Defining colchicine resistance/intolerance in patients with familial Mediterranean fever: a modified-Delphi consensus approach

OBJECTIVES: Colchicine is the main treatment for FMF. Although a number of individuals with FMF are intolerant/resistant to colchicine, there is no standard definition of colchicine resistance/intolerance. We developed a set of evidence-based core statements defining colchicine resistance/intolerance in patients with FMF that may serve as a guide for clinicians and health authorities. METHODS: A set of statements was identified using a modified-Delphi consensus-based approach. The process involved development of an initial colchicine resistance/intolerance-related questionnaire derived from a systematic literature review. The questionnaire, which was completed by an international panel of 11 adult and paediatric rheumatologists with expertise in FMF, was analysed anonymously. The results informed draft consensus statements that were discussed by a round-table expert panel, using a nominal group technique to agree on the selection and wording of the final statements. RESULTS: Consensus among the panel was achieved on eight core statements defining colchicine resistance/intolerance in patients with FMF. A definition of resistance was agreed upon that included recurrent clinical attacks (average one or more attacks per month over a 3-month period) or persistent laboratory inflammation in between attacks. Other core statements recognize the importance of assessing treatment adherence, and the impact of active disease and intolerance to colchicine on quality of life. CONCLUSION: Based on expert opinion, a set of evidence-based core statements defining colchicine resistance/intolerance in patients with FMF were identified to help guide clinicians and health authorities in the management of patients with FMF. © The Author(s) 2020. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: [email protected]

Mutant adenosine deaminase 2 in a polyarteritis nodosa vasculopathy.

BACKGROUND: Polyarteritis nodosa is a systemic necrotizing vasculitis with a pathogenesis that is poorly understood. We identified six families with multiple cases of systemic and cutaneous polyarteritis nodosa, consistent with autosomal recessive inheritance. In most cases, onset of the disease occurred during childhood. METHODS: We carried out exome sequencing in persons from multiply affected families of Georgian Jewish or German ancestry. We performed targeted sequencing in additional family members and in unrelated affected persons, 3 of Georgian Jewish ancestry and 14 of Turkish ancestry. Mutations were assessed by testing their effect on enzymatic activity in serum specimens from patients, analysis of protein structure, expression in mammalian cells, and biophysical analysis of purified protein. RESULTS: In all the families, vasculitis was caused by recessive mutations in CECR1, the gene encoding adenosine deaminase 2 (ADA2). All the Georgian Jewish patients were homozygous for a mutation encoding a Gly47Arg substitution, the German patients were compound heterozygous for Arg169Gln and Pro251Leu mutations, and one Turkish patient was compound heterozygous for Gly47Val and Trp264Ser mutations. In the endogamous Georgian Jewish population, the Gly47Arg carrier frequency was 0.102, which is consistent with the high prevalence of disease. The other mutations either were found in only one family member or patient or were extremely rare. ADA2 activity was significantly reduced in serum specimens from patients. Expression in human embryonic kidney 293T cells revealed low amounts of mutant secreted protein. CONCLUSIONS: Recessive loss-of-function mutations of ADA2, a growth factor that is the major extracellular adenosine deaminase, can cause polyarteritis nodosa vasculopathy with highly varied clinical expression. (Funded by the Shaare Zedek Medical Center and others.)