Faculty Bibliography

BACKGROUND. The safety and efficacy of minimally invasive oncologic procedures in children have not been well defined and only limited anecdotal experience has been published. METHODS. A retrospective review of all patients undergoing either a laparoscopic or thoracoscopic procedure at Childrens Cancer Group institutions between December 1, 1991, and October 1, 1993, was performed. RESULTS. Eighty-five children underwent 88 minimally invasive surgical procedures as part of the evaluation or treatment for cancer at 15 participating centers. In 25 patients, laparoscopy was performed and 60 patients underwent 63 thoracoscopic operations. Tissue biopsies were taken in 67 cases and diagnostic material was obtained in 99% of the biopsies. Seven complications occurred, all within the thoracoscopic group. These included conversion of six operations to an open procedure. One patient developed atelectasis postoperatively. CONCLUSIONS. In pediatric patients with suspected cancer, laparoscopy was highly accurate with minimal morbidity; thoracoscopy was nearly as efficient with slightly higher morbidity. Both modalities are useful for assessment of resectability, for staging purposes, and for evaluation of recurrent or metastatic disease

CD8+ T cells control immune responses, and recent studies suggest that this regulation is, in part, specifically directed towards TCR structures expressed by CD4+ cells. To develop a system to study the role of the TCR in regulatory interactions, we isolated clones of CD4+ cells expressing identified TCR V beta chains. These CD4+ clones were used to stimulate and expand autologous CD8+ cells, which kill the inducing CD4+ clone as well as independently isolated autologous CD4+ clones sharing the same TCR V beta as the inducing cell but not CD4+ T cells expressing different V beta TCRs. This V beta-specific cytotoxicity is dependent on the state of activation of the target cells and is not inhibited by an anti-class I monoclonal antibody, W6/32. We envision that V beta-specific CD8+ T cells of this type may regulate immune responses by direct interaction with antigen-activated CD4+ cells.