Clinical, laboratory and histological features of the patients with SS that were retrospectively recorded and their definition
| Features | Defined as/documented by |
| SS associated | |
| Clinical | |
| EULAR SS disease activity index (ESSDAI) | 31 |
| Arthralgias, arthritis | |
| Raynaud’s phenomenon | |
| Salivary gland enlargement (SGE) | |
| Lung involvement | Pulmonary function tests and X-ray and/or CT scans |
| Renal involvement | Persistent proteinuria and verification by renal biopsy |
| Liver involvement | Liver biopsy indicative of primary biliary cirrhosis |
| Palpable purpura | |
| Vasculitis | |
| Peripheral neuropathy | Nerve conduction studies |
| Laboratory | |
| Anti-Ro/SSA and/or anti-La/SSB autoantibodies | |
| Rheumatoid factor | |
| Complement C3 and C4 levels | |
| Hypocomplementaemia | C4 <16 mg/dL and C3 <75 mg/dL |
| Cryoglobulinaemia | |
| Hypergammaglobulinaemia | Total gammaglobulins >2 g/L |
| Anaemia | Haemoglobin <12 g/dL (females) and 13.5 g/dL (males) |
| Leucopenia | White cell count <4000/mm3 |
| Lymphopaenia | Lymphocyte count <1000/mm3 |
| Neutropaenia | Neutrophil count <1500/mm3 |
| Histological | |
| Biopsy focus score | Number of lymphocytic foci/4 mm2 |
| Germinal centre formation | |
| Lymphoma associated | |
| Non-Hodgkin’s lymphoma (NHL) subtype | |
| Eastern Cooperative Oncology Group performance status | 32 |
| Ann Arbor stage (I–IV) | 33 |
| Number and type of involved sites | |
| International Prognostic Index | 0–1 points: low risk, 2 points: low-intermediate risk, 3 points: high-intermediate risk, 4–5 points: high risk34 |
| Splenomegaly | |
| Lymphadenopathy | |
| Presence of B symptoms | |
| Serum lactate dehydrogenases | |
| β2-microglobulin levels | |
SS, Sjögren’s syndrome.