Increase in plasma sCD23 levels precedes immunoglobulin E elevation after coronary artery bypass graft surgery

INTRODUCTION: Recent reports have confirmed an increase in plasma immunoglobulin E (IgE), which had been previously observed in clinical situations associated with tissue injury. Studies on the regulation of IgE levels have pointed to the role of low‑affinity IgE receptor, i.e., sFcεRII (soluble CD23 [sCD23]). OBJECTIVES: The aim of the study was to assess the changes in the levels of this receptor in response to surgical injury during coronary artery bypass grafting. PATIENTS AND METHODS: The study group consisted of 33 patients (28 men and 5 women, aged 45–75 years). Blood samples were obtained from all patients before surgery and 24, 48, 72, and 120 hours after the surgery. The expression of FcεRII on B cells was measured using flow cytometry and plasma levels of sCD23 were determined by an enzyme‑linked immunosorbent assay. RESULTS: We observed a significant increase in the total number of leukocytes and a significant decrease in the total number of lymphocytes with a simultaneous increase in the proportion of B cells (P <0.001). At the same time, the percentage of CD23‑positive B cells (CD19/23+) decreased significantly (P <0.001) at 24 hours after surgery and remained low over the period of 72 hours. The plasma levels of sCD23 increased significantly (P <0.05) at 24 hours after surgery and remained elevated until the end of follow‑up. All the above changes in the immune status preceded an increase in plasma IgE levels (P <0.001), which reached peak values on the fifth day after surgery (120 h). CONCLUSIONS: Surgical procedures are associated with a transient increase in plasma IgE levels, which is preceded by an increase in the level of sCD23 and a simultaneous decrease in the expression of CD23 on B cells. FcεRII (CD23) and sFcεRII (sCD23) may be involved in the regulation of IgE levels after trauma.