Israel Medical Association Journal

Serum rheumatoid factors are autoantibodies of different isotypes directed against the Fc fraction of immunoglobulin G (IgG) and represent paradigmatic autoantibodies that have been largely used in clinical practice for decades. Traditionally IgG has been associated with rheumatoid arthritis and more recently included also in the classification criteria for Sjӧgren’s syndrome. Researchers have established that rheumatoid factors are positive in a variety of infectious, autoimmune, and neoplastic disorders, thus requiring a comprehensive evaluation of seropositive patients. Of note, hepatitis B and C viruses represent a crossroad that includes the high rheumatoid factor seroprevalence and chronic inflammatory disease, as well as progression to non-Hodgkin's lymphomas. Chronic antigen stimulation is the likely common ground of these processes and rheumatoid factors may represent mere bystanders or drivers of pathology. Mixed cryoglobulinemia and lymphoproliferative disease are prime examples of the deleterious effects of rheumatoid factor-B cell activity, possibly associated with hepatitis B and C. More importantly, they show a clear association in a physiological host response to infection, chronic inflammation, and the slide toward autoimmunity and malignancy. The association between hepatitis B and C infections and the appearance of serum rheumatoid factors is further supported by prevalence data, which support a coexistence of these markers in a significant proportion of cases, with viral infections being frequent causes of rheumatoid factors in patients without a rheumatic condition. We provide a comprehensive overview of the known connections between hepatitis B and C infections and rheumatoid factors.

Behçet’s disease (BD) is a systemic inflammatory disorder characterized by a protean clinical spectrum and an enigmatic pathogenesis. After being classified as an autoimmune disorder, spondyloarthritis and vasculitis, today BD is considered at the crossroad between autoimmune and auto-inflammatory syndromes. Many pathogenetic, clinical and therapeutic clues support this recent interpretation, enabling novel treatment choices such as interleukin (IL)-1 inhibition. Thus, in the last decade the IL-1 receptor antagonist anakinra and the anti-IL-1β monoclonal antibody canakinumab were increasingly administered in BD patients resistant to standard therapies, leading to interesting results and new intriguing pathogenetic implications. However, further studies are essential to both establish how the innate and acquired immune systems interact in BD patients and identify the best way of administering anti-IL-1 agents with regard to dosage, interval of administration and organ response.

Psoriatic arthritis (PsA) is a chronic inflammatory condition associated with skin psoriasis and manifests a wide clinical phenotype, with proposed differences between sexes. Current treatments are based on traditional disease-modifying anti-rheumatic drugs (DMARD), and biologic agents and studies have reported different clinical response patterns depending on sex factors. We aimed to identify sex differences in drug retention rate in patients with PsA and performed a systematic research on MEDLINE, EMBASE and Cochrane databases (1979 to June 2015) for studies regarding effectiveness (measured as drug retention rate) in PsA in both traditional DMARDs and biologics. Demographic data as well as retention rates between sexes were extracted. From a total 709 retrieved references, we included 9 articles for the final analysis. Only one study reported data regarding DMARDs, while eight studies reported retention rate for anti-tumor necrosis factor (TNF) biologics, mainly infliximab, adalimumab and etanercept. No differences were reported in retention rates between sexes for methotrexate, while women manifested lower retention rates compared to men with regard to anti-TNF. We highlight the need to include sex differences in the management flow chart of patients with PsA.