Background Previously we reported that salivary gland ultrasonography (SGUS) using a simplified score1,2 is a specific but not a sensitive diagnostic method in primary Sjögren’s syndrome (pSS). The purpose of the present work is to analyse intra-observer validity and association with lymphoma risk factors. We have investigated 160 individuals, of which 30 have been studied at two time-points by the same investigator.
Objectives To evaluate association with other lymphoma risk factors and intra-observer validity of SGUS in pSS.
Methods SGUS was performed scoring parenchymal inhomogeneity as 0 = completely normal, 1 = slight abnormalities/few hypoechogenic areas, 2 = multiple hypoechogenic areas or 3 = many or confluent hypoechogenic lesions1. Assessment of EULAR SS Disease Activity Index (ESSDAI), presence of autoantibodies, immunoglobulin levels, complement levels, lymphocyte subtypes, parotid swelling and palpable purpura were assessed in pSS patients. Salivary gland biopsies were evaluated with regard to focal sialadenitis and germinal centre (GC)-like structures by routine staining and light microscopy, when available.
Results Salivary glands of 105 pSS patients fulfilling the 2002 American European Consensus Criteria and of 56 controls (healthy n=10, sicca syndrome n=17, other rheumatic diseases 29) were studied. At first examination 54% of the pSS patients and none of the controls showed the characteristic pattern of multiple or confluent hypoechogenic rounded lesions typical for pSS, (p < 0.001).
Patients with SS-typical US pattern had significantly higher ESSDAI score (8.6 vs. 3.3) and IgG levels (22.2 vs.14.9g/l) (both p<0.001), significantly more often a history of systemic disease (78% vs. 49%, p=0.003), autoantibodies to Ro and La (93% vs. 55%), RF (79% vs 40%) (both p<0.001) and GC-like structures in the salivary gland biopsy (44% vs. 16%, p=0.018). Swollen parotid glands and palpable purpura were seen significantly more often. Flow-cytometry revealed lower percentages of CD4+ T-cells, memory B-cells (both p<0.001) and a lower CD4+/CD8+ ratio (p=0.003). Trends were seen towards lower levels of complement factor 3 and 4, and increased percentage of naive B cells.
In 30 individuals repeated SGUS was performed with a median 12 (range 2-23) months interval. Scores from the two investigations were highly correlated. Kappa: 0.54. Only 5 patients newly acquired the classical pSS pattern, mainly patients with short disease duration at baseline.
Conclusions SGUS is a non-radiating bedside investigation with high specificity for pSS. Patients with these lesions have higher disease activity and more often other risk markers for lymphoma development. Given the fact that pSS usually is characterized by a stable disease state and not treated with potent medication, the high consensus between the repeated investigations signals high intra-observer reliability of the method.
Hocevar A et al. Ultrasonographic changes of major salivary glands in primary Sjogren’s syndrome. Diagnostic value of a novel scoring system. Rheumatology (Oxford) 2005;44:768-72.
Theander E et al. Diagnostic utility and prognostic value of parotid gland ultrasonography in primary Sjögren’s Syndrome: The classical hypoechogenic pattern of parenchymal abnormality is highly specific, associated with higher disease activity and systemic disease. ARD 2012 June S 3 : 16,904
Disclosure of Interest None Declared