The detection of
antigen specific lymphocyte responses plays a vital role in the diagnosis of various diseases.
Beryllium-specific [3H]
thymidine lymphocyte proliferation test (LPT) is regarded as a gold standard in identifying chronic
beryllium disease (CBD) cases. Alternatively, flow cytometric based
carboxyfluorescein succinimidyl
ester (
CFSE) assay, has several benefits as opposed to LPT, since it further permits both phenotypical characterization and functional analysis of proliferating lymphocyte subsets. The suitability of both LPT and
CFSE assay to therefore detect
beryllium sensitivity in a group of Be-exposed
sarcoidosis patients with suspected
beryllium exposure, was evaluated in this study. The clinical relevance of the test responses, expressed as stimulation indices (SI), were additionally compared on a group and individual level. Agreement in clinical interpretation of the test responses between both methods was observed in 4 out of 5 recruited patients, when considering total lymphocyte population i.e., CD3+ and CD19+-cells combined, on day 7 and with
CFSE-SI >1.5, when compared with LPT-SI >2.5. Variability in responses to
beryllium was additionally evaluated in Be-exposed
sarcoidosis patients and compared with healthy controls. To conclude, both LPT and
CFSE assay are suitable assays to detect Be sensitivity in Be-exposed
sarcoidosis patients. At the same time, flow cytometric based
CFSE assay has the edge over LPT in identifying the relevant proliferating lymphocyte populations. As such, when comparing two or more methods, factors that contribute to assay variability such as timepoints, lymphocyte subsets and number of replicates should always be accounted for.