Circulating T cells to infliximab are detectable mainly in treated patients developing anti‐drug antibodies and hypersensitivity reactions

Antibodies recognizing infliximab (IFX) may develop in a proportion of treated patients, leading to loss of response or hypersensitivity reactions (HRs). T cell response to IFX has been poorly investigated. This paper was addressed to detect IFX‐specific T cells in treated patients with inflammatory diseases developing, or not, anti‐drug antibodies (ADA) and to correlate the presence of specific T cells with the clinical outcomes of the treatment. A co‐culture system of IFX‐loaded dendritic cells and purified autologous CD4(+) T cells was used to detect memory T cells in 32 ADA(+) and 39 ADA(–) IFX‐treated patients and control groups. The cytokine profile of IFX‐specific T cells was also studied in culture supernatants. IFX‐specific cell proliferation was detected mainly in cells from ADA(+) patients, irrespective of their different diseases. HR patients displayed higher T cell proliferation than non‐responder and tolerant patients. A mixed [interferon (IFN)‐γ, interleukin (IL)‐13, IL‐10] cytokine profile was shown in cells from ADA(+) patients, while IL‐10 was the most frequently detected cytokine in the supernatants of cultures from ADA‐ patients. Immunoglobulin (Ig)E(+)ADA(+) patients with previous HRs exhibited a more pronounced type 2 profile than IgE(–)ADA(+) patients. This work provides evidence that IFX‐specific circulating T cells are detectable mainly in ADA(+) patients with HRs, regardless of their disease. The IFX‐induced cytokine pattern partially correlates with the ADA isotype.