What is the risk of severe combined immunodeficiency?

summary

Severe combined immunodeficiency disease (SCID), Swiss agammaglobulinemia, thymic lymphodysplasia and reticular dysplasia are a group of severe immunodeficiency diseases. It is characterized by congenital and hereditary abnormalities of B lymphocyte and T lymphocyte system. These diseases are autosomal recessive or X-linked. 50% of SCID had positive family history. SCID with reticular dysplasia is caused by the deficiency of primitive hematopoietic stem cells, Swiss agammaglobulinemia is caused by the deficiency of lymphoid stem cells, and some SCID is caused by the poor differentiation of T lymphocytes and the disorder of B lymphocyte maturation. What about severe combined immunodeficiency disease? The disease is described below.

What is the risk of severe combined immunodeficiency?

First, more than 3 months after birth began to infect the virus, mold, protozoa and bacteria, and repeated pneumonia, chronic diarrhea, oral and skin Candida infection and otitis media. The growth and development of the sick children were impaired. Physical examination generally did not see superficial lymph nodes and tonsils. Chest X-ray showed no thymus shadow. If vaccinated with vaccinia vaccine or taking polio vaccine, it will cause fatal vaccinia and poliomyelitis.

Second, if the whole blood containing immunocompetent lymphocytes is infused into children, graft-versus-host disease will occur. Reticular dysplasia is the most severe form of SCID, characterized by double system immunodeficiency and severe agranulocytosis. Most of them died within 1 week after birth due to streptococcal sepsis. SCID can also be accompanied by bone hypoplasia, resulting in short legged dwarfism, early hair loss, erythroderma and ichthyosis.

Third, SCID is a kind of systemic immune deficiency disease with obvious abnormality of humoral and cellular immune function. Generally, IgG, IgA and IgM are very low, but a few patients may have one or two normal immunoglobulins. Almost all patients had no antibody reaction. In some cases, B lymphocytes in blood and lymphoid tissue decreased. The number of T lymphocytes in peripheral blood decreased significantly. Memory antigen test and intracutaneous phytohemagglutinin test showed poor response, T lymphocyte function test in vitro was also abnormal, and mitogen proliferation reaction was absent.

matters needing attention

In order to prevent the occurrence of graft-versus-host disease, the whole blood or blood products to be transfused should be irradiated by radiation to inactivate the immune active cells, or frozen red blood cells should be used. Bone marrow transplantation is the most effective method to treat the disease. The success rate was the highest when HLA matched sibling bone marrow was used. The donor bone marrow pretreated with phytohemagglutinin, monoclonal antibody, complement or immunotoxin to eliminate the mature T lymphocytes causing graft-versus-host disease can significantly improve the success rate of HLA incompatible bone marrow transplantation. In addition, fetal liver or thymus can also be transplanted, but the curative effect is limited.