Pathology - Pathology Service Staff

A stem cell has the unique capacity to both self-renew and to give rise to specialized cells. Until recently it was believed that only embryonic stem cells were pluripotent and only they could give rise to committed cells of various different tissues with different function. Over the past few years, it has become apparent that stem cells derived from differentiated adult tissue may also develop into mature cell types of disparate tissue. Hematopoietic stem cells are characteristically quiescent, multipotent cells with both the capacity for self-renewal and differentiation. After development in the fetus, these cells reside in adult bone marrow and serve to replenish lymphoid, megakaryocytic, erythroid and myeloid hematopoietic lineages throughout the lifetime of the host. Early investigations in this laboratory discerned that cells obtained from adult blood within a CD3-7+ lymphocyte compartment could develop predominantly in vitro into mature gamma delta+ T cells. Later studies fine-tuned this compartment into CD7+/CD7- and CD16+/CD16- divisions. Of particular present interest are side population [SP] cells, which are relatively rare cells found in both the circulation and bone marrow. These CD34 negative cells, when isolated from human blood, have been shown to be capable of developing into T, NK and possibly dendritic cells.

Other interests in the laboratory involve the study of patients administered HLA mismatched transplants, done in collaboration with the Transplantation Biology Research Center and Bone Marrow Transplantation Units. The goal of these studies is to establish a state of mixed chimerism in patients with hematologic malignancies, so as to provide a minimum of graft vs. host and a maximum of graft vs. leukemia effects. Additionally, our laboratory participates in numerous projects with the CNY AIDS Research Center and Harvard Medical School Center for AIDS Research [CFAR].

The flow cytometry laboratory in the Center for Regenerative Medicine is a valuable hospital core resource, and will entertain research collaborations from throughout the university. The laboratory contains a state-of-the-art 5-laser DiVa cell sorter and 7-laser LSR-2. The cell sorter has 11 photomultiplier tubes and is capable of 4-way high speed cell sorting. The numerous laser excitation lines and photomultiplier capacity provides a wide breadth of capability to the instrument, which is superbly operated by Mr. David Dombkowski. The research laboratory was the genesis of the clinical laboratory, which is located on Warren 1 on the MGH campus in Boston. Four- and six-color analytic instrumentation [FACSCalibur, FACSCanto] is available at that site.