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Development of sensitive immunoassays for free and total human glandular kallikrein 2

Vaisanen, V; Eriksson, S; Ivaska, KK; Lilja, Hans LU ; Nurmi, M and Pettersson, K (2004) In Clinical Chemistry 50(9). p.1607-1617
Abstract
Background: Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. Methods: PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426... (More)
Background: Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. Methods: PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426 noncharacterized serum samples. Free and total hK2 were measured in plasma from 103 patients with confirmed prostate cancer. Results: All 426 males in the control group had a total hK2 concentration above the detection limit of 0.0008 mug/L. The median total hK2 concentration was 0.022 mug/L (range, 0.0015-0.37 mug/L). hK2 concentrations were 0.1-58% of total PSA (median, 3.6%). hK2 concentrations were similar in men 41-50 and 51-60 years of age. The ratio of hK2 to PSA steadily decreased from 5-30% at PSA <1 mug/L to 1-2% at higher PSA concentrations. In 103 patients with prostate cancer, the median hK2 concentration in plasma was 0.079 mug/L (range, 0.0015-16.2 mug/L). The median free hK2 concentration was 0.070 (range, 0.005-12.2) mug/L. The proportion of free to total hK2 varied from 17% to 131% (mean, 85%). Conclusions: The wide variation in the free-to-total hK2 ratio suggests that hK2 in blood plasma is not consistently in the free, noncomplexed form in patients with prostate cancer. The new assay is sufficiently sensitive to be used to study the diagnostic accuracies of free and total hK2 for prostate cancer. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Clinical Chemistry
volume
50
issue
9
pages
1607 - 1617
publisher
American Association for Clinical Chemistry
external identifiers
  • wos:000223503800018
  • pmid:15247158
  • scopus:4344620719
ISSN
0009-9147
DOI
10.1373/clinchem.2004.035253
language
English
LU publication?
yes
id
2e96aa89-0284-4ffa-b7a0-06c8b22bd4fa (old id 269308)
date added to LUP
2007-10-26 09:24:00
date last changed
2017-09-03 03:36:38
@article{2e96aa89-0284-4ffa-b7a0-06c8b22bd4fa,
  abstract     = {Background: Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. Methods: PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426 noncharacterized serum samples. Free and total hK2 were measured in plasma from 103 patients with confirmed prostate cancer. Results: All 426 males in the control group had a total hK2 concentration above the detection limit of 0.0008 mug/L. The median total hK2 concentration was 0.022 mug/L (range, 0.0015-0.37 mug/L). hK2 concentrations were 0.1-58% of total PSA (median, 3.6%). hK2 concentrations were similar in men 41-50 and 51-60 years of age. The ratio of hK2 to PSA steadily decreased from 5-30% at PSA &lt;1 mug/L to 1-2% at higher PSA concentrations. In 103 patients with prostate cancer, the median hK2 concentration in plasma was 0.079 mug/L (range, 0.0015-16.2 mug/L). The median free hK2 concentration was 0.070 (range, 0.005-12.2) mug/L. The proportion of free to total hK2 varied from 17% to 131% (mean, 85%). Conclusions: The wide variation in the free-to-total hK2 ratio suggests that hK2 in blood plasma is not consistently in the free, noncomplexed form in patients with prostate cancer. The new assay is sufficiently sensitive to be used to study the diagnostic accuracies of free and total hK2 for prostate cancer.},
  author       = {Vaisanen, V and Eriksson, S and Ivaska, KK and Lilja, Hans and Nurmi, M and Pettersson, K},
  issn         = {0009-9147},
  language     = {eng},
  number       = {9},
  pages        = {1607--1617},
  publisher    = {American Association for Clinical Chemistry},
  series       = {Clinical Chemistry},
  title        = {Development of sensitive immunoassays for free and total human glandular kallikrein 2},
  url          = {http://dx.doi.org/10.1373/clinchem.2004.035253},
  volume       = {50},
  year         = {2004},
}