ABSTRACT
Familial Mediterranean fever [FMF] is a recessively inherited disorder. Some FMF patients present high IgD serum levels, and it is not yet known whether such an elevation is related to specific genotypes or correlated with a specific phenotype. The objective of this study is to evaluate the association between known FMF-related mutations and IgD levels in confirmed patients, as well as the correlation between those levels and the presence of specific clinical signs. Genotypic analysis and IgD plasma measurements were performed for 83 Syrian FMF patients. Most common mutational patterns were M694V heterozygotes [26%] and homozygotes [24%], and V726A heterozygotes [5%] and homozygotes [2%], and combining both mutations [17%]. Nine patients had elevated IgD levels [higher than 100 microg/ml]. The risk for high IgD levels was significantly associated with M694V homozygous status [OR=2] but not with heterozygous status [OR-1]. Similarly, the risk for high IgD was also found with V726A homozygotes [OR=9.5] but not with heterozygotes [OR=1.05]. Clinically, hyper IgD was also found significantly associated with arthritis [OR=18]. Homozygous status for M694V, and to a lesser extent V726A, is associated with an increased risk for higher IgD plasma levels. Elevated IgD plasma levels are also correlated with the severity of FMF manifestations, and especially with arthritis