The contribution of natural killer cells to the allograft response

The NK cells and the alloimmune CTL recovered from a rejecting sponge graft both possess the surface determinant AGM1. Both systemic and local treatment of sponge-bearing mice with anti-AGM1, results in severe inhibition of NK activity and alloimmune CTL activity recovered from the graft. From this evidence it is tempting to speculate that cells exhibiting the characteristics of NK cells may differentiate into alloimmune CTL.

Characterization of natural killer activity in sponge matrix allografts

NK cell activity, defined by the ability of infiltrating host cells to lyse the YAC-1 tumor target, can be detected in sponge matrix allografts across all genetic barriers tested. Nonspecific tumor cell killing cannot be detected either within bulk populations of host-infiltrating cells or in populations enriched for non-adherent lymphocytes. NK activity is also detected in cells infiltrating a syngeneic sponge matrix graft although to a much lesser extent than an allogeneic graft. NK cell functional activity at the graft site precedes the appearance of alloimmune CTL by several days. The surface phenotype of the NK cell is Thy-1.2+ and L3T4- as determined by depleting the various subpopulations with antibody and C. Systemic treatment of sponge-bearing animals with repeated injections of anti-asialo GM1 (AGM1) results in inhibition of both NK activity and CTL activity recovered from the graft on days 5 to 9 after grafting, but on days 11 to 13 after grafting both NK activity and CTL activity are found within the sponge graft. Treatment of sponge-associated cells with anti-AGM1 in vitro or intrasponge injection of anti-AGM1 at various times after grafting eliminates NK activity more readily than alloimmune CTL activity. The intimate association observed between NK cells and alloimmune CTL at the graft site prompts further investigation into the role of NK cells in the allograft response.

Characterization of natural killer activity in sponge matrix allografts

NK cell activity, defined by the ability of infiltrating host cells to lyse the YAC-1 tumor target, can be detected in sponge matrix allografts across all genetic barriers tested. Nonspecific tumor cell killing cannot be detected either within bulk populations of host-infiltrating cells or in populations enriched for non-adherent lymphocytes. NK activity is also detected in cells infiltrating a syngeneic sponge matrix graft although to a much lesser extent than an allogeneic graft. NK cell functional activity at the graft site precedes the appearance of alloimmune CTL by several days. The surface phenotype of the NK cell is Thy-1.2+ and L3T4- as determined by depleting the various subpopulations with antibody and C. Systemic treatment of sponge-bearing animals with repeated injections of anti-asialo GM1 (AGM1) results in inhibition of both NK activity and CTL activity recovered from the graft on days 5 to 9 after grafting, but on days 11 to 13 after grafting both NK activity and CTL activity are found within the sponge graft. Treatment of sponge-associated cells with anti-AGM1 in vitro or intrasponge injection of anti-AGM1 at various times after grafting eliminates NK activity more readily than alloimmune CTL activity. The intimate association observed between NK cells and alloimmune CTL at the graft site prompts further investigation into the role of NK cells in the allograft response.

Failure of freshly inplanted alloantigen in vivo to attract circulating allosensitized lymphocytes

The important role served by donor-specific T lymphocytes in allograft rejection is well accepted. However, the mechanisms that attract the first alloreactive T cells to the graft are unclear. This study was performed to determine whether circulating specifically sensitized lymphocytes are attracted to alloantigen expressed on the surface of donor cells prior to the initiation of inflammatory reactions by the host. 111Indium-oxine labeled, bulk sensitized lymphocytes were injected intravenously into syngeneic mice bearing allogeneic and syngeneic peritoneal exudate cells in opposite hind footpads. Initially, twice as many sensitized lymphocytes were attracted to feet bearing the syngeneic peritoneal cells rather than the allogeneic peritoneal cells. In fact, the activity recovered from the allogeneic peritoneal cell depot was no greater than a contralateral footpad bearing media alone. This selective recruitment was present as early as 30 min following the transfer of radiolabeled cells. Furthermore, the labeled specifically sensitized lymphocytes were attracted to syngeneic macrophages within the peritoneal cell population. No other syngeneic and no allogeneic cells, at all, were capable of attracting circulating sensitized cells. Like specifically sensitized lymphocytes, thymocytes and concanavalin A blasts preferentially homed to sites of syngeneic macrophage deposition. Finally, clones of allospecific cytolytic and helper T cells also failed to migrate to sites of the specified donor alloantigen deposition. Thus, highly immune T cells accumulated, preferentially at sites of syngeneic macrophage inoculation. There is therefore no evidence to support the hypothesis that circulating specifically sensitized lymphocytes are attracted to alloantigen in vivo. Rather, it appears that the initial attraction of specifically sensitized, as well as unsensitized, lymphocytes is directed toward syngeneic macrophages. These data lend support to the hypothesis that the development of alloimmunity within the allograft may be initiated by host macrophages participating in normal healing responses.

A randomized trial comparing cyclosporine with antilymphoblast-globulin-azathioprine for renal allograft recipients. Results at 2 1/2-6 years

Between September 1980 and June 1984, 246 splenectomized, transfused renal allograft recipients were stratified according to presence of diabetes and donor source, and randomized to treatment with either cyclosporine (CsA)-prednisone (pred) or antilymphoblast-globulin (ALG--azathioprine (AZA)--prednisone. As of August 1986, mean follow-up is 47 months. Over all, actuarial patient survival is 84% and 83%, respectively at 4 years. Corresponding graft survival is 70% and 63% for CsA-treated and ALG-AZA-treated patients (NS). Within the subgroup of diabetic recipients of cadaver grafts, graft survival is 70% for CsA-treated and 53% for ALG-AZA-treated recipients (P = .035). In the CsA group, 71% required either a significant reduction in CsA dosage with the addition of azathioprine or a complete switch to azathioprine, mainly because of CsA-associated nephrotoxicity. Of those CsA patients switched at a mean time of 21.3 +/- 16.4 months posttransplant with mean serum creatinine of 2.40 +/- .67, current serum creatinine is 1.79 +/- .63. Current mean serum creatinine values are significantly greater for patients randomized to CsA-pred (1.73 +/- .60) vs. ALG-AZA-pred (1.49 +/- .59), P = .014, even though most CsA-treated patients were eventually switched. The causes of graft loss are not different between CsA and ALG-AZA randomized patients. In nondiabetics, rejection is the most common cause of graft loss (17/33), whereas in diabetics loss due to complications from overimmunosuppression or death from cardiovascular events is significantly more common (27/44) than corresponding losses in nondiabetics (6/33, P less than .05). Switching does not seem to influence the incidence or cause of graft loss. Since most patients started on CsA-prednisone are ultimately switched to triple drug therapy, the latter is now the preferred initial treatment modality.

Thromboembolic complications in renal allograft recipients. A report from the prospective randomized study of cyclosporine versus azathioprine-antilymphocyte globulin

The incidence of arterial and venous thromboembolic complications was compared in 224 renal allograft recipients who were prospectively randomized and stratified by risk to treatment with either cyclosporine-prednisone (CsA-P) (n = 117) or azathioprine-prednisone-antilymphocyte globulin (AZA-P-ALG) (n = 107). Thirteen CsA patients (11%) had 22 thromboembolic events, while 19 AZA patients (18%) had 24 events (P = 0.22). There was no significant difference between the 2 regimens in the number of patients with each type of venous or arterial event or in the number of patients with multiple or lethal events. The incidence of "minor" complications (all except myocardial infarction and stroke) in the related donor subgroup (n = 85) and the overall incidence of thromboembolism in the diabetic subgroup (n = 125) were both significantly higher in AZA-treated patients (P = 0.008 and 0.045, respectively). Thus, CsA immunosuppression does not appear to be a risk factor for thromboembolic disease, and it may in fact lower the incidence of thromboembolism in diabetic renal allograft recipients.

Abdominal sonography after hepatic transplantation: results in 36 patients

Hepatic transplantation was performed in 46 patients over a 2-year period at the University of Minnesota. Thirty-six of these patients subsequently underwent 166 sonographic examinations of the upper abdomen. Forty-three examinations were performed within 2 weeks of transplantation, 47 between 2 and 8 weeks after transplantation, and 76 more than 8 weeks after transplantation. The sonograms were reviewed retrospectively and correlated with the available clinical and histopathologic data. Diffuse, nonspecific parenchymal abnormalities were seen in 27 patients. Focal regions of parenchymal abnormality seen in four patients were associated with abscess and infarction. Moderate to severe biliary dilatation was seen in seven patients with biliary obstruction diagnosed by percutaneous or T-tube cholangiography. Obstruction was seen most commonly in children who had undergone cholecystojejunostomy biliary reconstruction, and it required radiologic or surgical intervention. Routine sonographic assessment of the upper abdominal vasculature showed thrombosis of the portal vein in two cases, thrombosis of the inferior vena cava in one case, thrombosis of the donor aorta in three cases. Focal intraabdominal fluid collections were identified in 14 patients and represented hematomas in all but one. Free peritoneal fluid was detected in 19 patients. Sonography was used to guide percutaneous aspiration of abdominal fluid and to guide fine-needle puncture for percutaneous transhepatic cholangiography. Upper abdominal sonography provides a noninvasive means of evaluating and confirming a wide spectrum of complications that can follow hepatic transplantation. Because clinical and laboratory findings often are nonspecific in these patients, sonographic detection of focal parenchymal abnormalities, biliary dilatation, and vascular compromise is especially valuable.

Liver allograft transplantation: postoperative CT findings

The CT findings in the abdomen after liver transplantation as seen on 72 examinations in 23 allograft recipients are described. CT was most useful in the evaluation of the gross structural integrity of the allograft and in the detection of extrahepatic fluid collections. Low-density foci within the allograft parenchyma were seen in 10 patients (43%) and were associated with infarction and necrosis, infection, malignancy, and rejection. Localized extrahepatic fluid collections (hematomas, bilomas, and seromas) were present in 16 patients (70%); four of the focal fluid collections detected by CT were infected. Since the nature of these fluid collections could not always be determined by CT characteristics, fine-needle aspiration was sometimes required for a specific diagnosis. Prominence of the portal structures was associated with previous or ongoing episodes of rejection in eight of nine patients, likely reflecting increased resistance to portal flow. CT occasionally showed low, dense, and calcified thrombi in the donor aorta and inferior vena cava. CT also showed biliary obstruction in four patients (17%) without identifying its cause. CT is a noninvasive means of imaging the hepatic allograft recipient; providing data on the hepatic parenchyma, vasculature, and biliary system; and identifying the presence of intraabdominal fluid.

Ultrasound and computed tomographic evaluation in hepatic transplantation

Ultrasound and CT are valuable in the non-invasive evaluation of complications of hepatic transplantation. Ultrasound is particularly helpful in detecting biliary obstruction and in documenting vascular patency. As with renal transplantation, the value of US in the assessment of rejection will likely increase with time. Computed tomography is most valuable in identifying large parenchymal abnormalities and abdominal fluid. Both US and CT can be used to guide diagnostic and therapeutic percutaneous procedures in hepatic transplant recipients.

In vivo macrophage-directed lymphocyte traffic requires macrophage activation

Lymphocytes are attracted to activated macrophages in tissue. In the absence of exogenous activators, only syngeneic macrophages can become sufficiently activated, to produce lymphocyte attractants. Allogeneic macrophages require exogenous activation to accomplish lymphocyte recruitment. It is likely that graft rejection is initiated by a nonspecific inflammatory reaction within the graft. Once host macrophages have entered the graft they may be activated by the inflammatory process to produce lymphocyte attractants. As lymphocytes are called to the graft, those recognizing donor determinants may expand to effect graft loss.

The role of natural killer cells in the allograft response

NK cells, present in sponge allografts between all genetic barriers tested, are present at the graft site several days before alloimmune CTL are detected. Both NK and alloimmune CTL possess the AGM1 surface marker. Systemic as well as local treatment with AGM1 antisera depletes NK activity as well as alloimmune CTL at the graft site. NK cells may function at the graft site to facilitate development of alloimmune CTL and/or NK cells may themselves differentiate into alloimmune CTL.

Liver allograft rejection. An analysis of the use of biopsy in determining outcome of rejection

Two-hundred-seventy biopsy specimens from 47 patients undergoing liver transplants at the University of Minnesota were analyzed to determine if histological features could predict the eventual outcome of rejection episodes. Thirty-six patients (76.6%) rejected the transplant. Of these, five either suffered acute liver failure due to rejection (two cases) or developed chronic rejection (three cases). Features of significance in predicting such a bad outcome were arteritis, bile duct paucity, or simultaneous hepatocellular ballooning and hepatocellular dropout and necrosis. Other features, such as type and intensity of infiltrate, degree of bile duct damage, or simple presence of hepatocellular necrosis, were not predictive of outcome. Our conclusion is that biopsy is useful in predicting outcome. Since many of the histologic findings of predictive value were not present in initial pretreatment biopsy specimens, follow-up biopsies of patients being treated for rejection are recommended to assess efficacy of therapy.

Increased expression of class I major histocompatibility complex antigens on hepatocytes in rejecting human liver allografts

We studied hepatocellular expression of major histocompatibility (MHC) antigens in 43 serial liver transplant biopsies from 22 patients (42 percutaneous, 1 autopsy specimen), 4 normal liver biopsies, and 8 percutaneous biopsies of diseased livers from non-liver-transplant patients. Frozen tissue sections were stained by an indirect immunofluorescence technique using monoclonal antibodies (MCAb) that recognize nonpolymorphic human class I or class II MHC determinants. Ethidium bromide was used to stain nuclei and rhodamine-conjugated anti-basement-membrane antibodies to delineate epithelial and vascular structures. HLA-DR antigens recognized by MCAb OKIa1 and I2 were not detected on hepatocytes but were detected on the bile duct epithelium in 7 of 27 transplant biopsies, including 5 with acute rejection and 1 with chronic liver disease that later progressed to chronic rejection. HLA-A, B, C antigens recognized by MCAb 34/28 intensely stained cells lining the liver sinusoids but were negative on hepatocytes in 4 normal liver biopsies and 7 of 8 non-transplant biopsies. Expression of class I MHC antigens on hepatocyte membranes was increased in 17 of 21 (81%) biopsies from patients with acute rejection, in 4 of 4 with chronic transplant liver disease, but in only 3 of 18 (17%) biopsies from patients with no rejection (chi square = 8.62, P less than 0.01). Our observations demonstrate increased expression of MHC class I antigens in association with acute rejection in human orthotopic liver transplantation. Histologic resolution of the rejection episode is generally followed by a decrease in hepatocyte class I antigen expression. Further analysis of this response may have value in assessing the severity of the rejection and effectiveness of treatment.

Renal transplantation done safely without prior chronic dialysis therapy

The complications, cost, and inconvenience associated with pretransplant hemodialysis and peritoneal dialysis would be minimized if transplantation were instituted without prior dialysis. That preuremic transplantation is safe and efficacious in patients with immanent end-stage renal disease has not been established. All 1742 consecutive primary renal transplants performed at the University of Minnesota during the 16.5 year period from January 1968 through July 1984 were reviewed to determine whether graft and patient survival were adversely affected by transplantation prior to dialytic therapy. In the overall group of primary renal transplants, no differences in actuarial graft or patient survival were noted with or without prior dialysis. Likewise, outcome was not affected by the pretransplant dialysis status in recipients of allografts from HLA-identical mismatched living-related donors. However, in cadaveric transplantation graft function appeared to be adversely affected by transplantation prior to dialysis, with 52% vs. 66% two-year graft function for nondialyzed vs. chronically dialyzed recipients, respectively (P = 0.15). Patient survival was significantly (P = .04) decreased in the nondialyzed group, with 66% vs. 80% two-year survival in the chronic dialysis group. However, nearly all of the nondialyzed, cadaveric recipients were diabetic. The outcome of transplantation was found to be identical in these patients, as compared with chronically dialyzed diabetic recipients of cadaveric grafts. Thus, the apparent detrimental effect of predialytic transplantation in the cadaver group was due to the preponderance of diabetics in the nondialyzed group. Since July 1984, a single-armed therapeutic trial of combination therapy with azathioprine, prednisone, antilymphoblast globulin (ALG), and cyclosporine has been undertaken, Since that time, 36 primary graft recipients were transplanted prior to dialysis. Of these 36, 35 currently have a functioning graft. Thus, transplantation prior to chronic dialysis is safe irrespective of donor source, or choice of immunosuppressive agents.

MR evaluation of the portal vein in pediatric liver transplant candidates

Nine pediatric liver transplant candidates underwent preoperative MR evaluation of the portal vein and the inferior vena cava. Sonographic correlation was available in all patients and angiographic correlation was available in five. Pathologic correlation was obtained in seven cases either at liver transplantation or autopsy. MR demonstrated portal vein patency in three cases when it was not seen by angiography and confirmed portal vein patency in one patient when it was questionably identified on sonography. The portal vein was not seen on MR imaging in two cases when it was seen on sonography and angiography: in one case, it was small and to-and-fro flow was demonstrated angiographically; in the second case, the portal vein was occluded by tumor thrombus. Two vessels in two patients were misidentified by sonography and identified correctly by MR. These were an azygous continuation of the inferior vena cava and a large collateral vein in the portal region. Knowledge of the anatomy and documentation of vascular patency are essential in evaluation of patients before liver transplantation. In patients with complex anatomy or hemodynamics, it may be necessary to obtain this information from several imaging techniques (sonography, angiography, and MR).

The outcome of 304 primary renal transplants in children (1968-1985)

Of 304 children who received primary renal transplants at the University of Minnesota between January 1, 1968, and December 31, 1985, 48 (16%) were under the age of 24 months, 60 (20%) were 2-5 years old, and 196 (64%) were 6-17 years old at transplantation. Currently, 254 (84%) are alive at 2 months to 18 years following their first transplants, 77% with functioning grafts (188 first, 45 retransplants) and 7% on dialysis. Overall, patient and graft survival were not significantly different from the primary graft outcome of nondiabetic adults. The actuarial primary graft function rates at 1, 5, and 10 years were 100, 100, and 90% in 16 HLA-identical sibling kidneys; 84, 64, and 52% in 210 mismatched related kidneys; and 72, 54, and 47% in 78 cadaver kidneys (p less than 0.002). The 1-year patient survival and primary graft function rates in 44 mismatched related recipients under the age of 24 months were 92 and 88%. The use of deliberate, pretransplant random blood transfusion since 1979 has been associated with a decreased rejection rate. Primary graft function of mismatched related kidneys in children receiving standard immunosuppression has significantly improved from 78% at 1 year in the pretransfusion era to 91% (p less than 0.01) in the transfusion era. The overall primary cadaver graft function rate, however, did not improve in the transfusion era. Whether cyclosporine use will improve the cadaver renal allograft function in very young recipients remains to be established. However, with the use of related donors, even very young children can be transplanted safely and with excellent results.

Lymphocytes capable of mediating delayed-type hypersensitivity reactions accumulate within sponge matrix allografts

The rejection of sponge matrix allografts across H-2 barriers has generally been found to contain specifically sensitized cytotoxic T cells to donor alloantigen. There is one exception: sponge matrix allografts that differ only with respect to class II alloantigens do not contain specifically sensitized cytotoxic T cells. We therefore investigated the capacity of infiltrating cells removed from sponge matrix allografts to generate delayed hypersensitivity reactions after exposure to fresh alloantigen in a footpad assay. Cells infiltrating class I and II allografts were equally capable of eliciting delayed footpad reactions when injected with specific donor alloantigen into the footpads of naive responder strain mice. Allosensitized T-lymphocyte clones of helper or cytotoxic type were also capable of initiating delayed-type hypersensitivity (DTH) reactions in vivo. We conclude that rejecting allografts across class I or II alloantigenic barriers are infiltrated by cells capable of effecting DTH reactions, in addition to their capacity to exert specific helper or specific cytotoxic reactions. The results also support that both helper and cytotoxic T cells can participate in allospecific DTH reactions.

Fulminant Wilson's disease treated with postdilution hemofiltration and orthotopic liver transplantation

A 22-yr-old woman presented with fulminant Wilson's disease. The diagnosis was suspected clinically and was later confirmed with chemical and pathologic studies. She presented with acute hepatic failure, hemolysis, and acute anuric renal failure. Postdilution hemofiltration and continuous arteriovenous hemofiltration with oral D-penicillamine allowed removal of a total of 95,700 micrograms of copper; 78,665 micrograms of the total were removed via postdilution hemofiltration alone. On the 57th day, the patient received successful liver and renal transplants. We found that the determination of serum copper was instrumental in the diagnosis of fulminant Wilson's disease, that postdilution hemofiltration allowed a rapid removal of copper in the presence of renal failure, and that, finally, orthotopic liver transplantation should be performed early in the clinical course of these patients. This patient is the longest survivor of this serious condition.

Scintigraphic evaluation of liver transplant function

Since the initiation of liver transplantation at our institution 9 yr ago, 73 patients ranging in age from 8 mo to 64 yr have undergone this procedure. In the immediate postoperative period and at various times thereafter as deemed necessary, radionuclide studies were performed using one of the iminodiacetic acid (IDA) derivatives labeled with 99mTc. Initially, these studies were performed using labeled PIPIDA with a shift to diisopropyl IDA when this latter agent became available. The IDA agent is administered as a bolus so that the "flow" and "pooling" may be viewed immediately after injection. This is followed by sequential imaging at various times up to 24 hr, with optional graphic tracings of hepatic and bowel patterns of uptake and clearance of radioactivity. An analysis of the initial portion of the IDA scan yields useful information regarding the arterial and portal venous supply of the liver. The rapidity of hepatic concentration and excretion provides a direct measure of hepatocyte function which is particularly helpful when used sequentially to follow the response of the liver to therapy for rejection or infection. The study is also used to assess the biliary system for obstruction or leaks.

The migration of activated T lymphocytes in vitro. III. Paralysis and recovery of locomotor function during mitosis

Previous reports have stated that activated lymphocytes are more motile than unsensitized lymphocytes and that certain subpopulations of lymphocytes are more motile than others. In order to determine at what stage of activation lymphocytes become motile, we have examined lymphocyte motility as well as other functions at various times after mitogenic or allogeneic stimulation in culture. Lymphocytes cultured with concanavalin A (Con A) or with alloantigen become most motile after peak thymidine incorporation has occurred. Allosensitized lymphocytes need not possess cytolytic capacity in order to become motile. Allosensitized lymphocytes retain the ability to locomote at near maximal rates for at least 2 weeks after stimulation. When these motile, allosensitized lymphocytes are recultured in the presence of fresh irradiated stimulator cells, they lose their ability to locomote during active thymidine incorporation and become motile again when thymidine incorporation has abated. Lymphocyte clones demonstrated motility cycles similar to cycles observed with bulk cultures (i.e., peak motility is observed only after peak thymidine incorporation has occurred in the subculture). All T lymphocyte clones tested are motile, regardless of Lyt phenotype or function, if tested for motility on the appropriate day of subculture. Studies of clone motility at intervals less than 24 hr after restimulation revealed that motility ceased before tritiated thymidine uptake occurred. The migratory potential of lymphocytes in vitro does not seem to depend on phenotype or the nature of the mitogenic stimulus. It seems instead to be part of the cyclic response of the cell to activation, with early inhibition of motility and subsequent recovery of locomotor function. Whether ability to locomote is intrinsic to the activated cell or depends on environmental factors requires further investigation.