Humoral immune deficiency
B cells and antibody
Specialty	Hematology
Symptoms	Sinusitis[1]
Causes	Absent B cells(primary),[2][3] Multiple myeloma(secondary)[4]
Diagnostic method	B cell count, Family medical history[5][6]
Treatment	Immunoglobulin replacement therapy[5]

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.^[7] 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.^{[citation needed]}

Signs and symptoms

Signs/symptoms of humoral immune deficiency depend on the cause, but generally include signs of infection such as:^[1]

• 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:^[3][2]

• 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:^[4]

• Multiple myeloma
• Chronic lymphoid leukemia
• AIDS

Diagnosis

In terms of diagnosis of humoral immune deficiency depends upon the following:^[5][6]

• 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:^[5]

• Treatment of infection (antibiotics)
• Surveillance for malignancies
• Immunoglobulin replacement therapy