ALBERT

Description: Ten adult patients with human immunodeficiency virus (HIV)-associated malignancies (five with lymphoma and five with Kaposi's Sarcoma) were treated with a daily subcutaneous injection of interleukin-2 (IL-2) for 90 consecutive days in a phase I dose-escalation study. Seven patients had absolute CD4 counts below 200/mm3 at the time malignancy was diagnosed. Each lymphoma patient had obtained a complete or partial remission with standard chemotherapy before initiating IL-2. The daily dose of IL-2 did not change during the 90-day course of therapy. Seventeen courses of IL-2 therapy were completed at doses ranging from 0.4 x 10(6) U/m2/d to 1.2 x 10(6) U/m2/d without significant (grade III) toxicity. Two of two patients experienced grade III toxicity within 21 days of initiating IL-2 at a dose of 1.4 x 10(6) U/m2/d, but both patients subsequently completed 90 days of therapy at the maximum tolerated dose (MTD) of 1.2 x 10(6) U/m2/d. Although there were no significant increases or decreases in T-cell subsets at any dose level, there was an increase in absolute natural killer (NK) cell number at the three highest doses of IL-2 (mean percent increase 247; 95% confidence interval, 124 to 369) that was statistically significant (Wilcoxon one-sample signed rank test, P = .015). One patient developed an anti-IL-2 antibody titer that correlated with minimal NK cell expansion in vitro and in vivo. An increase in eosinophils was noted during 9 of 17 courses of IL-2 therapy without correlation to IL-2 dose, prior course of IL-2, or NK cell expansion. At the MTD, there was no consistent increase in the plasma HIV RNA level over time. Three of 10 patients had progressive disease while on study. During 50 months of IL-2 therapy, no patient was treated for an opportunistic infection. We conclude that daily low dose subcutaneous IL-2 can be self-administered safely with good compliance for prolonged periods of time to patients with HIV-associated malignancies, including those with profound immune deficiency. The majority of patients show selective expansion of innate immune effectors, ie, NK cells and/or eosinophils, in the absence of significant clinical toxicity or increased viral burden. These results suggest that low-dose IL-2 therapy should be studied further in phase II clinical trials for evidence of activity against malignancy and opportunistic infection in this patient population.

Description: Two members of the src proto-oncogene family of intracellular tyrosine kinases, c-fgr and hck, are selectively expressed in differentiated myeloid cells. To study the expression of these genes in acute myeloid leukemia (AML) and to determine the specific myeloid lineages and stages of myeloid differentiation at which the expression of these genes is acquired, we used a series of 79 cases of de novo AML as a differentiation model. The levels of c-fgr, hck, and c-fms (encoding the colony-stimulating factor-1 receptor) mRNA transcripts were correlated with the presence of specific cell surface antigens and the morphologic and cytochemical features in these AML blasts. Relatively undifferentiated leukemic myeloblasts with an HLA-DR, CD34, CD33, CD13+/- cell surface immunophenotype (French-American-British [FAB] M1 or M2) were characterized by a lack of c-fms and c-fgr expression, while low levels of c-fms and c-fgr could be detected in undifferentiated myeloblasts (FAB M1 or M2), which also expressed CD14 at low antigen density. The hck transcripts were either undetectable in these cells or were expressed at low levels. In contrast, only hck mRNA transcripts could be identified in blasts with progranulocytic morphology (FAB M3), while c-fms, c-fgr, and hck were all expressed at high levels in blasts with differentiated myelomonocytic or monocytic features (FAB M4 and M5). No c-fms, c-fgr, or hck transcripts were evident in leukemic cells of the erythroid lineage (FAB M6). When undifferentiated leukemic myeloblasts (HLA-DR, CD34, and CD33) were induced to differentiate in vitro to cells with monocytic characteristics, the expression of c-fms, c-fgr, and the CD14 cell surface antigen were induced to high levels, accompanied by the acquisition of hck and CD13 expression. In contrast, when HLA-DR, CD34, and CD33 blasts were induced to differentiate in vitro to cells with granulocytic characteristics, only hck and CD13 expression were induced. Our data suggest that the acquisition of c-fgr and/or hck expression is associated with early commitment and differentiation events in distinct myeloid lineages. Assessment of the expression of these kinases may provide a molecular tool to assign lineage in AML in conjunction with morphology, cytochemistry, and cell surface antigen expression.

Description: Four-color flow cytometry was used with a cocktail of antibodies to identify and isolate CD34+ hematopoietic progenitors from normal human peripheral blood (PB) and bone marrow (BM). Mature cells that did not contain colony forming cells were resolved from immature cells using antibodies for T lymphocytes (CD3), B lymphocytes (CD20), monocytes (CD14), and granulocytes (CD11b). Immature cells were subdivided based on the expression of antigens found on hematopoietic progenitors (CD34, HLA-DR, CD33, CD19, CD45, CD71, CD10, and CD7). CD34+ cells were present in the circulation in about one-tenth the concentration of BM (0.2% v 1.8%) and had a different spectrum of antigen expression. A higher proportion of PB-CD34+ cells expressed the CD33 myeloid antigen (84% v 43%) and expressed higher levels of the pan leukocyte antigen CD45 than BM-CD34+ cells. Only a small fraction of PB-CD34+ cells expressed CD71 (transferrin receptors) (17%) while 94% of BM-CD34+ expressed CD71+. The proportion of PB-CD34+ cells expressing the B-cell antigens CD19 (10%) and CD10 (3%) was not significantly different from BM-CD34+ cells (14% and 17%, respectively). Few CD34+ cells in BM (2.7%) or PB (7%) expressed the T-cell antigen CD7. CD34+ cells were found to be predominantly HLA-DR+, with a wide range of intensity. These studies show that CD34+ cells and their subsets can be identified in normal PB and that the relative frequency of these cells and their subpopulations differs in PB versus BM.

Description: Two members of the src proto-oncogene family of intracellular tyrosine kinases, c-fgr and hck, are selectively expressed in differentiated myeloid cells. To study the expression of these genes in acute myeloid leukemia (AML) and to determine the specific myeloid lineages and stages of myeloid differentiation at which the expression of these genes is acquired, we used a series of 79 cases of de novo AML as a differentiation model. The levels of c-fgr, hck, and c-fms (encoding the colony-stimulating factor-1 receptor) mRNA transcripts were correlated with the presence of specific cell surface antigens and the morphologic and cytochemical features in these AML blasts. Relatively undifferentiated leukemic myeloblasts with an HLA-DR, CD34, CD33, CD13+/- cell surface immunophenotype (French-American-British [FAB] M1 or M2) were characterized by a lack of c-fms and c-fgr expression, while low levels of c-fms and c-fgr could be detected in undifferentiated myeloblasts (FAB M1 or M2), which also expressed CD14 at low antigen density. The hck transcripts were either undetectable in these cells or were expressed at low levels. In contrast, only hck mRNA transcripts could be identified in blasts with progranulocytic morphology (FAB M3), while c-fms, c-fgr, and hck were all expressed at high levels in blasts with differentiated myelomonocytic or monocytic features (FAB M4 and M5). No c-fms, c-fgr, or hck transcripts were evident in leukemic cells of the erythroid lineage (FAB M6). When undifferentiated leukemic myeloblasts (HLA-DR, CD34, and CD33) were induced to differentiate in vitro to cells with monocytic characteristics, the expression of c-fms, c-fgr, and the CD14 cell surface antigen were induced to high levels, accompanied by the acquisition of hck and CD13 expression. In contrast, when HLA-DR, CD34, and CD33 blasts were induced to differentiate in vitro to cells with granulocytic characteristics, only hck and CD13 expression were induced. Our data suggest that the acquisition of c-fgr and/or hck expression is associated with early commitment and differentiation events in distinct myeloid lineages. Assessment of the expression of these kinases may provide a molecular tool to assign lineage in AML in conjunction with morphology, cytochemistry, and cell surface antigen expression.

Description: Four-color flow cytometry was used with a cocktail of antibodies to identify and isolate CD34+ hematopoietic progenitors from normal human peripheral blood (PB) and bone marrow (BM). Mature cells that did not contain colony forming cells were resolved from immature cells using antibodies for T lymphocytes (CD3), B lymphocytes (CD20), monocytes (CD14), and granulocytes (CD11b). Immature cells were subdivided based on the expression of antigens found on hematopoietic progenitors (CD34, HLA-DR, CD33, CD19, CD45, CD71, CD10, and CD7). CD34+ cells were present in the circulation in about one-tenth the concentration of BM (0.2% v 1.8%) and had a different spectrum of antigen expression. A higher proportion of PB-CD34+ cells expressed the CD33 myeloid antigen (84% v 43%) and expressed higher levels of the pan leukocyte antigen CD45 than BM-CD34+ cells. Only a small fraction of PB-CD34+ cells expressed CD71 (transferrin receptors) (17%) while 94% of BM-CD34+ expressed CD71+. The proportion of PB-CD34+ cells expressing the B-cell antigens CD19 (10%) and CD10 (3%) was not significantly different from BM-CD34+ cells (14% and 17%, respectively). Few CD34+ cells in BM (2.7%) or PB (7%) expressed the T-cell antigen CD7. CD34+ cells were found to be predominantly HLA-DR+, with a wide range of intensity. These studies show that CD34+ cells and their subsets can be identified in normal PB and that the relative frequency of these cells and their subpopulations differs in PB versus BM.