title: Serum C4 levels, Chido, Rodgers, and allotypes of C4 component of complement.
mesh_terms: D001789:Blood Group Antigens / Q000235:genetics*; D003181:Complement C4 / Q000235:genetics* / Q000378:metabolism; D005787:Gene Frequency; D008040:Genetic Linkage; D006801:Humans; D008285:Major Histocompatibility Complex; D011110:Polymorphism, Genetic
chemical_list: D001789:Blood Group Antigens; D003181:Complement C4