Transplantation. 97(8):846-853, April 27, 2014.
Many stable kidney transplant recipients receive annual vaccination with trivalent inactivated influenza vaccine, in keeping with recommendations by the American Society of Transplantation. Advances in technology are such that it is now possible to undertake single-cell quantification of the human peripheral B cell response to an antigen. Cowan et al, reporting in this issue, took advantage of this to assess the recall B and T cell immune response to influenza vaccine in kidney transplant recipients. They found that the frequency of influenza-specific antibody-secreting cells in peripheral blood was significantly lower than that of healthy controls, indicating that maintenance immunosuppression inhibits the differentiation of memory B cells into plasma cells. The serological response to influenza was also markedly reduced, as was the influenza-specific interferon- T cell response. While most patients had a reduced response to influenza vacine, there was considerable variability between patients. Moreover, there was no correlation between the magnitude of the influenza-specific Ig antibody-secreting plasma cell response and the T cell response. The authors raise the intriguing question as to whether the immune response to influenza vaccine might be a surrogate for the alloimmune response and might indicate under or over immunosuppression in stable transplant recipients.