AB1470 DOES TESTING FOR SAA IS MORE BENEFICIAL THAN CRP FOR THE FOLLOW-UP OF PATIENTS WITH FMF?

Abstract

BackgroundIn order to follow subclinical inflammation and adjust the therapy for an optimal disease control, clinicians seek for readily accessible, affordable and reproducible markers. C reactive protein (CRP) is widely used for this purpose. Some suggest that the Serum Amyloid A (SAA) is preferable to CRP as a biomarker of inflammation in FMF patients1.ObjectivesTo evaluate and to compare the sensitivity of the serum SAA and CRP levels in FMF patients.MethodsSerum SAA and CRP levels were measured in 45 patients. 153 measurements from 28 patients with M694V homozygous mutation and 74 measurements from 17 patients with M694V heterozygous mutation were obtained during a mean follow-up of 1 year. For the analysis, the folds of normal CRP and SAA values were used for correlation. 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 half fold increasement of CRP and SAA was defined as an active inflammation. The correlation coefficients and their significance were calculated using the Spearman test.ResultsExcept a patient, all patients in whole cohort were on prophylactic colchicine. Among 28 patients with M694V homozygous mutation, a patient with adalimumab, 12 (42,8%) patients with anti-IL-1 regimens. Of the 17 patients with M694V heterozygous mutation, four (23,5%) were under anti-IL-1 treatment. There was a total of 227 measurements of CRP and SAA from 45 patients. Twenty-five (11%) measurements were obtained during the attack period in and the remaining 202 measurements were collected in attack free period. Figure 1 demonstrates the correlation between CRP and SAA levels (r=0.8, p< 0,001). Both acute phase reactants were increased in 72 (31,7%) measurements, while in 13 (5,7%) CRP level was high but SAA level was normal and in 31 (13,6%) SAA level was high however CRP level was within the normal limits. The vast majority (30:31) of high SAA with normal CRP levels were observed in patients with M694V homozgous mutation. The mean increase in CRP of the entire cohort was 2,06 ± 3,34-fold, whereas mean increase in SAA was 6,23 ± 15,04-fold of the normal levels.Figure 1.The folds of the serum CRP and SAA levels in the entire cohort.ConclusionAccording to our results, serial testing of SAA does not provide any additional advantages over CRP. Readily accessible and affordable bio-marker CRP seems to be sufficient for follow-up of patients with FMF.