18F-FDG PET, genotype-corrected ACE and sIL-2R in newly diagnosed sarcoidosis.
OBJECTIVE
Angiotensin-converting enzyme (ACE) and soluble interleukin-2 receptor (sIL-2R) are serological markers, widely used for determining sarcoidosis activity. (18)F-FDG PET has proven to be a sensitive technique in the imaging of sarcoidosis. The aim of this study was to determine sensitivity of (18)F-FDG PET, genotype-corrected ACE and sIL-2R in active sarcoidosis as well as their correlation.


METHODS
This retrospective study included 36 newly diagnosed, symptomatic sarcoidosis patients. ACE and sIL-2R levels were simultaneously obtained within 4 weeks of (18)F-FDG PET. ACE was corrected for genotype and expressed as Z-score. (18)F-FDG PET was visually evaluated and scored as positive or negative. Maximum and average standardized uptake values (SUV(max) and SUV(avg)) were compared with ACE and sIL-2R.


RESULTS
(18)F-FDG PET was found positive in 34 of 36 patients (94%). Thirteen patients (36%) showed an increased ACE with the highest sensitivity found in patients with the I/I genotype (67%). Seventeen patients (47%) showed an increased sIL-2R. No correlation was found between SUV and ACE or sIL-2R. Increased ACE and sIL-2R correlated with a positive (18)F-FDG PET in 12 patients (92%) and 16 patients (94%), respectively.


CONCLUSIONS
(18)F-FDG PET is a very sensitive technique to assess active sarcoidosis, in contrast with ACE and sIL-2R, suggesting a pivotal role for (18)F-FDG PET in future sarcoidosis assessment.
Keijsers
Ruth G
RG
Department of Nuclear Medicine, St. Antonius Hospital Nieuwegein, P.O. Box 2500, 3430 EM, Nieuwegein, The Netherlands. r.keijsers@antonius.net
Verzijlbergen
Fred J
FJ
Oyen
Wim J
WJ
van den Bosch
Jules M
JM
Ruven
Henk J
HJ
van Velzen-Blad
Heleen
H
Grutters
Jan C
JC
D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D007703:Peptidyl-Dipeptidase A / Q000378:metabolism*; D049268:Positron-Emission Tomography; D015375:Receptors, Interleukin-2 / Q000737:chemistry* / Q000378:metabolism*; D012189:Retrospective Studies; D012507:Sarcoidosis / Q000000981:diagnostic imaging* / Q000235:genetics / Q000378:metabolism*; D012680:Sensitivity and Specificity; D012995:Solubility
D015375:Receptors, Interleukin-2; D019788:Fluorodeoxyglucose F18; D007703:Peptidyl-Dipeptidase A