Classification of disease manifestations in primary Sjögren's syndrome: present status and a new proposal

Establishing a model for classification of the clinical disease manifestations in primary Sjögren's syndrome is a challenge with important implications for handling individual patients and for describing and analyzing patient materials. Based on the pathobiology of primary SS we define three (1-3) "exocrine" and four (4-7) "nonexocrine" subgroups of disease manifestations. Accordingly, 1) "surface exocrine disease" includes the diagnostic features from eyes (keratoconjunctivitis sicca) and mouth (xerostomia), and the manifestations from upper airways (rhinitis sicca, xerotracheitis) and skin (xeroderma). Involvement of the excretory parenchyma of the lungs, hepatobiliary system, pancreas, intestinal tract and kidneys is designated 2) "internal organ exocrine disease". These manifestations are potentially severe, do not lead to subjective dryness, and none of them are diagnostic for the disease. We suggest 3) "monoclonal B-lymphocyte disease" (lymphoma) to be an exocrine disease manifestation because it originates mostly from the immunoinflammatory foci of the autoimmune exocrinopathy. The nonexocrine manifestations are subgrouped into: 4) "inflammatory vascular disease" (vasculitis and perivasculitis), 5) "noninflammatory vascular disease" (Raynaud), 6) "mediator-induced disease" (hematologic cytopenia, fever and fatigue) and 7) "autoimmune endocrine disease". Subdividing the seven subgroups leads to a third order of classification in which single and separate manifestations are placed. The descriptive and analytic power of the proposed model for classification of disease manifestations in primary Sjögren's syndrome should be evaluated in clinical studies.