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, 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
Signs/symptoms of humoral immune deficiency depend on the cause, but generally include signs of infection such as:
Sinusitis
Sepsis
Skin infection
Pneumonia
Causes
Cause of this deficiency is divided into primary and secondary:
Primary the International Union of Immunological Societies classifies primary immune deficiencies of the humoral system 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, 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
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:
Multiple myeloma
Chronic lymphoid leukemia
AIDS
Diagnosis
In terms of diagnosis of humoral immune deficiency depends upon the following:
Measure serum immunoglobulin levels
B cell count
Family medical history
Treatment
Treatment for B cell deficiency (humoral immune deficiency) depends on the cause, however generally the following applies:
Treatment of infection (antibiotics)
Surveillance for malignancies
Immunoglobulin replacement therapy
See also
Immunodeficiency
T cell deficiency
References
Further reading
Ahn, Sam; Cunningham-Rundles, Charlotte (2017-05-11). "Role of B cells in common variable immune deficiency". Expert Review of Clinical Immunology. 5 (5): 557–564. doi:10.1586/eci.09.43. ISSN 1744-666X. PMC 2922984. PMID 20477641.
Honjo, Tasuku; Reth, Michael; Radbruch, Andreas; Alt, Frederick (2014-10-09). Molecular Biology of B Cells. Elsevier. ISBN 9780123984906.