Immunoglobulin and T cell receptor gene rearrangements and in situ immunophenotyping in lymphoproliferative disorders

The Relevance of VDJ PCR Protocols in Detecting B-Cell Clonal Expansion in Lymphomas and Other Lymphoproliferative Disorders

Aims and background

The detection of immunoglobulin heavy chain variable (VH)-diversity (DH)-joining (JH) region gene rearrangement by polymerase chain reaction (VDJ PCR) has been recently proposed as a rapid approach to assess B-cell clonality in lymphoproliferative disorders. The aim of the present study was to determine the efficacy of VDJ PCR in a wide spectrum of lymphoproliferative disorders previously characterized by immunohistochemistry and Southern blot (SB).

Methods

83 SB-rearranged B-cell non-Hodgkin's lymphomas (NHL) of different histotype, 22 cases of SB-unrearranged classical Hodgkin's disease (HD), 18 cases of HIV-related reactive lymphadenopathy, and 4 frankly pre-lymphomatous lesions (MESA) in the course of Sjögren's syndrome were investigated by 2 different VDJ PCR protocols (FR3, FR2).

Results

The detection rate in NHL was 64% and 71% using the protocols FR3 and FR2, respectively. However, the overall VDJ PCR efficacy increased to 81% by combining the results of both protocols. In addition, differences in the combined, as well as in the single FR3 or FR2 protocol efficacy, were noted in the different NHL subgroups. B-cell clonality was also detected in 4/22 (18%) SB-unrearranged classical HD cases and in 2/18 (11%) reactive lymphadenopathy cases, whereas it was demonstrated in all the MESA lesions, 2 of them being SB-negative.

Conclusions

VDJ PCR represents a useful and rapid technique to detect B-cell clonality in NHL, although with some differences depending on the NHL histotype and the panel of primers employed. The technique may also be of value to investigate the possible progression of early B-cell clonal expansion into frankly B-cell malignancy and to contribute to the controversy about the clonal lineage origin of the putative HD malignant cells.

Clonal Analysis of Intrahepatic B Cells from HCV-Infected Patients With and Without Mixed Cryoglobulinemia

Clonal rearrangements of Ig heavy chain (IgH) genes and hepatitis C virus (HCV) genomic sequences were assayed on intrahepatic B lymphocytes isolated from HCV chronically infected patients with and without type II mixed cryoglobulinemia (MC). Liver tissue samples from eight patients with and nine without MC were subjected to routine histologic studies, immunophenotyping, and genotypic analysis including IgH V-D-J region gene rearrangements by PCR. RT-PCR, signal amplification by branched DNA assay, and in situ hybridization technique were used to detect and quantitate HCV RNA genomic sequences in selected B cells purified from each tissue sample. Although HCV infection of intrahepatic B cells was shown in all patients both with and without MC, frank B cell monoclonal and oligoclonal patterns were found in only three and four patients with MC, respectively. No monoclonal profile was seen in the noncryoglobulinemic patients, whereas an oligoclonal profile was demonstrated in four of them. No clonalities were shown in HCV-unrelated patients matched for age and severity of liver disease. No obvious difference in HCV genotype distribution was found in relation to the clonal expansion profile. Noncryoglobulinemic patients showing clonal expansion in liver tissue had higher titers of serum rheumatoid factor (RF). Spontaneous production of RF was shown in cell cultures of intrahepatic B cells, suggesting their persistent stimulation in vivo. These data indicate that HCV infection of B cells and B cell clonal expansions occur in the liver microenvironment and preferentially involve RF-producing cells.

Characterization of prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome

OBJECTIVE

To determine whether the prelymphomatous stages of B cell lymphoproliferation in Sjögren's syndrome (SS) may be better characterized by the integration of clinical, pathologic, and molecular data, the latter focusing on the expansion, persistence, and dissemination of clonal B cells in the course of the disease.

METHODS

Multiple tissue lesions (synchronous from different tissues and metachronous from the same tissue) were evaluated in biopsy specimens obtained from 6 consecutive patients with SS who had an associated lymphoproliferative disorder. Fully benign gastric lesions were evaluated in tissue from an additional 11 patients with SS who had no associated lymphoproliferative disorder. Multiple and complementary molecular analyses of B cell clonality were used: Southern blot, polymerase chain reaction, single-strand conformation polymorphism, DNA sequencing, and hybridization with clonospecific oligoprobes. All the patients were then strictly followed up for the appearance of lymphoma.

RESULTS

Different scenarios of SS-associated B cell lymphoproliferation were identified: 1) the ongoing expansion of the same dominant clone, localized or disseminated, in tissue from 2 patients, 1 of whom later developed an overt B cell lymphoma; 2) different dominant clones in different synchronous or metachronous tissues from the remaining 4 patients with an associated lymphoproliferative disorder; and 3) small oligoclonal expansions in 7 of the 11 benign gastric lymphoid infiltrates.

CONCLUSION

Prelymphomatous B cell lymphoproliferation in SS was better characterized following integration of the findings. The different types of B cell clonal expansion (oligoclonal or monoclonal, smaller or larger in size, fluctuating or established, localized or disseminated) may imply a different risk of lymphoma progression. An accurate clinical, histopathologic, and molecular characterization may therefore be crucial in future studies aimed at clarifying the pathobiology of SS-associated lymphoproliferation.

Immunophenotypic and molecular analyses of acquired immune deficiency syndrome-related and Epstein-Barr virus-associated lymphomas: a comparative study

Limited information is current available on the molecular and immunophenogenotypic characteristics of CD30-positive anaplastic large cell (ALC) lymphomas occurring in human immunodeficiency virus (HIV)-infected individuals. To address this issue, the authors have undertaken a combined analysis of these lymphomas in a comparison with other Epstein-Barr virus (EBV)-associated tumors in the setting of HIV infection. Twenty-one AIDS-related lymphomas, including five CD30-positive ALC and 11 small noncleaved cell (SNCC) lymphomas, and five Hodgkin's disease (HD) specimens were characterized regarding the immunophenogenotypic features, the frequency and subtype distribution of EBV (as defined by in situ hybridization [ISH], Southern blot, and a polymerase chain reaction [PCR] amplification of the EBV nuclear antigen-2 [EBNA-2] region) antigen expression (latent membrane protein-1 [LMP-1], EBNA-2, and for alterations of the tumor suppressor gene p53. Combined immunophenotypic and immunogenotypic analyses showed a derivation from anomalously matured B cells in four of five CD30-positive ALC lymphomas, whereas SNCC showed features of mature B cells; no evidence of immunoglobulin or TCR gene rearrangement could be obtained in HD cases. Combined ISH and Southern blot analyses revealed that EBV was more strictly associated with HD (five of five) and CD30-positive ALC lymphomas (four of five) than with SNCC lymphomas (four of 11). EBV-positive samples from CD30-positive ALC lymphomas carried type 1 EBV (two of two specimens tested), whereas both EBV subtypes were observed in SNCC lymphomas and HD samples. All three forms of viral latent gene expression were found in the EBV positive CD30-positive ALC lymphomas. SNCC specimens did not express LMP-1 or EBNA-2, whereas HD specimens expressed LMP-1 (four of five tested) but no EBNA-2. Immunostaining for ZEBRA was consistently negative. HHV-6 DNA sequences were detected by PCR in one SNCC of the 19 specimens analyzed. Three out of five CD30-positive ALC lymphoma specimens and six of 10 SNCC showed nuclear staining for p53. No mutation was detected in any of the three CD30-positive Alc lymphoma analyzed, whereas an aberrant SSCP pattern was found in all the four SNCC samples tested. At variance with SNCC lymphomas, AIDS-related B-cell CD30- positive ALC lymphomas are strictly associated with EBV infection and may also express the broad lymphoblastoid cell line-like (LMP-1-positive, EBNA-2-positive) pattern, and lack p53 genetic lesions. Unlike EBV, HHV-6 probably does not represent a relevant factor involved in the pathogenesis of CD30-positive ALC and other HIV related lymphomas.

Characteristics of EBV-infected cells in HIV-related lymphadenopathy: implications for the pathogenesis of EBV-associated and EBV-unrelated lymphomas of HIV-seropositive individuals

The present study was performed with the aim of better defining the possible role of Epstein-Barr-virus (EBV)-infected cells in the pathogenesis of HIV-related lymphadenopathy syndrome (LAS). In addition, since LAS has been considered as a pre-lymphomatous lesion, we also wished to elucidate the possible contribution of EBV-carrying cells present in LAS tissues to the development of HIV-associated malignant lymphomas. To this end, we have characterized EBV-infected cells in LAS lymph nodes in terms of EBV DNA prevalence, tissue distribution in relation to HIV-carrying cells, virus sub-type, expression of latent and replicative antigens, and presence of clonal EBV episomes. When compared with HIV-unrelated lymphadenopathies (4/10, 40%), LAS showed a higher prevalence of EBV DNA (14/20, 70%). Comparable values of EBV prevalence were detected in LAS with follicular hyperplasia (12/16, 75%) and with follicular involution (4/4, 100%). All EBV+ non-neoplastic lymph nodes from HIV-seronegative patients carried type-I EBV, whereas LAS specimens showed almost equivalent distribution of the 2 EBV sub-types. Of the 14 EBV-carrying LAS, 4 (29%) were positive by Southern-blot analysis for the BamHI-W region of the virus genome but negative for the presence of monoclonal EBV episomes. In situ hybridization revealed a remarkably higher load of EBV-infected cells in LAS than in HIV-unrelated lymphadenopathies. In LAS lymph nodes, EBV-carrying cells were identified as isolated, cytologically normal elements, sometimes with immunoblastic morphology, usually scattered throughout the interfollicular areas. By contrast, the expression of HIV p24 was restricted to germinal center cells. All the EBV+ LAS samples were negative for the expression of EBV-encoded latent (LMP-1 and EBNA-2) and replicative proteins (BZLF-1, BHLF-1, EA-D, EA-R and VCA). In addition, amplification of the immunoglobulin heavy-chain genes using 2 different polymerase-chain-reaction protocols showed evidence of B-cell clonal expansion in 2/20 (10%) LAS, one EBV- case, and one sample with low numbers of EBV-infected cells. These results suggest that (i) EBV-carrying cells are probably not involved in the development of LAS, either directly or indirectly; (ii) type-2-EBV-infected cells are present in LAS lymph nodes from the early phases of HIV infection; (iii) EBV-carrying LAS per se probably does not constitute a lesion at high risk for subsequent development of EBV+ lymphomas; (iv) it is unlikely that a high viral load or strong EBV-mediated antigenic stimulation plays a contributory role in the development of EBV-unrelated lymphomas of HIV-seropositive individuals.

Genotypic and immunohistological demonstration of the progression of an unusual reactive-like B-cell lymphoproliferative disorder to a high grade diffuse lymphoma

In the present study the clinical and pathological evolution of a reactive-like B-cell lymphoproliferative disorder with an unusually high content of T cells is described. Immunogenotypic analysis showed that the same phenotypically atypical B-cell clone, characterized by the unusual presence of an immunoglobulin (Ig)K gene rearrangement, with the heavy chain (IgH) gene in germline configuration, was invariantly present in all phases of the disease. The disorder showed an indolent course for a long period of time during which the clonal B-cell population coexisted with an abundant, reactive T-cell component in different locations of the disease. These findings, together with the observation of spontaneous progression and regression phases of the disorder and its responsiveness to corticosteroids, suggest that functional interactions between the B-cell clone and the polyclonal infiltrating T cells probably were involved in the pathogenesis of the disease. After the administration of the antiblastic treatment, a progressive reduction of the reactive T-cell component was observed with the concomitant evolution to a diffuse large cell (immunoblastic) B-cell lymphoma and the appearance of an IgH gene rearrangement. The biological characteristics and the clinical evolution of the case described here are similar to those reported for the so-called "T-cell-rich B-cell lymphomas" (TCRBCLs). These findings suggest that the T-cell-rich pattern may identify a group of B-cell lymphoproliferations with common pathogenetic mechanisms and clinical behavior.

Diagnostic and prognostic significance of clonal T-cell receptor beta gene rearrangements in lymph nodes of patients with mycosis fungoides

In this study, 25 involved and uninvolved lymph nodes from 22 patients with mycosis fungoides (MF) and seven dermatopathic lymph nodes from patients with benign skin disorders were studied for the presence of clonal T-cell receptor beta (TCR beta) gene rearrangements by Southern blot analysis. These results were correlated with the histological classification, follow-up data, and survival. The results of the histological classification and Southern blot analysis were concordant in 26 of 32 cases. Clonal TCR beta gene rearrangements were found in all six MF lymph nodes showing (partial) effacement of the normal lymph node architecture, but in none of the eight uninvolved dermatopathic MF lymph nodes and in none of the seven dermatopathic control lymph nodes. In addition, in 5 of 11 dermatopathic MF lymph nodes that were considered to have early involvement by MF at histological examination, clonal TCR beta gene rearrangements were detected. In the group of MF patients with dermatopathic lymphadenopathy, patients with detectable clonal T-cell populations had a significantly shorter survival than patients without such a population (P < 0.01). The results of this study indicate that within the group of dermatopathic MF lymph nodes, prognostically different groups can be distinguished and that TCR beta gene rearrangement analysis may be an important adjunct in the early diagnosis of lymph node involvement by MF.

High incidence of monoclonal EBV episomes in Hodgkin's disease and anaplastic large-cell KI-1-positive lymphomas in HIV-1-positive patients

A series of selected lymphoid malignancies (LMs) occurring in Italian HIV-1-infected (HIV+) patients, principally intravenous drug users, was investigated. In addition to small non-cleaved-cell (SNCC) and large-cell immunoblastic (LCI) non-Hodgkin's lymphomas (NHLs), a relatively high occurrence of anaplastic large-cell Ki-I-positive (ALC Ki-I+) lymphomas and Hodgkin's disease (HD) was observed, at variance with other reported series of HIV+ patients. Combined results of in situ hybridization and Southern-blot analyses, in conjunction with immunohistochemical detection of Epstein-Barr virus (EBV)-encoded latent membrane protein-I (LMP-I), showed an almost complete association of ALC Ki-I+ lymphomas and HD cases with EBV. The neoplastic cells of both these LMs also showed common immunophenotypic features such as frequent absence of B- and T-cell differentiation markers and expression of the Ki-I activation marker, while SNCC and LCI lymphomas were mainly of mature B-cell origin and Ki-I-. The concomitant high incidence of ALC Ki-I+ lymphomas and HD in a specific group of HIV+ patients, their almost complete association with EBV in clonal and episomal form and the great similarity in differentiation, activation and virological markers which they display suggest that these LMs are pathological variants of a continuous spectrum of HIV-I-associated disorders etiopathologically linked to EBV.

A multidisciplinary approach to the diagnosis of cutaneous T-cell lymphomas

The cutaneous T-cell lymphomas (CTCLs) comprise a spectrum of non-Hodgkin lymphomas with a predilection for the skin. This heterogeneous group of CTCLs include the prototypic CTCL mycosis fungoides (MF) and the recently described Ki-1+ lymphomas. MF is notoriously difficult to diagnose in its early stages. The histologic appearance of early MF is indistinguishable from that of chronic dermatitis. The limitations of light microscopy in the diagnosis of the CTCLs have led to the development of other diagnostic laboratory techniques. The best approach to the diagnosis of the CTCLs is a multidisciplinary one and should include ultrastructural morphometry, immunophenotyping, immunogenotyping, and histologic evaluation whenever possible. It is the purpose of this overview to point out the strengths and weaknesses of each of these techniques and, together with clinical input, to provide a comprehensive and rational approach to patient care.

Diagnostic value of T-cell receptor beta gene rearrangement analysis on peripheral blood lymphocytes of patients with erythroderma

Differentiation between Sézary's syndrome (SS) and benign forms of erythroderma may be extremely difficult. In this study T-cell receptor beta (TCR beta) gene rearrangement analysis was performed on peripheral blood lymphocytes (PBL) from 32 patients with erythroderma, including 10 patients with SS, three patients with another type of cutaneous T-cell lymphoma, and 19 patients with a benign form of erythroderma. The aim of this study was to define the sensitivity and specificity of this technique in the diagnosis of SS. Clonal TCR beta gene rearrangements were found in eight of 10 patients with SS, one T-CLL patient, one of two patients with erythrodermic mycosis fungoides, and only one of 19 patients from the benign group. In the two "false-negative" cases of SS clonal TCR beta gene rearrangements were detected in PBL obtained during follow-up. The results indicate that TCR beta gene rearrangement analysis on PBL is a sensitive and highly specific technique, that may contribute significantly to the differential diagnosis of patients with erythroderma. However, because both "false-positive" and "false-negative" results may occur, the results of gene-rearrangement analysis should always be considered in conjunction with clinical, histologic, and immunophenotypical data.

A clinicopathologic study of lymphoid neoplasias associated with human immunodeficiency virus infection in Italy

The clinicopathologic features of 45 human immunodeficiency virus (HIV)-infected patients (mainly intravenous drug users [IVDU]) with lymphoid neoplasias seen from September 1984 through July 1990 at an Italian cancer center are reviewed. Thirty-five had systemic non-Hodgkin's lymphoma (NHL), and ten had Hodgkin's disease (HD). Histologically, 27 NHL cases were intermediate grade (five cases) or high grade (22 cases, 14 of the small noncleaved cell type), according to the Working Formulation. Eight NHL cases, including four anaplastic large cell (ALC) BerH2 (CD30)-positive lymphomas, were in the miscellaneous group. Immunohistologic and/or gene rearrangement analysis showed the B-cell origin of 20 of the 24 NHL cases studied. At presentation, 71% of NHL patients had advanced stages (Stage III or IV), and 85% had extranodal disease (predominantly gastrointestinal tract and marrow). Of the 23 patients evaluable for treatment, only seven had a complete clinical response after lymphoma therapy; the median survival of 34 evaluable patients was 22 months after the diagnosis of NHL. Fifteen patients died; most deaths were attributable to progressive lymphoma and opportunistic infections. As with NHL, advanced disease, extranodal involvement, aggressive histologic findings, and poor response to therapy were also observed in patients with HD. This study shows that lymphoid neoplasias occurring in Italian IVDU with HIV infection and those previously reported in North American homosexual men with HIV infection share similar clinicopathologic features. However, some features such as the absence of history of Kaposi's sarcoma at diagnosis, the lack of detection of primary brain and rectal NHL, and the occurrence of B-cell ALC BerH2 (CD30)-positive NHL were observed uniquely in this series of patients.

Histopathologic, immunophenotypic, and genotypic analysis of Ki-1 anaplastic large cell lymphomas that express histiocyte-associated antigens

CD30/Ki-1 antigen expression in 243 cases of malignant lymphomas was examined using Ber-H2 monoclonal antibody. Among them 20 cases were categorized as Ki-1 anaplastic large cell lymphoma. In two of these cases histiocyte-associated markers were also expressed. In these cases histopathologic and extensive in situ immunophenotypic analyses were used with genotypic studies in the determination of cell lineage. A sinusoid histologic pattern of involvement with partial lymph node infiltration by pleomorphic neoplastic cells was noticed in the nodes from both patients. Solid areas of node replacement resembling metastatic carcinoma were seen in Patient 1. Immunohistologically, tumor cells of both cases were positive for CD30, CD25, CD71, LN3 (HLA-DR), EMA, CD45, CD74, vimentin, alpha-1-antichymotrypsin, and CD68. Patient 1 was also CD45RO+, CD43+, whereas Patient 2 was positive for alpha-1-antitrypsin and CD4 tumor cells. Genotypic studies revealed that TCR beta and TCR gamma chain genes were clonally rearranged in Patient 1, whereas no rearrangements were detected in Patient 2. This study supports the view that some Ki-1 anaplastic large cell lymphomas may express multiple histiocyte-associated antigens and confirms that this group of neoplasms have immunophenotypic heterogeneity. The results of genotypic analyses used with immunophenotyping does not exclude that the tumor cells in these cases may be of true histiocytic origin despite the Ki-1-positive phenotype.

Anti-vimentin antibody reactivity with Reed-Sternberg cells of Hodgkin's disease

There are few data on the reactivity of Reed-Sternberg (RS) cells with antibodies against vimentin. In a preliminary survey of biopsy specimens from 16 cases of Hodgkin's disease (HD), we found that the antivimentin (V9) monoclonal antibody stained RS cells in 6 cases. We therefore examined vimentin expression on RS cells immunohistologically in 38 Bouin-fixed and paraffin-embedded lymph nodes with HD [lymphocyte predominance (LP) 4; nodular sclerosis (NS) 23; mixed cellularity (MC) 7; lymphocyte depletion (LD) 4]. The results were correlated with the histopathological features, the immunohistological phenotype of the RS cells, and the findings obtained from molecular genetics studies (available in 13 cases). RS cells were found to express strong and diffuse cytoplasmic staining for vimentin in 13 cases, all of the NS subtype. No differences in antigenic expression on RS cells were found between the vimentin-positive and negative cases within the NS subtype. DNA analysis revealed no B- or T-cell clonal populations in the tested samples. The results indicated that RS cells were immunostained by anti-vimentin (V9) antibody with a relatively high frequency, but only in the NS subtype of HD. This subtype, however, was heterogeneous according to vimentin immunostaining on RS cells. The significance of this finding concerning the RS cell origin in this subset is discussed.