Clinical-scale isolation of the total Aspergillus fumigatus-reactive T-helper cell repertoire for adoptive transfer.

BACKGROUND AIMS: Evidence of the criticality of the adaptive immune response for controlling invasive aspergillosis has been provided. This observation is supported by the fact that invasive aspergillosis, a grave complication of allogeneic stem cell transplantation, occurs long after myeloid reconstitution in patients with low T-cell engraftment and/or on immunosuppressants. Adoptive T-cell transfer might be beneficial, but idiosyncrasies of Aspergillus fumigatus and the anti-Aspergillus immune response render established selection technologies ineffective. METHODS: We developed a Good Manufacturing Practice (GMP)-compliant protocol for preparation of A. fumigatus-specific CD4+ cells by sequentially depleting regulatory and cytotoxic T cells, activating A. fumigatus-specific T-helper cells with GMP-grade A. fumigatus lysate, and immuno-magnetically isolating them via the transiently up-regulated activation marker, CD137. RESULTS: In 13 full-scale runs, we demonstrate robustness and feasibility of the approach. From 2 × 10(9) peripheral blood mononuclear cells, we isolated 27 × 10(3)-318 × 10(3)Aspergillus-specific T-helper cells. Frequency among total T cells was increased, on average, by 200-fold. Specific studies indicate specificity and functionality: After non-specific in vitro expansion and re-stimulation with different antigens, we observed strong cytokine responses to A. fumigatus and some other fungi including Candida albicans, but none to unrelated antigens. DISCUSSION: Our technology isolates naturally occurring Aspergillus-specific T-helper cells within 2 days of identifying the clinical indication. Rapid adoptive transfer of Aspergillus-specific T cells may be quite feasible; the clinical benefit remains to be demonstrated. A manufacturing license as an advanced-therapy medicinal product was received and a clinical trial in post-transplantation invasive aspergillosis patients approved. The product is dosed at 5 × 10E3/kg T cells (single intravenous injection), of which at least 10% must be A. fumigatus-specific.

Candida-Reactive T Cells for the Diagnosis of Invasive Candida Infection-A Prospective Pilot Study.

Background: Blood or tissue culture or histology prove invasive Candida infection, but long time to result, limited feasibility and sensitivity call for new approaches. In this pilot project, we describe the diagnostic potential of quantitating Candida-reactive, CD4/CD69/CD154 positive lymphocytes in blood of patients with invasive Candida infection. Methods: We used flow cytometry quantitating Candida-reactive, CD4/CD69/CD154 positive lymphocytes from peripheral blood of patients with invasive Candida infection, from patients at risk and healthy volunteers as controls. Results: Elevated levels of Candida-reactive lymphocytes were measured in 13 patients with proven invasive Candida infection and in one patient with probable hepatosplenic candidiasis. Results of three candidemia patients were uninterpretable due to autofluorescence of samples. Twelve of 13 patients had Candida identified to species level by conventional methods, and T cell reactivity correctly identified Candida species in 10 of 12 patients. Nine hematological high-risk patients and 14 healthy donors had no elevated Candida-reactive T cell counts. Conclusions: This Candida-reactive lymphocyte assay correctly identified the majority of patients with invasive Candida infection and the respective species. Our assay has the potential to support diagnosis of invasive Candida infection to species level and to facilitate tailored treatment even when biopsies are contraindicated or cultures remain negative.

A pilot study of peripheral blood BDCA-1 (CD1c) positive dendritic cells pulsed with NY-ESO-1 ISCOMATRIX™ adjuvant.

AIM: Pilot clinical trial of NY-ESO-1 (ESO) protein in ISCOMATRIX™ adjuvant pulsed onto peripheral blood dendritic cells (PBDC), to ascertain feasibility, evaluate toxicity and assess induction of ESO-specific immune responses. PATIENTS & METHODS: Eligible participants had resected cancers expressing ESO or LAGE-1 and were at high risk of relapse. PBDC were produced using CliniMACS®plus, with initial depletion of CD1c+ B cells followed by positive selection of CD1c+ PBDC. Patients received three intradermal vaccinations of ESO/IMX-pulsed PBDC at 4-week intervals. RESULTS: The process was feasible and safe. No vaccine-induced immune responses were detected. Assays of immunomodulatory cells did not correlate with outcomes. One patient had a long lasting complete remission. CONCLUSION: This method was feasible and safe but was minimally immunogenic.