T‐Cell Responses to Hepatitis B Surface Antigen in Lung Transplant Recipients

Study Objective . To determine whether lung transplant recipients would have a less vigorous T‐cell response to hepatitis B surface antigen (HBsAg) than that of patients awaiting lung transplantation and healthy subjects, we sought to measure and compare T‐cell responses among these three groups. Design . Prospective study. Setting . Lung transplant clinic at a university hospital. Subjects . Twelve lung transplant recipients, 12 patients awaiting lung transplantation, and 15 healthy subjects. All participants had received the hepatitis B vaccine series and had a documented antibody response to it. Intervention . Blood samples were obtained from each participant. Measurements and Main Results . Participants' sex, age, time since lung transplantation (if applicable), and time since hepatitis B immunization were recorded. Peripheral blood mononuclear cells were isolated from the participants' blood samples for the trans vivo delayed‐type hypersensitivity (DTH) assay. These cells were mixed with saline, tetanus toxoid, or HBsAg and injected into the footpads of immunodeficient mice. Resultant swelling of the footpad was used as an index of human T‐cell response. The healthy subjects were younger than the patients in both transplant groups. However, we found no significant difference in DTH response elicited by HBsAg among the healthy subjects, patients awaiting lung transplantation, and lung transplant recipients (mean ± standard error [SE] 34.7 ± 4.3, 32.1 ± 3.1, and 33.5 ± 4.0 × 10 −4 in., respectively, p>0.8) or when tetanus toxoid was used as a positive control (15.7 ± 2.8, 22.8 ± 6.5, and 21.7 ± 3.9 × 10 −4 in., respectively, p>0.3). No correlation between age or time since immunization and DTH response was noted. Conclusion . Lung transplant recipients maintained a T‐cell response to HBsAg that was similar in vigor to that of both patients awaiting transplantation and healthy subjects even though their antibody concentrations waned rapidly after transplantation. The role of these T cells as a correlate of protection from infection remains to be investigated.