HRR as a Novel Plasma Inflammatory Biomarker in Sjögren's Syndrome: Findings From a Case-control Study

Sjögren's syndrome (SS) is an autoimmune disorder characterized by chronic salivary and lacrimal gland dysfunction leading to dry mouth (xerostomia) and dry eye (xerophthalmia) sensation (1). Although dry mouth and dry eye are the main symptoms, the disease may influence many organs and systems. Diagnosis is made with ocular surface staining scores, anti-SS-A/SS-B auto-antibody positivity, and minor salivary gland biopsy (2). The Complete blood count (CBC) is a simple, inexpensive, accessible, and routinely used laboratory parameter that can be linked to oxidative stress, inflammation and microvascular flow resistance. Parameters include NLR and PLR values may be calculated by using CBC parameters (3). Neutrophil/lymphocyte ratio is used as an inflammatory marker in the diagnosis and prognosis of many cardiovascular diseases, malignancies, and infections (4-6). Peripheral inflammatory biomarkers of hematologic indices had been suggested by numerous studies to play a role during SS onset and progression.

Sjögren's syndrome (SS) is a chronic autoimmune disease that primarily affects the exocrine glands, resulting in their functional impairment. In SS, lymphocytic infiltration of salivary and lacrimal glands, and deposition of several types of autoantibodies, mainly anti-SS-A (anti-Ro) and anti-SS-B (anti-La), lead to chronic inflammation, with xerostomia and keratoconjunctivitis sicca. In its primary form (pSS), SS does not involve additional connective tissue diseases. SS presents in association with other rheumatic autoimmune diseases, mainly rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and systemic sclerosis.

Obviously, a prerequisite step in answering this critical question was to depict the change of inflammatory biomarkers of hematologic indices and disease activity progression in a detailed and comprehensive manner, and actually there were several studies aimed at answering this question. Along the hematologic indices field, most of the studies agreed that RDW was critical parameter in SS activity indication.

As in most autoimmune diseases, environmental, hormonal and genetic factors are implicated in SS pathogenesis. have been shown to be a good serum marker in primary SS (pSS). All these indicated a potential linkage between systemic inflammation and the risk of SS. However, sparse evidence has been available on this association between the hematologic indices and SS. The aim of the present study, therefore, was to evaluate the association between systemic inflammation indices and SS.