AA-amyloidosis in autoinflammatory diseases

AA amyloidosis complicates various chronic inflammatory disorders and is characterized by the accumulation of amyloid fibrils composed of serum amyloid A protein, an acute phase reactant. In recent decades, the role of chronic infections and rheumatoid arthritis in the ethiology of AA amyloidosis have decreased significantly as a result of their treatment improvement, whereas both monogenic (familial Meditarranean fever, cryopirin-associated periodic syndrome, etc.) or polygenic (ankylosing spondilitis, psoriatic arthritis, adult onset Still’s disease, etc) autoinflammatory diseases more frequently account for AA-amyloidosis today. Autoinflammatory diseases are a consequence of innate immunity disorders although the latter can contribute to the pathogenesis of autoimmune diseases as well. In patients with autoinflammatory diseases, the suppression of inflammation, even subclinical, is essential to prevent development or progression of AA amyloidosis. The choice of inflammatory agents that can be used to achieve this aim depends on the pathogenesis of autoinflammation, e.g. key mediators that are involved in the activation of inflammatory cascade.

Ankylosing spondylitis: diagnostic challenges and efficacy of upadacitinib

Ankylosing spondilitis (AS) is a relatively common disease mainly affecting young males and presenting with chronic inflammation of the spine and the sacroiliac joints. AS is one of the forms of axial spondyloarthritis (SpA). Diagnosis of AS is usually delayed on average by 8-10 years from the first symptoms. SpA should be considered both in males and females who present with chronic low back pain starting before the age of 45 years and at least one additional factor (inflammatory back pain, HLA-B27, sacroileitis, peripheral arthritis, enthesitis, dactylitis, psoriasis, uveitis, inflammatory bowel disease, family history for SpA, elevated ESR and/or C-reactive protein, and good response to NSAIDs). Such patients should be referred to rheumatologist. MRI improves early diagnosis of AS since it detects inflammatory changes, which precede structural damage of the sacroiliac joints (nonradiographic SpA). Physical exercises and NSAIDs are the first-line treatment for AS, whereas TNF and interleukin-17 inhibitors are widely used as a second-line therapy. Upadacitinib is the first JAK-inhibitor that was approved for the treatment of active AS in adult patients who have responded inadequately to conventional therapy. The authors discuss clinical cases demonstrating efficacy of upadacinitib in patients with AS.

MO223MEMBRANOUS NEPHROPATHY ASSOCIATED TO ANKYLOSING SPONDYLITIS: CASE REPORT

Background and Aims Ankylosing Spondylitis (AS) is a chronic inflammatory rheumatic disease diagnosed by the presence of the HLA-B27 antigen with joint and extra-articular manifestations. Its pathogenesis was initially based on auto-inflammatory phenomena, mainly involving innate immunity. However, many studies carried out in the recent years focus on its adaptive immunity aspect, especially autoimmune. These mechanisms seem to interact with each other, resulting in a complex pathophysiology. The general autoimmune characteristics of AS were investigated by Yuan and al, who reviewed recent reports of autoantibodies levels in AS patients. Their analysis shows that none of the autoantibodies considered in the study meet the criteria to be considered as a biomarker for the disease (including antibodies Anti- :CD74; beta2-Microglobulin; mutated Citrullinated Vimentin (MCV); Heat Shock Protein 65 (HSP65); 14-3-3 eta autoantibodies (14-3-3η); 1A-dependent autoantibody magnesium anti-protein phosphatase (PPM1A); sclerostin (SOST); and Anti-microbial antibodies). Renal involvement in AS is dominated by amyloidosis and IgA nephropathy. In rare cases, this disease has been associated with Membranous Nephropathy (MN). The pathogenetic link between the two disorders remains obscure. However, the recent connection of AS to autoantibodies potentially indicates the involvement of immune complexes formed from these autoantibodies in the development of MN. Method We report the case of a 36-years-old woman with a 7 years history of sacroiliitis, who also developed a pedal edema in May 2020. AS was diagnosed in 2014 by the presence of positive HLA-B27, and clinical and radiological manifestations of bilateral sacroiliitis without extra renal manifestations treated by indometacin during periods of pain . A pure nephrotic syndrome was revealed with a 24h proteinuria of 12g / 24h.The patient’s Albumin levels were at 16g/l, without HTA or hematuria, and with a correct renal function (Creatinine at 60mmol/l). A renal biopsy showed a MN with type I polytypical. Light microscopy showed a thickening of capillary loops, while IF staining revealed granular deposits of IgG along the capillary wall. Investigations of further secondary MNs were negative, and the patient was aPLA2R-negative. Results A treatment by corticosteroids was initiated prior biopsy to her referral , which resulted in pain relief and urinary protein reduction (prot 24h 1.5g/24h). Given her good response to this initial treatment, corticotherapy was maintained. As the levels of inflammation and discomfort were low, the patient did not wish to be treated by biotherapy. Conclusion This case suggests a secondary MN in association with AS.The discovery of new autoantibodies associated with AS opens up promising perspectives, and could potentially lead to the characterization of biomarkers for screening and monitoring this disease. However, more studies are needed in order to improve our understanding of the role played by possible immune complex diseases, (in particular MN), in relation to this Ankylosing spondilitis.