A novel assay to diagnose hereditary angioedema utilizing inhibition of bradykinin-forming enzymes

K. Joseph, S. Bains, B. G. Tholanikunnel, A. Bygum, A. Aabom, C. Koch, H. Farkas, L. Varga, B. Ghebrehiwet, A. P. Kaplan

Research output: Article

12 Citations (Scopus)

Abstract

Background Hereditary angioedema types I and II are caused by a functional deficiency of C1 inhibitor (C1-INH), leading to overproduction of bradykinin. The current functional diagnostic assays employ inhibition of activated C1s; however, an alternative, more physiologic method is desirable. Methods ELISAs were developed using biotinylated activated factor XII (factor XIIa) or biotinylated kallikrein bound to avidin-coated plates. Incubation with plasma was followed by detection of bound C1-INH. Results After standard curves were developed for quantification of C1-INH, serial dilutions of normal plasma were employed to validate the ability to detect known concentration of C1-INH in the plasma as a percent of normal. Hereditary angioedema (HAE) types I and II were then tested. The level of functional C1-INH in all HAE types I and II plasma tested was less than 40% of our normal control. This was evident regardless of whether we measured factor XIIa-C1-INH or kallikrein-C1-INH complexes, and the two assays were in close agreement. By contrast, testing the same samples utilizing the commercial method (complex ELISA, Quidel Corp.) revealed the levels of C1-INH between 0 and 57% of normal (mean, 38%), and 42 samples were considered equivocal (four controls and 38 patients). Conclusions Diagnosis of HAE types I and II can be ascertained by inhibition of enzymes of the bradykinin-forming cascade, namely factor XIIa and kallikrein. Either method yields functional C1-INH levels in patients with HAE (types I and II) that are clearly abnormal with less variance or uncertainty than the commercial method.

Original languageEnglish
Pages (from-to)115-119
Number of pages5
JournalAllergy: European Journal of Allergy and Clinical Immunology
Volume70
Issue number1
DOIs
Publication statusPublished - jan. 1 2015

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Hereditary Angioedema Types I and II
Hereditary Angioedemas
Bradykinin
Factor XIIa
Kallikreins
Enzymes
Enzyme-Linked Immunosorbent Assay
Avidin
Uncertainty

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy
  • Medicine(all)

Cite this

A novel assay to diagnose hereditary angioedema utilizing inhibition of bradykinin-forming enzymes. / Joseph, K.; Bains, S.; Tholanikunnel, B. G.; Bygum, A.; Aabom, A.; Koch, C.; Farkas, H.; Varga, L.; Ghebrehiwet, B.; Kaplan, A. P.

In: Allergy: European Journal of Allergy and Clinical Immunology, Vol. 70, No. 1, 01.01.2015, p. 115-119.

Research output: Article

Joseph, K. ; Bains, S. ; Tholanikunnel, B. G. ; Bygum, A. ; Aabom, A. ; Koch, C. ; Farkas, H. ; Varga, L. ; Ghebrehiwet, B. ; Kaplan, A. P. / A novel assay to diagnose hereditary angioedema utilizing inhibition of bradykinin-forming enzymes. In: Allergy: European Journal of Allergy and Clinical Immunology. 2015 ; Vol. 70, No. 1. pp. 115-119.
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abstract = "Background Hereditary angioedema types I and II are caused by a functional deficiency of C1 inhibitor (C1-INH), leading to overproduction of bradykinin. The current functional diagnostic assays employ inhibition of activated C1s; however, an alternative, more physiologic method is desirable. Methods ELISAs were developed using biotinylated activated factor XII (factor XIIa) or biotinylated kallikrein bound to avidin-coated plates. Incubation with plasma was followed by detection of bound C1-INH. Results After standard curves were developed for quantification of C1-INH, serial dilutions of normal plasma were employed to validate the ability to detect known concentration of C1-INH in the plasma as a percent of normal. Hereditary angioedema (HAE) types I and II were then tested. The level of functional C1-INH in all HAE types I and II plasma tested was less than 40{\%} of our normal control. This was evident regardless of whether we measured factor XIIa-C1-INH or kallikrein-C1-INH complexes, and the two assays were in close agreement. By contrast, testing the same samples utilizing the commercial method (complex ELISA, Quidel Corp.) revealed the levels of C1-INH between 0 and 57{\%} of normal (mean, 38{\%}), and 42 samples were considered equivocal (four controls and 38 patients). Conclusions Diagnosis of HAE types I and II can be ascertained by inhibition of enzymes of the bradykinin-forming cascade, namely factor XIIa and kallikrein. Either method yields functional C1-INH levels in patients with HAE (types I and II) that are clearly abnormal with less variance or uncertainty than the commercial method.",
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T1 - A novel assay to diagnose hereditary angioedema utilizing inhibition of bradykinin-forming enzymes

AU - Joseph, K.

AU - Bains, S.

AU - Tholanikunnel, B. G.

AU - Bygum, A.

AU - Aabom, A.

AU - Koch, C.

AU - Farkas, H.

AU - Varga, L.

AU - Ghebrehiwet, B.

AU - Kaplan, A. P.

PY - 2015/1/1

Y1 - 2015/1/1

N2 - Background Hereditary angioedema types I and II are caused by a functional deficiency of C1 inhibitor (C1-INH), leading to overproduction of bradykinin. The current functional diagnostic assays employ inhibition of activated C1s; however, an alternative, more physiologic method is desirable. Methods ELISAs were developed using biotinylated activated factor XII (factor XIIa) or biotinylated kallikrein bound to avidin-coated plates. Incubation with plasma was followed by detection of bound C1-INH. Results After standard curves were developed for quantification of C1-INH, serial dilutions of normal plasma were employed to validate the ability to detect known concentration of C1-INH in the plasma as a percent of normal. Hereditary angioedema (HAE) types I and II were then tested. The level of functional C1-INH in all HAE types I and II plasma tested was less than 40% of our normal control. This was evident regardless of whether we measured factor XIIa-C1-INH or kallikrein-C1-INH complexes, and the two assays were in close agreement. By contrast, testing the same samples utilizing the commercial method (complex ELISA, Quidel Corp.) revealed the levels of C1-INH between 0 and 57% of normal (mean, 38%), and 42 samples were considered equivocal (four controls and 38 patients). Conclusions Diagnosis of HAE types I and II can be ascertained by inhibition of enzymes of the bradykinin-forming cascade, namely factor XIIa and kallikrein. Either method yields functional C1-INH levels in patients with HAE (types I and II) that are clearly abnormal with less variance or uncertainty than the commercial method.

AB - Background Hereditary angioedema types I and II are caused by a functional deficiency of C1 inhibitor (C1-INH), leading to overproduction of bradykinin. The current functional diagnostic assays employ inhibition of activated C1s; however, an alternative, more physiologic method is desirable. Methods ELISAs were developed using biotinylated activated factor XII (factor XIIa) or biotinylated kallikrein bound to avidin-coated plates. Incubation with plasma was followed by detection of bound C1-INH. Results After standard curves were developed for quantification of C1-INH, serial dilutions of normal plasma were employed to validate the ability to detect known concentration of C1-INH in the plasma as a percent of normal. Hereditary angioedema (HAE) types I and II were then tested. The level of functional C1-INH in all HAE types I and II plasma tested was less than 40% of our normal control. This was evident regardless of whether we measured factor XIIa-C1-INH or kallikrein-C1-INH complexes, and the two assays were in close agreement. By contrast, testing the same samples utilizing the commercial method (complex ELISA, Quidel Corp.) revealed the levels of C1-INH between 0 and 57% of normal (mean, 38%), and 42 samples were considered equivocal (four controls and 38 patients). Conclusions Diagnosis of HAE types I and II can be ascertained by inhibition of enzymes of the bradykinin-forming cascade, namely factor XIIa and kallikrein. Either method yields functional C1-INH levels in patients with HAE (types I and II) that are clearly abnormal with less variance or uncertainty than the commercial method.

KW - bradykinin

KW - factor XIIa

KW - hereditary angioedema

KW - hereditary angioedema diagnosis

KW - kallikrein

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