What Is Immunodeficiency?

Immunodeficiency disease (IDD) is a group of diseases caused by a deficiency in immune function caused by an underdeveloped or damaged immune system. There are two types: Primary immunodeficiency disease, also known as congenital immunodeficiency disease, is related to genetics and occurs in infants and young children. Secondary immunodeficiency disease, also known as acquired immunodeficiency disease, can occur at any age, mostly due to severe infections, especially infections that directly invade the immune system, malignant tumors, application of immunosuppressants, radiation therapy, and chemotherapy. cause.

Basic Information

English name: immunodeficiency disease
Visiting department: Internal medicine
Multiple groups: Primary: Infants
Common causes: Primary: genetically related; secondary: severe infections, malignant tumors, application of immunosuppressive agents, radiation therapy, and chemotherapy

Common symptoms: Increased susceptibility to various infections, malignant tumors, concomitant autoimmune diseases, multisystem involvement and variability of symptoms, genetic predisposition

Causes of immunodeficiency

Primary immunodeficiency disease

Is a rare group of diseases, genetically related.

2. Secondary immunodeficiency

It is often caused by multiple factors, including infection (rubella, measles, leprosy, tuberculosis, cytomegalovirus infection, HIV infection, coccidioid infection, etc.), malignant tumors (Hodgkin's disease, acute and chronic leukemia, myeloma, etc. ), Autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, etc.), protein loss (nephrotic syndrome, protein loss bowel disease), insufficient immunoglobulin synthesis, lymphocyte loss (due to drugs, systemic infections, etc.) And other diseases (such as diabetes, cirrhosis, subacute sclerosing panencephalitis) and immunosuppressive treatment. Secondary immunodeficiency disease can be temporary, and when the primary disease is treated, the immune deficiency can return to normal or it can be persistent. Secondary immunodeficiency is often caused by multiple factors. For example, secondary immunodeficiency disease associated with cancer can be caused by tumors, anticancer treatment, and malnutrition.

Clinical manifestations of immunodeficiency disease

Infection

Increasing susceptibility to various infections is the main, most common and most severe manifestation and consequence of immunodeficiency, and infections are also the leading cause of patient death. The younger the patient, the higher the frequency of infection and the worse the condition. Infections can be recurrent or persistent, acute or chronic. There was no significant gap between the two infections. The infection site is most common in the respiratory tract. The nature of the infection mainly depends on the type of immune deficiency, such as humoral immunity, phagocytic cells and complement deficiency. The infection is mainly caused by purulent cells such as staphylococcus, streptococcus, and pneumococcus. The clinical manifestations are tracheitis, pneumonia, and otitis media. , Purulent meningitis and pyoderma. Infection during cellular immune deficiency is mainly caused by viruses, fungi, intracellular parasites, and protozoa.

The normal flora and immune-deficient microorganisms in the air, soil, and water, such as E. coli, Pseudomonas aeruginosa, and Proteus, are very susceptible. This type of infection is called chance. Sexual infection.

Malignant tumor

The World Health Organization (WHO) reports that the incidence of malignant tumors in primary immunodeficiency patients with T-cell immunodeficiency is 100 to 300 times higher than that of the normal population of the same age, with leukemia and lymphatic tumors being the most common.

3. Concomitant autoimmune diseases

People with primary immunodeficiency have a high tendency to accompany autoimmune diseases. The incidence of autoimmune diseases in the normal population is 0.001% to 0.01%, while those in immunodeficiency patients can reach 14%. Systemic lupus erythematosus and rheumatoid arthritis And pernicious anemia.

4. Multiple system involvement and variability of symptoms

In terms of clinical and pathological manifestations, immunodeficiency is highly heterogeneous. Different immunodeficiency is caused by defects in different components of the immune system, so the symptoms are different, and patients with the same disease may behave differently. Immune deficiency can affect the respiratory system, digestive system, hematopoietic system, endocrine system, bone and joint system, nervous system, and skin and mucous membranes, and the symptoms of corresponding dysfunction appear.

5. Genetic predisposition

Most primary immunodeficiency diseases are genetically predisposed, about 1/3 are autosomal and 1/5 are recessive.

Immunodeficiency test

When immunodeficiency is suspected, laboratory screening tests should be performed, including total blood cell counts and differential counts and platelet counts; determination of IgG, IgM, and IgA concentrations; determination of antibody function; clinical and laboratory judgment of infection.

Diagnosis of immunodeficiency disease

The diagnosis of immunodeficiency disease should include: whether there is an immunodeficiency; primary or secondary, persistent or temporary; the location and extent of the immune system defect. The diagnosis is mainly based on medical history, physical examination and corresponding auxiliary examinations.

Immunodeficiency disease treatment

1. Treatment principles

Protective isolation of patients to reduce exposure to infection sources; Patients with immune deficiency are prohibited from receiving live vaccines to prevent severe vaccine infections; Generally do not do tonsillectomy and lymphadenectomy, and forbid splenectomy, Immunosuppressive drugs should be used with caution; Use antibiotics to clear bacterial and fungal infections; Replacement therapy or immune reconstruction according to the type of immune deficiency.

2. Application of immune preparations

Most patients with primary immunodeficiency disease are accompanied by a lack of IgG or other antibodies, and Ig supplementation is the most common treatment. Patients whose serum Ig content is less than 2.5g / L should be given an intravenous infusion of human gamma globulin. Other alternative treatments include specific immune serum, transfusion of white blood cells, cytokines, etc. to improve the body's immune function.

3 Immune reconstruction

Thymus transplantation, bone marrow transplantation, hematopoietic stem cell transplantation, and fetal liver transplantation are used to reconstruct immune function, which can relieve the condition of some primary immunodeficiency diseases and is an effective cure. Fetal thymus tissue transplantation is to implant the embryo thymus within 16 weeks under the peritoneum or subcutaneously to treat cellular immunodeficiency diseases, especially thymic hypoplasia. After fetal thymus transplantation, thymic remodeling appears quickly (often within a few days) and persists.

Stem cell transplantation includes cord blood stem cell transplantation and peripheral blood stem cell transplantation. Cord blood is rich in hematopoietic stem cells and can be used as an important source of stem cells for immune reconstruction in patients with primary immunodeficiency disease.

Bone marrow transplantation includes allogeneic homozygote bone marrow transplantation, allogeneic hemizygous bone marrow transplantation, and unrelated donor bone marrow transplantation, which should be selected according to the patient's condition and specific circumstances.

4 Gene therapy

Some primary immunodeficiency diseases are caused by single gene defects, and some mutation sites have been identified, thus laying a foundation for future gene therapy. The normal target gene fragment is integrated into the patient's stem cell genome (gene transformation). The gene-transformed cells undergo mitosis, so that the transformed gene fragment can replicate in the patient and continue to function. Theoretically, all diseases with successful bone marrow transplantation are indications of gene therapy.