Detection of Epstein-Barr virus DNA in Hodgkin- and Reed-Sternberg-cells by single cell PCR

Role of Viral Infections in Testicular Cancer Etiology: Evidence From a Systematic Review and Meta-Analysis

The most represented histotype of testicular cancer is the testicular germ-cell tumor (TGCT), both seminoma and non-seminoma. The pathogenesis of this cancer is poorly known. A possible causal relationship between viral infections and TGCTs was firstly evoked almost 40 years ago and is still a subject of debate. In the recent past, different authors have argued about a possible role of specific viruses in the development of TGCTs including human papillomavirus (HPV), Epstein-Barr virus (EBV), cytomegalovirus (CMV), Parvovirus B-19, and human immunodeficiency virus (HIV). The aim of this present review was to summarize, for each virus considered, the available evidence on the impact of viral infections on the risk of developing TGCTs. The review was reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We included all observational studies reported in English evaluating the correlations between viral infections (HPV, CMV, EBV, Parvovirus B19, and HIV) and TGCTs. The methodological quality of studies included in the meta-analysis was evaluated using a modified version of the "Newcastle-Ottawa Scale." Meta-analyses were conducted using the "Generic inverse variance" method, where a pooled odds ratio (OR) was determined from the natural logarithm (LN) of the studies' individual OR [LN (OR)] and the 95% CI. A total of 20 studies (on 265,057 patients) were included in the review. Meta-analysis showed an association with TGCTs only for some of the explored viruses. In particular, no association was found for HPV, CMV, and Parvovirus B-19 infection (p = ns). Conversely, EBV and HIV infections were significantly associated with higher risk of developing TGCTs (OR 7.38, 95% CI 1.89-28.75, p = 0.004; OR 1.71, 95% CI 1.51-1.93, p < 0.00001). In conclusion, we found adequate evidence supporting an oncogenic effect of HIV and EBV on the human testis. Conversely, available data on HPV and TGCTs risk are conflicting and further studies are needed to draw firm conclusions. Finally, current evidence does not support an effect of CMV and Parvovirus B-19 on testicular carcinogenesis.

Epstein-Barr virus (EBV)-associated lymphoid proliferations, a 2018 update

Epstein-Barr virus (EBV) has been linked to many human neoplasms including hematopoietic, epithelial, and mesenchymal tumors. Since our original review of EBV-associated lymphoproliferative disorders in 2007, many advances and developments have been reported. In this review, we will examine the recent advances in EBV-associated lymphoid/histiocytic proliferations, dividing them into reactive, B cell, T/NK cell, immunodeficiency-related, and histiocytic/dendritic cell proliferations.

Insights into the evolution of lymphomas induced by Epstein-Barr virus

Epstein-Barr virus (EBV) encodes a wealth of oncogenic instructions, including the abilities to drive a resting normal B cell to proliferate and to override apoptotic stimuli. EBV is found in almost all types of lymphomas at varying frequencies. However, the particular viral genes expressed differ considerably among tumors. We have examined the role of EBV in several lymphomas by conditionally evicting the extrachromosomal viral genome from tumor cells in vitro and have found a graded dependence on the virus. Tumor cells that express all the known latent viral genes have been found to depend on the virus to drive proliferation and to block apoptosis at least in part by repressing the proapoptotic protein Bim. Other tumor cells, which express fewer viral genes, also depend on the virus to block apoptosis, but rely on the virus to promote but not to drive proliferation. Lastly, tumor cells with the fewest viral genes expressed have been found to require EBV to prevent the inefficient induction of a Bim-independent apoptosis. We present a model for the evolution of EBV-induced lymphomas in which tumors are initially "addicted" to the virus for almost all oncogenic functions. These tumors are targets for the immune system because they express multiple immunogenic viral proteins. Therefore, EBV-induced tumors are under selective pressure to acquire cellular mutations that can replace viral functions. We posit that the heterogeneity in viral gene expression among different EBV-associated lymphomas reflects a dynamic process by which tumors evolve to be less dependent on the virus.

Proof for EBV's sustaining role in Burkitt's lymphomas

We have found that not all Epstein-Barr viral (EBV) plasmids are duplicated each cell cycle. This inefficiency is intrinsic to EBV's mechanism of DNA synthesis in latently infected cells and necessarily leads to a loss of EBV plasmids from proliferating cells. If EBV provides its host cells advantages that allow those cells that retain EBV to outgrow those that lose it, then such proliferating populations will be EBV-positive. EBV-associated human tumors are EBV-positive. Thus, the presence of EBV plasmids in most cells of a tumor demonstrates that EBV sustains these tumors in vivo. The virus can provide multiple selective advantages to tumor cells, including promoting cell proliferation and inhibiting cell death. In the case of Burkitt's lymphomas (BL), most current evidence indicates that the tumor requires the virus minimally to block apoptosis.

Prognostic significance of cell proliferation and apoptosis-regulating proteins in Epstein-Barr virus positive and negative pediatric Hodgkin lymphoma

Apoptosis-related genes and proteins and proliferation activity and their relationship with Epstein-Barr virus (EBV) is a contemporary issue. In this study, prognostic or pathogenetic roles of EBV latent infection, proliferating activity, and apoptosis-regulating proteins in pediatric Hodgkin lymphomas were explored. EBV-EBER, lmp-1, ki-67, bcl-2, survivin, Bax, fas, c-myc, and p53, and apoptotic index were analyzed in 63 pediatric Hodgkin lymphoma cases. The results were evaluated by chi-square, Mann Whitney U test, Pearson correlation analysis, and Kaplan Meier survival analysis. Thirty-two cases were stage I or II, whereas 31 cases were stage III or IV. The mean age was 8.4 +/- 63.54 years. EBV was positive in 52 (82.5%) cases. Overall survival was 94% and event-free survival 83.6%. Bax expression was observed 74.6%, bcl-2 47.6%, survivin 43%, p53 33.3%, fas 54%, and c-myc 25.4%. The mean apoptotic index was 18.22%. The mean proliferation index was 57.83%. The proliferation index was positively related with EBV but not with prognosis. None of the parameters were related with prognosis. EBV was negatively related with the apoptotic index. There were no relationships between bax, bcl-2, survivin, p53, fas, and c-myc with EBV. These results suggest that EBV might play a role in Hodgkin lymphoma pathogenesis by inducing proliferative activity and inhibiting apoptosis. Apoptosis-related proteins were not correlated with EBV. None of the parameters was found to predict prognosis.

Epstein-Barr virus–associated lymphoproliferative disorders

Epstein-Barr virus (EBV) is a member of the human herpesvirus family that was initially isolated from a cultured Burkitt lymphoma cell line by Epstein et al in 1964. Subsequent studies have proven that it is the causative agent in most cases of infectious mononucleosis. Primary infection is usually asymptomatic in childhood; but in adulthood, it is associated with a self-limiting infectious mononucleosis syndrome in approximately one third of the cases. EBV has been linked to many human neoplasms including hematopoietic, epithelial, and mesenchymal tumors. In this review, we will only discuss the EBV-associated lymphoproliferative disorders, dividing them into B-cell, T/NK-cell, and HIV-related lymphoproliferative disorders.

Homogeneous immunophenotype and paucity of secondary genomic aberrations are distinctive features of endemic but not of sporadic Burkitt's lymphoma and diffuse large B-cell lymphoma withMYC rearrangement

The present study has compared immunohistological marker expression profiles and genomic imbalances in seven African endemic Burkitt's lymphomas (eBLs) with those in ten European B-cell lymphomas with MYC rearrangement as shown by fluorescence in situ hybridization (FISH) analysis. eBLs showed a typical histomorphology and a homogeneous immuno-profile: CD10+, CD38+, CD77+, bcl-2-, and IgM+. Epstein-Barr virus (EBV) DNA was present in all cases. On comparative genomic hybridization (CGH), only three out of six eBLs showed imbalances (median number of imbalances = 2), with gains on chromosome 17 in two eBLs. The European lymphomas were all highly proliferating, with a Ki-67 index of at least 90%, and included seven with morphology typical of sporadic Burkitt's lymphoma (sBL) and three immunoblastic diffuse large B-cell lymphomas with MYC rearrangement (MYCre+DLBCL). In contrast to eBL, the immuno-profiles of the European lymphomas were less homogeneous and inconsistent for CD10, CD38, CD77, IgM and bcl-2 expression. EBV DNA was not detected. In five of seven sBLs, CGH showed a higher number of imbalances (median = 6), with recurrent gains on chromosome 1q (3/7) and losses on 12q and 17p (2/7), whereas all three MYCre+DLBCLs had fewer imbalances (median = 4), with gains on 17q in two of three lymphomas. It is concluded that eBL has a homogeneous immunohistology and few secondary genomic aberrations, whereas MYC-rearranged and highly proliferating European B-cell lymphomas are a heterogeneous group that includes sBL and a subgroup of diffuse large B-cell lymphomas.

Semiquantitative PCR analysis of Epstein-Barr virus DNA in clinical samples of patients with EBV-associated diseases

The laboratory diagnosis of primary and reactivated Epstein-Barr virus (EBV) infection is based on serologic methods in immunocompetent patients. However, in immunocompromised patients, serologic data are difficult to interpret and do not often correlate with clinical data. In order to find a useful and practical marker for diagnosis of EBV-related diseases, a polymerase chain reaction (PCR) assay was established for semiquantitative detection of EBV sequences. The method was based on a nested PCR, using primers of the virus capsid antigen p23 region and an endpoint dilution. This method was carried out on 68 plasma samples, 68 samples of peripheral blood mononuclear cells and 5 cerebrospinal fluid samples of 39 patients with various diseases to evaluate the EBV-genome copy number. Samples from patients suffering from infectious mononucleosis served as positive controls for active EBV infection. In 5 patients with infectious mononucleosis, high copy numbers of EBV genomes in peripheral blood mononuclear cells were detected within a range of 1,000-40,000 copies in 10(5) peripheral blood mononuclear cells. In contrast, samples from 19 latently infected persons either showed low copy numbers (10-100 in 10(5) peripheral blood mononuclear cells) or were EBV PCR negative. Comparable results were observed in seven renal transplant patients without any symptoms. The practical value of the semiquantitative detection of EBV DNA was demonstrated in three bone marrow transplant recipients. Two developed a lymphoproliferative disease associated with extremely high amounts of EBV DNA in plasma (16,000 and 50,000 copies/ml, respectively) and peripheral blood mononuclear cells (100,000 and 6.5 million copies in 10(5) peripheral blood mononuclear cells, respectively). The high EBV load in plasma and peripheral blood mononuclear cells was reduced dramatically after successful antiviral therapy in one case. The third bone marrow transplant recipient developed an EBV-induced transverse myelitis with an increased number of EBV-genome copies in peripheral blood mononuclear cells and EBV-positive cerebrospinal fluid samples. After combined antiviral and immune therapy, the EBV-genome copy numbers decreased and the patient recovered completely. These data demonstrate a good correlation between semiquantitative detection of EBV genomes and clinical findings. The method is recommended for the diagnosis of EBV-associated diseases in patients after transplantation, as well as for monitoring the response to therapy.

The correlation of Epstein-Barr virus expression and lymphocyte subsets with the clinical presentation of nodular sclerosing Hodgkin disease

BACKGROUND

The pathogenesis of nodular sclerosing Hodgkin disease (HD) has been correlated with Epstein-Barr virus (EBV). The phenotype of lymphocytes in HD and its relations to clinical presentation and to EBV expression have not been characterized fully. Grade II HD is a more aggressive form of the disease. The authors studied cases of HD by flow cytometry (FCM) in an attempt to analyze the phenotype of lymphocytes in the involved lymph nodes and to characterize the phenotype of these lymphocytes in relation to EBV expression, tumor grade, and clinical presentation. MATERIALS AND METHODS The authors prospectively studied lymph nodes from 48 patients with the diagnosis of HD by FCM for T (CD3, CD4, and CD8) and B (CD19) lymphocytes. Ratios of helper to suppressor (CD4 to CD8) and ratios of T to B (CD3 to CD19) lymphocytes were calculated. In situ hybridization for EBV also was performed. The tumors were graded. Clinical data related to age and stage of the disease were retrospectively analyzed.

RESULTS

There were 30 male and 18 female patients with an age range of 7 to 77 years (median, 17 yrs). EBV expression was seen in 24 (50%) cases. Eleven (23%) cases were classified as Grade II disease. All Grade II cases showed EBV expression, whereas only 13 (39%) cases of Grade I disease were positive (P = 0.03). EBV-positive cases had a median CD4 to CD8 ratio of 1.62, whereas EBV-negative cases had a ratio of 3.86 (P = 0.01). Grade I cases had a median CD4 to CD8 ratio of 4.58, whereas Grade II cases had a ratio of 1.62 (P = 0.007). EBV-positive cases had a median T-lymphocyte to B-lymphocyte ratio of 2.72, whereas EBV-negative cases had a ratio of 3.17 (P = 0.77). Grade I cases had a median T-lymphocyte to B-lymphocyte ratio of 3.51, whereas Grade II cases had a ratio of 1.71 (P = 0.001). A higher percentage of children was seen in the EBV-positive cases than in the negative ones (58% vs. 29%). Cases with low (< 1.5) CD4 to CD8 ratios showed more incidence of high-stage disease (Stages III and IV) than patients with higher ratios (81% vs. 51%). High-stage disease also was seen more frequently in patients with low (< 3) T- to B-lymphocyte ratios (71% vs. 50%).

CONCLUSION

The authors found that the local immune response in HD may vary from one case to another. The findings also suggest that EBV may play a role in the pathogenesis of the disease in relation to T- and B-lymphocyte response. A more profound immune suppression and decrease in overall T and helper lymphocytes may be seen in aggressive EBV-positive variants of the disease. These changes may impact the initial presentation of the disease and perhaps its overall biologic behavior.

B lymphocyte involvement in ankylosing spondylitis: the heavy chain variable segment gene repertoire of B lymphocytes from germinal center-like foci in the synovial membrane indicates antigen selection

The synovial membrane (SM) of affected joints in ankylosing spondylitis (AS) is infiltrated by germinal center-like aggregates (foci) of lymphocytes similar to rheumatoid arthritis (RA). We characterized the rearranged heavy chain variable segment (VH) genes in the SM for gene usage and the mutational pattern to elucidate the B lymphocyte involvement in AS. Cryosections from an AS-derived SM were stained for B and T lymphocytes. B cells were isolated from different areas of a focus. The rearranged VH genes were amplified by semi-nested polymerase chain reaction (PCR) using oligonucleotides specific for the six different VH families and heavy chain joining segments (JHs). PCR products were cloned and sequenced.Fifty-nine of 70 different heavy chain gene rearrangements were potentially functional. Most of the rearranged genes were mutated (range, 1-15%). Thirty of 70 products had a mutational pattern typical for antigen selection. Most of the rearranged VH genes belonged to the VH3 family (54%), consistent with data from healthy donors and patients with RA, while VH4 genes, in contrast to RA, were identified less frequently (10%) and VH5 genes were over-represented (11%). In contrast to RA, neither VH6 genes nor the autoimmunity-prone VH4-34 were seen, whereas another autoimmunity-prone gene, V3-23, was predominantly used (11%). One VH1-derived and one VH3-derived B cell clone were expanded. CDR3 were shorter and more variable in length than in RA. Comparable with RA and reactive arthritis, there is a biased repertoire of selected VH genes, whereas the panel of represented genes is different and less clonal expansion was observed.

Deletions within the epstein-barr virus latent membrane protein-1 oncogene in adult ordinary, HIV-associated and paediatric Hodgkin's disease

The aims of this study were the following: a) to perform Epstein-Barr virus (EBV) strain type assignment in three groups of Hodgkin's disease(HD): adult ordinary (39 cases), paediatric (24 cases), and HIV-associated (30 cases) and to compare the prevalence of type 1 and type 2 in each of the groups with that existing in two reference populations made up of 50 adults and 39 children; b) to assess the frequency of latent membrane protein-1 (LMP-1) 30-base pair (bp) deletions in the HD groups and in the healthy controls; and c) to relate the presence of LMP-1 deletions with EBV type. Type 2 EBV was observed in 12.8% of ordinary HD, in 26.7% of HIV-associated HD, in 25% of paediatric HD, in 4% of adult controls, and in none of the healthy children. The existence of double infections by type 1 and 2 EBV was also observed in 5.1% of ordinary HD, in 6.7% of HIV-associated HD, and in 10% of adult controls. The 30-bp deletion was identified overall in 33.3% of ordinary HD, in 83.3% of HIV-positive HD, 79.2% of paediatric HD, 34.7% of adult controls, and 36.4% of healthy children. Statistical analysis showed a significant association of the deleted strains with HD occurring in HIV-positive patients (P= 0.00003) and childhood HD (P= 0.006). On the other hand, the prevalence of the 30-bp deletion in the adult ordinary HD group reflects the prevalence of the deletion in the general population. Co-infections by deleted and non-deleted EBV strains were detected in 12.8% of ordinary HD, in 33.3% of HIV-associated HD, in 50% of paediatric HD, in 26.5% of adult controls, and in 27.3% of healthy children. Concerning the relationship between the deletion and the EBV typing, 26% of type 1 specimens carried the 30-bp deletion in an isolated manner compared with 64.7% of type 2. The statistical analysis showed that the deletion was associated with type 2 strains when coinfections were excluded and only the cases in which the deletion appeared alone were considered (P=0.003).

Epstein-Barr virus in the pathogenesis of Hodgkin's disease

Epidemiologic and clinico-pathologic features of Hodgkin's disease suggest that an infectious agent may be involved in the pathogenesis of this puzzling disorder. Recently accumulated data provide direct evidence supporting a causal role of Epstein-Barr virus in a significant proportion of cases. In addition to allowing a better understanding of the complex pathogenesis of Hodgkin's disease, these virological advances, briefly reviewed herein, also constitute an important basis for the development of new therapeutic strategies.

Epstein-Barr virus expression in Hodgkin's disease: Correlation with histologic subtypes and T and B lymphocyte distribution

BACKGROUND

The pathogenesis of Hodgkinâs disease (HD) has been linked to Epstein-Barr virus (EBV). Some histologic subtypes show a high level of viral expression. These include mixed cellularity (MCHD) and nodular sclerosis (NSHD) subtypes. Grade II NSHD is a more aggressive variant of HD. Lymphocyte predominant (LPHD) is a B cell lymphoproliferative disorder that has not been associated with EBV expression. Infiltrating lymphocytes in HD are predominantly T lymphocytes, with a minor component of B lymphocytes. In the current study, EBV expression was tested in cases of HD in relation to histologic subtypes. An attempt was made at correlating EBV expression with T and B lymphocyte distribution in lymph nodes involved by HD.

METHOD

Formalin-fixed paraffin-embedded tissue from 62 cases of HD were tested for EBV mRNA expression, using the EBER-1 probe and in situ hybridization. T and B lymphocyte distribution and their ratios were evaluated using antibodies to T and B lymphocytes (UCHL-1 [CD45 RO] and CD 20, respectively), and the immunoperoxidase technique.

RESULTS

The cases were seen in 38 male and 24 female patients, with an age range of 3 to 72 years (median 25 years). There were 30 cases of grade I and 15 cases of grade II NSHD, 9 cases of MCHD and 8 cases of LPHD. EBV mRNA expression was seen in 29 cases (46%). This expression was seen in 8 cases of grade I NSHD (26%), 13 cases of grade II NSHD (86%) and 8 cases of MCHD (88%). None of the cases of LPHD showed viral expression. T to B lymphocyte ratios in EBV-positive cases ranged from 1/6 to 8/1, and ranged from 2/1 to 20/1 in EBV-negative cases (P=0.06). Nine of the 29 positive cases (31%) showed equal T/B lymphocyte ratios (n=4), or predominance of B lymphocytes (n=5). None of the EBV-negative cases showed predominance of B lymphocytes.

CONCLUSION

Our study confirms previously reported findings of the prevalence of EBV expression in MCHD and NSHD. Our findings also suggest that EBV expression may be more commonly seen in aggressive forms of HD. Decreased numbers of T lymphocytes in these aggressive subtypes may suggest that a process of more profound T lymphocyte depletion is occurring in these cases, leading to uncontrolled EBV replication and more aggressive disease.

Cell kinetics, morphology, and molecular IgVH gene rearrangements in Hodgkin's disease

The present study dealt with the question of whether any cellular kinetic patterns correlate with clonal rearrangement of the IgVH gene as revealed by polymerase chain reaction on DNA extracted from lymph nodes with classical Hodgkin's disease (HD) and/or from single CD30+ cells (Hodgkin [H] and Reed-Sternberg [RS] cells). In 15/4 cases with H-RS cells of B or Null phenotype, signs of such monoclonality could be detected (group I) but not in the others (group II). CD30+/H-RS cells in group I differed slightly but significantly from those in group II in that they a) exhibited a larger fraction of cells attaining the anaphase/telophase stage of mitosis, and b) produced relatively more mononucleated cells (H) at the expense of multinucleated (RS) cells. In addition, reactive lymphoid cell (CD30-) infiltrates were considerably less dense in group I that in group II. These findings suggest that the cytokinesis of H-RS cells in group I was moderately more efficient than in group II. However, signs of monoclonality were not associated with the normalization of the mitotic process, which also proved to be disturbed in group I.

Lytic Replication of Epstein-Barr Virus in the Peripheral Blood: Analysis of Viral Gene Expression in B Lymphocytes During Infectious Mononucleosis and in the Normal Carrier State

Epstein-Barr virus (EBV) has been shown to establish latency in resting B lymphocytes of the peripheral blood. This creates a virus reservoir in contrast to lytic virus replication, which is thought to be restricted to differentiated epithelial cells in vivo. So far, the route of transmission between B cells and the production of progeny virus in the epithelial tissue has remained unclear. Reverse transcriptase–polymerase chain reaction (RT-PCR) and immunohistochemistry analysis of 16 patients with acute infectious mononucleosis (IM) and 25 healthy seropositive donors was performed to detect lytic replication gene products in B lymphocytes of the peripheral blood. Transcriptional activity was found in peripheral blood B lymphocytes (PBLs) for BZLF1 in 88%, BALF2 in 50%, and BcLF1 in 25% of the tested IM patients. All positive results were further confirmed in enriched B-cell populations by antigen determination using immunostaining with the APAAP technique. Furthermore, we detected transcripts for BZLF1 in 72% and for BALF2 in 16% of peripheral B lymphocytes of healthy seropositive donors. In contrast to patients with IM, no signals for BcLF1 were ever found in healthy seropositive donors. In these individuals, lytic replication of EBV is probably restricted by immunologic and gene regulatory mechanisms, whereas in the absence of immunologic control, reflected here by IM patients, the production of infectious virus becomes visible in PBLs.

Lytic Replication of Epstein-Barr Virus in the Peripheral Blood: Analysis of Viral Gene Expression in B Lymphocytes During Infectious Mononucleosis and in the Normal Carrier State

Epstein-Barr virus (EBV) has been shown to establish latency in resting B lymphocytes of the peripheral blood. This creates a virus reservoir in contrast to lytic virus replication, which is thought to be restricted to differentiated epithelial cells in vivo. So far, the route of transmission between B cells and the production of progeny virus in the epithelial tissue has remained unclear. Reverse transcriptase–polymerase chain reaction (RT-PCR) and immunohistochemistry analysis of 16 patients with acute infectious mononucleosis (IM) and 25 healthy seropositive donors was performed to detect lytic replication gene products in B lymphocytes of the peripheral blood. Transcriptional activity was found in peripheral blood B lymphocytes (PBLs) for BZLF1 in 88%, BALF2 in 50%, and BcLF1 in 25% of the tested IM patients. All positive results were further confirmed in enriched B-cell populations by antigen determination using immunostaining with the APAAP technique. Furthermore, we detected transcripts for BZLF1 in 72% and for BALF2 in 16% of peripheral B lymphocytes of healthy seropositive donors. In contrast to patients with IM, no signals for BcLF1 were ever found in healthy seropositive donors. In these individuals, lytic replication of EBV is probably restricted by immunologic and gene regulatory mechanisms, whereas in the absence of immunologic control, reflected here by IM patients, the production of infectious virus becomes visible in PBLs.

Single-cell analysis of T-cell receptor-gamma rearrangements in large-cell anaplastic lymphoma

Large-cell anaplastic lymphomas (LCAL) are characterized by their distinctive morphology together with expression of the CD30 antigen. In addition, a chromosomal translocation, t(2;5) (p23; q35), can be detected in most cases. A significant proportion of LCALs carry rearrangements of the T-cell receptor-gamma (TCR-gamma) locus and display a T-cell phenotype. In about a third of the cases, another type of non-Hodgkin-lymphoma precedes LCAL. Early transformations of non-Hodgkin's lymphoma into LCAL might escape clinical detection in a significant number of cases. The existence of clonally related lymphoid cells within the lymph node infiltrates must be claimed in these cases. Recently, a small-cell-predominant variant of LCAL was described in which only few large tumor cells expressing the CD30 antigen are found together with numerous small lymphocytes, which are frequently CD30-. This observation in particular prompted us to investigate the clonal relationship of the tumor cell compartment and admixed small lymphocytes in one case of common LCAL with T-cell genotype. For this purpose, we chose to amplify rearranged TCR-gamma sequences from single cells isolated from immunostained frozen sections by using a micromanipulator. A total of 119 cells were investigated. Amplification products were obtained in 17 of 79 CD3+ cells, 12 of 30 CD30+ cells, and three of 10 CD20+ cells. The nucleotide sequences were determined in 28 cells by nonradioactive sequencing. In 11 CD30+ cells, the predominant rearrangement of TCR-gamma was identified. No clonal diversity was observed. The small CD3+ lymphocytes were unrelated to the anaplastic CD30+ tumor cells. This report describes a method to analyze rearrangements of the TCR-gamma in single cells isolated from immunostained frozen sections. Application of this technique revealed an absence of clonal diversity in a case of LCAL and documented the polyclonal nature of admixed small CD3+ lymphocytes.

Single cell PCR for the analysis of Hodgkin's disease: four years later

BACKGROUND

Single cell-based studies represent a promising alternative to conventional molecular approaches in the study of Hodgkin's disease since the malignant Hodgkin and Reed-Sternberg cells (H & RS) represent only a small minority of the cellular infiltrate in affected nodes.

METHODS

Single cell polymerase chain reaction (PCR) assays were developed for the analysis of specific genomic DNA sequences and the detection of gene expression. Single H & RS cells were isolated by micromanipulation from cytospin slides or fresh cell suspensions after staining with an anti-CD 30 MoAB.

RESULTS

The status of oncogenes and immune receptor genes was examined by DNA-PCR. So far, no IgH or TCR gamma rearrangements were detected in H & RS cells of T- and B-antigen negative classical Hodgkin's cases but were detected in two cases of nodular paragranuloma. Global cDNA amplification was successfully performed from single H & RS cells, and specific gene transcripts were detected with a novel PCR method.

CONCLUSION

Single cell PCR is a novel and promising method that will help to elucidate many of the open questions in the biology of Hodgkin's disease. In the case of contradictory results, collaborations between different groups utilizing similar approaches have to be performed.

Detection of immunoglobulin heavy-chain gene rearrangement at the single-cell level in malignant lymphomas: no rearrangement is found in Hodgkin and Reed-Sternberg cells

Hodgkin and Reed-Sternberg (HRS) cells, the neoplastic cells of Hodgkin's disease (HD), represent only a minority of the cellular infiltrate in affected tissue. Therefore, rearrangements of the immunoglobulin heavy-chain (IgH) gene detected in DNA extracted from an entire Hodgkin's lymph node cannot be attributed to the HRS cells and cannot be used as an argument for the B-cell origin of HRS cells. We developed a new method for the amplification of rearranged DNA of the IgH gene from single cells. Using 6 "forward primers" which were constructed corresponding to consensus sequences of the 6 known families of the IgH variable (V) region (framework region I) and a mix of 2 "reverse primers" corresponding to consensus sequences of the different joining (J) segments, rearrangements of all 6 V-families were detected in human peripheral blood lymphocytes. Rearranged IgH DNA could be amplified from single cells of B-cell lymphoma-cell lines and from 13 patients with B-cell non-Hodgkin's lymphomas. However, analysis of HRS cells isolated from lymph nodes of 13 patients with Hodgkin's disease did not show any rearrangement of the IgH gene locus. These findings, obtained by polymerase chain reaction (PCR) on isolated single HRS cells, contrast with previous studies that used Southern-blot analysis of entire tissues affected by Hodgkin's disease. We conclude that the neoplastic HRS cells in Hodgkin's disease--with the possible exception of the nodular paragranuloma subtype--are probably not derived from B cells.