Immunopathology refers to the science that studies the pathological phenomena caused by functional abnormalities (or secondary abnormalities) and immune responses.
It is one of the branches of immunology, covering a wide range, including (allergic reactions), autoimmunity, immune hyperplasia and immune deficiency, etc. Although the immune system's recognition and rejection of antigenic foreign substances are beneficial to the body in most cases, there are also some immune responses that are detrimental to the body and can cause functional disorders or/and tissue damage, such as rejection of grafts and immune responses to one's own components.
When there is excessive proliferation, the primary pathological process occurs, namely immunoproliferative diseases. Normal (reactive) immune hyperplasia can self-restrict and recover after a period of disease course. Malignant immune hyperplasia, such as Hodgkin's disease, macroglobulinemia, heavy chain disease, multiple myeloma, etc. Multiple myeloma is a disease characterized by the massive proliferation of plasma cells, affecting bones, bone marrow, kidneys and the nervous system. The vast majority of patients only have a sexual change in a certain clone of B cells, presenting an abnormal immunoglobulin with unknown antibody activity, namely myeloglobulin.
The body reduces or loses its normal immune function due to some reason of the immune system. Immune deficiency can be primary (caused by genetic or congenital reasons) or acquired (caused by other diseases). Immune deficiency can also be classified into two types: humoral immune deficiency and cellular immune deficiency.
Primary immunodeficiency can be hereditary, such as sexual interlocking or autosomal inheritance; There are congenital ones, such as poor embryonic development, which leads to the loss of a certain tissue component or abnormal enzyme system. Common types include ① immunoglobulin (Ig) deficiency: Some patients have a deficiency or low level of all types of Ig, while others only have a defect in one or several types of Ig, with the rest being normal. Among them, the common one is selective IgA deficiency, with one patient in every 500 to 700 people. The common symptom is recurrent severe bacterial infections. The main cause of Ig deficiency is abnormal B-cell system, but in some cases, it is hyperfunction of inhibitory T cells, which inhibits B-cell function. ② Cellular immune deficiency: A disease caused by abnormal thymus development. Typical examples are Digigeorge syndrome and Nezzelov syndrome. The former is caused by congenital hypoplasia of the thymus, while the latter is caused by hypoplasia of the thymus. The main manifestations are multiple intracellular parasitic bacterial and fungal infections as well as viral infections. Degeorge's syndrome is also accompanied by parathyroid gland and cardiovascular system abnormalities. ③ Combined immune deficiency: That is, the lack of both humoral immunity and cellular immunity.
