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Calcein release assay as a method for monitoring serum complement activity during monoclonal antibody therapy in patients with B-cell malignancies

Stasiłojć, Grzegorz ; Felberg, Anna ; Urban, Aleksandra ; Kowalska, Daria ; Ma, Shuo ; Blom, Anna M. LU orcid ; Lundin, Jeanette ; Österborg, Anders and Okrój, Marcin LU (2020) In Journal of Immunological Methods 476. p.1-5
Abstract

Monoclonal antibodies ofatumumab (anti-CD20) and alemtuzumab (anti-CD52) which are approved for usage in patients with chronic lymphocytic leukemia (CLL), efficiently activate the classical complement pathway. However complement is an exhaustible component and high doses of its activators may deplete complement-dependent cytotoxicity (CDC) potential, thus reducing the effect of repeated mAb dosing. Widely used method to measure CDC activity of patients' serum is hemolytic assay (CH50) on sheep erythrocytes. Despite its simplicity, such CH50 assay may not reflect pivotal interactions between patient serum and human complement inhibitors on the surface of target cells. We propose calcein release assay performed on tumor cells similar to... (More)

Monoclonal antibodies ofatumumab (anti-CD20) and alemtuzumab (anti-CD52) which are approved for usage in patients with chronic lymphocytic leukemia (CLL), efficiently activate the classical complement pathway. However complement is an exhaustible component and high doses of its activators may deplete complement-dependent cytotoxicity (CDC) potential, thus reducing the effect of repeated mAb dosing. Widely used method to measure CDC activity of patients' serum is hemolytic assay (CH50) on sheep erythrocytes. Despite its simplicity, such CH50 assay may not reflect pivotal interactions between patient serum and human complement inhibitors on the surface of target cells. We propose calcein release assay performed on tumor cells similar to those targeted by therapeutic antibodies as an alternative method. We analyzed serum samples collected from 12 patients participating in the clinical study, receiving s.c. 30 mg alemtuzumab three times per week combined with i.v. ofatumumab at an initial dose of 300 mg in week 3 further escalated to 2000 mg every other week. All serum samples were measured by hemolytic assay on sheep erythrocytes as well as using calcein release assay on CD20-positive Raji cells. Our data show that results obtained from both assays are related to each other at the level of the whole group (n = 96 samples, Spearman r = 0.504, p < .001) but may substantially differ when analyzing individual patients. Furthermore, by using CDC assay on Raji cells, we found that in the presented clinical study CDC serum potential was not significantly affected when measured before consecutive administrations in most of the patients.

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author
; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Alemtuzumab, CLL, Complement system, Ofatumumab
in
Journal of Immunological Methods
volume
476
article number
112675
pages
1 - 5
publisher
Elsevier
external identifiers
  • scopus:85073831803
  • pmid:31629742
ISSN
0022-1759
DOI
10.1016/j.jim.2019.112675
language
English
LU publication?
yes
id
a194e48a-20cf-42d9-bef6-76112e1d9216
date added to LUP
2019-11-01 10:11:29
date last changed
2024-06-12 03:33:51
@article{a194e48a-20cf-42d9-bef6-76112e1d9216,
  abstract     = {{<p>Monoclonal antibodies ofatumumab (anti-CD20) and alemtuzumab (anti-CD52) which are approved for usage in patients with chronic lymphocytic leukemia (CLL), efficiently activate the classical complement pathway. However complement is an exhaustible component and high doses of its activators may deplete complement-dependent cytotoxicity (CDC) potential, thus reducing the effect of repeated mAb dosing. Widely used method to measure CDC activity of patients' serum is hemolytic assay (CH50) on sheep erythrocytes. Despite its simplicity, such CH50 assay may not reflect pivotal interactions between patient serum and human complement inhibitors on the surface of target cells. We propose calcein release assay performed on tumor cells similar to those targeted by therapeutic antibodies as an alternative method. We analyzed serum samples collected from 12 patients participating in the clinical study, receiving s.c. 30 mg alemtuzumab three times per week combined with i.v. ofatumumab at an initial dose of 300 mg in week 3 further escalated to 2000 mg every other week. All serum samples were measured by hemolytic assay on sheep erythrocytes as well as using calcein release assay on CD20-positive Raji cells. Our data show that results obtained from both assays are related to each other at the level of the whole group (n = 96 samples, Spearman r = 0.504, p &lt; .001) but may substantially differ when analyzing individual patients. Furthermore, by using CDC assay on Raji cells, we found that in the presented clinical study CDC serum potential was not significantly affected when measured before consecutive administrations in most of the patients.</p>}},
  author       = {{Stasiłojć, Grzegorz and Felberg, Anna and Urban, Aleksandra and Kowalska, Daria and Ma, Shuo and Blom, Anna M. and Lundin, Jeanette and Österborg, Anders and Okrój, Marcin}},
  issn         = {{0022-1759}},
  keywords     = {{Alemtuzumab; CLL; Complement system; Ofatumumab}},
  language     = {{eng}},
  pages        = {{1--5}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Immunological Methods}},
  title        = {{Calcein release assay as a method for monitoring serum complement activity during monoclonal antibody therapy in patients with B-cell malignancies}},
  url          = {{http://dx.doi.org/10.1016/j.jim.2019.112675}},
  doi          = {{10.1016/j.jim.2019.112675}},
  volume       = {{476}},
  year         = {{2020}},
}