Polymorphism of properdin factor B (Bf) in some Italian populations.

In order to contribute to the definition of a map of the distribution of Bf polymorphism in Italy, we typed numerous population samples (for a total of 2033 individuals) from several regions of Italy: provinces of Bologna, Potenza and Matera, middle Sangro valley (Chieti) and northern, central and southern Sardinia. A new method was used which consisted of cellulose acetate electrophoresis followed by immunofixation and staining with Coomassie blue. The results obtained highlight marked differences in the distribution of Bf phenotypes and allele frequencies in Italy. To be noted in particular are the relatively high incidence of the BfS allele and the low incidence of BfF in Potenza and the significantly different pattern of the Sardinian samples compared to those from mainland Italy. This may be due to the low incidence in Sardinia of the BfS allele and above all to the exceptionally high frequency of the BfF1 variant.