Recurrent miscarriages are defined as those with 2 or more spontaneous miscarriages, which according to the literature is 15% for spontaneous miscarriages, 2.3% for 2 spontaneous miscarriages and 0.34% for 3 spontaneous miscarriages. There is no precise definition of recurrent implantation failure, most believe that in 2-6 IVF cycles, more than 10 quality embryos were transferred without implantation, however, it has been suggested that in the case of 3 failed implantations of quality embryos, we need to look further for the cause. The main causes of recurrent miscarriage and recurrent implantation failure that we know of so far include chromosomal causes, anatomical abnormalities, infectious causes, endocrine factors, immune factors, and unexplained factors. After excluding the known causes, there is no shortage of patients with unknown causes of recurrent miscarriage and recurrent implantation failure in clinical practice. Normal pregnancy is a complex physiological process similar to allogeneic transfer, in which the embryo is equivalent to carrying 1/2 tissue antigens that are different from those of the mother, yet the essence of not being rejected by the maternal immune system depends on the immune tolerance relationship between mother and fetus, and once the immune tolerance is imbalanced, recurrent miscarriage and recurrent implantation failure may occur for unknown reasons. Blocking antibodies play an important role in regulating maternal immune tolerance to maintain normal pregnancy and embryo implantation. Blocking antibodies are produced mainly against embryonic human leukocyte class II antigens (HLA-II) and trophoblast lymphocyte cross-antigens (TLX), which prevent embryonic paternal antigens from being recognized and killed by the maternal immune system by binding to fetal placental trophoblast antigens or maternal lymphocytes, preventing immune attack on embryonic trophoblast cells. In addition, the mother may produce anti-closing antibody unique type antibodies that interact locally at the maternal-fetal immune interface and in the body circulation with harmful immunoreactive cells (e.g., killer T cells, natural killer cells, etc.) and related factors such as IL-22 to block harmful immune responses, thus helping to maintain pregnancy and implantation. Lymphocyte active immunotherapy mainly uses the husband’s lymphocytes injected into the woman to stimulate her immune system and induce the production of closed antibodies (including anti-HLA, anti-TLXBA, etc.) in her body, thus preventing the embryo paternal antigens from being recognized and killed by the maternal immune system, so that the embryo is protected and grows back. And by repeatedly stimulating the woman’s immune system, improving her immune memory facilitates the success of the next pregnancy. The procedure of lymphocyte immunotherapy is as follows: the husband’s venous blood is taken, the immune cells are extracted, and the patient’s forearm is inoculated subcutaneously by multi-point injection, usually with 6-8 spots, once every 2-3 weeks, for a course of 3-4 months; after 1 course, the patient’s venous blood is retested for “closed antibodies”, and if no antibodies are still produced, additional treatment is given for 1 or 2 times. -If antibodies have been produced, it is recommended to conceive within 6 months. If the patient is infertile for 3 months, it is recommended to use ovulation promotion or artificial insemination to speed up the pregnancy. Once early pregnancy is diagnosed, maintenance treatment is required, approximately once every 3-4 weeks, with the same procedure as above, continuing until the second trimester of pregnancy.