COMMENTARY

Sjögren Syndrome: An A-to-Z Update

Robert I. Fox, MD, PhD; Carla M. Fox, RN

Disclosures

December 03, 2013

In This Article

Diagnostic Methodology

One of the most important presentations at ACR was by Cornec and colleagues.[8] Salivary gland ultrasound, performed by experts, was shown to improve the sensitivity and specificity of both the AECG and SICCA criteria. The correlation of ultrasound and histopathologic changes on biopsies remains unclear.[9] Key issues are the lack of standardization as well as interobserver variation, even among experts in ultrasonography.[10] This variability even among experts provides a cautionary note as rheumatologists in the United States rush to install "in-office" ultrasound machines.[11]

One of the main findings on ultrasound is hypoechogenicity in Sjögren syndrome, presumably resulting from scar tissue, but this histologic finding has not been reported in either initial or repeat biopsies from patients with Sjögren syndrome.[8] This may reflect that the usual site of biopsy is a minor salivary gland, whereas ultrasounds are done on major salivary glands.[12]

Studies of histology of parotid biopsies from patients with Sjögren syndrome and clinical correlations were presented by Pijpe and coworkers from Amsterdam.[13,14,15,16,17]

It will be important to perform ultrasound on the major glands of these patients with Sjögren syndrome in The Netherlands because parotid biopsies are not done by ear-nose-throat surgeons in other countries, perhaps because of medical-legal concerns about potential fistulas from the parotid biopsy.

Different methods of antibody detection may yield conflicting results. Although the antigen termed "SS-A" is frequently considered as a single molecule, it is historically composed of 2 molecules termed Ro-60 and Ro-52. These molecules are blended in commercial assays and may lead to different results.[18]

Herold[19] pointed out that not all patients with a positive ANA have an associated autoimmune disease and that a frequent cause of misdiagnosis of Sjögren syndrome could be fibromyalgia symptoms in a patient with a positive ANA resulting from dense fine speckle 70 KD antigen (DFS70/LEDG). The positive immune fluorescence was confirmed by immunoprecipitation and ouchterlony results.

Of importance, almost 9% of "clinically normal individuals" referred to a rheumatology clinic because of a positive ANA had a DFS70 pattern chromatin binding protein (termed LEDG).[20]

Thus, there is actually a negative correlation of anti-DFS70 antibody with development of either Sjögren syndrome or systemic lupus erythematosus (SLE).[21] This is important because a large proportion of patients referred to rheumatologists have only symptoms of fibromyalgia and a positive ANA. Recognition of this subset may save both time and money for the healthcare system.

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