New insight into the autoimmunogenicity of the complement protein C1q

Stoyanova, Vishnya; Petrova, Svetla; Tchorbadjieva, M.; Deliyska, Boriana; Vasilev, Vasil; Tsacheva, Ivanka

doi:10.1016/j.molimm.2010.11.010

Cited by 15 publications

(13 citation statements)

References 26 publications

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“…In our study, 18% (6/33) of women with IUP have shown strong IgG anti-C1q antibody reactivity. This percentage is comparable to that of 20% recently reported in a study testing 30 women with normal pregnancies [14]. Antibodies to C1q are found in SLE (including pregnant women) and a variety of other autoimmune and nonautoimmune conditions, including healthy individuals, and their role in the induction of pathological processes remains elusive [10, 15–20].…”

Section: Discussionsupporting

confidence: 71%

“…Antibodies to C1q are found in SLE (including pregnant women) and a variety of other autoimmune and nonautoimmune conditions, including healthy individuals, and their role in the induction of pathological processes remains elusive [10, 15–20]. Stoyanova et al [14] have suggested that the presence of anti-C1q antibodies in women with normal pregnancies could be associated with their physiological and pregnancy state or their current hormonal status. This hypothesis needs to be explored further, as our data argue in support of the notion that failed pregnancies and in particular those with EPs are immunologically privileged in respect to the loss of immunological tolerance to C1q.…”

Section: Discussionmentioning

confidence: 99%

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Interleukin-15 (IL-15) and Anti-C1q Antibodies as Serum Biomarkers for Ectopic Pregnancy and Missed Abortion

Daponte

Deligeoroglou

Pournaras

et al. 2013

Clinical and Developmental Immunology

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Given the present lack of clinically useful tests for the accurate diagnosis of ectopic pregnancy (EP), there is a need to select out those immunological factors measured in the maternal serum, as potential biomarkers. Our assumption was that C1q/anti-C1q antibody complexes and serum levels of interleukin-15 (IL-15) may play a role in differentiating abortions (MAs) and EPs and normal pregnancies. We assessed whether their measurement could set the diagnosis in a case control study at 6–8 weeks consisting of 60 women with failed early pregnancy (30 EPs, 30 MAs) and 33 women with intrauterine pregnancies. Normal pregnancies contain anti-C1q antibodies more frequently compared to women with failed pregnancies, the lowest levels being found in EPs, but this lacked statistical significance and anti-C1q could not serve as a marker. However EP pregnancies had elevated IL-15 levels that could statistically significantly differentiate them from MAs and IUPs. Furthermore, when assessing IL-15 for the clinically important differentiation between IUP and EP, we found at a cut-off of 16 pg/mL a negative predictive value of 99 with a sensitivity for diagnosing an EP of 92%. According to these results, serum IL-15 is a promising marker differentiating an MA from an EP.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Interleukin-15 (IL-15) and Anti-C1q Antibodies as Serum Biomarkers for Ectopic Pregnancy and Missed Abortion

Daponte

Deligeoroglou

Pournaras

et al. 2013

Clinical and Developmental Immunology

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“…Stoyanova et al . found increased anti‐C1q antibody levels in six of 31 (19%) healthy pregnant women . Mosca et al .…”

Section: Discussionmentioning

confidence: 95%

Anti-C1q autoantibodies are linked to autoimmune thyroid disorders in pregnant women

Vítková

Jiskra

Springer

et al. 2016

Clinical and Experimental Immunology

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Anti-C1q antibodies (anti-C1q) have been implicated in the pathogenesis of autoimmune diseases, including autoimmune thyroid disorders (AITD). The aim of this study was to evaluate the association between anti-C1q and thyroid function in pregnancy-associated AITD. In 96 pregnant women screened positive for AITD (thyroid dysfunction and/or antibodies against thyroperoxidase - TPOAb), anti-C1q were measured during the 9-11th gestational week and after delivery (median 16 months after delivery), and compared to the corresponding serum levels of thyroid hormones. As controls, 80 healthy pregnant women, 72 non-pregnant AITD patients and 72 blood donors were included. In the non-pregnant AITD group, two serum samples ≥ 6 months apart were analysed. Compared to blood donors, anti-C1q levels were substantially higher in all pregnant women analysed. In pregnancy, anti-C1q levels were higher in the TPOAb-positive women than in controls (37 versus 17·5%, P < 0·0001). Anti-C1q-positive pregnant women screened positive for AITD had higher thyroid-stimulating hormone (TSH) levels than anti-C1q-negative women (2·41 versus 1·94 mU/l, P = 0·01), and TSH correlated positively with anti-C1q (r = 0·226, P = 0·045) in the TPOAb-positive women. After delivery, serum levels of anti-C1q decreased in the positively screened TPOAb-negative women (8·8 versus 5·9 U/l, P = 0·002), but not in the TPOAb-positive ones, and they no longer correlated with TSH. Anti-C1q antibody levels increase during pregnancy in general and even more in the context of AITD, where they correlate with thyroid stimulating hormone levels.

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“…It has been reported that HCV-encoded core protein interacts directly with the receptor for the globular domain of C1q protein (gC1q-R) representing an efficient way to affect the host T-and B-cell immunity (Stoyanova et al, 2011). Herein, we further analyzed association of anti-C1q antibodies levels with the presence and absence of different autoimmune extrahepatic involvements.…”

Section: Discussionmentioning

confidence: 99%

“…C1q binds immune complexes by its 6 globular domains while it binds a variety of other ''nonimmune'' activators of the complement system, like C-reactive protein by its collagen-like region (CLR) (Kallenberg, 2008). C1q along with its physiological role in maintenance of homeostasis is involved in pathological conditions associated with the generation of anti-C1q autoantibodies in which CLR of C1q is the target of anti-C1q antibodies (Stoyanova et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Anti-C1q in chronic hepatitis C Virus genotype IV infection: association with autoimmune rheumatologic manifestations

Fadda

Bassyouni

Hamdy

et al. 2014

Immunological Investigations

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A growing body of evidence suggests that anti-complement-1q (anti-C1q) antibodies are elevated in a variety of autoimmune disease. Therefore, we investigated their prevalence and clinical significance in plasma of patients with hepatitis C virus (HCV) genotype IV in the presence and absence of autoimmune extra hepatic manifestations in comparison to normal healthy individuals. Plasma Anti-C1q Abs levels were assessed by an Enzyme Linked Immunosorbant Assay in 91 chronic HCV-infected patients (51 with and 40 without autoimmune rheumatic manifestations) and 40 healthy volunteers matched for age and gender. Epidemiological, clinical, immunochemical and virological data were prospectively collected. Positive Anti-C1q antibodies were more frequent among HCV patients with extra-hepatic autoimmune involvement, than those without and healthy control subjects. No significant correlations were found between Anti-C1q levels with either the liver activity or the fibrosis scores. In HCV-patients with autoimmune involvements, plasma Anti-C1q levels were significantly higher in patients with positive cryoglobulin, and in those with lymphoma than in those without. These results were confirmed by multivariate analysis. Further large scale longitudinal studies are required to assess and clarify the significance and the pathogenic role of anti-C1q antibodies among HCV infected patients with positive cryoglobulinaemia and lymphoma.

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New insight into the autoimmunogenicity of the complement protein C1q

Cited by 15 publications

References 26 publications

Interleukin-15 (IL-15) and Anti-C1q Antibodies as Serum Biomarkers for Ectopic Pregnancy and Missed Abortion

Interleukin-15 (IL-15) and Anti-C1q Antibodies as Serum Biomarkers for Ectopic Pregnancy and Missed Abortion

Anti-C1q autoantibodies are linked to autoimmune thyroid disorders in pregnant women

Anti-C1q in chronic hepatitis C Virus genotype IV infection: association with autoimmune rheumatologic manifestations

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