Ku protein and DNA strand breaks in lip glands of normal and primary Sjögren's syndrome subjects: lack of correlation with apoptosis.
The aim was to examine tissue expression of Ku protein in lower lip salivary gland (LSG) biopsies from cases of primary Sjögren's syndrome (SS) and from normal subjects.


METHODS
immunohistochemistry was used with antibodies to Ku70/86 and also Ki67, PCNA and p53. In addition, the Klenow method was applied in order to detect evidence of apoptosis. Sections of hyperplastic tonsil served as additional controls.


RESULTS
in normal controls, LSG acinar cells stained negatively whereas LSG excretory duct cell nuclei stained positively with Ku and Klenow and occasionally with PCNA but negatively with Ki67 and p53. In LSG focal sialadenitis of SS cases, some lymphocytic cells showed staining with Ku, Ki67, PCNA, Klenow and p53. In addition to duct cell Ku and Klenow as well as PCNA staining which was not much different from normals, a few ductal epithelial and also mononuclear cells stained with p53. In focal sialadenitis, some acinar cells showed staining with PCNA as well as with Klenow.


CONCLUSIONS
our findings in LSG biopsies of SS cases added little to an increased understanding about the pathogenetic mechanisms in the development of focal sialadenitis in SS. However, in normal LSG, ductal epithelial but not acinar cells seem to express a constitutively specific Ku protein and Klenow profile, suggestive of DNA strand breaks but not clearly associated with ongoing apoptotic events. It may reflect an enhanced stress response, which may be pathogenetically important in the early events of focal sialadenitis development in primary Sjögren's syndrome.
Larsson A
Department of of Oral Pathology, Centre for Oral Health Sciences, Malmö University, Sweden. ake.larsson@od.mah.se
Henriksson
G
G
Manthorpe
R
R
Sallmyr
A
A
Bredberg
A
A
D000918:Antibody Specificity; D034961:Antigens, Nuclear; D017209:Apoptosis; D002460:Cell Line; D004249:DNA Damage; D004265:DNA Helicases; D004256:DNA Polymerase I / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D000072200:Ku Autoantigen; D008046:Lip / Q000033:anatomy & histology*; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D014066:Palatine Tonsil / Q000737:chemistry / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D012469:Salivary Glands / Q000737:chemistry / Q000378:metabolism*; D012793:Sialadenitis / Q000235:genetics / Q000378:metabolism; D012859:Sjogren's Syndrome / Q000235:genetics* / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53; D004256:DNA Polymerase I; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen