Specialty hematology ICD-9-CM 279.0 | ICD-10 D80 | |
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Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency. It can be mediated by insufficient number or function of B cells, the plasma cells they differentiate into (with these two potentially being caused by B cell lymphocytopenia), or the antibody secreted by the plasma cells. The most common such immunodeficiency is inherited selective IgA deficiency, occurring between 1 in 100 and 1 in 1000 persons, depending on population.
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They are associated with increased vulnerability to infection, but can be difficult to detect (or asymptomatic) in the absence of infection.
They can be associated with increased risk of gastric cancer.
Signs and symptoms
The signs and symptoms of humoral immune deficiency depend on the cause, but generally include signs of hypogammaglobulinemia (decrease of one or more types of antibodies) with presentations including repeated mild respiratory infections, and/or agammaglobulinemia (lack of all or most antibody production) which results in frequent severe infections and is often fatal.
Causes
One way of classifying humoral immune deficiencies is into primary (or hereditary) versus secondary (or acquired) ones.
Primary
The International Union of Immunological Societies classifies primary immune deficiencies of the humoral system (here termed "Predominantly antibody deficiencies") as follows:
- Absent B cells with a resultant severe reduction of all types of antibody: X-linked agammaglobulinemia (btk deficiency, or Bruton's agammaglobulinemia), μ-Heavy chain deficiency, l 5 deficiency, Igα deficiency, BLNK deficiency, thymoma with immunodeficiency
- B cells low but present or normal, but with reduction in 2 or more isotypes (usually IgG & IgA, sometimes IgM): common variable immunodeficiency (CVID), ICOS deficiency, CD19 deficiency, TACI (TNFRSF13B) deficiency, BAFF receptor deficiency.
- Normal numbers of B cells with decreased IgG and IgA and increased IgM: Hyper-IgM syndromes
- Normal numbers of B cells with isotype or light chain deficiencies: heavy chain deletions, kappa chain deficiency, isolated IgG subclass deficiency, IgA with IgG subsclass deficiency, selective immunoglobulin A deficiency
- Specific antibody deficiency to specific antigens with normal B cell and normal Ig concentrations
- Transient hypogammaglobulinemia of infancy (THI)
Secondary
Secondary (or acquired) forms of humoral immune deficiency are mainly due to hematopoietic malignancies and infections that disrupt the immune system:
Treatment
In most cases, treatment consists of avoiding infection and managing infections with antibiotics or antivirals. In case of life-threatening diseases, bone marrow transplant may be attempted.