Background:
Immunoglobulins are antibodies.
Five types exist: IgG, IgA, IgM, IgE and IgD
Hypogammaglobulinaemia is low immunoglobulins.
It may be either primary or secondary.
Primary hypogammaglobulinaemia
- 2 main types
- Common variable immune deficiency
- Characterized by frequent infections (sinusitis, bronchitis, pneumonia) with encapsulated organisms (such as strep pneumoniae, haemophilus influenza)
- There are reduced concentrations of all IGs and IgG levels must be more than 2 SD below the mean
- Between 25 and 48% of patients have splenomegaly
- Up to 50% of patients have transient or persistent diarrheoa – giardia lamblia is the most commonly identified organism
- Associated with increased risk of
- Non-Hodgkin lymphoma (up to 8% of patients)
- Gastric cancer
- Thymoma (known as Good syndrome when associated with hypogammaglobulinaemia)
- Systemic granulomatous disease
- Associated with
- Treatment is monthly IVIG infusions
- Selective IgA deficiency
- Inherited in an autosomal dominant pattern with variable penetrance
- Low IgA but normal other IGs
- Commonest immune deficiency – 1 in 875 in the UK
- Most patients (85-90%) have no symptoms; some may have recurrent infections
- Management is to treat infections as they occur
Secondary hypogammaglobulinaemia
- May occur due to
- Nephrotic syndrome
- Protein-losing enteropathies
- Some malignancies
- Medications
- Phenytoin
- Carbamazepine
- Sulfasalazine
- Gold
- Systemic steroids
- High-stress states
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