Immunity in pregnancy, ontogenesis of immunity Uterine mechanisms of fetus protection against mother´s immune system •Majority of cells does not cross placental barrier. •No classical HLA- antigens are expressed on trophoblast. •Non classical HLA-G antigens protect trophoblast cells from NK cells. Their presentation of antigens probably leads to suppression of speciphic immune response. •CD46 on the surface of trophoblast cleaves C3b. Maternal mechanisms protection fetus from the immune system attack •Mother is in Th2 predominance •Possible immunosuppressive effects of HCG, high serum levels of progesterone, alfa-feto protein •Partial block of lymph nodes draining the uterus • Immunological causes of sterility and infertility •In approximately in 10% of infertile couples immunopathological mechanisms play a significant role. •Antibodies against various antigens of the gonadal system (sperms, corpus lutem) may play a role. •Antiphospholipid syndrome causes abortions in the first trimester. Antiphospholipid syndrome •It is the most common immunological disorder leading to recurrent miscarriages. •Patients suffer from recurrent thrombosis (venous and arterial) leading to a variable clinical manifestation according to the affected organs. •Thrombocytopenia may be present. •Laboratory: antiphospholipid (anticardiolipin) antibodies, lupus anticoagulant. •It may be a primary disease or accompany various systemic autoimmune diseases (eg. systemic lupus erythematosus). Serum immunoglobulin levels in pre- and postnatal period Immune system in infancy •IgG is actively transferred though the placenta , protective IgG, but also autoantibodies. Gradual increase of own production of IgG •IgM may be produced by the fetus in the late pregnancy, does not cross the placenta •IgA produced by the newborn, in secretions in almost normal levels. •T lymphocyte function – almost normal. •Nonspecific immunity- function of granulocytes, complement system – mildly decreased in the first year of life. Immune system-related diseases in infancy and childhood •Increased susceptibility to infectious diseases. •Clinical course of infections is usually mild. •Exception – severe course of infections caused by encapsulated bacteria during the first two years. •Atopic diseases usually begin in early childhood. •Autoimmune diseases are relatively rare. •Many primary immunodeficiency diseases manifest in infancy or early childhood. Immune system-related diseases in adulthood •Infectious diseases are infrequent, but may be severe in course. •Autoimmune diseases typically begin in early adulthood. •High prevalence of allergic diseases continues from childhood Immunity in seniors •Weak primary immune response, secondary immune response is usually normal. •Decrease in lymphocytes, mainly CD4+ •Serum immunoglobulin levels are usually increased. •Immune response is generally decreased, clinical symptoms of infection are milder than in young persons. •Disturbed regulation of the immune system leads to frequent positivity of autoantibodies and paraproteins, but this does not lead to clinical diseases.