immunology
Last reviewed 04/2022
Early in the disease the lymphocyte counts are normal, the chief defect being the absence of an IgM response to polysaccharide antigens. These polysaccharides are classical TI-2 (thymus independent type 2) antigens and are important in the acquisition of immunity to encapsulated pyogenic bacteria. Even at this early stage the platelets and lymphocytes are smaller than normal.
With time there is progressive depletion of lymphocytes in the peripheral blood and in the paracortical (T cell) areas of the lymph nodes. This results in a more severe immunosuppression.
In contrast to the low levels of IgM, there are high concentrations of IgE and IgA:
Raised IgE is associated with:
- allergic eczema
- diarrhoea - possibly due to food allergy
Raised IgA is associated with:
- nephrotic syndrome
- glomerulonephritis
The high frequency of malignant lymphoma may be the result of chronic infection with lymphotropic viruses.