FRI0498 DOES TESTING FOR SAA IS MORE BENEFICIAL THAN CRP FOR THE FOLLOW-UP OF FMF PATIENTS WITH M694V HETEROZYGOUS OR M694V HOMOZYGOUS MUTATIONS?

Abstract

Background:In order to follow subclinical inflammation and adjust the therapy for an optimal Familial Mediterranean Fever (FMF) disease control, clinicians seek for readily accessible, affordable and reproducible markers. C-reactive protein (CRP) is widely used for this purpose. Some suggest that CRP measures are not conclusive in all cases, especially at initial stages of inflammation. It is suggested that Serum Amyloid A (SAA) may be more reliable and sensitive in predicting an ongoing inflammation.Objectives:In order to evaluate and to compare the sensitivity of SAA and CRP in FMF patients with M694V homozygous and M694V heterozygous mutations respectively.Methods:Blood samples from 28 patients with M694V homozygous mutation and from 15 patients with M694V heterozygous mutation were obtained during a mean follow-up of 1 year. Multiple samples were drawn in both attacks and attack-free periods of FMF (153 from M694V Homozygous and 31 from M694V Heterozygous). For the analysis of the correlation, the folds of normal CRP and SAA levels were used. Serum levels of the given markers were measured with nephelometric kits (normal CRP levels <5 mg/L and SAA levels <6,8 mg/L). More than one-and-a-half-fold increase of CRP and SAA was defined as an active inflammation.Results:Except in one patient, all patients in the whole cohort were on prophylactic colchicine. Among 28 patients with M694V homozygous mutation, one patient was treated with adalimumab, and 12 patients with anti-IL-1 regimens. Among 15 patients with M694V heterozygous mutation, 4 were under anti-IL-1 treatment. There were a total of 183 measurements of CRP and SAA from 43 patients. Twenty-three measurements were obtained during the attack period in M694V homozygous group and the remaining 160 measurements were obtaine in attack-free period. The figure demonstrates the correlation between CRP and SAA results (r=0.745, p<0.001). Both acute phase reactants were increased in 69 measurements, while in 13, CRP was high but SAA was normal and in 31, SAA was high however CRP was within normal limits. The mean increase in CRP of the whole cohort was 2,37 ± 3,22-fold of the normal, whereas mean increase in SAA was 6,77 ± 13,23-fold of the normal.Conclusion:According to these results, serial testing of SAA does not provide any additional advantages over CRP. As it is readily accessible and affordable, CRP seems to be sufficient for the follow-up of FMF patients.Figure:Figure.The folds CRP and SAA in whole M694V homozygous and heterozygous mutant populationDisclosure of Interests:None declared