Lysosomal enzyme activities: new potential markers for Sjögren's syndrome.
OBJECTIVE
To evaluate the changes in lysosomal enzyme activities in leukocytes of patients with Sjögren's syndrome.


METHODS
Leukocytes were obtained from 38 patients with Sjögren's syndrome and 36 healthy subjects. The activities of the following glycosidases were measured: alpha-glucosidase (AGU), beta-galactosidase (BGA), alpha-mannosidase (AMAN), beta-glucuronidase (GCU), beta-hexosaminidase (HEX), and the following proteases: cathepsin B (CATH B), dipeptidyl peptidase I (DPP I), cathepsin H (CATH H), dipeptidyl peptidase II (DPP II), tripeptidyl peptidase I (TPP I), and cathepsin D (CATH D) activity.


RESULTS
Activity of the glycosidases beta-galactosidase, alpha-mannosidase, beta-glucuronidase and beta-hexosaminidase, as well as of the peptidases cathepsin B, cathepsin D, dipeptidyl peptidase I, and tripeptidyl peptidase I, was elevated during the first 5 years of SS, and it increased further between 5 and 10 years after diagnosis.


CONCLUSIONS
The elevated activities of the lysosomal enzymes in Sjögren's syndrome patients may play a role in tissue damage by accelerated breakdown of glycoproteins in lysosomes.
Sohar
Nicolette
N
Department of Ophthalmology, University of Szeged, A. Szent-Györgyi Medical and Pharmaceutical Center, Szeged, Hungary. nicolette_sohar@yahoo.com
Sohar
Istvan
I
Hammer
Helga
H
D015415:Biomarkers / Q000378:metabolism; D004789:Enzyme Activation; D004798:Enzymes / Q000378:metabolism*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000201:enzymology*; D008247:Lysosomes / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012859:Sjogren's Syndrome / Q000175:diagnosis* / Q000201:enzymology* / Q000378:metabolism; D000091346:Tripeptidyl-Peptidase 1
D015415:Biomarkers; D004798:Enzymes; D000091346:Tripeptidyl-Peptidase 1; C000717267:TPP1 protein, human