Aspergillus fumigatus suppresses the human cellular immune response via gliotoxin-mediated apoptosis of monocytes.

Aspergillus fumigatus (AF) is a ubiquitous mold and is the most common cause of invasive aspergillosis, an important source of morbidity and mortality in immunocompromised hosts. Using cytokine flow cytometry, we assessed the magnitude of functional CD4+ and CD8+ T-cell responses following stimulation with Aspergillus antigens. Relative to those seen with cytomegalovirus (CMV) or superantigen stimulation, responses to Aspergillus antigens were near background levels.

Functional assessment and specific depletion of alloreactive human T cells using flow cytometry.

Human T-cell alloreactivity plays an important role in many disease processes, including the rejection of solid organ grafts and graft-versus-host disease (GVHD) following allogeneic stem cell transplantation. To develop a better understanding of the T cells involved in alloreactivity in humans, we developed a cytokine flow cytometry (CFC) assay that enabled us to characterize the phenotypic and functional characteristic of T cells responding to allogeneic stimuli. Using this approach, we determined that most T-cell alloreactivity resided within the CD4(+) T-cell subset, as assessed by activation marker expression and the production of effector cytokines (eg, tumor necrosis factor alpha [TNF]alpha) implicated in human GVHD.

Microgranular and t(11;17)/PLZF-RARalpha variants of acute promyelocytic leukemia also present the flow cytometric pattern of CD13, CD34, and CD15 expression characteristic of PML-RARalpha gene rearrangement.

Acute promyelocytic leukemia (APL) is a subtype acute myeloid leukemia in which leukemic promyelocytes predominate in the bone marrow (BM). Rapid diagnosis is critical for treatment decision since all-trans-retinoic acid must be administrated promptly. The microgranular variant may be of difficult diagnosis, as it may be confused with other diseases on morphological grounds.

CD25 expression on donor CD4+ or CD8+ T cells is associated with an increased risk for graft-versus-host disease after HLA-identical stem cell transplantation in humans.

Graft-versus-host disease (GVHD) occurs in an unpredictable fashion after 30% to 50% of matched-related transplantations. The presence of increased frequencies of CD4(+)CD25(+) regulatory T cells in donor grafts has been shown to ameliorate GVHD after allogeneic transplantation in murine models. To determine whether a similar relationship exists in humans, we quantitated the coexpression of CD25 on CD4(+) and CD8(+) T cells within 60 donor grafts infused into matched siblings and examined GVHD incidence in the respective recipients.

Expression of CD117 and CD11b in bone marrow can differentiate acute promyelocytic leukemia from recovering benign myeloid proliferation.

The morphologic characteristics of bone marrow aspirates from patients recovering from acute agranulocytosis may be closely similar to the pattern observed in cases of acute promyelocytic leukemia (APL). The clinical manifestation also can be ambiguous in a substantial number of cases. The immunophenotypic features of bone marrow from 5 patients recovering from acute agranulocytosis, showing an increase in the percentage of promyelocytes (26%-66%), were compared with the immunophenotype of 31 consecutive patients with APL whose diagnosis was confirmed by PML-RAR alpha gene rearrangement.