Serological investigation of IgG levels and subclasses in rheumatoid arthritis patients following ingestion of bovine type II collagen: results of a double blind, randomised controlled trial

Is collagen supplementation friend or foe in rheumatoid arthritis and osteoarthritis? A comprehensive systematic review

Rheumatoid arthritis (RA) and osteoarthritis (OA) both are chronic diseases affecting joints. Immune response against collagen in both diseases may have a role in the initiation and progression of the disease. There is a hypothesis that suppression of immune response vs collagen could be a therapeutic approach in RA and OA. Exposure of gut immune system to collagen is a way to suppress immune response against collagen in the joints. So, the current systematic review is aimed to evaluate the effects of collagen supplementation in OA and RA patients. In the current systematic review, online electronic databases including PubMed/MEDLINE, Web of Sciences and Scopus were searched and finally 19 articles were included. The enrolled articles evaluated the effects of collagen supplementation on treatment of OA (n = 9) and RA (n = 10). Intact (n = 4) and hydrolyzed (n = 5) collagen were used to treat OA. All of the studies on RA used intact and type II collagen in their intervention. The last trials on collagen supplementation in RA and OA patients were performed in 2011 and 2016, respectively. High adverse effects of collagen supplementation and its low efficiency compared to routine treatments were reported by several included studies. Also, risk of bias assessment showed that most of the studies had poor quality. Therefore, it is not possible to definitely decide on the beneficial or detrimental effects of collagen supplementation on OA and RA patients. Further studies are needed to reach a final decision.

Frequency and Clinical Significance of Elevated IgG4 in Rheumatoid Arthritis: A Systematic Review

Immunoglobulin (Ig)G4 is a unique protein molecule and its role in autoimmune diseases remains elusive and controversial. Accumulating evidence suggests a pathogenic role of IgG4 in rheumatoid arthritis (RA). Rheumatoid factors (RF) in RA can recognize the Fc domains of IgG4 to form RF-IgG4 immune complexes that may activate the complement system leading to synovial injury. The aim of this article was to systematically review the literature from the past 2 decades to determine the frequency of elevated IgG4 and its clinical significance in RA. We comprehensively searched the Pubmed, Scopus, and Web of Science databases with the following terms: “IgG4”, “rheumatoid arthritis”, and “immunoglobulin G4”, and scrutinized all of the relevant publications. Based on the selection criteria, 12 studies were incorporated, which involved a total of 1715 RA patients. Out of 328 subjects from three studies, the pooled frequency of elevated non-specific IgG4 was 35.98%. There was a significant positive correlation between the IgG4 levels and the RA disease activity based on DAS-28 measurements (r = 0.245–0.253) and inflammatory markers, i.e., erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels (r = 0.262–0.389). Longitudinal studies that measured the serial levels of IgG4 consistently showed a decline in the concentrations (up to 48% less than baseline) with disease modifying anti-rheumatic drug (DMARD) treatment. Current evidence suggests that serum IgG4 levels are significantly elevated in RA compared to the general population. This review indicates that IgG4 is a promising biomarker of disease activity and tends to decline in response to DMARD therapies. Biologic therapies have revolutionized the therapeutic armamentarium of RA in the recent decade, and IgG4 appears to be a potential treatment target.

Evaluation of serum immunoglobulins concentrations and distributions in vitiligo patients

Vitiligo is a dermatological disorder with an autoimmune mechanism characterized by production of a variety of autoantibodies. Different levels of immunoglobulins can indicate the presence and the stage of some autoimmune diseases. We aimed to investigate serum IgA, IgM and IgG subclass levels and melanocyte-reactive antibodies in 65 vitiligo patients by the immunonephelometric assay (35 healthy people as controls). Compared with normal controls, a significant increase in total IgG, IgG1 and IgG2 (p = .005, p = .003 and p = .043, respectively) was observed in progressive nonsegmental vitiligo patients. Also, we found a significant decrease in IgG3 (p = .000 and p = .023) in progressive nonsegmental vitiligo patients and segmental patients. Moreover, we found the serum levels of IgG4 subclass in stable nonsegmental patients were significantly higher than those in normal controls (p = .018). Compared with controls, the positive rates of melanocyte-reactive antibodies were higher in progressive nonsegmental patients and stable nonsegmental patients (p = .032 and p = .046, respectively). Furthermore, we found higher level of IgG4 and lower level of IgM in male than those in female. Higher IgG1 level was also observed in patients with a family history than in those without a family history. In addition, there was a significant inverse correlation between the concentrations of IgG4 and disease duration. Our evaluation about the level of immunoglobulins might provide a useful insight into the pathological process of vitiligo.