High prevalence of Foxp3 and IL17 in MMR-proficient colorectal carcinomas.

BACKGROUND AND AIMS: Colorectal cancer (CRC) harbours different types of DNA alterations, including microsatellite instability (MSI). Cancers with high levels of MSI (MSI-H) are considered to have a good prognosis, probably related to lymphocyte infiltration within tumours. The aim of the present study was to characterise the intratumoural expression of markers associated with the antitumour immune response in mismatch repair (MMR)-proficient (MSS) colon cancers. METHODS: Ninety human colon cancers (T) and autologous normal colon mucosa (NT) were quantified for the expression of 15 markers of the immune response with quantitiative reverse transcription-PCR (qRT-PCR). mRNA expression levels were correlated with MMR status. Immunohistochemistry (IHC) was performed using both interleukin 17 (IL17) and CD3 antibodies. RESULTS: Expression of cytotoxic markers (FasL, granzyme B and perforin), inflammatory cytokines (IL1beta, IL6, IL8, IL17 and transforming growth factor beta (TGFbeta)) and a marker of regulatory T cells (forkhead box P3 (Foxp3)) was significantly higher in tumours than in autologous normal tissues. Adjusting for MMR status, higher tumoural expression of both granzyme B and perforin was associated with the MSI-H phenotype, and the perforin T/NT ratio was higher in MSI-H tissues than in MSS tissues. Higher tumoural expression of Foxp3, IL17, IL1beta, IL6 and TGFbeta was associated with the MSS phenotype, and the IL17 T/NT ratio was higher in MSS tissues than in MSI-H tissues as assessed by both qRT-PCR and IHC. CONCLUSIONS: Immune gene expression profiling in CRC displayed different patterns according to MMR status. Higher Foxp3, IL6, TGFbeta and IL17 expression is a particular determinant in MMR-proficient CRC. These may be potential biomarkers for a new prognostic "test set" in sporadic CRCs.

Recombinative events of the T cell antigen receptor delta gene in peripheral T cell lymphomas.

Recombinative events of the T cell antigen receptor (TCR) delta-chain gene were studied in 37 cases of peripheral T cell lymphoma (PTCL) and related to their clinical presentation and the expression of the alpha beta or gamma delta heterodimers as determined by immunostaining of frozen tissue samples. There were 22 cases of alpha beta, 5 cases of gamma delta, and 10 cases of silent TCR expressing neither the alpha beta nor gamma delta TCR. 5 different probes were used to examine the delta locus. The 22 cases of alpha beta PTCL displayed biallelic and monoallelic deletions; a monoallelic V delta 1 J delta 1 rearrangement was observed in 1 case and a monoallelic germ line configuration in 7 cases. The 5 cases of gamma delta PTCL displayed biallelic rearrangements: the productive rearrangements could be ascribed to V delta 1J delta 1 joining in 3 cases and VJ delta 1 joining in 2 cases according to the combined pattern of DNA hybridization with the appropriate probes and of cell reactivity with the TCR delta-1, delta TCS-1, and anti-V delta 2 monoclonal antibodies. In the VJ delta 1 joining, the rearranged V segments were located between V delta 1 and V delta 2. Interestingly, in the third group of 10 cases of silent PTCL, 5 cases were found to have a TCR gene configuration identical to that in the TCR alpha beta PTCL, as demonstrated by biallelic delta gene deletion. These 5 cases were CD3 positive. The 5 remaining cases showed a monoallelic delta gene rearrangement with a monoallelic germ line configuration in 4 and a monoallelic deletion in 1. Four of these cases were CD3 negative, which was consistent with an immature genotype the TCR commitent of which could not be ascertained. Finally, TCR gamma delta PTCL consisted of a distinct clinical morphological and molecular entity whereas TCR alpha beta and silent PTCL had a similar presentation.

CD3 hyporesponsiveness and in vitro apoptosis are features of T cells from both malignant and nonmalignant secondary lymphoid organs.

There is a dogma in tumor immunology that tumor-infiltrating lymphocytes (TIL) are defective based on their lack of antitumoral efficacy in vivo and on impaired response to in vitro functional tests. However, TIL have been compared usually with peripheral blood T lymphocytes, raising doubts on the conclusions drawn. Therefore, we compared TIL from B cell non-Hodgkin's lymphomas (NHL) with T cells from nonmalignant secondary lymphoid organs. NHL-TIL were unresponsive to activation by immobilized anti-CD3 mAb, although bypassing T cell receptor (TCR)/CD3 signaling led to proliferation. The poor proliferative responses of NHL-TIL could not be explained by quantitative defects in TCRzeta expression. NHL-TIL underwent marked spontaneous apoptosis in vitro with loss of approximately 50% of cells after 24 h of culture. This was associated with downregulation of the antiapoptotic Bcl-xL and Bcl-2 proteins, whereas viable NHL-TIL maintained their expression. IL-2, anti-CD3/IL-2, and manipulation of the Fas/Fas-ligand death pathway had no effect on NHL-TIL survival. Apoptosis was not due to increased cell cycling, as NHL-TIL were quiescent, nonproliferating cells. T cells from inflammatory, nonmalignant tissues gave similar functional results to NHL-TIL, suggesting the existence of factors common to the microenvironment of these diverse pathologies. Thus, the quiescent, anergic phenotype of NHL-TIL cannot be attributed solely to tumor factors, but rather is a feature of T cells from chronic inflammatory lesions.

Phenotypic and genotypic heterogeneity in large granular lymphocyte expansion.

The cellular heterogeneity of large granular lymphocyte expansions has been illustrated by the phenotypic and genotypic findings in five patients. In one patient whose circulating cells were CD2+, CD3-, CD5-, CD7+, CD8-, CD11+, Leu7+, CD16+, and displayed strong natural killer activity, no rearrangement of the T cell receptor beta-chain gene and T cell rearranging gene gamma was detected. The four other patients presented with neutropenia without overt lymphocytosis. In these patients the circulating lymphocytes expressed a predominant T cell phenotype CD2+, CD3+, CD5+, CD7+, CD8+, Leu7+. In three of them the presence of a T cell clone was demonstrated on the basis of a unique pattern of rearrangement of the T cell receptor beta-chain genes.

Vasculitis in hairy-cell leukemia.

Vasculitis associated with hairy-cell leukemia (HCL) has been reported occasionally. We determined the clinical and biological significance of this association by the retrospective study of a series of 50 patients with HCL, including nine patients with vasculitis. The development of vasculitis was not related to a variant of HCL on the basis of hematologic findings and survival. Vasculitis could occur at any time during the course of HCL, and was the circumstance for the diagnosis of HCL in three cases. Clinical and immunohistologic findings were those of hypersensitivity vasculitis in the nine patients. Infection was found to be an associated factor. Thus, eight of nine patients were infected at vasculitis onset, four died of their infection with no remittance of the cutaneous lesions, and three recovered from both infection and vasculitis. The monocyte deficiency in HCL is known to favor intracellular pathogen infection; however, we could not demonstrate that it also correlates with a decrease in the clearance of IgG-sensitized erythrocytes. Finally, vasculitis in HCL appears to be associated with a lasting infection in most cases.

Pregnancy in women with immune thrombocytopenic purpura.

Thirty-six women with immune thrombocytopenic purpura were studied during 37 pregnancies, and maternal characteristics with predictive value for the fetal platelet count were determined. Nine neonates were thrombocytopenic, with a platelet count of less than 50 x 10(9)/L in eight. Four of these nine neonates delivered to a subgroup of 31 mothers were studied prospectively; the frequency of thrombocytopenia in neonates of women with immune thrombocytopenic purpura was thus 13%. Only two of these nine neonates presented with hemorrhagic syndromes (two, petechial purpura; one, intracranial bleeding). The frequency of neonatal thrombocytopenia was higher in mothers with deep thrombocytopenia and in those who had not responded to corticosteroid treatment following diagnosis. No prognostic value could be assigned to the other maternal characteristics studied, such as a history of splenectomy, maternal treatment at the time of delivery, or the presence of platelet autoantibodies evaluated either with the platelet immunofluorescence test or the platelet Western blot immunoassay.

Legionnaires' disease and hairy-cell leukemia. An unfortuitous association?

Four cases of legionnaires' disease were diagnosed by specific serologic tests in a group of 33 immunocompromised patients admitted to the same hematologic department for acute febrile pneumonitis. The underlying disease of these four patients was hairy-cell leukemia (HCL) in three cases and allogeneic bone marrow transplantation in the other. This article stresses the enhanced susceptibility of patients with HCL to Legionella pneumophila and discusses its possible causes, especially monocyte deficiency. We propose the use of erythromycin as part of the initial empiric antibiotic therapy in immunocompromised hosts with acute pneumonitis until the results of specific serologic tests or isolation of L pneumophila is obtained.

A hypereosinophilic syndrome with retinal arteritis and tuberculosis.

A 35-year-old man was initially seen with a decrease in visual acuity, renal insufficiency, and elevation of the eosinophil count in the blood. The ocular syndrome was caused by extensive arterial occlusions of the retina. The subsequent apparition of cardiac, pulmonary, and neurologic signs fulfilled the criteria for the diagnosis of hypereosinophilic syndrome (HES). Most symptoms, including ocular, were temporarily but notably improved by hydroxyurea. The patient died after two years. An autopsy showed an endomyocardial fibrosis and disclosed destruction of the left kidney by an active tuberculosis. A pathogenic relationship between the infectious disease and the HES is envisaged.

Hepatic vein obstruction in idiopathic hypereosinophilic syndrome.

We report an association between idiopathic hypereosinophilic syndrome and obstruction of the hepatic veins (Budd-Chiari syndrome). Budd-Chiari syndrome was assessed by liver biopsy and hepatic phlebography and documented by computed tomography. Postmortem examination revealed fibrous occlusion of the hepatic venous tree, as well as fibrosis of the endocardium and of myocardial and pulmonary vessels. To our knowledge, the association between idiopathic hypereosinophilic syndrome and Budd-Chiari syndrome has never previously been reported. Since it has been suggested that hypereosinophilia might cause endothelium damage, a link between these two entities is postulated.

Human primary lymphocyte colony formation in agar culture: polyclonal origin and significance.

Primary human lymphocyte colonies, which grow on the surface of agar culture under PHA stimulation, arise from more than one progenitor cell: they contain both type A and B of G6PD when the donor is heterozygous for the isoenzymes. The distribution pattern of electrophoretic bands indicates that, on the average, two T lymphocyte clones proliferate per colony. Colony formation in the present circumstances appears as an in vitro system more suitable for the study of cellular cooperation between a limited number of cells than for the characterization of immature lymphocyte precursors in man.

Human lymphocyte colony formation in agar culture: cell phenotype studies on individual colonies indicate a polyclonal origin of such colonies.

Monoclonal origin of human lymphocyte colonies grown in agar culture under mitogenic stimulation is still disputed. To solve this question we used different markers: we failed with the G6PD technic and with the successive staining for X and Y chromosomes on individual colonies. Therefore, individual colonies were investigated for the presence of different cell types using membrane receptor identification and cytochemistry. At different stages of the colony formation, presence of a macrophage surrounded by lymphocytes, of a mixture of T cells and B cells, plasma cells and c.Ig negative cells, in the same colony was demonstrated. The mixture of cells from different lineages in individual colonies indicated a polyclonal origin of such colonies, the capacity for the cells to migrate in a short distance, and the involvement of cell-cell contact throughout the colony formation. Human lymphocyte colony formation appears as a new technic for the study of cellular cooperation.

Clonal T-cell colony formation in agar culture: an attractive assay to test the T-cell depletion from bone marrow.

Current studies suggest that the depletion of T-lymphocytes from donor marrow is an effective method for preventing acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation in man. To deplete the T-lymphocytes from bone marrow cells we use either monoclonal anti-T-cell antibodies and complement or T101 ricin A-chain immunotoxin. Residual T-lymphocytes are analyzed by their capacity to form clonal T-cell colonies in the presence of phytohemagglutinin (PHA), accessory cells, and recombinant interleukin 2. The method is compared to immediate indirect immunofluorescence (iF) and thymidine incorporation by marrow cells stimulated by PHA. IF is not suitable for evaluating the depletion by immunotoxin, and the interpretation of thymidine incorporation is generally questionable. The results of the colony formation show that the sensitivity of the colony assay is close to that of iF when T cells are depleted by complement lysis, and the sensitivity of the colony assay is not dependent upon the depletion procedure. Therefore, the T-cell colony assay is a simple functional control for the quality of bone marrow T-cell depletion, especially for T-cell depletion by immunotoxin.

Differentiation of antitumor-specific cytotoxic T lymphocytes from autologous tumor infiltrating lymphocytes in non-Hodgkin's lymphomas.

The present study describes a new culture protocol allowing the activation and proliferation of autologous tumor infiltrating T lymphocytes (TIL), and the generation of antitumor specific CTL in non-Hodgkin's lymphoma (NHL). Cells from eight patients with indolent NHL were used. We performed 3-week co-cultures of TIL with irradiated autologous malignant B cells in the presence of low doses of IL-1beta, IL-2 and IL-12. The proliferation, phenotype and cytotoxicity, and antitumor specificity of T cells recovered were studied. T-cell clonality was analyzed using TCRgamma gene rearrangement amplification by a multiplex PCR. Under these culture conditions, TIL proliferated, and the CD8+ T lymphocytes that were in a minority at the beginning of the culture increased dramatically in 6 out of 8 cases. In two cases, CD4+ T lymphocytes expanded. We showed that an oligoclonal selection of reactive T cells occurred in culture. Specific cytotoxicity developed against autologous malignant B cells in the 6 cases where there was an expansion of CD8+ T lymphocytes. Inhibition experiments performed with mAb directed against HLA class I and II molecules, CD4, CD8 and TCRgammadelta showed that the cytotoxic effector cells were CD8+ T lymphocytes probably expressing TCRalphabeta+. Cytokine secretion was analyzed in culture medium, and we detected significant levels of IFN-gamma, TNF-alpha, and IL-10 and no IL-4 (except in one case). Our results demonstrate that memory T cells from lymphoma patients can be amplified and differentiated into antitumor cytotoxic cells using a combination of the cytokines IL-1beta, IL-2, and IL-12 in association with non modified tumor cells.

Dominant T-cell clones of unknown significance in patients with idiopathic sensory neuropathies.

OBJECTIVE: To determine whether idiopathic sensory neuropathies could be associated with circulating dominant T-cell clones, a T-cell equivalent to monoclonal gammopathy of unknown significance. BACKGROUND: A number of predominantly sensory neuropathies remain of unknown etiology. Circulating dominant T-cell clones may be observed in the elderly, in autoimmune disorders, and in chronic viral infections. METHODS: Twenty patients with chronic sensory or predominantly sensory neuropathies considered idiopathic after intensive investigation were evaluated for the presence of dominant T-cell clones in blood using PCR amplification of the variable region of the T-cell receptor gamma-chain gene. They were classified as chronic idiopathic axonal polyneuropathy (CIAP) or sensory neuronopathy, i.e., chronic idiopathic ataxic neuropathy (CIAN), according to clinical and electrophysiologic criteria. RESULTS: Occurrence of clonal expansions of T cells was strikingly high in patients with idiopathic sensory neuropathies (16/20, 80%), with a similar proportion in CIAP (12/15, 80%) and CIAN (4/5, 80%), as compared with elderly normal controls (2/10, 20%), elderly controls with degenerative neurologic diseases (2/10, 20%), and elderly patients with idiopathic chronic inflammatory demyelinating polyneuropathy (2/10, 20%) (all p < 0.005). CONCLUSION: Both CIAN and CIAP are associated with dominant T-cell clones of unknown significance that cannot simply be attributed to the age of patients. Relevance of T-cell clones to the pathogenesis of idiopathic sensory neuropathies remains to be determined.

Serum concentrations of cytokines in patients with Hodgkin's disease.

Serum concentrations of interleukin (IL)-1 alpha, IL-2, IL-4, IL-6 and tumour necrosis factor (TNF) were measured in 24 untreated patients with Hodgkin's disease and in 24 healthy volunteers matched for age and sex. Serum levels of IL-1 alpha were significantly higher in patients with Hodgkin's disease. The number of patients with detectable serum IL-2 or IL-6 levels was significantly higher in patients with Hodgkin's disease as compared to the control group. No difference was observed for TNF. IL-4 was undetectable in all patients. Serum cytokine levels were not significantly different in patients with and without systemic "B" symptoms (weight loss or fever and night sweats) in the different histological subtypes and clinical stages. Serum concentrations of IL-1 alpha, IL-2, IL-6 and TNF were not correlated to the erythrocyte sedimentation rate, fibrinogenaemia or thrombocyte number. These results indicate that subsets of patients with Hodgkin's disease have detectable serum IL-1 alpha, IL-2 and IL-6 levels, but that other mediators are likely to be involved in the associated clinical and biological inflammatory syndrome.

Activation by PHA of CD8 lymphocytes into clonal colony forming cells. Role of interleukin-1.

Monoclonal T cell colonies can be grown in agar culture from quiescent T lymphocytes under PHA stimulation, provided that (1) a low number of T lymphocytes (less than or equal to 5 X 10(4)/ml) is seeded, (2) IL-2 is added to the culture, and (3) a high number of accessory B cells (greater than or equal to 5 X 10(5)/ml) is present in contact with the T lymphocytes. Under these culture conditions the colony progenitors can be ascribed to the CD4 subset, whereas CD8 lymphocytes do not generate colonies. This finding is surprising since both CD4 and CD8 lymphocytes may be cloned in liquid culture. We now report the appropriate conditions required to grow cytotoxic CD8 lymphocyte colonies in agar. CD8 colony growth is dependent upon IL-2-IL-2 receptor interaction and is inhibited by anti-IL-2 receptor antibodies. In addition to PHA, accessory B cells and IL-2, an additional signal provided by recombinant IL-1 is necessary for CD8 colony formation. Exogenous IL-1 can be replaced by irradiated CD4 lymphocytes which stimulate the expression of membrane IL-1 activity in the accessory B cells. In addition, colony growth from quiescent but not preactivated CD8 lymphocytes is inhibited by anti-IL-1 antibodies. Altogether, the data show that an IL-1 signal is required for the induction of IL-2 responsive IL-2 receptors on quiescent CD8 colony forming cells.

Adenoviral transduction of human 'clinical grade' immature dendritic cells enhances costimulatory molecule expression and T-cell stimulatory capacity.

The therapeutic use of dendritic cells (DC) in antigen-specific anti-tumor vaccines, requires sufficient numbers of functional DC, the preparation of which should comply with the code of Good Manufacturing Practice. In addition, the expression of tumor specific antigen should be possible in these DC. As a preclinical step, the method reported here was developed in healthy volunteers. Monocytes (Mo) were isolated by leukapheresis from 12 donors, purified by elutriation and then cultured for 6 days in sealed bags in AIM-V serum free medium with granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-13 (IL-13). Between 6x10(8) and 1x10(9) immature DC (iDC) could be differentiated from one leukapheresis. Cells displayed a characteristic iDC phenotype (CD1a(+), CD14(-), CD80(+), CD86(+), HLA DR(+), CD83(-)), and had potent allogeneic and antigen dependent autologous T cell-stimulatory capacity. Moreover, iDC could be further differentiated into mature DC by CD40 ligation as assessed by CD83 expression and the upregulation of HLA-DR and costimulatory molecules. After infection with a recombinant adenovirus encoding for beta-galactosidase (betaGal), 50% to 80% of iDC expressed betaGal without toxicity. Adenovirus infection increased the expression of both costimulatory molecules and CD83, and also increased allogeneic stimulatory capacity. Thus, the method developed here allows us to use large numbers of functional iDC as will be required for therapeutic uses in man. These DC can express a transgenic protein.

Human immunodeficiency virus-related lymphoma treatment with intensive combination chemotherapy. French-Italian Cooperative Group.

PURPOSE: An increased risk of high-grade non-Hodgkin's lymphoma is observed in patients who are seropositive for human immunodeficiency virus (HIV). Treatment of such patients is complicated by their underlying acquired immunodeficiency syndrome (AIDS). Intensive strategies such as those used in non-HIV-related lymphoma may be poorly tolerated. However, patients without severe AIDS may derive significant benefits from such an approach. In a prospective multicenter study, treatment outcomes were assessed in 141 cases of HIV-seropositive lymphomas submitted to aggressive chemotherapy. PATIENTS AND METHODS: Adult patients with lymphoma with a performance status less than 3 and no active opportunistic infection were consecutively treated with three cycles of doxorubicin 75 mg/m2, cyclophosphamide 1,200 mg/m2, vindesine 2 mg/m2 for 2 days, bleomycin 10 mg for 2 days, and prednisolone 60 mg/m2 for 5 days (ACVB). This treatment was followed by a consolidation phase of high-dose methotrexate plus leucovorin, ifosfamide, etoposide, asparaginase, and cytarabine (LNH84). Central nervous system prophylaxis with intrathecal methotrexate was routinely used. Zidovudine maintenance therapy was started after chemotherapy. Ninety-three patients had high-grade lymphomas (59 Burkitt's type) and 48 had intermediate-grade lymphomas. Disseminated stage III-IV was present in 86 patients, meningeal involvement in 29, and bone marrow infiltration in 30; 62 patients had more than 2 extranodal localizations. Lactate dehydrogenase levels were above the normal value in 95 cases. The median CD4-positive lymphocyte count was 227 x 10(6)/L. RESULTS: Eighty-nine patients (63%) achieved complete remission (CR) and 19 (13%) partial remission, whereas 13 did not respond and 20 (14%) died during the course of ACVB, 8 of them from progressive disease. With a median follow-up of 28 months, median survival and disease-free survival were 9 and 16 months, respectively. Median survival for nonresponders was 5 months; 23 patients died of opportunistic infections while in persistent CR. In multivariate analysis, four factors were strongly associated with shorter survival: (1) CD4 count less than 100 x 10(6)/L, (2) performance status greater than 1, (3) immunoblastic lymphoma, and (4) prior AIDS. In the absence of all risk factors, the probability of survival at 2 years was 50%. CONCLUSION: In a selected group of HIV-related lymphomas, intensive chemotherapy with LNH84 is feasible and yields a high CR rate. Survival is short due to death from HIV-related infections; however, in a subgroup of patients without adverse prognostic factors, long-term remission was observed.

Hepatosplenic alphabeta T-cell lymphoma: an unusual case with clinical, histologic, and cytogenetic features of gammadelta hepatosplenic T-cell lymphoma.

Hepatosplenic gammadelta T-cell lymphoma is a recently identified entity in which lymphoma cells bearing the gammadelta T-cell receptor (TCR) infiltrate the sinusoids of the liver and the sinuses of the splenic red pulp and bone marrow, without lymph node involvement. It is also characterized by a recurrent cytogenetic finding, isochromosome 7q (i7q10). The authors report a case of hepatosplenic lymphoma of alphabeta T-cell phenotype that shares the same clinical, histologic, and cytogenetic characteristics of the previously described hepatosplenic gammadelta T-cell lymphoma. Fluorescent in situ hybridization performed with chromosome 7 probes showed the typical pattern of isochromosome 7q. Genomic analysis of the TCR gamma locus failed to detect a clonal rearrangement. This unique case of hepatosplenic lymphoma of alphabeta T-cell phenotype supports the possibility that lymphoid populations of different alphabeta or gammadelta phenotype that share similar homing and presumably functional properties could give rise to lymphomas displaying similar clinical and pathologic findings.

Patterns of Epstein-Barr virus latent and replicative gene expression in Epstein-Barr virus B cell lymphoproliferative disorders after organ transplantation.

B cell lymphoproliferative disorders arising in organ transplant recipients (B cell posttransplant lymphoproliferative disorders [PTLD]) are generally associated with EBV. In previous reports, B cell PTLD were shown to express the full pattern of EBV latent genes, as in vitro-established lymphoblastoid cell lines. Although viral linear DNA was detected in 40% of lymphoproliferative disorders from immunocompromised hosts, immunophenotypic studies failed to detect late EBV replicative antigens. The aim of this study was to investigate the relationship of EBV latent gene expression in B cell PTLD to morphology, clonality, and immunophenotype, and to examine the replicative state of EBV in malignant cells. For this purpose, 9 cases of EBV-related B cell PTLD were analyzed. Immunoglobulin gene rearrangements were detected by Southern blot analysis. The presence of EBV was assessed by Southern blot and by in situ hybridization. B cell differentiation antigens, adhesion and activation molecules, and EBV latent and replicative gene expression were studied using immunohistochemistry techniques. We demonstrated that EBV-related B cell PTLD exhibited varying patterns of latent viral gene expression. Higher levels of adhesion molecules were detected in latent membrane protein 1 (LMP1) or LMP1 plus EBV nuclear antigen 2 (EBNA2)-positive tumors than in LMP1 and EBNA2-negative tumors. In contrast, there was no relationship between CD21 and CD23 expression and latent EBV phenotype. Activation of the EBV replicative cycle was highlighted by BamHI Z left frame 1 expression in 5 of 9 cases. Less frequent expression of late viral proteins suggested that the initiation of the EBV lytic cycle might not always lead to virions production.