AA amyloidosis treated with tocilizumab: case series and updated literature review.

BACKGROUND: In published case reports, tocilizumab (TCZ) has shown good efficacy for AA amyloidosis in almost all patients. We investigated the efficacy and safety of TCZ in AA amyloidosis in a multicentre study of unselected cases. METHODS: We e-mailed rheumatology and internal medicine departments in France, Switzerland and North Africa by using the Club Rhumatismes Inflammation (CRI) network and the French TCZ registry, Registry RoAcTEmra (REGATE), to gather data on consecutive patients with histologically proven AA amyloidosis who had received at least one TCZ infusion. Efficacy was defined as a sustained decrease in proteinuria level and/or stable or improved glomerular filtration rate (GFR) and by TCZ maintenance. RESULTS: We collected 12 cases of AA amyloidosis treated with TCZ as monotherapy (mean age of patients 63 ± 16.2 years, amyloidosis duration 20.6 ± 31.3 months): eight patients had rheumatoid arthritis (RA), six with previous failure of anti-tumor necrosis factor α (anti-TNF-α) therapy. In total, 11 patients had renal involvement, with two already on hemodialysis (not included in the renal efficacy assessment). For the nine other patients, baseline GFR and proteinuria level were 53.6 ± 32.8 mL/min and 5 ± 3.3 g/24 h, respectively. The mean follow-up was 13.1 ± 11 months. TCZ was effective for six of the eight RA patients (87.5%) according to European League Against Rheumatism response criteria (four good and two moderate responders). As expected, C-reactive protein (CRP) level decreased with treatment for 11 patients. Renal amyloidosis (n = 9) progressed in three patients and was stabilized in three. Overall, three patients showed improvement, with sustained decrease in proteinuria level (42%, 82% and 96%). Baseline CRP level was higher in subsequent responders to TCZ than other patients (p = 0.02). Among the six RA patients with previous anti-TNF-α therapy, amyloidosis was ameliorated in one and stabilized in three. Three serious adverse events occurred (two diverticulitis and one major calciphylaxia due to renal failure). Finally, 7 of 12 (58%) patients continued TCZ. CONCLUSIONS: The efficacy of TCZ for AA amyloidosis varies depending on the inflammatory status at treatment onset. Discrepancies between our study of unselected consecutive patients and reported cases may be due to publication bias. These results support further prospective trials of TCZ for AA amyloidosis.

Multiplicative interaction of functional inflammasome genetic variants in determining the risk of gout.

INTRODUCTION: The acute gout flare results from a localised self-limiting innate immune response to monosodium urate (MSU) crystals deposited in joints in hyperuricaemic individuals. Activation of the caspase recruitment domain-containing protein 8 (CARD8) NOD-like receptor pyrin-containing 3 (NLRP3) inflammasome by MSU crystals and production of mature interleukin-1β (IL-1β) is central to acute gouty arthritis. However very little is known about genetic control of the innate immune response involved in acute gouty arthritis. Therefore our aim was to test functional single nucleotide polymorphism (SNP) variants in the toll-like receptor (TLR)-inflammasome-IL-1β axis for association with gout. METHODS: 1,494 gout cases of European and 863 gout cases of New Zealand (NZ) Polynesian (Māori and Pacific Island) ancestry were included. Gout was diagnosed by the 1977 ARA gout classification criteria. There were 1,030 Polynesian controls and 10,942 European controls including from the publicly-available Atherosclerosis Risk in Communities (ARIC) and Framingham Heart (FHS) studies. The ten SNPs were either genotyped by Sequenom MassArray or by Affymetrix SNP array or imputed in the ARIC and FHS datasets. Allelic association was done by logistic regression adjusting by age and sex with European and Polynesian data combined by meta-analysis. Sample sets were pooled for multiplicative interaction analysis, which was also adjusted by sample set. RESULTS: Eleven SNPs were tested in the TLR2, CD14, IL1B, CARD8, NLRP3, MYD88, P2RX7, DAPK1 and TNXIP genes. Nominally significant (P < 0.05) associations with gout were detected at CARD8 rs2043211 (OR = 1.12, P = 0.007), IL1B rs1143623 (OR = 1.10, P = 0.020) and CD14 rs2569190 (OR = 1.08; P = 0.036). There was significant multiplicative interaction between CARD8 and IL1B (P = 0.005), with the IL1B risk genotype amplifying the risk effect of CARD8. CONCLUSION: There is evidence for association of gout with functional variants in CARD8, IL1B and CD14. The gout-associated allele of IL1B increases expression of IL-1β - the multiplicative interaction with CARD8 would be consistent with a synergy of greater inflammasome activity (resulting from reduced CARD8) combined with higher levels of pre-IL-1β expression leading to increased production of mature IL-1β in gout.

Single amino acid charge switch defines clinically distinct proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1)-associated inflammatory diseases.

BACKGROUND: Hyperzincemia and hypercalprotectinemia (Hz/Hc) is a distinct autoinflammatory entity involving extremely high serum concentrations of the proinflammatory alarmin myeloid-related protein (MRP) 8/14 (S100A8/S100A9 and calprotectin). OBJECTIVE: We sought to characterize the genetic cause and clinical spectrum of Hz/Hc. METHODS: Proline-serine-threonine phosphatase-interacting protein 1 (PSTPIP1) gene sequencing was performed in 14 patients with Hz/Hc, and their clinical phenotype was compared with that of 11 patients with pyogenic arthritis, pyoderma gangrenosum, and acne (PAPA) syndrome. PSTPIP1-pyrin interactions were analyzed by means of immunoprecipitation and Western blotting. A structural model of the PSTPIP1 dimer was generated. Cytokine profiles were analyzed by using the multiplex immunoassay, and MRP8/14 serum concentrations were analyzed by using an ELISA. RESULTS: Thirteen patients were heterozygous for a missense mutation in the PSTPIP1 gene, resulting in a p.E250K mutation, and 1 carried a mutation resulting in p.E257K. Both mutations substantially alter the electrostatic potential of the PSTPIP1 dimer model in a region critical for protein-protein interaction. Patients with Hz/Hc have extremely high MRP8/14 concentrations (2045 ± 1300 μg/mL) compared with those with PAPA syndrome (116 ± 74 μg/mL) and have a distinct clinical phenotype. A specific cytokine profile is associated with Hz/Hc. Hz/Hc mutations altered protein binding of PSTPIP1, increasing interaction with pyrin through phosphorylation of PSTPIP1. CONCLUSION: Mutations resulting in charge reversal in the y-domain of PSTPIP1 (E→K) and increased interaction with pyrin cause a distinct autoinflammatory disorder defined by clinical and biochemical features not found in patients with PAPA syndrome, indicating a unique genotype-phenotype correlation for mutations in the PSTPIP1 gene. This is the first inborn autoinflammatory syndrome in which inflammation is driven by uncontrolled release of members of the alarmin family.

Inflammatory articular disease in patients with inflammatory bowel disease : result of the Swiss IBD Cohort Study

BACKGROUND: Inflammatory bowel diseases (IBD) are systemic conditions that commonly display extraintestinal manifestations. Inflammatory articular disease (IAD: axial or peripheral) is the most common extraintestinal manifestation. The aim of this study was to evaluate the prevalence and the clinical characteristics associated with IAD in patients with IBD. METHODS: We analyzed patients enrolled in the Swiss IBD cohort study. IAD was defined as persistent or recurrent joint pain with an inflammatory pattern (night pain, progressive relief during the day, morning stiffness lasting at least 30 minutes) or the presence of arthritis as diagnosed by the physicians. A multivariate logistic regression was performed to analyze which disease characteristics were independently associated with the presence of IAD. RESULTS: A total of 2353 patients with IBD, 1359 with Crohn's disease, and 994 with ulcerative colitis (UC) were included. Forty-four percent of patients fulfilled the criteria for IAD, whereas 14.5% presented with other extraintestinal manifestations. IAD was associated with Crohn's disease, with female sex, with older age, and generally in patients with more active intestinal disease. Only in UC, IAD was further associated with tobacco smoking and with increasing body mass index. CONCLUSIONS: This population of patients with IBD displays a high prevalence of IAD. IAD was more strongly associated with Crohn's disease than UC. Other risk factors for IAD were female sex, advanced age, active digestive disease, and tobacco consumption in patients with UC, which is interesting given the established association between smoking and other inflammatory arthritides.

Maladie de Whipple: quand y penser [Whipple's disease, when to think about it?].

Whipple's disease is a chronic, systemic, bacterial infection caused by Tropheryma whipplei. Its cardinal symptoms include intermittent and recurrent arthralgia or arthritis together with chronic diarrhoea, abdominal pain and weight loss. It may mimick many chronic inflammatory diseases, and the diagnosis remains a challenge. Salivary and faecal quantitative PCR for T. whipplei should be ensued, if positive, by an upper endoscopy for duodenal biopsies. The treatment consists of a combination of oral doxycycline and hydroxychloroquine for 12 months followed by life-long doxycycline. Whipple's disease, although rare, is an entity that should be considered regularly, as its progression may be fatal if left untreated.