The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema?
Abstract Background C1 inhibitor (C1-INH) and complement 4 (C4) have historically been referred to as positive acute phase reactants, however this has never been evaluated in hereditary angioedema (HAE) patients. Low function of C1-INH and low levels of C4 are important in the diagnosis of HAE type...
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| Format: | Article |
| Language: | English |
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BMC
2021-10-01
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| Series: | Allergy, Asthma & Clinical Immunology |
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| Online Access: | https://doi.org/10.1186/s13223-021-00607-5 |
| _version_ | 1818404495599599616 |
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| author | Peter Stepaniuk Ana-Maria Bosonea Persia Pourshahnazari Adrienne Roos Amin Kanani |
| author_facet | Peter Stepaniuk Ana-Maria Bosonea Persia Pourshahnazari Adrienne Roos Amin Kanani |
| author_sort | Peter Stepaniuk |
| collection | DOAJ |
| description | Abstract Background C1 inhibitor (C1-INH) and complement 4 (C4) have historically been referred to as positive acute phase reactants, however this has never been evaluated in hereditary angioedema (HAE) patients. Low function of C1-INH and low levels of C4 are important in the diagnosis of HAE type 1 and 2. If C1-INH and/or C4 are significant acute phase reactants, their levels may be falsely “normal” in patients with HAE when measured during times of infection or inflammation resulting in missed or delayed diagnosis. Case presentation We present a case series of four HAE patients who had C4, C1-INH, c-reactive protein (CRP) and ferritin measured at baseline and again during a self-reported upper respiratory tract infection (URTI) or flu-like illness. We did not identify any HAE patients who had a significant change in their C1-INH functional level in the context of a mild infection. However, the C4 level did increase into the normal range on three occasions (2 patients, with 1 patient having elevation during two separate illnesses). Conclusions C1 inhibitor may not be a clinically significant acute phase protein and appears to still be a reliable diagnostic marker of hereditary angioedema, even in times of modest acute inflammation, unlike complement C4 which can be elevated in this setting. |
| first_indexed | 2024-12-14T08:41:04Z |
| format | Article |
| id | doaj.art-1ce021a0dc7a4717adee56371291ecea |
| institution | Directory Open Access Journal |
| issn | 1710-1492 |
| language | English |
| last_indexed | 2024-12-14T08:41:04Z |
| publishDate | 2021-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Allergy, Asthma & Clinical Immunology |
| spelling | doaj.art-1ce021a0dc7a4717adee56371291ecea2022-12-21T23:09:18ZengBMCAllergy, Asthma & Clinical Immunology1710-14922021-10-011711410.1186/s13223-021-00607-5The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema?Peter Stepaniuk0Ana-Maria Bosonea1Persia Pourshahnazari2Adrienne Roos3Amin Kanani4Division of Allergy and Immunology, Department of Medicine, University of British ColumbiaAllergy and Immunology, Internal MedicineDivision of Allergy and Immunology, Department of Medicine, University of British ColumbiaDivision of Hematology/BMT, Department of Medicine, University of British ColumbiaDivision of Allergy and Immunology, Department of Medicine, University of British ColumbiaAbstract Background C1 inhibitor (C1-INH) and complement 4 (C4) have historically been referred to as positive acute phase reactants, however this has never been evaluated in hereditary angioedema (HAE) patients. Low function of C1-INH and low levels of C4 are important in the diagnosis of HAE type 1 and 2. If C1-INH and/or C4 are significant acute phase reactants, their levels may be falsely “normal” in patients with HAE when measured during times of infection or inflammation resulting in missed or delayed diagnosis. Case presentation We present a case series of four HAE patients who had C4, C1-INH, c-reactive protein (CRP) and ferritin measured at baseline and again during a self-reported upper respiratory tract infection (URTI) or flu-like illness. We did not identify any HAE patients who had a significant change in their C1-INH functional level in the context of a mild infection. However, the C4 level did increase into the normal range on three occasions (2 patients, with 1 patient having elevation during two separate illnesses). Conclusions C1 inhibitor may not be a clinically significant acute phase protein and appears to still be a reliable diagnostic marker of hereditary angioedema, even in times of modest acute inflammation, unlike complement C4 which can be elevated in this setting.https://doi.org/10.1186/s13223-021-00607-5Hereditary angioedemaAcute phaseC1 inhibitorC4ReactantInfection |
| spellingShingle | Peter Stepaniuk Ana-Maria Bosonea Persia Pourshahnazari Adrienne Roos Amin Kanani The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? Allergy, Asthma & Clinical Immunology Hereditary angioedema Acute phase C1 inhibitor C4 Reactant Infection |
| title | The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? |
| title_full | The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? |
| title_fullStr | The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? |
| title_full_unstemmed | The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? |
| title_short | The role of C1 inhibitor and complement as acute phase reactants: are we missing the diagnosis of hereditary angioedema? |
| title_sort | role of c1 inhibitor and complement as acute phase reactants are we missing the diagnosis of hereditary angioedema |
| topic | Hereditary angioedema Acute phase C1 inhibitor C4 Reactant Infection |
| url | https://doi.org/10.1186/s13223-021-00607-5 |
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