James M. Crawford

Tumor necrosis factor- alpha production to lipopolysaccharide stimulation by donor cells predicts the severity of experimental acute graft-versus-host disease.

Donor T cell responses to host alloantigen are known predictors for graft-versus-host disease (GVHD); however, the effect of donor responsiveness to an inflammatory stimulus such as lipopolysaccharide (LPS) on GVHD severity has not been investigated. To examine this, we used mouse strains that differ in their sensitivity to LPS as donors in an experimental bone marrow transplant (BMT) system. Lethally irradiated (C3FeB6)F1 hosts received BMT from either LPS-sensitive (LPS-s) C3Heb/Fej, or LPS-resistant (LPS-r) C3H/ Hej donors. Mice receiving LPS-r BMT developed significantly less GVHD as measured by mortality and clinical score compared with recipients of LPS-s BMT, a finding that was associated with significant decreases in intestinal histopathology and serum LPS and TNF-alpha levels. When donor T cell responses to host antigens were measured, no differences in proliferation, serum IFN-gamma levels, splenic T cell expansion, or CTL activity were observed after LPS-r or LPS-s BMT. Systemic neutralization of TNF-alpha from day -2 to +6 resulted in decreased intestinal pathology, and serum LPS levels and increased survival after BMT compared with control mice receiving Ig. We conclude that donor resistance to endotoxin reduces the development of acute GVHD by attenuating early intestinal damage mediated by TNFalpha. These data suggest that the responsiveness of donor accessory cells to LPS may be an important risk factor for acute GVHD severity independent of T cell responses to host antigens.

Interleukin-11 Promotes T Cell Polarization and Prevents Acute Graft-Versus-Host Disease after Allogeneic Bone Marrow Transplantation

Administration of IL-11 prevented lethal graft-versus-host disease (GVHD) in a murine bone marrow transplant (BMT) model (B6 --> B6D2F1) across MHC and minor H antigen barriers (survival at day 50: 90 vs 20%, P < 0.001). Surpisingly, IL-11 administration polarized the donor T cell cytokine responses to host antigen after BMT with a 50% reduction in IFNgamma and IL-2 secretion and a 10-fold increase in IL-4. This polarization of T cell responses was associated with reduced IFNgamma serum levels and decreased IL-12 production in mixed lymphocyte cultures (MLC). In addition, IL-11 prevented small bowel damage and reduced serum endotoxin levels by 80%. Treatment with IL-11 also reduced TNFalpha serum levels and suppressed TNFalpha secretion by macrophages to LPS stimulation in vitro. IL-11 thus decreased GVHD morbidity and mortality by three mechanisms: (a) polarization of donor T cells; (b) protection of the small bowel; and (c) suppression of inflammatory cytokines such as TNFalpha. We conclude that brief treatment with IL-11 may represent a novel strategy to prevent T cell-mediated inflammatory processes such as GVHD.

LPS antagonism reduces graft-versus-host disease and preserves graft-versus-leukemia activity after experimental bone marrow transplantation

Acute graft-versus-host disease (GVHD) and leukemic relapse remain the two major obstacles to successful outcomes after allogeneic bone marrow transplantation (BMT). Recent studies have demonstrated that the loss of gastrointestinal tract integrity, and specifically the translocation of LPS into the systemic circulation, is critical to the induction of cytokine dysregulation that contributes to GVHD. Using a mouse BMT model, we studied the effects of direct LPS antagonism on GVHD severity and graft-versus-leukemia (GVL) activity. Administration of B975, a synthetic lipid-A analogue from day 0 to day +6, reduced serum TNF-alpha levels, decreased intestinal histopathology, and resulted in significantly improved survival and a reduction in clinical GVHD, compared with control-treated animals. Importantly, B975 had no effect on donor T cell responses to host antigens in vivo or in vitro. When mice received lethal doses of P815 tumor cells at the time of BMT, administration of B975 did not impair GVL activity and resulted in significantly improved leukemia-free survival. These findings reveal a critical role for LPS in the early inflammatory events contributing to GVHD and suggest that a new class of pharmacologic agents, LPS antagonists, may help to prevent GVHD while preserving T cell responses to host antigens and GVL activity.

Differential roles of IL-1 and TNF-α on graft-versus-host disease and graft versus leukemia

We demonstrate an increase in graft-versus-host disease (GVHD) after experimental bone marrow transplant (BMT) when cyclophosphamide (Cy) is added to an otherwise well-tolerated dose (900 cGy) of total body irradiation (TBI). Donor T cell expansion on day +13 was increased after conditioning with Cy/TBI compared with Cy or TBI alone, although cytotoxic T lymphocyte (CTL) function was not altered. Histological analysis of the gastrointestinal tract demonstrated synergistic damage by Cy/TBI and allogeneic donor cells, which permitted increased translocation of LPS into the systemic circulation. TNF-α and IL-1 production in response to LPS was increased in BMT recipients after Cy/TBI conditioning. Neutralization of IL-1 significantly reduced serum LPS levels and GVHD mortality, but it did not affect donor CTL activity. By contrast, neutralization of TNF-α did not prevent GVHD mortality but did impair CTL activity after BMT. When P815 leukemia cells were added to the bone marrow inoculum, allogeneic BMT recipients given the TNF-α inhibitor relapsed at a significantly faster rate than those given the IL-1 inhibitor. To confirm that the role of TNF-α in graft versus leukemia (GVL) was due to effects on donor T cells, cohorts of animals were transplanted with T cells from either wild-type mice or p55 TNF-α receptor–deficient mice. Recipients of TNF-α p55 receptor–deficient T cells demonstrated a significant impairment in donor CTL activity after BMT and an increased rate of leukemic relapse compared with recipients of wild-type T cells. These data highlight the importance of conditioning in GVHD pathophysiology, and demonstrate that TNF-α is critical to GVL mediated by donor T cells, whereas IL-1 is not. n nJ. Clin. Invest. 104:459-467 (1999).

Radiation pneumonitis in mice: A severe injury model for pneumocyte engraftment from bone marrow

OBJECTIVEnTo better understand the process by which pneumocytes can be derived from bone marrow cells, we investigated the in vivo kinetics of such engraftment following lethal irradiation.nnnMETHODSnA cohort of lethally irradiated B6D2F1 female mice received whole bone marrow transplants (BMT) from age-matched male donors and were sacrificed at days 1, 3, 5, and 7 and months 2, 4, and 6 post-BMT (n = 3 for each time point). Additionally, 2 female mice who had received 200 male fluorescence-activated cell sorter (FACS)-sorted CD34(+)lin(-) cells were sacrificed 8 months post-BMT.nnnRESULTSnLethal irradiation caused histologic evidence of pneumonitis including alveolar breakdown and hemorrhage beginning at day 3. To identify male-derived pneumocytes, simultaneous fluorescence in situ hybridization (FISH) for Y-chromosome and surfactant B messenger RNA was performed on lung tissue. Y(+) type II pneumocytes were engrafted as early as day 5 posttransplant, and eventually from 2 to 14% of the pneumocytes were donor derived in individual mice. Co-staining for epithelial-specific cytokeratins demonstrated that by 2 months, marrow-derived pneumocytes could comprise entire alveoli, suggesting that type I cells derived from type II pneumocytes.nnnCONCLUSIONSnWe conclude that alveolar lining cells derive from bone marrow cells immediately after acute injury. Also, the CD34(+)lin(-) subpopulation is capable of such pulmonary engraftment.

Utilization of acidophil bodies in the diagnosis of recurrent hepatitis C infection after orthotopic liver transplantation.

The distinction between acute rejection and early recurrent hepatitis C infection (RHCV) in the setting of orthotopic liver transplantation is often difficult. In liver biopsies acidophil bodies and lobular hepatitis are used to suggest a diagnosis of RHCV over rejection, however, the reliability of this practice has not been established. Because portal tract changes in RHCV and rejection often overlap, we sought to determine whether the degree of hepatocyte acidophil body formation seen on liver biopsies could be used to distinguish between these two conditions. Methods: Quantification of acidophil bodies was performed on liver biopsies in orthotopic liver transplant patients with RHCV (n = 10), non-hepatitis C orthotopic liver transplant patients with uncomplicated rejection episodes (n = 10) and non-transplant patients with chronic hepatitis C infection (n = 10). Hematoxylin and Eosin stained slides from all three groups were randomized and tissue segments 1.0 cm in length and of variable width (0.04–0.13 cm) were examined at 200 × magnification in a blinded fashion by two pathologists in order to quantify the number of acidophil bodies/cm2. Lobular chronic inflammation was also graded on a 0–3+ scale. Results: Liver biopsies taken at the onset of RHCV exhibited 606 ± 101 acidophil bodies/cm2 (mean ± standard error of mean, range 200–1390). These counts were significantly greater (P = .0061, paired 2-tailed t-test) than the 241 ± 53 acidophil bodies/cm2 (range 80–514) for acute rejection, and the 194 ± 21 acidophil bodies/cm2 (range 100–333) for non-liver transplant chronic hepatitis C infection (P = .0013). No difference in lobular inflammation between index RHCV and rejection biopsies was detected. Conclusions: Although there is overlap, on average there are twice as many acidophil bodies in the initial stage of RHCV when compared with acute rejection (average of 55 per linear cm in RHCV versus 21 per linear cm for rejection). Lobular inflammation was not a reliable indicator of the initial onset of RHCV.

Strategies for a Successful Anatomic Pathology Subspecialty Workgroup The 26-Year Collaboration of “The Elves”

From 1990 to present, 14 liver pathologists and 2 clinical hepatologists from 9 countries have met annually to hold thematic 2.5-day meetings centered on case-based discussion. The goal of these meetings has been to identify gaps in knowledge in our field and fuel scholarly effort to address these gaps. The founding principles were worldwide representation, good representation of women, compatibility of participants, commitment to stable membership and regular attendance, mutual education and friendship, and free exchange of ideas. A summary report of the 2.5-day meeting constituted an enduring document that captured the free flow of ideas discussed. These ideas were open to all participants for the pursuit of scholarship back at their home institutions. However, any idea borne out of an Elves meeting merits open invitation for other Elves to participate in, using established standards for meaningful coauthorship. Over 26 consecutive meetings (1990-2015), themes covered the breadth of liver pathology. With retirement of 2 individuals, resignation of 3, and death of 1, six new members were nominated and voted into membership. Over these same 26 years, active members published 2025 articles indexed in PubMEd Central under the topic “liver;” 3% of these articles represented collaborations between members. This international group represents a successful model in a subspecialty of anatomic pathology for open exchange of ideas, mutual education, and generation of topics worthy of scholarly investigation. We conclude that a self-selected group of subspecialty pathologists can meet successfully over 26 years, maintain a high state of engagement through each annual meeting, self-renew as a result of retirement or resignation, and provide a creative stimulus for highly productive academic careers.

Real-time in vivo endoscopic imaging of fluorescence from human colonic adenomas

Previous in vitro studies showed that autofluorescence images of colonic mucosa collected endoscopically can be used to detect dysplasia with high sensitivity. This method is extended to collection of fluorescence images of adenomatous polyps in vivo. Fluorescence images were collected during colonoscopy in 30 patients. A total of 12 adenomatous and 6 hyperplastic polyps were identified. An optical fiber excitation probe, located in the instrument channel of the colonoscope, delivered 300 mW of near- ultraviolet light at (lambda) ex equals 351 and 364 nm. Mucosal fluorescence in the spectral bandwidth between 400 and 700 nm was imaged, processed, and displayed with various likelihoods of associated dysplasia. Adenomatous polyps exhibited decreased fluorescence intensity compared to adjacent mucosa with normal appearance. With the fluorescence threshold set to 80% of the average intensity of normal mucosa, a sensitivity of 83% for dysplasia detection was achieved. All hyperplastic polyps were correctly identified as being non-dysplastic. Optimal identification of dysplastic regions was obtained with the colonoscope oriented at near-normal incidence to the polyps. At higher angles of incidence, artifacts due to illumination shadows were introduced. The dysplasia associated with adenomatous polyps can be detected in vivo on fluorescence imaging with high sensitivity, thus demonstrating the potential to guide endoscopic biopsy.