[B, C2 and C4 complement factors, the HLA system and diseases. Genetic relation].

Close linkage of the complement factor loci C2, C4 and Bf to HLA loci has been firmly documented. A review of the literature was made about genetic defects of these components associated with a variety of disorders, especially immunologic diseases. Some allotypes of these factors are also closely linked to several diseases. Relationship between these diseases and the genes controlling the synthesis of C2, C4 and Bf and their allelic variants is not yet known but this association suggested several pathogenic hypotheses.