Ex vivo generation of effective Epstein-Barr virus (EBV)-specific CD8+ cytotoxic T lymphocytes from the peripheral blood of immunocompetent Epstein Barr virus-seronegative individuals

BACKGROUND

Although readily accomplished from immunocompetent Epstein-Barr virus- (EBV) seropositive individuals, the effective ex vivo generation of EBV-specific cytotoxic T lymphocytes (CTL) from the peripheral blood mononuclear cells (PBMC) of EBV-seronegative subjects has proven to be a challenge. The focus of our study was to ascertain optimized culture conditions required for the ex vivo generation of EBV-reactive autologous CTL from the PBMC of EBV-seronegative volunteers.

METHOD

Freshly isolated PBMC obtained from immunocompetent EBV-seronegative and -seropositive individuals were used to generate EBV-specific autologous CTL lines using both conventional and a novel, modified ex vivo culture technique.

RESULTS

In contrast to responses observed in EBV-seropositives after two to three rounds of ex vivo stimulation, gamma-irradiated autologous lymphoblastoid cell lines (LCL) were incapable of eliciting an effective anti-EBV cytotoxic response when freshly-isolated PBMC from EBV-seronegative individuals were used as responders. Under these culture conditions, CD4+ T cells with preferential expression of the Th2-type cytokine IL-4 were predominantly expanded in the PBMC obtained from EBV-seronegative individuals. However, the addition of recombinant human (rh) IL-12 during the primary phase of ex vivo stimulation resulted in augmentation of EBV-specific cytolysis of autologous LCL by CD8+ T cells. Furthermore, there was down-regulation in the secretion of IL-4 and up-regulation in that of the Th1-type cytokine IFN-gamma by responder CD4+ and CD8+ T cells.

CONCLUSIONS

Taken together these data suggest that the addition of rhIL-12 during the primary phase of ex vivo stimulation of freshly isolated PBMC from EBV-seronegative individuals results in skewing of the immune response predominantly towards a CD4+ Th1-type (IFN-gamma) with the generation of an efficacious CTL-mediated anti-EBV reactivity. This novel ex vivo approach for generating effective autologous EBV-specific CTL could be adopted to treat refractory post-transplant lymphoproliferative disorders, which may be encountered in EBV-seropositive-->EBV-seronegative organ transplant recipients. Additionally, these ex vivo generated anti-EBV T cells could also be infused perioperatively to enhance prophylactically immunity against EBV infection in high-risk EBV-seronegative organ allograft recipients.

Enhanced synthesis and reduced metabolism of endothelin-1 (ET-1) by hepatocytes--an important mechanism of increased endogenous levels of ET-1 in liver cirrhosis

BACKGROUND/AIMS

Hepatic concentration of endothelin-1 (ET-1) is increased in human and experimental liver cirrhosis. Because of its potent actions in the liver, ET-1 has been suggested to play an important role in the pathophysiology of cirrhosis. Since hepatocytes are the major cell type to metabolize ET-1, we investigated whether their reduced capacity to degrade ET-1 is a mechanism of its elevated levels in cirrhosis.

METHODS

The expression of ET-1 receptors, ET-1 and endothelin converting enzyme (ECE), and metabolism of ET-1 and ECE activity were compared in hepatocytes isolated from control and carbon tetrachloride-induced cirrhotic rats.

RESULTS

ET-1 receptor density and receptor-mediated internalization of ET-1 were significantly increased in cirrhotic hepatocytes relative to the control cells. However, compared to control hepatocytes, metabolism of ET-1 by the cirrhotic cells was reduced significantly. Interestingly, hepatocytes were found to contain preproET-1 mRNA, ECE-1 mRNA and ET-1. PreproET-1 mRNA and ET-1 levels were increased in cirrhotic hepatocytes but their ECE mRNA and ECE activity were not altered.

CONCLUSIONS

These results provide the first evidence that hepatocytes have the ability to synthesize ET-1 and demonstrate that decreased metabolism and enhanced synthesis, of ET-1 in hepatocytes are an important mechanism of its elevated levels in cirrhosis.

Infarcted regenerative nodules in cirrhosis: CT and MR imaging findings with pathologic correlation

OBJECTIVE. The purpose of this article is to present the imaging findings and correlative pathologic findings of infarcted regenerative nodules in the cirrhotic liver. CONCLUSION. Infarcted regenerative nodules exhibit a spectrum of imaging appearances in the cirrhotic liver and can resemble hypovascular hepatocellular carcinoma or other neoplasms on CT and MR imaging. Although uncommon, this abnormality must be included in the differential diagnosis of focal liver lesions in patients with cirrhosis, particularly in patients with a history of substantial gastrointestinal bleeding. Serial imaging may help differentiate these lesions from malignant tumors.

Renal cortical neoplasms in long term survivors of solid organ transplantation

BACKGROUND

Renal cortical neoplasms have been reported after organ transplantation, but the level of risk as well as the histological features are poorly defined.

METHODS

A retrospective autopsy-based study was performed to evaluate renal neoplasms occurring in patients who underwent solid organ transplantation, died, and received an autopsy from 1981 to 1997 (383 liver, 125 heart, 52 lung, 39 heart/lung, 98 kidney, 4 bowel). Patients were divided into those with short (less than 101 days), medium (101 days to 5 years), and long-term survival (more than 5 years). The control group consisted of hospital autopsies on nontransplanted patients from the odd-numbered years, 1983 through 1997.

RESULTS

Renal cortical neoplasms were identified in 32/1325 of nontransplanted patients and 15/701 transplanted patients. In transplanted patients, neoplasms were identified in 14 native and 1 allograft kidney: 2/391 in short-term survivors, 3/234 in medium, and 10/76 in long term survivors. While transplant patients with short and medium length survival had no increased risk for neoplasms, patients with long-term survival showed a 9-fold increase in cortical neoplasms. Transplant patients with neoplasms averaged 47 years of age at death, significantly younger than the average age of 70 for nontransplanted control patients with renal neoplasms. The neoplasms in transplanted patients were all tubulopapillary, except for one clear cell neoplasm and ranged in size from 0.1 to 2 cm.

CONCLUSIONS

Long-term survivors of solid organ transplants have an 9-fold increased risk of developing tubulopapillary renal cortical neoplasms.

Epstein-Barr virus-negative post-transplant lymphoproliferative disorders: a distinct entity?

Post-transplant lymphoproliferative disorders (PTLDs) are usually but not invariably associated with Epstein-Barr virus (EBV). The reported incidence, however, of EBV-negative PTLDs varies widely, and it is uncertain whether they should be considered analogous to EBV-positive PTLDs and whether they have any distinctive features. Therefore, the EBV status of 133 PTLDs from 80 patients was determined using EBV-encoded small ribonucleic acid (EBER) in situ hybridization stains with or without Southern blot EBV terminal repeat analysis. The morphologic, immunophenotypic, genotypic, and clinical features of the EBV-negative PTLDs were reviewed, and selected features were compared with EBV-positive cases. Twenty-one percent of patients had at least one EBV-negative PTLD (14% of biopsies). The initial EBV-negative PTLDs occurred a median of 50 months post-transplantation compared with 10 months for EBV-positive cases. Although only 2% of PTLDs from before 1991 were EBV negative, 23% of subsequent PTLDs were EBV negative (p <0.001). Of the EBV-negative PTLDs, 67% were of monomorphic type (M-PTLD) compared with 42% of EBV-positive cases (p <0.05). The other EBV-negative PTLDs were of infectious mononucleosis-like, plasma cell-rich (n = 2), small B-cell lymphoid neoplasm, large granular lymphocyte disorder (n = 4) and polymorphic (P) types. B-cell clonality was established in 14 specimens and T-cell clonality was established in three (two patients). None of the remaining specimens were studied with Southern blot analysis and some had no ancillary studies. Rearrangement of c-MYC was identified in two M-PTLDs with small noncleaved-like features, and rearrangement of BCL-2 was found in one large noncleaved-like M-PTLD. Ten patients were alive at 3 to 63 months (only three patients received chemotherapy). Seven patients, all with M-PTLDs, are dead at 0.3 to 6 months. Therefore, EBV-negative PTLDs have distinct features, but some do respond to decreased immunosuppression, similar to EBV-positive cases, suggesting that EBV positivity should not be an absolute criterion for the diagnosis of a PTLD.

A combination study design to examine mycophenolate mofetil (MMF) and PTLD in renal transplant patients

Renal transplant recipients who are chronically immunosuppressed by drugs are at a higher risk of developing malignancies. Commonly observed malignancies are several forms of posttransplant lymphoproliferative disorders (PTLD), skin, lip and gynaecological cancers. The risk is associated with many risk factors including the extent of immunosuppression. Mycophenolate mofetil (MMF) is an immunosuppressant, indicated for the prophylaxis of organ rejection in patients receiving allogenic renal and heart transplants. During the European approval of MMF for renal transplantation, the question was raised as to whether the use of MMF was associated with an increased risk of PTLD in comparison with alternate immunosuppressive regimens. In response, F. Hoffman-La Roche Ltd set up a prospective observational cohort study with a companion case-control study. This paper describes the objectives and the methods of these studies along with the rationale of the methodology.

Epstein-Barr virus-induced posttransplant lymphoproliferative disorders. ASTS/ASTP EBV-PTLD Task Force and The Mayo Clinic Organized International Consensus Development Meeting

Epstein-Barr virus-induced posttransplant lymphoproliferative disease (EBV-PTLD) continues to be a major complication after solid organ transplantation in high-risk patients. Despite the identification of risk factors that predispose patients to develop EBV-PTLD, limitations in our knowledge of its pathogenesis, variable criteria for establishing the diagnosis, and lack of randomized studies addressing the prevention and treatment of EBV-PTLD hamper the optimal management of this transplant complication. This review summarizes the current knowledge of EBV-PTLD and, as a result of two separate international meetings on this topic, and provides recommendations for future areas of study.

A fresh look at augmenter of liver regeneration in rats

Augmenter of liver regeneration (ALR) is a hepatotrophic protein originally identified by bioassay in regenerating rat and canine livers following partial hepatectomy and in the hyperplastic livers of weanling rats, but not in resting adult livers. The ALR gene and gene product were subsequently described, but little is known about the cellular/subcellular sites of ALR synthesis in the liver, or about the release and dissemination of the peptide. To obtain this information in rats, we raised antibodies in rabbits against rat ALR for development of an enzyme-linked immunosorbent assay (ELISA). ALR concentrations were then determined in intact livers of unaltered weanling and adult rats; in regenerating residual liver after partial hepatectomy; in cultured hepatocytes and nonparenchymal cells (NPCs); and in culture medium and serum. ALR in the various liver cells was localized with immunohistochemistry. In addition, hepatic ALR and ALR mRNA were assayed with Western blotting and reverse-transcriptase polymerase chain reaction (RT-PCR), respectively. The hepatocyte was the predominant liver cell in which ALR was synthesized and stored; the cultured hepatocytes secreted ALR into the medium in a time-dependent fashion. Contrary to previous belief, the ALR peptide and ALR mRNA were present in comparable concentrations in the hepatocytes of both weanling and resting adult livers, as well as in cultured hepatocytes. A further unexpected finding was that hepatic ALR levels decreased for 12 hours after 70% hepatectomy in adult rats and then rose with no corresponding change in mRNA transcripts. In the meantime, circulating (serum) ALR levels increased up to 12 hours and declined thereafter. Thus, ALR appears to be constitutively expressed in hepatocytes in an inactive form, and released from the cells in an active form by unknown means in response to partial hepatectomy and under other circumstances of liver maturation (as in weanling rats) or regeneration.

Cytokine mRNA profiles in Epstein-Barr virus-associated post-transplant lymphoproliferative disorders

Cytokine mRNA patterns were analyzed in 11 post-transplant lymphoproliferative disorder (PTLD) specimens using qualitative reverse-transcriptase polymerase chain reaction (RT-PCR). In each case, a pattern of IL2-, IFN gamma-, IL4+, IL10+ was seen. A similar pattern was observed in a spleen sample from 1 patient with contemporaneous PTLD elsewhere. Semiquantitative RT-PCR for cytokine message was performed using RNA from bronchoalveolar lavage (BAL) specimens obtained from 2 patients with pulmonary PTLD. In both cases, IL4 message predominated. Reduction of message coincided with resolution of the tumors. The pattern differed from that seen in 1 patient with acute pulmonary rejection, in which RT-PCR of BAL cells showed predominance of IL6 and IFN gamma. We conclude that at least some PTLDs exist within a T-helper cell type 2 (Th2)-like cytokine microenvironment. The presence of a similar mRNA pattern in an extratumoral specimen at the time of PTLD suggests that it may reflect a systemic phenomenon. Disappearance of this pattern following PTLD resolution indicates its dynamic nature and is consistent with the hypothesis that specific cytokines contribute to the development of PTLDs.

De novo hepatocellular carcinoma in a hepatic allograft with recurrent hepatitis C cirrhosis

We report a case of de novo hepatocellular carcinoma (HCC) in a patient with recurrent hepatitis C (HCV) and cirrhosis 7 years after orthotopic liver transplantation (OLT). This is a previously unreported observation in the natural history of posttransplantantion HCV infection and reiterates the strong oncogenic potential of HCV.

Clinicopathologic features of posttransplant lymphoproliferative disorders

Posttransplant lymphoproliferative disorders (PTLD) are primarily B lymphocyte tumors which are related to the Epstein-Barr virus. Recent studies have more clearly delineated neoplastic from hyperplastic forms of this disease. Factors associated with increased PTLD risk include recipient EBV seronegative status and heavy immunosuppression. The clinical presentation of PTLD is reviewed and lesser known features such as respiratory compromise or localization of tumors to skin are highlighted. The pathologic classifications of PTLD are surveyed and related to one another. Newer approaches to therapy, including the use of monoclonal antibodies and adoptive cellular immunotherapy are discussed.

Comparative incidence of de novo nonlymphoid malignancies after liver transplantation under tacrolimus using surveillance epidemiologic end result data

BACKGROUND

An increased incidence of de novo nonlymphoid malignancies has been shown in immunocompromised patients. However, the true risk over time compared to the general population has not been determined.

METHODS

One thousand consecutive patients were carefully followed for an average of 77.8+/-11.1 (range, 56.3-96.3) months after primary liver transplantation at a single center. All de novo nonlymphoid malignancies were recorded. Each malignancy was compared with a standard Occupational Cohort Mortality Analysis Program population matched for age, sex, and length of follow-up using modified life table technique and surveillance epidemiology end result (SEER) data.

RESULTS

Fifty-seven patients accounted for de novo malignancies and contributed 4795.3 total person years, a mean+/-SD of 36+/-21 (median, 36; range, 6-74) months after liver transplantation. Twenty-two of these malignancies were skin malignancies including two melanomas. Oropharyngeal cancers (n=7) were found to be 7.6 times higher (P<0.05) and respiratory malignancies (n=8) were 1.7 times higher (P>0.05) compared to the SEER incidence rate. Female reproductive system malignancies including breast cancer (n=3) were 1.9 times lower (P>0.05) and genitourinary malignancies were (n=5) 1.5 times lower (P>0.05) than their matched cohorts. No differences was observed in gastrointestinal malignancies (n=5). There was a significant difference in survival of the patients after diagnosis of malignancy depending on the type of cancer. There were two Kaposi's sarcomas, two metastatic unknown primaries, one thyroid, one brain, and one ophthalmic malignancies in the series. Mortality for Kaposi's and metastatic disease of unknown primary was 100% within 5 months, while the 1-year mortality for oropharyngeal cancer was 57.1% and that for lung cancers was 62.5%. Long-term survival for skin cancer was highest: 86.4% at 3 years (P=0.015 by log-rank test).

CONCLUSION

An increased incidence of de novo cancers in the chronically immunocompromised patient demands careful long-term screening protocols which will help to facilitate the diagnosis at an early stage of the disease. This is particularly true for oropharyngeal cancers where the risk is more than 7 times higher compared to SEER incidence data matched for age, sex, and length of follow-up.

Clonal and morphological variation in a posttransplant lymphoproliferative disorder: evolution from clonal T-cell to clonal B-cell predominance

The majority of posttransplant lymphoproliferative disorders (PTLD) are Epstein-Barr virus (EBV)-associated and of B-cell origin. A much smaller proportion of PTLD are of T-cell origin. We report the clinical, morphological, immunophenotypic, and genotypic results of a unique PTLD, initially diagnosed as immune mediated thrombocytopenia (ITP), which at presentation was predominantly an anaplastic appearing EBV-associated T-cell PTLD and, after reduction in immunosuppression and the administration of antiviral agents, predominantly an EBV-associated plasma cell rich B-cell PTLD. Subsequent chemotherapy resulted in a complete remission. This case has both practical and biological implications. It highlights how PTLD may be misdiagnosed as other entities, how biclonal cases can have different morphological appearances and include both B- and T-cell clones, how PTLD can evolve over time possibly related to immune reconstitution, and why PTLD should be rebiopsied when the disease does not respond to decreased immunosuppression or recurs.

Transforming growth factor alpha (TGFalpha) in hepatocellular carcinomas and adjacent hepatic parenchyma

We examined stage T1 to T4 hepatocellular carcinomas (HCC) to determine whether transforming growth factor alpha (TGFalpha) presence differed between early- and late-stage HCC and between tumors with low and high proliferative rates. Paraffin sections from 36 HCC were evaluated for TGFalpha and the proliferation markers Kiel 67 antigen (Ki67) or proliferating cell nuclear antigen (PCNA) by immunoperoxidase staining. In 12 cases, double staining for TGFalpha and Ki67 was also performed. Eighty-one percent of tumors and 94% of adjacent liver sections contained TGFalpha. A trend toward inverse correlation was seen between the percentage of TGFalpha-positive tumor cells and the proliferative rate as determined by Ki67 staining. No clear correlation of TGFalpha to either tumor stage or percentage of PCNA-positive cells was seen. This study confirms the presence of TGFalpha in the majority of early- and late-stage HCC. Positivity within tumor tissue is consistent with autocrine or paracrine stimulation. A trend toward inverse correlation between TGFalpha-producing cells and the number of cycling cells suggests that rapidly proliferating tumors may consume this growth factor at an accelerated rate. Alternatively, other hepatic mitogens may have more functional significance in these latter tumors. Finally, the presence of TGFalpha in peritumoral hepatocytes suggests these cells as potential sources of paracrine stimulation for HCC.

Effects of immunotherapy on experimental immunodeficiency-related lymphoproliferative disease

BACKGROUND

Human lymphokine-activated cells (LAK cells) and interferon alpha (IFN-alpha) have been used clinically in the therapy of posttransplant lymphoproliferative disease (PTLD). However, the efficacy of such therapy has not been extensively tested under controlled experimental conditions.

METHODS

A B-cell line, derived from PTLD tissue and clonally related to the parent lesion, was tested for its response to IFN-alpha in vitro. The effects of LAK cells and IFN-alpha therapy were examined in a severe combined immunodeficiency disease (SCID) mouse model in vivo.

RESULTS

The PTLD cell line studied showed a 30% decrease in the rate of growth upon incubation with 500 U/ml of IFN-alpha. This in vitro response was also reproduced in vivo, in tumor therapy studies conducted in SCID mice. The magnitude of this inhibitory effect in vivo was a function of tumor burden and dose of IFN-alpha. In parallel experiments, LAK cells reduced the tumorigenicity of a lymphoblastoid cell line derived from the peripheral blood of a patient with PTLD, and prolonged the survival of SCID-beige mice with established lymphoproliferative disease. In contrast with two prior studies, in which the use of autologous cytotoxic T cells was found to be necessary, we found the administration of third-party non-HLA-matched LAK cells also to be effective in reducing tumor burden.

CONCLUSIONS

These observations demonstrate the efficacy of immunotherapy for lymphoproliferative disease under controlled experimental conditions, and validate currently ongoing efforts exploring the utility of such therapy in the clinical setting.

Causes of death in autopsied liver transplantation patients

Liver transplantation is an established treatment for multiple end-stage liver diseases, yet little information is available on the autopsy-determined causes of death in liver transplant recipients. We undertook a retrospective study of the immediate causes of death in all liver transplant recipients who underwent autopsy at the University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, from January 1982 to January 1997. Infections were the most frequent cause of death, present in 64% of a total of 321 cases. Overall, the infections were bacterial in 48% of the cases, fungal in 22%, and viral in 12%. The ratio of infectious to noninfectious causes of death did not change significantly during the 15-year study period, and the relative percentages of bacterial, fungal, and viral infections showed relatively little variation on a year-to-year basis. Two-thirds of all infections occurred during the first 100 days post transplantation. A precipitous drop in the number of infections (and the number of deaths) occurred by Day 90. Other major causes of death included liver failure (12%), pulmonary failure (10%), multiple organ system (8%), and cardiovascular causes (6%). Infections were the most frequent cause of death in this study population, suggesting that improvement in the prevention and treatment of infections is an important way to improve survival of liver transplant recipients.

Herpesvirus 6 variant A infection after heart transplantation with giant cell transformation in bile ductular and gastroduodenal epithelium

Herpesvirus 6 (HHV-6) is a ubiquitous virus known to cause febrile syndromes and exanthema subitum in children. Less commonly, and particularly in organ transplant recipients, it may result in hepatitis, bone marrow suppression, interstitial pneunonitis, and meningoencephalitis. This report expands the spectrum of clinical disease associated with HHV-6 by documenting viral infection in a 44-year-old heart transplant recipient presenting with gastroduodenitis, pancreatitis, and hepatitis. On histopathologic examination, the gastric, duodenal, and bile ductular epithelium showed a multinucleate giant cell transformation similar to the cytopathic effect caused by the virus in human T-lymphocytes infected in vitro. Electron microscopy showed herpes particles with a thick tegument layer in the duodenum. Polymerase chain reaction amplified HHV-6 variant A sequences from multiple sites. Serology confirmed the presence of an acute HHV-6 infection. Thus, HHV-6 variant A can cause gastroduodenitis and pancreatitis in immunosuppressed individuals. Multinucleate giant cells and enveloped virions with a prominent tegument can be used as morphologic criteria to raise the possibility of HHV-6 infection in human biopsy tissue.

Utilization of hepatocyte-specific antibody in the immunocytochemical evaluation of liver tumors

A monoclonal antibody highly specific for benign and malignant hepatocytes (HepPar 1) was evaluated as part of an antibody panel used to differentiate hepatocellular from nonhepatocellular neoplasms. Sixty-five liver tumors and two extrahepatic tumors from patients with documented liver tumors were studied. Twenty-two neoplasms were of hepatocellular origin, three were combined hepatocellular/cholangiocarcinomas, and the remainder were of nonhepatocellular origin. HepPar 1 alone had an 82% sensitivity and 90% specificity for the detection of hepatocellular neoplasms. The corresponding values for alpha-fetoprotein were 57% and 97%. Polyclonal antibody to carcinoembryonic antigen (canalicular pattern) had a sensitivity of 79% and specificity of 97% for these tumors. The use of antibody panels provided superior results when compared with individual antibodies. In summary, HepPar 1 monoclonal antibody is a useful reagent for the differential diagnosis of hepatocellular tumors. Its utility is enhanced when it is used as part of a diagnostic antibody panel.

Cytologic features of post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorders (PTLD) are Epstein-Barr virus (EBV)-associated lymphoid proliferations which affect approximately 2% of organ allograft recipients. Although the histologic features of PTLD are well described, they have been described only rarely in cytologic specimens. The cytomorphologic features of PTLD in body fluid specimens, needle aspirations, and a gastric brushing specimen from seven patients with histologically confirmed PTLD were therefore reviewed. In the cytologic specimens, PTLD was characterized by a mostly polymorphous population of lymphoid cells containing many large transformed lymphocytes, occasional immunoblast-like atypical lymphocytes, necrosis, and, frequently, obvious plasmacytoid differentiation. The presence of EBV was documented in five of the seven cases in the corresponding tissue biopsies. The four patients with PTLD in a body fluid specimen all died within 3 months of detection of the PTLD in the body fluid. The three remaining patients are alive with resolution of PTLD (follow-up of 7, 8, and 14 months). The diagnosis of PTLD should be suggested when cytologic specimens from organ allograft recipients show a polymorphous atypical lymphoid proliferation, frequently with plasmacytoid differentiation and necrosis. Cytologic samples may provide the initial diagnosis of this potentially fatal disease and allow appropriate intervention. The presence of PTLD in a body fluid specimen is a poor prognostic indicator.

Autologous lymphokine-activated killer cell therapy of Epstein-Barr virus-positive and -negative lymphoproliferative disorders arising in organ transplant recipients

Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2 x 10(9) to 5.6 x 10(10) LAK cells was given intravenously. Systemic interleukin 2 was not administered. The four patients with EBV+ PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV- lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor. In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+ organ transplant recipients. LAK cell efficacy for three patients with EBV- PTLD was not evaluable under the management circumstances in which this treatment was utilized.