Reference typing report for complement factor B

Factor B (BF) reference typing was carried out on the occasion of the VIIth Complement Genetics Workshop in Mainz, May 1998. Two different sets of sam ples were analysed by agarose electrophoresis and/or isoelectric focusing a t the protein level, and by PCR-RFLP analysis at the DNA level. These resul ts confirmed the reliability of the standard agarose electrophoresis techni que for the identification of the major BF alleles as well as for the ident ification of cathodic and anodic variants. However, the exact alphanumeric designation of individual variants relative to the reference distance betwe en alleles S and F1 turned out to be more difficult. Using PCR-RFLP analysi s, the common alleles F and S as well as the FA and FB subtypes in 6 sample s containing an F allele were all assigned correctly. However, the variants F1 and S07 were not detected by this method, as they could not be distingu ished from the accompanying S allele. Therefore, a combined application of all three typing methods is recommended for a reliable identification of fa ctor B alleles, variants and FA/FB subtypes.