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[Hereditary angioedema: changes in serum levels of C4 in response to danazol]
J Egidio Fabiani1, L Squiquera, J Leoni
1Instituto Argentino de Alergia e Inmunología.
Insights
Danazol treatment improved complement levels in hereditary angioedema (HAE) patients. Complement component C4 and C1 inhibitor (C1-INH) levels increased, resolving circulating immune complexes (CIC).
Area of Science:
- Immunology
- Complement System Biology
Context:
- Hereditary Angioedema (HAE) is a rare genetic disorder.
- Complement system dysregulation is implicated in HAE pathogenesis.
Purpose:
- To evaluate the effect of Danazol on complement levels in HAE patients.
- To investigate the relationship between complement components and circulating immune complexes (CIC).
Summary:
- Twelve HAE patients received 400 mg/day of Danazol for 10 days.
- Treatment led to the disappearance of CIC and significant increases in C4, C1-inhibitor (C1-INH), Cls, and CH50 levels.
- C4 levels showed a more rapid increase than C1-INH.
Impact:
- Suggests a potential primary defect in C4 synthesis in some HAE patients with CIC.
- Postulates Danazol may stimulate C4 synthesis, offering a therapeutic insight for HAE management.
Abstract:
12 patients (7 males and 5 females) suffering from the common form of HAE were included in the study protocol. All patients were older than 18 years. They were evaluated Cl INH, C4, Clq, Cls, C3, C5, C8, Bf, CH 50% and CIC. For the purpose of the study they were only considered Cl INH, C4, CH 50%, CIs and CIC levels. The rest of the complement components were among normal values. Data were recorded at day 0 and after 10 days on treatment with 400 mg/day of Danazol. Results were as follows: 50% of the patients had CIC when CH 50% values were below 120 U/ml., after treatment CIC disappeared and CH 50, Cls, C4 and Cl INH increased significatively. C4 seemed to increase more and quicker than Cl INH in terms of absolute values. We postulate that in the group of patients with CIC, the primary cause of the disease may be an alteration in C4 synthesis and that Cl INH may be lowered because of its consumption. We postulate that Danazol could act in these cases stimulating C4 synthesis independently or in accordance with Cl INH.