Due to the well-known association between HLA class II alleles and autoantibody production, as well as the association between p-MBL deficiency and some autoimmune diseases, we found it important to investigate whether autoantibody formation is an intermediate variable between the two RPL-associated genetic factors HLA-DRB1 and low p-MBL and RPL. The gene discussed is MBL2; the disease is autoimmune disease.