Cyclooxygenase inhibitors inhibit antibody response through interference with MAPK/ERK pathways and BLIMP-1 inhibition.

Fever is a common symptom of illness in children, and although not harmful in itself, fever and its associated symptoms are often treated with antipyretic drugs. A number of national and other guidelines now recommend against their routine use; a conclusion that was initially supported by a study showing that the prophylactic use of paracetamol might reduce antibody response to some vaccine antigens, although data from booster vaccinations are more equivocal. Although in vivo data on the cause of this inhibition are scarce, in vitro data suggests that the cause may be due to inhibition of the mitogen activated protein kinase/extracellular regulated protein kinase pathways, and a subsequent reduction in the process of plasma cell differentiation at the beginning of the antibody response. This suggests that in high-risk patients these drugs could be avoided in the early part of an infection when plasma-cell differentiation is occurring. More data are needed to define this period; until then existing data support the recommendation against the routine use of these drugs.