[Therapeutic monoclonal antibodies: update on the risk of opportunistic infections]

The large experience accumulated with the therapeutic use of monoclonal antibodies has revealed undesirable effects, among which opportunistic infections when prescribed in inflammatory or hematological diseases. This deleterious effect is a direct consequence of the immunosuppression induced by these antibodies through the blockade of several key pathways involved in both innate and adaptative immune responses, including migration of effector cells, depletion of B or T lymphocytes, inhibition of key cell-cell interactions. Four antibodies are concerned, targeting CD52, CD20, TNF-a and VLA-4, and major risks include activation of latent tuberculosis, or of normally silent viruses. Precise evaluation of these risks and understanding of their mechanisms have now led to the improvement of clinical safety, based on the detection of patients at risk, weighting of the benefit/risk ratio, and a very rigorous detection of latent infections before the onset of treatment by monoclonal antibodies know to induce immunosuppression.