Use of long-term human marrow cultures to demonstrate progenitor cell precursors in marrow treated with 4-hydroperoxycyclophosphamide.

The continued retrieval of progenitor cells (CFU-GEMM, BFU-E, CFU-E, CFU-GM) from human long-term marrow cultures (LTMC) is not uncommonly used as evidence that proliferation and differentiation are occurring in more primitive hematopoietic stem cells (HSC) in these cultures. Alternatively, the continued presence of progenitors in LTMC could be the result of survival and/or limited self-renewal of progenitor cells present when the culture was initiated, and such progenitors would have little relevance to the parent HSC. The following studies were designed to determine the relative contributions of precursors of progenitor cells to the total progenitor cells present in LTMC using a two-stage regeneration model.

Spontaneous regression of a monoclonal proliferation of large granular lymphocytes associated with reversal of anemia and neutropenia.

A 43-year-old male with a phenotypically homogeneous, expanded subset of T cells presented in 1981 with anemia and neutropenia. The surface antigen phenotype of 99% of the peripheral blood lymphocytes was T3+, T8+, T4-, and they were morphologically large granular lymphocytes (LGL). The same cells comprised 37% of the marrow nucleated cells.

Studies on the use of nonhuman primates to determine the DR status of the human hematopoietic stem cell.

Monoclonal antibodies that recognize monomorphic determinants of human DR are potentially useful for the in vitro elimination of malignant cells from marrow for use in autologous transplantation. While DR is expressed on normal hematopoietic progenitor cells and the cells of the majority of the hematologic and lymphoid malignancies, there is the possibility that DR may not be expressed on the hematopoietic stem cells responsible for marrow regeneration after transplantation. To resolve the uncertainty regarding the DR status of the human stem cell, we determined whether antihuman DR monoclonal antibodies recognized analogous antigens on nonhuman primate hematopoietic progenitor cells to determine an appropriate animal transplant model.