Procalcitonin and C-reactive protein do not discriminate between febrile reaction to anti-T-lymphocyte antibodies and Gram-negative sepsis

Treatment with antibodies against T-lymphocytes usually triggers a febrile response potentially mimicking or masking infection. Procalcitonin (PCT) is considered a sensitive and specific marker of systemic bacterial and fungal infection. It was the aim of this study to investigate the characteristics of PCT and C-reactive protein (CRP) during treatment with polyclonal or monoclonal anti-T-cell antibodies, in order to examine the ability of these parameters to distinguish between systemic bacterial infection and reaction to antibody treatment. Thus, 15 consecutive febrile episodes after T-cell antibody infusion without clinical signs of infection were compared with nine episodes of Gram-negative sepsis. After T-cell antibody infusion PCT and CRP serum levels increased to a similar extent as in Gram-negative sepsis. Therefore, during T-cell antibody treatment neither PCT nor CRP are adequate for differentiating between fever due to infection or to unspecific cytokine release.