Heavy Chain Constant Region Usage in Antibodies to Peptidylarginine Deiminase 4 as a Marker of Disease Subsets in Rheumatoid Arthritis.

OBJECTIVE: The study of autoantibody isotypes in autoimmune diseases is useful for identifying clinically relevant endotypes. This study was undertaken to study the prevalence and clinical significance of different isotypes and IgG subclasses of anti-peptidylarginine deiminase 4 (anti-PAD4) autoantibodies in individuals with rheumatoid arthritis (RA). METHODS: In 196 RA subjects and 64 healthy controls, anti-PAD4 antibody types were determined using enzyme-linked immunosorbent assay. We investigated associations between anti-PAD4 antibodies and clinical outcomes, and relevant features were confirmed in an independent RA cohort. RESULTS: Anti-PAD4 IgG1, anti-PAD4 IgG2, anti-PAD4 IgG3, anti-PAD4 IgG4, anti-PAD4 IgA, and anti-PAD4 IgE antibodies were more frequent in RA patients than healthy controls (P < 0.001). Anti-PAD4 IgG1, anti-PAD4 IgG3, and anti-PAD4 IgE were associated with distinct clinical features. Anti-PAD4 IgG1 was predictive of progressive radiographic joint damage (odds ratio [OR] 4.88, P = 0.005), especially in RA patients without baseline joint damage (40% versus 0%, P = 0.003) or in those negative for anti-cyclic citrullinated peptide and/or rheumatoid factor (OR 32; P = 0.009). IgG1 was also associated with higher levels of C-reactive protein (P = 0.006) and interleukin-6 (P = 0.021). RA patients with anti-PAD4 IgG3 had higher baseline joint damage scores (median Sharp/van der Heijde score 13 versus 7, P = 0.046), while those with anti-PAD4 IgE had higher Disease Activity Score in 28 joints (median 4.0 versus 3.5, P = 0.025), more frequent rheumatoid nodules (31% versus 16%, P = 0.025), and more frequent interstitial lung disease (ground-glass opacification) (24% versus 9%, P = 0.014). Anti-PAD4 IgG1 antibody associations with joint damage were corroborated in an independent RA cohort. CONCLUSION: Anti-PAD4 IgG1, anti-PAD4 IgG3, and anti-PAD4 IgE antibodies identify discrete disease subsets in RA, suggesting that heavy chain usage drives distinct effector mechanisms of anti-PAD4 antibodies in RA.

Active haematological manifestations of systemic lupus erythematosus lupus are associated with a high rate of in-hospital mortality.

The aim of this study was to estimate the impact of the haematological manifestations of systemic lupus erythematosus (SLE) on mortality in hospitalized patients. For that purpose a case-control study of hospitalized patients in a medical referral centre from January 2009 to December 2014 was performed. For analysis, patients hospitalized for any haematological activity of SLE ( n = 103) were compared with patients hospitalized for other manifestations of SLE activity or complications of treatment ( n = 206). Taking as a variable outcome hospital death, an analysis of potential associated factors was performed. The most common haematological manifestation was thrombocytopenia (63.1%), followed by haemolytic anaemia (30%) and neutropenia (25.2%). In the group of haematological manifestations, 17 (16.5%) deaths were observed compared to 10 (4.8%) deaths in the control group ( P < 0.001). The causes of death were similar in both groups. In the analysis of the variables, it was found that only haematological manifestations were associated with intra-hospital death (odds ratio 3.87, 95% confidence interval 1.8-88, P < 0.001). Our study suggests that apparently any manifestation of haematological activity of SLE is associated with poor prognosis and contributes to increased hospital mortality.

Still's disease, lupus-like syndrome, and silicone breast implants. A case of 'ASIA' (Shoenfeld's syndrome).

In recent years, four conditions, siliconosis, Gulf War syndrome (GWS), macrophagic myofasciitis syndrome (MMF) and post-vaccination phenomena, were linked to a previous exposure to an adjuvant, suggesting a common denominator, and it has been proposed to incorporate comparable conditions under a common syndrome entitled Autoimmune/inflammatory Syndrome Induced by Adjuvants (ASIA). We report a case of a female who at the age of 11 years was diagnosed with Still's disease. At the age of 22 she underwent silicone breast implants and presented with a transient lupus-like syndrome. Then, at 25 years old she had a severe activation of Still's disease in association with rupture of silicone breast implants. When the prostheses were removed, the clinical picture improved. This case fulfills the criteria for ASIA and complements seven previous reports of Still's disease in association with silicone breast implants.