CR1 allelic distribution in healthy italians and SLE patients

Complement receptor type 1 (CR1; CD35), the receptor for C3b/C4b, has a molecular weight polymorphism involving four co-dominantly expressed alleles CR1*1, CR1*2, CR1*3 and CR1*4. The most common allotype in the Caucasian population is CR1*1. Previous studies on the frequency of the CR1 allele in Systemic Lupus Erythematosus (SLE) patients reported conflicting results. Recently an increased frequency of the CR1*2 allele was reported in Caucasian SLE patients. The aim of our study is to assess the frequency of CR1 structural alleles in a sample of the Italian population and in a cohort of Italian SLE patients equally distributed nationwide. We found that the most common phenotype was CR1*1.1 (71%) and the other phenotypes found were CR1*1.2 (25%), CR1*1.4 (3%), and CR1*2.2 (1%). Our data show that the allelic frequency distribution in healthy Italians is not different from that of other Caucasian cohorts reported in previous studies. Moreover, the structural polymorphism frequencies in the Italian population show no difference between SLE patients and healthy individuals.