Methods of determining levels of cleaved and/or intact kininogen
The present disclosure provides methods of evaluating a subject, e.g., a subject at risk for or suffering from a pKal-mediated or bradykinin-mediated disorder, based on values (e.g., percentages) of intact and/or cleaved kininogen in a sample of the subject. Provided methods permit analysis of patients with plasma kallikrein-mediated angioedema (KMA), or other diseases mediated by pKal useful in the evaluation and treatment. Such methods can involve the use of a detection agent that preferentially binds cleaved kininogen or intact kininogen.
1. A method comprising:
(a) contacting a sample suspected of containing intact and cleaved high molecular weight kininogen (HMWK) with at least one antibody under conditions allowing for binding between the antibody and the intact HMWK or between the antibody and the cleaved HMWK; and
(b) measuring the level of cleaved HMWK or the level of intact HMWK in the sample based on detecting binding between the cleaved HMWK or the intact HMWK and the antibody;
wherein the sample is obtained from a human patient at risk for or having a plasma kallikrein (pKal)-mediated disorder; and wherein the antibody specifically binds intact HMWK or cleaved HMWK.
2. The method of claim 1 , wherein the method further comprises (c) determining the percentage of the cleaved HMWK or the percentage of the intact HMWK based on the levels of the cleaved HMWK and intact HMWK measured in step (b).
3. The method of claim 2 , wherein the percentage of the cleaved HMWK is determined.
4. The method of claim 1 , wherein the levels of the intact HMWK and cleaved HMWK are measured by Western blot assay.
5. The method of claim 1 , wherein the sample is a blood sample or a plasma sample.
6. The method of claim 1 , wherein the pKal-mediated disorder is hereditary angioedema (HAE), rheumatoid arthritis, ulcerative colitis, or Crohn's disease.
7. The method of claim 1 , wherein the human patient has a symptom of the pKal-mediated disorder.
8. The method of claim 1 , wherein the human patient has no symptom of the pKal-mediated disorder at the time the sample is collected, has no history of a symptom of the pKal-mediated disorder, or has no history of the pKal-mediated disorder.
9. A method for treating a plasma kallikrein (pKal)-mediated disorder, the method comprising:
(a) contacting a sample of a human patient with at least one antibody under conditions allowing for binding between the antibody and intact high molecular weight kininogen (HMWK), between the antibody and cleaved HMWK, or both;
(b) measuring the level of cleaved HMWK and the level of intact HMWK in the sample based on their interaction with the antibody;
(c) determining a value of the cleaved HMWK, a value of the intact HMWK, or both, in the sample based on the amounts of the cleaved HMWK and intact HMWK measured in step (b),
(d) identifying the human patient as at risk for or having the pKal-mediated disorder, if the value of the cleaved HMWK is at or above a reference value; and
(e) administering an effective amount of a pKal inhibitor to the human patient, if the human patient is identified as being at risk for or having a pKal-mediated disorder in step (d);
wherein the pKal-mediated disorder is hereditary angioedema (HAE), rheumatoid arthritis (RA), ulcerative colitis (UC), or Crohn's disease (CD).
10. The method of claim 9 , wherein the pKal inhibitor is DX-88, EPIKAL-2 or DX-2930.
11. The method of claim 9 , wherein the sample is a blood sample or a plasma sample.
12. A method for identifying a plasma kallikrein (pKal)-mediated disorder as being susceptible to treatment with a pKal inhibitor, the method comprising:
(a) contacting a sample of a human patient at risk for or having a pKal-mediated disorder with at least one antibody under conditions allowing for binding between the antibody and intact high molecular weight kininogen (HMWK), between the antibody and cleaved HMWK, or both;
(b) measuring the level of cleaved HMWK and the level of intact HMWK in the sample based on their interaction with the antibody; and
(c) determining a value of the cleaved HMWK, a value of the intact HMWK, or both, in the sample based on the amounts of the cleaved HMWK and intact HMWK,
(d) identifying the pKal-mediated disorder as being susceptible to treatment with a pKal inhibitor, if the value of the cleaved HMWK deviates a reference value; and
(e) administering an effective amount of a pKal inhibitor to the human patient, if the pKal-mediated disorder is identified as being susceptible to treatment with the pKal inhibitor in step (d);
wherein the pKal-mediated disorder is hereditary angioedema (HAE), rheumatoid arthritis (RA), ulcerative colitis (UC), or Crohn's disease (CD).
13. The method of claim 12 , wherein the method further comprises identifying the treatment as being effective based on changes in the values of the cleaved HMWK and/or intact HMWK in the samples over the course of the treatment.
14. The method of claim 12 , wherein the sample is a blood sample or a plasma sample.
15. The method of claim 12 , wherein the pKal inhibitor is DX-88, EPIKAL-2 or DX-2930.