Nonimmediate β-lactam reactions in patients with cystic fibrosis.

PURPOSE OF REVIEW

The aim of this review is to present and discuss new developments regarding β-lactam hypersensitivity in patients with cystic fibrosis. It is a common complication that can have significant implications for a patient. Up to 30% of patients have had multiple β-lactam reactions.

RECENT FINDINGS

For the first time drug-specific lymphocytes have been identified in patients with cystic fibrosis. This supports the clinical viewpoint that the nonimmediate reactions seen are T-cell mediated. Furthermore, in piperacillin hypersensitivity mass spectrometric methods have been used to characterise hapten formation both in vivo and in vitro. The synthetic piperacillin-albumin conjugate is able to stimulate patients' lymphocytes and T cell clones. Lymphocyte proliferation was not seen with ceftazidime; this may be due to undetectable protein reactivity in vitro. Skin testing was not sensitive in this cohort and many patients have uncertain allergy status. Desensitisation is performed with some success; however, at present it is not known whether any immune modulation takes place.

SUMMARY

The piperacillin model provides us with a useful tool to characterise the mechanisms of drug hypersensitivity. Prospective studies are needed to assess how drug sensitivity develops and whether clinical practice could be modified to reduce the risk.