Debra L. Williams

Role of CXCR3-induced donor T-cell migration in acute GVHD

OBJECTIVE The chemokine receptor CXCR3 has an important role in the migration of effector T cells. To investigate the role of CXCR3 on donor cells in acute graft vs host disease (GVHD) we used a well-defined experimental bone marrow transplantation (BMT) model where acute GVHD is mediated by donor CD8(+) T cells against minor histocompatibility antigens. METHODS; Lethally irradiated C3H.SW recipients were transplanted from either wild-type B6 or CXCR3(-/-) B6 donors. Donor T-cell expansion was analyzed in the spleen and small intestine of recipients by FACS. Donor T-cell function was analyzed by cytokine secretion. The severity of acute GVHD was assessed by histopathological analysis of intestine and liver, GVHD clinical scores, and survival after BMT. RESULTS Significantly higher numbers of donor CD8(+) CXCR3(-/-) T cells were found in the spleen on days +7 and +14 compared to donor wild-type T cells. By contrast, the number of CD8(+) T cells in the small bowel of BMT recipients from CXCR3(-/-) donors was sevenfold lower than from wild-type donors. Systemic concentrations of INF-gamma and TNF-alpha were equivalent between groups. Animals that received CXCR3(-/-) donor T cells demonstrated diminished GI tract and liver damage and showed improved survival after BMT compared to recipients of wild-type donor cells (43% vs 0%, p<0.001). CONCLUSION The migration of donor CD8(+) T cells to GVHD target organs such as the intestine depends on the expression of CXCR3 and contributes significantly to GVHD damage and overall mortality.

A role for CD54 (intercellular adhesion molecule-1) in leukocyte recruitment to the lung during the development of experimental idiopathic pneumonia syndrome

Background. Idiopathic pneumonia syndrome (IPS) is a frequently fatal complication of allogeneic bone marrow transplantation (BMT). IPS is associated with elevated bronchoalveolar lavage (BAL) fluid levels of tumor necrosis factor-&agr; and lipopolysaccharide, both of which are potent activators of endothelial cells (ECs). EC expression of the adhesion molecule CD54 (intercellular adhesion molecule [ICAM]-1) has been shown to be a major regulator of pulmonary inflammation in various experimental models. Methods. Using a well-established murine BMT system in which lung injury and graft-versus-host disease (GvHD) are induced by minor histocompatibility antigenic differences between donor and host, the RNase Protection Assay, mice deficient in ICAM-1 expression, and a monoclonal blocking antibody to ICAM, we evaluated the role of the pulmonary vascular expression of CD54 in the development of IPS. Results. Enhanced pulmonary vascular expression of ICAM-1 coincided with the development of IPS. When ICAM-1 −/− mice were used as allogeneic BMT recipients, IPS severity (measured by lung histopathology, BAL cellularity, and cytokine expression) was significantly reduced compared with wild-type controls. Similar results were also observed when wild-type recipients were treated with a monoclonal blocking antibody to ICAM-1. Surprisingly, ICAM-1 had differential effects on leukocyte infiltration into GvHD target organs; ICAM-1 deficiency had no impact on intestinal histopathology, whereas ICAM-1 −/− BMT recipients had significantly enhanced hepatic injury. Conclusions. These data demonstrate that although the expression of ICAM-1 is critical for the development of IPS, different mechanisms of leukocyte recruitment are operative in other GvHD target organs.

Rapid, Presumptive Identification of Torulopsis (Candida) Glabrata and Candida Krusei Using Calcofluor White

Background: Torulopsis glabrata and Candida krusei are both resistant to fluconazole; therefore, rapid identification of these species may prevent unnecessary prescribing of this commonly-used antifungal agent. Methods: A total of 290 organisms were examined for their fluorescent appearance using epi-illumination with ultra-violet excitation and their fluorescence was compared. Results: Incorporating the fluorochrome calcofluor white at a concentration of 0.0025% in a peptone/glucose medium, and in sera for the germ tube test with Candida albicans, enhances the recognition of germ tubes. Several other species of yeast-like organisms were found to have characteristic fluorescent appearances in these and in aqueous solutions at this concentration. Conclusion: The use of these appearances as a rapid (in minutes) identification criteria for Torulopsis glabrata and Candida krusei is described. This may be of value as infections with these 2 species are often not treatable with fluconazole. Received 11.22.06 | Revisions Received 12.12.06 | Accepted 12.12.06