":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T00:00:00Z","timestamp":1753660800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Clinical Laboratory Analysis"],"published-print":{"date-parts":[[2025,9]]},"abstract":"<jats:title>ABSTRACT<\/jats:title><jats:sec><jats:title>Objective<\/jats:title><jats:p>To investigate prevalence and clinical correlates of serum C1q and anti\u2010C1q antibody titres in black South Africans with systemic lupus erythematosus (SLE).<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>Cross\u2010sectional study of 96 SLE patients, 49 with lupus nephritis (LN). Anti\u2010C1q antibodies were tested by ELISA. Serum C1q was measured as a percentage of normal by immunoelectrophoresis. Disease activity was assessed using the SELENA\u2010SLE disease activity index.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Most patients were female (90.7%), mean (SD) age and follow\u2010up period diagnosis of 38.1 (13.0) and 4.2 (4.4) years, respectively. Low serum C1q and positive anti\u2010C1q 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\u2010C1q antibodies titres (<jats:italic>r<\/jats:italic>\u2009=\u2009\u22120.22, <jats:italic>p<\/jats:italic>\u2009=\u20090.03) and a direct correlation of anti\u2010C1q antibodies titres with SELENA\u2010SLEDAI scores (<jats:italic>r<\/jats:italic>\u2009=\u20090.27, <jats:italic>p<\/jats:italic>\u2009=\u20090.008). Patients with an active urine sediment (<jats:italic>n<\/jats:italic>\u2009=\u200921) had higher anti\u2010C1q antibodies titres (<jats:italic>p<\/jats:italic>\u2009=\u20090.007) and low serum C1q (OR\u2009=\u20094.51, <jats:italic>p<\/jats:italic>\u2009=\u20090.01), compared to the remainder of patients. Anti\u2010C1q antibody titres were higher in patients with C3\/C4 hypocomplementaemia (<jats:italic>n<\/jats:italic>\u2009=\u200914) than those with normal C3\/C4 (<jats:italic>p<\/jats:italic>\u2009=\u20090.02). A positive Coombs test (without evidence of red cell haemolysis) (<jats:italic>n<\/jats:italic>\u2009=\u200917) was associated with a positive anti\u2010C1q antibody test (OR\u2009=\u20094.29, <jats:italic>p<\/jats:italic>\u2009=\u20090.02), low serum C1q (OR\u2009=\u20093.37, <jats:italic>p<\/jats:italic>\u2009=\u20090.04) and C3\/C4 hypocomplementaemia (OR\u2009=\u20094.84, <jats:italic>p<\/jats:italic>\u2009=\u20090.02).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Our findings broadly confirm the clinical utility of the anti\u2010C1q antibody test in SLE. Raised anti\u2010C1q antibody titres were associated with active LN, as evidenced by an active urine sediment. The association of a positive anti\u2010C1q antibody and low serum C1q with a positive Direct Coombs' test merits further study and confirmation.<\/jats:p><\/jats:sec>","DOI":"10.1002\/jcla.70087","type":"journal-article","created":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T13:05:22Z","timestamp":1753707922000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Clinical and Serological Correlates of Serum C1Q and Anti\u2010C1Q Antibodies in South Africans With Systemic Lupus Erythematosus"],"prefix":"10.1002","volume":"39","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7850-3538","authenticated-orcid":false,"given":"Mohammed","family":"Tikly","sequence":"first","affiliation":[{"name":"Division of Rheumatology, Department of Internal Medicine Faculty of Health Sciences, University of the Witwatersrand  Johannesburg South Africa"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lillemor","family":"Skattum","sequence":"additional","affiliation":[{"name":"Lund University  Lund Sweden"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mohamed Amin","family":"Makda","sequence":"additional","affiliation":[{"name":"Division of Rheumatology, Department of Internal Medicine Faculty of Health Sciences, University of the Witwatersrand  Johannesburg South Africa"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,7,28]]},"reference":[{"key":"e_1_2_7_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.autrev.2024.103648"},{"key":"e_1_2_7_3_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.immunol.22.012703.104549"},{"issue":"16","key":"e_1_2_7_4_1","first-page":"459","article-title":"A Review of Complement Activation in SLE","volume":"23","author":"Weinstein A.","year":"2021","journal-title":"Current Rheumatology Reports"},{"key":"e_1_2_7_5_1","doi-asserted-by":"publisher","DOI":"10.1084\/jem.134.3.228"},{"key":"e_1_2_7_6_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0171-2985(98)80032-6"},{"key":"e_1_2_7_7_1","doi-asserted-by":"publisher","DOI":"10.1097\/00041552-200311000-00008"},{"key":"e_1_2_7_8_1","doi-asserted-by":"publisher","DOI":"10.3389\/fimmu.2024.1410032"},{"key":"e_1_2_7_9_1","doi-asserted-by":"publisher","DOI":"10.1196\/annals.1313.020"},{"key":"e_1_2_7_10_1","doi-asserted-by":"publisher","DOI":"10.1002\/art.1780400819"},{"key":"e_1_2_7_11_1","doi-asserted-by":"publisher","DOI":"10.1002\/1529-0131(199901)42:1<187::AID-ANR24>3.0.CO;2-U"},{"key":"e_1_2_7_12_1","doi-asserted-by":"publisher","DOI":"10.1093\/rheumatology\/kem180"},{"key":"e_1_2_7_13_1","doi-asserted-by":"publisher","DOI":"10.1177\/0961203316676380"},{"key":"e_1_2_7_14_1","doi-asserted-by":"publisher","DOI":"10.1002\/art.1780400928"},{"key":"e_1_2_7_15_1","doi-asserted-by":"publisher","DOI":"10.1191\/096120399680411281"},{"key":"e_1_2_7_16_1","doi-asserted-by":"publisher","DOI":"10.1002\/art.1780390303"},{"key":"e_1_2_7_17_1","doi-asserted-by":"publisher","DOI":"10.1002\/art.21625"},{"key":"e_1_2_7_18_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-3083.1992.tb02982.x"},{"key":"e_1_2_7_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1523-1755.2004.00443.x"},{"key":"e_1_2_7_20_1","doi-asserted-by":"publisher","DOI":"10.1093\/ndt\/gfl436"},{"key":"e_1_2_7_21_1","doi-asserted-by":"publisher","DOI":"10.1177\/0961203318770024"},{"key":"e_1_2_7_22_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10067-009-1139-6"},{"key":"e_1_2_7_23_1","doi-asserted-by":"publisher","DOI":"10.1177\/0961203319856091"},{"key":"e_1_2_7_24_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF02229704"},{"key":"e_1_2_7_25_1","first-page":"230","article-title":"IgG Autoantibodies Against C1q Are Correlated With Nephritis, Hypocomplementemia, and dsDNA Antibodies in Systemic Lupus Erythematosus","volume":"18","author":"Siegert C.","year":"1991","journal-title":"Journal of Rheumatology"},{"key":"e_1_2_7_26_1","first-page":"OC39","article-title":"Danda D: Anti\u2010C1q Antibody Is Associated With Renal and Cutaneous Manifestations in Asian Indian Patients With Systemic Lupus Erythematosus","volume":"11","author":"Kabeerdoss J.","year":"2017","journal-title":"Journal of Clinical and Diagnostic Research"},{"key":"e_1_2_7_27_1","article-title":"Anti\u2010Double\u2010Stranded DNA Isotypes and Anti\u2010C1q Antibody Improve the Diagnostic Specificity of Systemic Lupus Erythematosus","volume":"20","author":"Jia Y.","year":"2018","journal-title":"Disease Markers"},{"key":"e_1_2_7_28_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.kint.2024.10.018"},{"key":"e_1_2_7_29_1","doi-asserted-by":"crossref","first-page":"1436","DOI":"10.1136\/annrheumdis-2019-eular.7816","article-title":"SAT0673\u2009Anti\u2010C1q Antibodies Have Higher Correlation With Lupus Nephritis Disease Activity","volume":"78","author":"Xue W. 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