ZAP-70 protein expression and CD38 positivity in B-cell chronic lymphocytic leukemia.

BACKGROUND: The clinical course, disease progression, and survival of B-cell chronic lymphocytic leukemia (B-CLL) have been correlated with immunoglobulin heavy-chain variable region mutation status. The biologic parameters 70-kDa zeta-associated protein (ZAP-70) and CD38 expression are easier and faster surrogate markers for mutational status. OBJECTIVE: To assess retrospectively ZAP-70 expression in B-CLL cells using flow cytometry and examine its relationship with CD38 expression and the median time from diagnosis to initial therapy. METHODS: Ninety-four unselected patients who had their follow-up in the outpatient clinic from 2004 to 2005 were reviewed for immunophenotyping ZAP-70 and CD38 expression. Direct immunolabeling with clone 2E3.2, isotype IgG2a, enabled easy quantification of ZAP-70 by flow cytometry in association with CD38 expression; in addition, the mean fluorescence intensity ratio (MFIR) of CD19+CD5+ B-CLL cells compared to an isotype control monoclonal antibody was determined. RESULTS: ZAP-70 expression levels in B-CLL cells varied widely (0.3-99%). The median time to therapy was significantly shorter for the 54 patients with 20% or more ZAP-70+ cells (30 months) than for the 40 patients with less than 20% ZAP-70+ cells (median time to treatment not reached). The optimal MFIR for classifying patients as ZAP-70+ was 2. Thirty-two patients had a threshold of ZAP-70+CD38+ greater than 30%, with a median time from diagnosis to treatment of 19 months. Regardless of CD38 expression level, CD38 and ZAP-70 expressions were significantly associated. The median interval from diagnosis to initial therapy was 16.2 months for ZAP-70+CD38+ patients, 60 months for ZAP-70+CD38- or ZAP-70-CD38+ patients, and had not yet been reached for ZAP-70-CD38- patients. CONCLUSION: The association of ZAP-70+CD19+CD5+ B-CLL cells and percentage of CD38+CD19+CD5+ B-CLL cells evaluated by flow cytometry provide reliable methods that could be introduced into a routine diagnostic B-CLL panel to predict outcome.

CD95 ligand-dependant endothelial cell death initiates oral mucosa damage in a murine model of acute graft versus host disease.

Oral mucosa lesions are one of the common pathological consequences of acute graft versus host disease (aGVHD), the major complication of allogeneic bone marrow transplantation caused by mature T lymphocytes of donor origin. Oral mucosa damage in aGVHD is characterized by apoptosis induction in the basal keratinocytes, associated with immune effector T-cell infiltration, but its pathogenesis remains unclear because these lesions might result from the patient conditioning therapy that includes radiation and/or chemotherapy. Here, using a murine model of aGVHD that does not involve any conditioning treatment, we show that the earliest detectable oral mucosa lesion is apoptosis of the endothelial cells from chorion capillaries, which precedes basal keratinocyte apoptosis induction. Neither vascular damage nor epithelial-cell death occurred in recipients of allogeneic lymphocytes from CD95 ligand (CD95L)-defective mice. Our findings indicate that oral mucosa lesions in aGVHD are initiated by endothelial-cell death and require CD95L expression by the allogeneic lymphocytes. This early vascular damage may contribute to the induction of further tissue damage in the oral mucosa, through the induction of hypoxia and vascular leakage of immune cells or soluble proapoptotic mediators.

Pericapillary hemorrhage as criterion of severe human digestive graft-versus-host disease.

In an experimental model we demonstrated that endothelial cells of all organs are targets of the alloimmune reaction. Here, in 68 digestive biopsies, we found endothelial lesions by immunohistochemistry and ultrastructure in patients with severe acute graft-versus-host disease (GVHD). In contrast, no such endothelial cell alterations were found either in patients without GVHD or in nongrafted controls. In the biopsies with severe GVHD lesions, ultrastructure showed rupture of the capillary basal membrane and extravased red blood cells. These pericapillary hemorrhages were highly correlated with GVHD severity. In a separate cohort of 39 patients who underwent an allogeneic transplantation after a nonmyeloablative conditioning, 8 patients had intestinal biopsies. Three of these latter patients had both severe pathologic lesions of GVHD and similar endothelial lesions, thus, strengthening the concept that endothelial lesions are linked to GVHD severity and not to the intensity of the conditioning regimen. (Blood. 2004;103:4681-4684)