Humoral immune deficiency
|Humoral immune deficiency|
|B cells and antibody|
|Classification and external resources|
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.
They are associated with increased vulnerability to infection, but can be difficult to detect (or asymptomatic) in the absence of infection.
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.
One way of classifying humoral immune deficiencies is into primary (or hereditary) versus secondary (or acquired) ones.
- 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 (or acquired) forms of humoral immune deficiency are mainly due to hematopoietic malignancies and infections that disrupt the immune system:
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.
- den Hartog G, Jansen JB, van der Meer JW, Lamers CB (1992). "Gastric abnormalities in humoral immune deficiency syndromes". Scand. J. Gastroenterol. Suppl. 194: 38–40. PMID 1298045.
- Immunodeficiency by Dr. Saul Greenberg. University of Toronto. Last updated, on February 5, 2009
- Notarangelo L, Casanova JL, Conley ME, et al. (2006). "Primary immunodeficiency diseases: an update from the International Union of Immunological Societies Primary Immunodeficiency Diseases Classification Committee Meeting in Budapest, 2005". J. Allergy Clin. Immunol. 117 (4): 883–96. doi:10.1016/j.jaci.2005.12.1347. PMID 16680902.
- Page 432, Chapter 22, Table 22.1 in: Jones, Jane; Bannister, Barbara A.; Gillespie, Stephen H. (2006). Infection: Microbiology and Management. Wiley-Blackwell. ISBN 1-4051-2665-5.