Anaphylaxis in response to drugs administered during anaesthesia is a rare but potentially catastrophic event. The anaesthetic drugs most commonly associated with anaphylaxis are neuromuscular blocking agents. As these drugs act on the nicotinic acetylcholine receptor of the neuromuscular junction, potentiation of anaphylaxis by a nicotinic receptor on basophils and mast cells is plausible. The aim of this study was to investigate whether nicotinic acetylcholine receptors are present on a human basophil and mast cell lines as their presence may suggest a mechanism of associated anaphylaxis. Nicotinic receptors were demonstrated on a basophil and a mast cell line using an alpha-bungarotoxin-fluorescein conjugate by flow cytometry and by both conventional and confocal microscopic techniques. The identity of this receptor was confirmed by reverse transcriptase PCR and quantitative PCR.

The investigation of anaphylactic reactions in the peri-operative period is difficult. Elevation of serum tryptase levels is a good indicator of an anaphylactic event but the ability of subsequent investigations to identify the drug(s) responsible for the reaction is still potentially unreliable. The aim of this study was to examine basophil activation as an investigative tool. We performed flow cytometric analysis of the expression on the cell surface of the basophil activation markers CD63 and CD203c and measured histamine release in 21 patients who were referred with possible peri-operative anaphylaxis. The sensitivity of CD63, CD203c, basophil histamine release and skin prick for the muscle relaxants was found to be 79%, 36%, 36% and 64%, respectively; the specificity was found to be 100%. These results demonstrate the difficulty in investigating the cause of an unexpected clinical event following drug administration, but the higher sensitivity of neo-expression on the cell surface of CD63 suggests that flow cytometric analysis of its neo-expression on basophils in vitro may be a diagnostic aid.

Induction of CTL responses specific for prostate-specific antigen (PSA)-derived peptides in healthy individuals and patients with prostate cancer (PC) was investigated. Eight PSA-derived peptides that have the potential to bind HLA-A2 molecules were examined. Peripheral blood lymphocytes isolated from HLA-A2-positive volunteers were expanded using autologous mature, PSA-derived peptide-pulsed dendritic cells. The expansion of IFN-gamma-secreting CD8+ T cells specific for three of the eight PSA-derived peptides (PSA-2(108-117), PSA-4(141-150) and PSA-6(146-154)) was detected in healthy individuals, but not in patients with PC. Using HLA-A2/peptide tetramers, the PSA-specific CD8+ T cells were detectable at low frequency both in healthy individuals and patients with PC. Using flow cytometric cytotoxicity assays, the expanded effectors from healthy individuals were able to kill the PSA-expressing epithelial cell line LNCaP and the peptide-pulsed T2 cells in a MHC class I-restricted manner without involving NK activity. However, such killing by effectors expanded from prostatectomized patients involved a complete or a significant NK activity. Specific recognition of PSA-derived peptides in healthy individuals may occur by an adaptive CTL immune response, while such recognition in PC patients may additionally or alternatively be mediated by an innate NK immune response. In conclusion, our work indicates that the PSA-specific CD8+ T cells exist in both healthy individuals and PC patients, but they have impaired function in patients as they failed to release IFN-gamma and to kill targets without involving NK activity.

Dept of Anaesthetics and Immunology, University of Wales College of Medicine, Cardiff, United Kingdom