The Relation of Autologous Serum Skin Test and Autologous Plasma Skin Test Result with Various Clinical and Laboratory Findings in Patients with Chronic Spontaneous Urticaria

Background Despite the autologous serum skin test (ASST) and autologous plasma skin test (APST) is widely used test accessing whether a patient with chronic spontaneous urticaria (CSU) has autoreactivity or not, the clinician often encounter difficulty making correlation between the test result and clinical implications. Objective This study was aimed to find any clinical and laboratory findings related to the ASST and APST response. Agreement and correlation between the two tests was also analyzed. Methods A retrospective study was conducted on 300 CSU patients who underwent ASST, APST. The subjects were divided into four groups according to the skin test result. Also, the degree of serum and plasma response was recorded. Results Both ASST and APST positive group had shorter duration of the disease, higher incidence of at least one episode of angioedema than negative group. There were no significant differences in the positivity for autoantibodies including antinuclear, ds-DNA, and thyroid-related between the two groups. The predicted positive rate of ASST and APST according to age showed bimodal peak and decreasing pattern according to disease duration. Predicted positivity of both tests declined with increase in total immunoglobuline E (IgE) level. In the correlation study, the two tests showed high correlation coefficients. Conclusion ASST and APST positivity may be related to disease duration and severity of CSU. The two tests showed a generally consistent result. Autoreactivity may be gradually lost as disease continues. We suggest the autoreactivity in CSU could arise independently from IgE mediated immune process.