Detection of ABCB5 tumour antigen-specific CD8+ T cells in melanoma patients and implications for immunotherapy.

ATP binding cassette subfamily B member 5 (ABCB5) has been identified as a tumour-initiating cell marker and is expressed in various malignancies, including melanoma. Moreover, treatment with anti-ABCB5 monoclonal antibodies has been shown to inhibit tumour growth in xenotransplantation models. Therefore, ABCB5 represents a potential target for cancer immunotherapy. However, cellular immune responses against ABCB5 in humans have not been described so far. Here, we investigated whether ABCB5-reactive T cells are present in human melanoma patients and tested the applicability of ABCB5-derived peptides for experimental induction of human T cell responses. Peripheral blood mononuclear cells (PBMNC) isolated from blood samples of melanoma patients (n = 40) were stimulated with ABCB5 peptides, followed by intracellular cytokine staining (ICS) for interferon (IFN)-γ and tumour necrosis factor (TNF)-α. To evaluate immunogenicity of ABCB5 peptides in naive healthy donors, CD8 T cells were co-cultured with ABCB5 antigen-loaded autologous dendritic cells (DC). ABCB5 reactivity in expanded T cells was assessed similarly by ICS. ABCB5-reactive CD8+ T cells were detected ex vivo in 19 of 29 patients, melanoma antigen recognised by T cells (MART-1)-reactive CD8+ T cells in six of 21 patients. In this small, heterogeneous cohort, reactivity against ABCB5 was significantly higher than against MART-1. It occurred significantly more often and independently of clinical characteristics. Reactivity against ABCB5 could be induced in 14 of 16 healthy donors in vitro by repeated stimulation with peptide-loaded autologous DC. As ABCB5-reactive CD8 T cells can be found in the peripheral blood of melanoma patients and an ABCB5-specific response can be induced in vitro in naive donors, ABCB5 could be a new target for immunotherapies in melanoma.

Expansion of recipient-derived antiviral T cells may influence donor chimerism after allogeneic stem cell transplantation.

Donor chimerism (DC) analysis is an important marker in the hematopoietic stem cell transplant follow-up. Here, we present evidence for a possible relationship of infectious complications and declines in DC. We analyzed the DC in patients experiencing cytomegalovirus (CMV) reactivation. In addition, in some patients chimerism analyses of T-cell subsets were performed. CMV-specific cytotoxic T-lymphocytes (CMV-CTL) were monitored using human leukocyte antigen-restricted multimer staining. Interestingly, CMV reactivation was accompanied by changes in DC in 11 of 67 patients transplanted. For example, DC declined in a cord blood recipient, in both total leukocytes and CD4 and CD8 T-cell subsets upon CMV reactivation. The latter was controlled after only 5 days through expanding CMV-CTL of 96% recipient origin, according to chimerism analysis of CMV-CTL (enriched beyond 50%). In another patient, transplanted after reduced-intensity conditioning from a DQB1 mismatched, CMV seronegative donor, incipient CMV reactivation was completely aborted by CMV-CTL of recipient origin. However, at the same time, mixed chimerism dropped from 51% to 0% donor type, resulting in late graft rejection. Our data indicate that chimerism analyses in subset populations lead to a better understanding of declining total leukocyte chimerism. Furthermore, recipient-derived CMV-CTL may be able to control CMV reactivation after reduced-intensity conditioning. We speculate that autologous CMV-CTL may be instrumental to overcome recurrent CMV reactivations, especially in patients transplanted from CMV-seronegative donors. In addition, the expansion of recipient-derived CMV-CTL may contribute to both, graft failure or to conversion to full DC.

Tetramer monitoring to assess risk factors for recurrent cytomegalovirus reactivation and reconstitution of antiviral immunity post allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Reactivation of cytomegalovirus (CMV) is a major cause of morbidity after allogeneic hematopoietic stem cell transplantation (HSCT). In healthy individuals, virus-specific T cells (CMV-CTL) control the reactivation of latent CMV. The monitoring of virus-epitope-binding CD8(+) T cells using major histocompatibility complex-I-peptide complexes (tetramers) has recently been established, allowing assessment of the reconstitution of CMV-CTL post HSCT. PATIENTS AND METHODS: In order to study immune reconstitution and reactivation control through CMV-CTL, we regularly monitored all patients undergoing allogeneic HSCT in our department for 2 years, who matched at least 1 of 6 commercially available tetramers for common human leukocyte antigen (HLA) types. To verify risk factors for CMV reactivations in our cohorts, clinical characteristics of all patients transplanted within the last 10 years were included in statistical analyses determining the relative risk for single and recurrent CMV reactivations. RESULTS: As expected, CMV serostatus, HLA match, and donor source significantly influenced the risk of recurrent CMV reactivation. Applying CMV-CTL tetramer monitoring for 2 years allowed the monitoring of 114 (85%) of 134 patients, by testing a set of tetramers representing 6 epitopes from 3 different CMV proteins. The presence of CMV-CTL before day + 50 and their expansion post reactivation seem to protect against recurrent CMV reactivations. The mean number of CMV-CTL by day +100 was >5-fold higher in the recipient CMV-positive/donor-positive (R +/D +) group (91/µL) compared with the R +/ D- (13/µL) and the R -/D +(2/µL) group. Seventy-nine percent of patients from the R +/D + setting recovered >10 CMV-CTL per µL by day + 100, while almost 50% of the other groups failed to mount a CMV-specific response by that time (R +/D -: 58%; R -/D +: 43%). CONCLUSION: Tetramer monitoring can help to predict (recurrent) CMV reactivation and is a useful approach to monitor individual patients with increased risk for recurrent reactivation post HSCT; thus, it could help to identify patients in need of adoptive transfer of CMV-CTL or to optimize the use of antiviral drugs.

Training college-age women to perform the pull-up exercise.

The purpose of this investigation was to determine the effect of a combined strength and aerobic conditioning program on the ability of college-age women to perform the pull-up exercise and to identify the characteristics of women successful in performing a pull-up at the end of the program. Participants significantly increased upper body strength and fat-free mass and deceased fat mass and percentage of body fat. Participants successful at performing a pull-up had significantly greater 1 repetition maximum strength, strength to mass ratio, and strength to fat-free mass ratio. A two variable equation (% body fat and strength to fat-free mass ratio) was developed to predict which women would be successful at completing a pull-up at the end of a similar training program.

Flexible bronchoscopy.

Fiberoptic bronchoscopy is an excellent tool for the evaluation of the airways and lung parenchyma. The history of flexible bronchoscopy, anesthesia, technique, indications, contraindications, and complications in using the bronchoscopy are reviewed.

Generalized staphylococcal scalded skin syndrome in an anephric boy undergoing hemodialysis.

Generalized staphylococcal scalded skin syndrome (SSSS) is a toxin-related epidermolytic disease that predominantly affects previously healthy infants and children younger than 5 years. In contrast, the majority of the reported adult cases have been associated with underlying diseases, suggesting that immunosuppression and renal insufficiency are important predisposing conditions for this age group. We report herein a case of adult-type SSSS in an anephric 10-year-old boy. Patients undergoing hemodialysis who have chronic renal failure may be uniquely predisposed to the SSSS by virtue of their decreased glomerular filtration rate, associated uremic immunodeficiency, and a high incidence of Staphylococcus aureus bacteremia.