The comparison of Histocompatibility Testing in 82 MS Patients and 368 controls is presented. The increase in HL-A7 and decrease in HL-A12 are confirmed. A significant increase in HL-A8 is reported. Mixed Lymphocyte Reaction confirms the LD7a increase (19 out of 24 Multiple Sclerosis patients tested); 100% of the patients bearing the HL-A7 determinant are found to be LD7a. The presence of specific Immune Response genes in Multiple Sclerosis is discussed.