Leukocyte adhesion molecule deficiency type II in children

Introduction to type II defects of leukocyte adhesion molecules in children Leukocyte adhesion molecule deficiency type II (LADII) is a rare primary immunodeficiency disease, and only 2 cases have been reported so far. LADII is an abnormality in fucose metabolism, which leads to defects in the leukocyte surface selectin ligand fucosylation antigen SLeX, and the rolling function of leukocytes is abnormal, which affects its adhesion to vascular endothelial cells and does not penetrate the blood vessel wall into the inflammatory region. basic knowledge The proportion of illness: 0.001% Susceptible people: children Mode of infection: non-infectious Complications: mental retardation

Pediatric leukocyte adhesion molecule deficiency type II etiology

Cause:

The leukocyte surface SLeX antigen acts as a ligand binding site for endothelial cell surface selectin, participates in the adhesion of leukocytes to endothelial cells, promotes leukocyte migration to the inflammatory region, abnormal fucose metabolism, and makes fucosylated substances such as selectins The lack of SLeX antigen in the body leads to leukocyte adhesion dysfunction, growth and intelligent development.

Pathogenesis

These patients were found to have defects in neutrophils that could not adhere to the surface of many natural and artificial objects, nor to interact with conditioned objects because they could not express some surface glycoproteins, which are now known as Leukocyte integrin CDL1/CD18 complex, these proteins include the lymphocyte function-associated antigen LFA-1 (CDL1a/CDL8), Mac-1 (CDL1b/CDl8) and P150, 95 (CDL1c/CDl8), which are composed of their respective Chains are distinguished, but -chains (CDl8) are common. These molecules play a decisive role in the adhesion-dependent function of neutrophils and other phagocytic cells. If they are lacking, they directly affect the adhesion, movement and phagocytosis of leukocytes. The mechanism of abnormal fucose metabolism is still unclear, and may be autosomal recessive inheritance.

Pediatric leukocyte adhesion molecule defect type II prevention

Pregnant woman health care

It is known that the occurrence of some immunodeficiency diseases is closely related to embryonic dysplasia. If pregnant women are exposed to radiation, receive certain chemical treatments or develop viral infections (especially rubella virus infections), they can damage the fetal immune system. Especially in the early pregnancy, it can affect multiple systems including the immune system. Therefore, it is very important to strengthen the health care of pregnant women, especially in the early pregnancy. Pregnant women should avoid receiving radiation, use some chemical drugs with caution, and inject rubella vaccine to prevent as much as possible. Virus infection, but also to strengthen the nutrition of pregnant women, timely treatment of some chronic diseases.

2. Genetic counseling and family survey

Although most diseases cannot determine the genetic pattern, genetic counseling for diseases with defined genetic patterns is valuable if genetically immunodeficiency in adults will provide the developmental risk of their children; if a child has autosomals Recessive genetic or sexually linked immunodeficiency disease, it is necessary to tell parents that their next child is likely to be sick, for patients with antibodies or complement deficiency patients should check the antibody and complement levels to determine the family disease For some diseases that can be genetically mapped, such as chronic granulomatosis, parents, siblings and their children should be genetically tested. If a patient is found, it should also be performed among his or her family members. Check that the child's child should be carefully observed at the beginning of the birth for any disease.

3. Prenatal diagnosis

Some immunodeficiency diseases can be prenatally diagnosed, such as cultured amniotic fluid cell enzymology can diagnose adenosine deaminase deficiency, nucleoside phosphorylase deficiency and some combined immunodeficiency diseases; fetal blood cell immunological test can be Diagnosis of CGD, X-linked no-gammaglobulinemia, severe combined immunodeficiency disease, thereby terminating pregnancy, preventing the birth of children, leukocyte adhesion molecule deficiency type II is a relatively rare disease, 2 cases reported so far, both For close relatives to marry, it is very important to avoid close relatives, early accurate diagnosis, early specific treatment and genetic counseling (prenatal diagnosis or even intrauterine treatment).

Pediatric leukocyte adhesion molecule defect type II complications Complications, mental retardation

Shortly after birth, there were various, repeated bacterial infections, severe mental retardation, and short stature.

Pediatric leukocyte adhesion molecule deficiency type II symptoms common symptoms mental retardation repeated infection abnormally short

Repeated bacterial infections occur shortly after birth, including pneumonia, periodontitis, otitis media, localized soft tissue inflammation and skin infections. The infection site is characterized by no pus formation, the severity of infection is less than LADI, and there is no umbilical cord shedding delay. Other manifestations include severe mental retardation, short stature, and a special face.

Examination of type II defects of leukocyte adhesion molecules in children

Peripheral blood neutrophils are abnormally elevated, even in the absence of infection, neutrophils can be as high as (25 ~ 30) × 109 / L, acute infection is as high as 150 × 109 / L, neutrophil chemotaxis The function was significantly reduced, the phagocytic function was normal, and the neutrophils in the children were found to have no SLeX expression. The half-life of neutrophils in the blood vessels was only 3.2 h (normally 6 to 9 h), and the metabolic rate was also significantly increased. High, neutrophils are released from the bone marrow into the blood eight times as much as normal.

Generally, various auxiliary examinations are selected according to clinical needs, and chest X-ray and B-ultrasound are often required.

Type II diagnosis and differentiation of leukocyte adhesion molecule defects in children

Repeated infections but no pus formation, accompanied by special facial and intellectual disabilities, as well as laboratory tests of parents and close relatives can be confirmed.

Identification with LADI.

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