How can the monitoring of complement parameters help to treat angioedema
due to C1-inhibitor deficiency?
Background: Acquired angioedema due to C1-inhibitor deficiency
(C1-INH-AAE) is a rare disease that can be diagnosed by complement
testing. It often accompanies lymphoproliferative underlying diseases.
Methods: In the last 30 years, from the 3938 patients who were sent to
the Angioedema Center with angioedema symptoms, we have diagnosed
C1-INH-AAE in 19 cases, and monitored them regularly. The connections
between the underlying disease, its treatment, the angioedema symptoms
and complement parameters were investigated. Results: The 19 C1-INH-AAE
patients were followed up for 6 years on average. Underlying disease was
diagnosed in case of 15 patients. Most often lymphoma (6/19 patients)
and monoclonal gammopathy of undetermined significance (6/19 patients)
were found. There was no difference between the sexes regarding the
complement parameters. Connection was found between the presence and
activity of any underlying disease, the frequency of the angioedema
attacks and the decreased level of proteins of the complement system.
Angioedema specific long-term prophylaxis did not make an improvement in
neither the frequency of the attacks nor in the complement parameters.
Rituximab treatment reduced the number of attacks or completely made
them disappear, and we experienced positive changes in complement
parameters. Conclusion: Complement parameters supported the long-term
efficacy of rituximab treatment for C1-INH-AAE. The change in complement
parameters can predict the relapse of the underlying disease, and it is
a good indicator for the prediction of angioedematous attacks. In case
of C1-INH-AAE, it is significantly important to examine the patients for
underlying disease, and to regularly follow up the patient’s complement