Immunohistochemical aspects of acute rejection of the allografted rat lung

Adoptive T-Cell Therapy for B-Cell Acute Lymphoblastic Leukemia: Preclinical Studies

We have previously shown that leukemia-specific cytotoxic T cells (CTL) can be generated from the bone marrow of most patients with B-cell precursor acute leukemias. If these antileukemia CTL are to be used for adoptive immunotherapy, they must have the capability to circulate, migrate through endothelium, home to the bone marrow, and, most importantly, lyse the leukemic cells in a leukemia-permissive bone marrow microenvironment. We demonstrate here that such antileukemia T-cell lines are overwhelmingly CD8+ and exhibit an activated phenotype. Using a transendothelial chemotaxis assay with human endothelial cells, we observed that these T cells can be recruited and transmigrate through vascular and bone marrow endothelium and that these transmigrated cells preserve their capacity to lyse leukemic cells. Additionally, these antileukemia T-cell lines are capable of adhering to autologous stromal cell layers. Finally, autologous antileukemia CTL specifically lyse leukemic cells even in the presence of autologous marrow stroma. Importantly, these antileukemia T-cell lines do not lyse autologous stromal cells. Thus, the capacity to generate anti–leukemia-specific T-cell lines coupled with the present findings that such cells can migrate, adhere, and function in the presence of the marrow microenvironment enable the development of clinical studies of adoptive transfer of antileukemia CTL for the treatment of ALL.

Effect of ischemic injury on subsequent rat lung allograft rejection

BACKGROUND

It has been suggested that the frequency and severity of allograft rejection may be related to the degree of allograft ischemia. The purpose of this study was to determine whether ischemic insult correlates with lung allograft rejection.

METHODS

Forty-eight left lung transplants were performed from Lewis donor rats into F344 recipient rats. Allografts were divided into two groups based on the degree of ischemic insult. Transplantation was performed immediately (group 1, minimum injury) or after 18 hours of cold (1 degree C) preservation (group 2, severe injury). Allografts were evaluated radiographically based on aeration scores (0 = opaque to 6 = normal). Animals were randomly sacrificed on days 7, 14, or 21 for histologic and immunohistochemical evaluation of rejection.

RESULTS

On postoperative day 3, significantly lower aeration score was demonstrated in group 2 (3.69 +/- 1.71) compared to group 1 (5.0 +/- 1.09) (p < 0.05) as a result of the difference in reperfusion injury. However, by day 7 and thereafter, there was no significant difference. Histologic rejection was present by day 7 and peaked at day 14 with no significant difference between groups. There was also no difference in CD4+, CD8+ infiltrating lymphocyte population or expression of class II major histocompatibility complex antigen on bronchial epithelium.

CONCLUSIONS

We conclude that ischemic injury in rat lung allograft does not correlate with the onset or severity of rejection.

Bronchoalveolar lavage and transbronchial lung biopsy during acute rejection and infection in heart-lung transplant patients. Studies of cell counts, lymphocyte phenotypes, and expression of HLA-DR and interleukin-2 receptor

The total and differential cell counts of 135 bronchoalveolar lavages (BAL) in 48 heart-lung transplant (HLT) patients were compared with the histologic findings in concurrent transbronchial lung biopsies (TBBs). Counts of CD3+, CD4+, and CD8+ lymphocytes were recorded, and a semiquantitative assessment of HLA-DR and interleukin-2 receptor (IL-2R) expression was made on 29 occasions. There were five diagnostic categories: normal (n = 8), acute rejection (ALR) (n = 57), treated rejection (TR) (n = 19), infection (INF) (n = 24), and chronic rejection (CR) (n = 24). Total cell counts in INF were significantly higher than counts in all the other diagnostic groups. The highest BAL lymphocyte counts, significantly higher than in INF, were found in ALR because of increased CD8+ cells, exceeding 15% in 13 of 57 BALs. TBBs in ALR by contrast showed significantly increased numbers of both CD8+ and CD4+ cells. High dose corticosteroid treatment of ALR caused a fall in cellularity of BAL and TBB specimens but not always to values seen when patients were well. During INF and CR, significantly increased numbers of PMNs were seen in the BAL. HLA-DR and IL-2R expression was enhanced in cells of BAL and TBB in all complications. BAL can only supplement at present histologic examination of TBB in the diagnosis of complications after HLT.

Histopathologic correlates of acute laryngeal allograft rejection in a rat model

This study used both clinical and histopathologic criteria to define the sequence and time parameters of rejection in histoincompatible vascularized rat laryngeal allografts. Clinical onset of rejection was characterized at 1 week by graft edema. Pathologic examination at this time revealed arterial wall thickening and a diffuse lymphocytic and macrophage mucosal infiltrate. At 14 days, the graft was encased in an inflammatory exudate with no visible cartilaginous structure. This correlated microscopically with a lymphocytic infiltrate of the lamina propria, loss of minor salivary glands, and squamous metaplasia of the surface respiratory epithelium. Arterial thrombosis was always correlated with tissue necrosis, but venous occlusion, occurring more than 2 days after transplantation, was not an independent determinant of graft viability. Definition of the time sequence and histopathology of rejection will allow future determination of the efficacy of various immunosuppressive regimens.