Although knowledge of bivalve immune-related genes has increased in the last few years, the available information is still scarce and fragmentary. Most of the data concern mussels and Eastern and Pacific oysters [9] [10] [11] [12] [13] [14] , and very limited information is available on the expressed immune genes of R. philippinarum. Recently, the expression of 13 immune-related genes of Ruditapes philippinarum and Ruditapes decussatus were characterized in response to a Vibrio alginolyticus challenge [15] . Also, a recent 454 pyrosequencing study was carried out by Milan et al. [16] , who sequenced two normalized cDNA libraries representing a mixture of adult tissues and larvae from R. philippinarum. Even more recently Ghiselli et al. [17] , have de novo assembled the R. philippinarum gonad transcriptome with the Illumina technology. Moreover, a few transcripts encoded by genes putatively involved in the clam immune response against Perkinsus olseni have been reported by cDNA library sequencing [18] . Currently (19/12/ 2011) , there are 5,662 ESTs belonging to R. philippinarum in the GenBank database.