Selective defect of anti-pneumococcal IgG in a patient with persistent polyclonal B cell lymphocytosis.

Background: Persistent polyclonal B cell lymphocytosis (PPBL) is a rare condition characterized by increased IgM and large excess of B cells with an IgD(+) CD27(+) phenotype. In normal individuals, these cells play a central role in the defense against pneumococcal infection. So far, few studies have characterized humoral immune responses in PPBL patients.

Evidence for neo-generation of T cells by the thymus after non-myeloablative conditioning.

Background: Background and objective. We investigated immune recovery in 50 patients given either unmanipulated or CD8-depleted allogeneic peripheral blood stem cells after non-myeloablative conditioning.

Design And Methods: Fifty patients were randomized to receive either CD8-depleted (n=22) or non-manipulated (n=28) peripheral blood stem cells.

Downregulation of CD94/NKG2A inhibitory receptors on CD8+ T cells in HIV infection is more pronounced in subjects with detected viral load than in their aviraemic counterparts.

The CD94/NKG2A heterodimer is a natural killer receptor (NKR), which inhibits cell-mediated cytotoxicity upon interaction with MHC class I gene products. It is expressed by NK cells and by a small fraction of activated CD8+ T lymphocytes. Abnormal upregulation of the CD94/NKG2A inhibitory NKR on cytotoxic T cells (CTLs) could be responsible for a failure of immunosurveillance in cancer or HIV infection.

T-cell reconstitution after unmanipulated, CD8-depleted or CD34-selected nonmyeloablative peripheral blood stem-cell transplantation.

Background: We have previously shown that CD8 depletion or CD34 selection of peripheral blood stem cells (PBSC) reduced the incidence of acute graft-versus-host disease (GvHD) after nonmyeloablative stem-cell transplantation (NMSCT). In this study, we analyze the effect of CD8 depletion or CD34 selection of the graft on early T-cell reconstitution.

Methods: Nonmyeloablative conditioning regimen consisted in 2 Gy total-body irradiation (TBI) alone, 2 Gy TBI and fludarabine, or cyclophosphamide and fludarabine.

Nonmyeloablative stem cell transplantation with CD8-depleted or CD34-selected peripheral blood stem cells.

To decrease the incidence of graft-versus-host disease (GVHD) observed after nonmyeloablative stem cell transplantation (NMSCT), we studied the feasibility of CD8-depleted or CD34-selected NMSCT followed by CD8-depleted preemptive donor lymphocyte infusion (DLI) given in incremental doses on days 40 and 80. Fourteen patients with high-risk malignancies and an HLA-identical sibling (n = 8) or alternative donor (n = 6) but ineligible for a conventional transplant were included. Nonmyeloablative conditioning regimen consisted in 2 Gy total body irradiation (TBI) alone, 2 Gy TBI and fludarabine (previously untreated patients) or cyclophosphamide and fludarabine (patients who had previously received > or =12 Gy TBI).

Pre-emptive immunotherapy with CD8-depleted donor lymphocytes after CD34-selected allogeneic peripheral blood stem cell transplantation.

Background And Objectives: To maximize graft-versus-leukemia (GVL) effects while minimizing the risk of graft-versus-host disease (GVHD), we undertook a study of allogeneic CD34-selected peripheral blood stem cell (PBSC) transplantation followed by CD8-depleted donor lymphocyte infusion (DLI).

Design And Methods: Twenty-four patients with advanced hematologic malignancies were included. PBSC were collected in matched (N=16) or one-mismatch (N=8) related donors and CD34-selected.