Chronic Spontaneous Urticaria – an evaluation of an indirect immunofluorescence method for detecting anti-mast cell IgG antibodies

Background An autoimmune basis is believed to be responsible for about half of all cases of chronic spontaneous urticaria (CSU) with specific IgG antibodies directed at the high affinity receptor sites for IgE on the mast cell. The autologous serum skin test (ASST) is used to identify this autoimmune form of CSU. Currently, basophil histamine release assay and basophil activation test (BAT) have been used as an alternative to the ASST. These tests are not widely available and are limited in that they only provide evidence that the patient’s serum is capable of inducing basophil degranulation. We have developed an indirect immunofluorescence method to demonstrate the presence of anti-mast cell antibodies using skin sections from a patient with severe bullous mastocytosis.