AA amyloidosis complicating cryopyrin-associated periodic syndrome: a study of 86 cases including 23 French patients and systematic review

Abstract

Abstract Objective Cryopyrin-associated periodic syndrome (CAPS) is a rare but treatable inherited autoinflammatory condition including familial cold autoinflammatory syndrome (FCAS), Muckle–Wells syndrome (MWS) and chronic infantile neurologic cutaneous articular syndrome (CINCA). Our objective was to describe the main features of CAPS AA amyloidosis (AA-CAPS) associated and the efficacy of IL-1 inhibitors in this indication. Methods Retrospective study in France associated with a systematic literature review. Results Eighty-six patients were identified: 23 new French cases and 63 from the literature, with a median age at amyloidosis diagnosis of 39 years old. CAPS subtypes were MWS (n = 62), FCAS (n = 9), frontier forms between MWS and FCAS (n = 12) and between CINCA and MWS (n = 3). NLRP3 had been sequenced in 60 patients (70%) and the most frequent mutation was R260W (60%). Three AA-CAPS patients displayed somatic NLRP3 mutations. Death occurred in 35 patients (41%), none of whom having ever received IL-1 inhibitors. Twenty-eight patients (33%) received IL-1 inhibitors, with a >50% decrease in proteinuria in 89% of cases. Conclusion AA amyloidosis can occur in nearly all CAPS subtypes. IL-1 inhibitors are effective, underlining the necessity of an early diagnosis of CAPS in order to start this treatment as soon as possible among AA-CAPS patients.