Gastroesophageal variceal bleeding caused by hepatoportal arteriovenous fistula.

Hepatoportal arteriovenous fistulas are usually traumatic in origin and may result in portal hypertension and serious complications. We report a 34-year-old female with a history of abdominal trauma, who developed symptoms of tarry stools and hematemesis 5 years later. Esophageal and gastric varices with bleeding were diagnosed by upper gastrointestinal endoscopy. Abdominal ultrasonography and computerized tomography favored noncirrhotic portal hypertension. An extrahepatic hepatoportal arteriovenous fistula was demonstrated by angiography. The patient underwent surgery to correct the condition. The liver had a smooth surface and both the common hepatic and gastroduodenal arteries were ligated during surgery. The postoperative course was uneventful. The varices later disappeared.

Quantitation of glioma-reactive cytolytic T lymphocyte precursors by means of limiting dilution analysis.

The purpose of the present study was to define the usefulness of limiting dilution analysis (LDA) to enumerate glioma-reactive cytolytic T lymphocytes (CTL) as a constituent of tumor infiltrating lymphocytes (TIL) isolated from rat gliomas. Optimum LDA microculture conditions were defined by co-cultivating graded numbers of responder TIL together with 10(5) irradiated syngeneic rat splenocytes, 10(3) irradiated glioma cells, and 10 U/well of recombinant interleukin-2 incubated for 8 days. Antigenic specificity of the anti-tumor response was demonstrated by high levels of [3H]thymidine incorporation by TIL derived from F98 gliomas following stimulation with irradiated F98 glioma cells compared to low levels following stimulation with the antigenically distinct D74 glioma cells. Limiting dilution analysis showed that cytolytic T lymphocyte-precursors were present in TIL of F98 gliomas of immunized rats at an approximate frequency of 300 CTL/10(6) TIL, indicating that less than 1% of the TIL were tumor-reactive CTL. As determined by cell depletion experiments using various MoAbs and complement, the majority of the cytolytic activity detected against glioma targets was mediated by OX-8+ TIL. Split culture experiments revealed that high levels of glioma-reactive CTL activity and low levels of NK activity, which are simultaneously detected among TIL, were mediated by separate cell populations. Our data demonstrate that LDA microcultures can be used as a powerful tool to differentiate tumor-reactive CTL from other effector cell populations.

Phenotype and functional activity of tumor-infiltrating lymphocytes isolated from immunogenic and nonimmunogenic rat brain tumors.

The purpose of the present study was to define the immunogenicity of two transplantable rat gliomas, designated F98 and D74, and to relate this to the phenotype and functional activity of tumor-infiltrating lymphocytes (TIL). Fischer rats, immunized with irradiated F98 tumor cells and challenged with intracerebral implants of ten F98 cells, had a median survival time of 49 days compared to 36 days for nonimmunized controls. In contrast, no statistically significant increases in survival times were noted in animals similarly immunized and challenged with the D74 tumors. No in vivo protection could be demonstrated in animals immunized and cross-challenged with either F98 or D74 glioma cells. Lymph node lymphocytes and TIL, isolated from animals immunized and challenged with F98 cells, were more cytolytically active than effector cells obtained from D74-immunized animals. Phenotypes of TIL isolated from intracerebral F98 gliomas of immunized rats were 52% OX-8+ and 21% W3/25+ compared to 31% OX-8+ and 19% W3/25+ for D74-immunized animals. Cytolytic activity against glioma targets was mediated by OX-8+ TIL, as determined by cell depletion experiments. Limiting dilution analysis showed that cytolytic T-lymphocyte precursors were present in TIL of F98 gliomas of immunized rats at a frequency of 1/3547 and were specific for F98 targets, while natural killer cell-like activity was low. Our data indicate that the F98 glioma was more immunogenic than the D74 glioma, as evidenced by increased numbers and activity of cytolytic effector cells and their precursors among TIL. This may explain in part the longer survival times observed in immunized animals challenged intracerebrally with the F98 gliomas compared to D74-immunized and -challenged hosts.

Adoptive immunotherapy of a rat glioma using lymphokine-activated killer cells and interleukin 2.

The aim of the present study was to develop an animal model to test the therapeutic potential of purified adherent lymphokine-activated killer (A-LAK) cells against an intracerebrally implanted rat glioma, designated F98. Highly purified A-LAK cells demonstrated greater activity against F98 tumor cells than conventional lymphokine-activated killer cells, as determined by means of 51Cr-release and clonogenic assays. Therapeutic efficacy was evaluated by means of a Winn neutralization assay, in which F98 targets and A-LAK cells or control nonadherent mononuclear cells were incubated for 18 h in vitro and then implanted stereotactically into the right caudate nuclei of Fischer rats. Animals given injections of 4000 F98 cells alone or control nonadherent mononuclear cells had a mean survival time of 22.3 days, compared to 46.1 days (P less than 0.001) for rats treated with A-LAK cells. Increasing the tumor inoculum to 12,500 cells reduced the survival time of A-LAK-treated animals to 27.8 days, compared to 20.8 days for untreated controls. Systemic administration of 50,000 units/kg of interleukin 2 every 12 h for 5 days failed to improve survival. The mean survival time of rats implanted with the F98 tumor ranged from 16 days for 10(5) cells to 29 days for 10(2) cells. Extrapolating from these survival data, treatment with A-LAK cells may have decreased the number of F98 cells to less than 10, but even this small number was still lethal. Supernatants from F98 cells had immunoinhibitory activity that, further, may have modulated the antitumor effects of A-LAK cells. Our results indicate that curative, adoptive immunotherapy of the F98 glioma by means of A-LAK/interleukin 2 is impossible to achieve and provide some explanation for the clinical failures that have been observed in the adoptive immunotherapy of malignant gliomas.

Sensitivity of B16 melanoma sublines to lymphokine-activated killer cells as determined by 51Cr-release and clonogenic assays.

The aim of this study was to compare the differential sensitivities of B16 melanoma sublines to LAK cells by means of the standard 51Cr release assay and a clonogenic assay, which measures both cell survival and proliferation. LAK cells, generated after 4 days incubation with 150 international units (IU)/ml of interleukin-2 (IL-2), showed both cytolytic and anti-proliferative activities against B16 targets. Using an 18 h 51Cr release assay, murine LAK cells showed the highest cytolytic activity against B16 parental cells compared to B16-F1, B16-F10, B16-FLR and B16-BL6 sublines at effector/target (E/T) ratios ranging from 6/1 to 100/1. Purified adherent LAK (A-LAK) cells showed greater cytolytic activity against B16 parental cells and other B16 sublines compared to LAK cells, but otherwise the pattern of reactivity was similar. Using a clonogenic assay, the surviving fraction of B16 parental cells co-cultivated with LAK cells decreased to 0 at an E/T ratio of 50/1, while a 400/1 ratio was required to achieve a similar reduction of B16-F1, B16-F10, B16-FLR, and B16-BL6 sublines. No differences in subline sensitivity were seen with the 51Cr release assay, but these were observed using the clonogenic assay. An inverse linear relationship existed between % surviving fraction, as determined by the clonogenic assay, and cytolytic activity, as determined by the 51Cr release assay. Our data indicate that the clonogenic assay can detect differences in target cell sensitivity that otherwise are undetectable by the standard 51Cr release assay. The clonogenic assay may prove useful in delineating the long-term anti-adherent and anti-proliferative properties of effector cells from their cytolytic activity.

Distinct and non-cross-reactive epitopes are recognized on B16 melanoma by LAK cells and anti-B16 monoclonal antibodies.

Two rat anti-B16 melanoma monoclonal antibodies (MoAb), designated IB16-6 and IB16-8, recognize an epitope expressed with high density on the surface of B16 parental cells and B16-F1, F10, F10FLR, and BL6 sublines. The purpose of this study was to define by means of cytolytic and clonogenic assays whether these MoAbs reacted with the same or distinct determinants as those recognized on B16 targets by lymphokine-activated killer (LAK) cells. Using 125I-labeled antibody and Scatchard analysis, the affinity constant (KA) of IB16-6 was determined to range from 5.6 to 9.4 x 10(8) liter/M and the number of receptor sites per B16 cell was 4.8 x 10(4) to 2.5 x 10(5). The effects of anti-B16 MoAb on LAK activity were determined by either preincubating 51Cr-labeled B16 target cells with varying concentrations of MoAb, followed by the cytolytic assay, or exposing unlabeled B16 cells to MoAb, and then carrying out a 10-day clonogenic assay. Over a wide range of antibody concentrations, IB16-6 and IB16-8 had minimal effects on LAK activity, and even at MoAb concentrations up to 1 mg there were no changes in target cell sensitivity or colony-forming ability. Enzymatic treatment of B16 melanoma cells with either trypsin or pronase completely removed the epitope recognized by MoAb IB16-6 but did not alter B16 sensitivity to LAK cells. These observations indicate that the LAK recognition unit was distinct from the epitope reactive with MoAb IB16-6 and that the B16 determinant(s) recognized by LAK cells is resistant to proteolytic enzymes. The molecular structure of each of these remains to be determined.