Secondary immunodeficiency refers to immune dysfunction secondary to severe infections, certain physical and chemical factors, malignant tumors, nutritional disorders, etc., leading to increased susceptibility to infections. The disease often affects multiple immune functions simultaneously, most commonly cellular immunodeficiency and neutrophil immune dysfunction. This condition is usually temporary and can often return to normal after the causative factors are eliminated.

bubble_chart Clinical Manifestations

1. Increased susceptibility, often presenting with infectious diseases.
2. Factors causing secondary immunodeficiency diseases can be identified, with common factors as follows: (1) Severe infections: Both viral and bacterial infections can affect immunocompetent cells, alter T-cell activity, reduce interleukin-2 (IL-2) activity, and impair granulocyte function, leading to compromised cellular immunity and neutrophil function. (2) Physical and chemical factors: Radiation can damage cellular immune function; antibiotics and antimetabolites can suppress immune system function; corticosteroids can break down lymphoblasts, reduce lymphocyte counts, cause thymic atrophy, weaken granulocyte phagocytic function, and decrease complement components; aspirin and phenylbutazone can inhibit neutrophil function. (3) Cytotoxic drugs and immunosuppressants: Cytotoxic drugs such as cyclophosphamide can interfere with cell proliferation, division, and metabolism, suppressing cellular and humoral immunity; immunosuppressants like cyclosporine A, antilymphocyte globulin, and azathioprine can significantly inhibit immune system function. (4) Nutritional disorders: Protein malnutrition can hinder T-cell activation, reduce IL-1 production, impair macrophage antigen-processing ability, and lower IgG levels; protein-energy malnutrition can damage cellular immune function and reduce specific antibody formation; iron deficiency can lead to reduced T-cell counts, inhibit lymphocyte-associated enzyme system activity, and cause deficiencies in IL—
   1. IL—
   2. IL-6 production. Zinc deficiency can affect certain enzyme activities, leading to underdeveloped immune organs
   3. IL-1
   , reduced IL-2 activity, IgG subclass deficiencies, and cellular immune dysfunction; vitamin B6 deficiency can impair thymic epithelial cell function, reducing thymosin activity in the blood; vitamin C deficiency also affects cellular immune function. (5) Malignancies: Leukemia, cervical malignancy with cachexia, histiocytosis, and other diseases can result in low cellular immune function. (6) Post-splenectomy, serum immunoglobulin levels decline, especially in children under 4 years old, where the lack of opsonins reduces phagocytic function and increases susceptibility. Anesthesia and major surgery can affect the body's immune status.

﹝Auxiliary Examinations﹞

1. Selective immune function tests should be performed based on the condition. 2. Diagnostic tests for disease causes should be conducted to identify the causative factors.

bubble_chart Treatment Measures

﹝Treatment﹞

(1) Treat the primary disease and remove the causative factors. (2) Provide symptomatic treatment and actively prevent and control various infections. (3) For patients with recurrent severe infections, appropriate immune replacement and immune enhancement therapies can be applied, such as blood transfusion, injection of immunoglobulins, transfer factor, thymosin, interferon, etc.