Background Familial Mediterranean Fever (FMF) is an autosomal recessive, inherited, autoinflammatory disease characterized by recurrent, self-limited febrile episodes of inflammation of serous membranes and marked elevation of acute phase proteins. In some patients with FMF, the laboratory markers of inflammation do not return to normal levels during attack-free periods, and complications related with persistent subclinical inflammation may occur.
Objectives The aim of this study was to evaluate the clinical role of serum amyloid A (SAA) and other acute-phase proteins during the treatment and follow-up of children with FMF.
Methods The children with the diagnosis of FMF were enrolled in the study. Information including clinical and laboratory findings, erythrocyte sedimentation rate (ESR), SAA and C-reactive protein (CRP) levels, type of MEFV mutation were collected from the hospital's records following approval by the local ethics committee. Children were divided into four groups according to the time of SAA determination: group I during diagnostic evaluation (before colchicine treatment), group II asymptomatic children treated with low-dose colchicine, group III asymptomatic compliant children treated with adequate dose colchicine according to the their body weight, group IV non-compliant children with colchicine treatment.
Results A total of 141 children, 73 (51.8%) girls with a median age of 11 years (1.5–18) and a median follow-up period of 12 months (3–135) were included in the study. Thirty two children, (22.7%) had parental consanguinity and 79 children (56.0%) had family history of FMF. Thirty three children (23.4%) were homozygous, 66 children (46.8%) were compound heterozygous and 42 children (29.8%) were heterozygous for MEFV gene. Colchicine treatment was started in all patients. The main clinical characteristics of the children were: abdominal pain in 87.2%, fever in 61.7%, arthralgia/myalgia in 52.5%, arthritis in 15.6%, chest pain in 10.6%, erysipelas-like erythema in 4.3%, history of appendectomy in 6.2%, microalbuminuria in 15.6% and proteinuria 6.4%. There were 21 children in group I, 9 in group II, 84 in group III and 27 in group IV. Elevated SAA levels (>10 mg/L) found in 55 children (39.0%), elevated CRP levels (>0.5 mg/dl) in 45 children (31.9%) and elevated ESR (>20 mm/hour) in 42 children (29.8%). Comparison of the acute-phase proteins revealed significant differences between four groups as expected (Table 1). In group II, number of children who had elevated SAA levels was higher than the number of children with elevated CRP levels (88.9% vs 44.4%) and none of these children had elevated ESR.
Conclusions Our findings suggest that SAA level is important laboratory parameter for determination of subclinical inflammation especially in asymptomatic children treated with low-dose colchicine. Monitoring of SAA levels should be part of routine follow-up of children with FMF for the prevention of the development of FMF-related complications.
Disclosure of Interest None declared