The synergistic value of focus score and IgA% score of sublabial salivary gland biopsy for the accuracy of the diagnosis of Sjögren's syndrome: a 10-year comparison.
OBJECTIVE
Increasing the accuracy of the diagnosis of Sjögren's syndrome (SS) by placing emphasis on objective findings such as the presence of anti-Ro and anti-La autoantibodies and abnormal salivary gland tissue (SGT) histology is a current issue. In order to obtain optimal disease sensitivity and specificity of SGT findings, histological and immunohistological SGT examinations were compared. The first describes the extent of the lymphocytic infiltrate as a focus score (LFS), whereas the latter describes the composition of the infiltrate as a percentage of IgA-containing plasma cells (IgA%).


METHODS
Both the LFS and IgA% score were assessed in 279 SGT biopsies taken from patients with symptoms suggestive of SS. In case histological conclusions did not match immunohistological conclusions patients were assigned to so-called mismatch groups. Patients in the mismatch groups were further classified using objective, serological parameters [rheumatoid factor (RF), anti-Ro, anti-La, anti-nuclear antibodies, gammaglobulin level].


RESULTS
In 249 samples (89%), LFS and IgA% resulted in the same conclusion. Within this group a total of 63 SGT samples (25%) were characteristic for SS showing LFS >1.0 and IgA% <70. In the mismatch groups after serological classification, both false positive as well as false negative scores were observed less frequently for IgA% as compared with LFS (50 vs 75% and 25 vs 50%, respectively).


CONCLUSIONS
Additional immunohistological SGT examination provides greater disease sensitivity and specificity than histological SGT examination alone, thereby increasing accuracy of SS diagnosis.
Zandbelt
M M
MM
Department of Rheumatology, University Medical Center St Radboud, Nijmegen, The Netherlands.
Wentink
J R M
JR
de Wilde
P C M
PC
van Damme
P A
PA
van de Putte
L B A
LB
van den Hoogen
F H J
FH
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology*; D015203:Reproducibility of Results; D012470:Salivary Glands, Minor / Q000276:immunology / Q000473:pathology*; D012680:Sensitivity and Specificity; D012859:Sjogren's Syndrome / Q000276:immunology / Q000473:pathology*
D007070:Immunoglobulin A