Combined polymerase chain reaction approach for clonality detection in lymphoid neoplasms

Molecular Testing of Lymphoproliferative Disorders: Current Status and Perspectives

Molecular pathologic testing plays an important role for the diagnosis, prognostication and decision of treatment strategy in lymphoproliferative disease. Here, we briefly review the molecular tests currently used for lymphoproliferative disease and those which will be implicated in clinical practice in the near future. Specifically, this guideline addresses the clonality test for B- and T-cell proliferative lesions, molecular cytogenetic tests for malignant lymphoma, determination of cell-of-origin in diffuse large B-cell lymphoma, and molecular genetic alterations incorporated in the 2016 revision of the World Health Organization classification of lymphoid neoplasms. Finally, a new perspective on the next-generation sequencing for diagnostic, prognostic, and therapeutic purpose in malignant lymphoma will be summarized.

Prognostic value of bone marrow involvement by clonal immunoglobulin gene rearrangements in follicular lymphoma

Aims

We aimed to evaluate the prognostic value of routine use of PCR amplification of immunoglobulin gene rearrangements in bone marrow (BM) staging in patients with follicular lymphoma (FL).

Methods

Clonal rearrangements were assessed by immunoglobulin heavy and light-chain gene rearrangement analysis in BM aspirates from 96 patients diagnosed with FL and related to morphological detection of BM involvement in biopsies. In 71 patients, results were also compared with concurrent flow cytometry analysis.

Results

BM involvement was detected by PCR in 34.4% (33/96) of patients. The presence of clonal rearrangements by PCR was associated with advanced clinical stage (I–III vs IV; p<0.001), high FL International Prognostic Index (FLIPI) score (0–1, 2 vs ≥3; p=0.003), and detection of BM involvement by morphology and flow cytometry analysis (p<0.001 for both). PCR-positive patients had a significantly poorer survival than PCR-negative patients (p=0.001, log-rank test). Thirteen patients positive by PCR but without morphologically detectable BM involvement, had significantly poorer survival than patients with negative morphology and negative PCR result (p=0.002). The poor survival associated with BM involvement by PCR was independent of the FLIPI score (p=0.007, Cox regression). BM involvement by morphology or flow cytometry did not show a significant impact on survival.

Conclusions

Our results showed that routine use of PCR-based clonality analysis significantly improved the prognostic impact of BM staging in patients with FL. BM involvement by PCR was also an independent adverse prognostic factor.

Primary follicular lymphoma of the duodenum is a distinct mucosal/submucosal variant of follicular lymphoma: a retrospective study of 63 cases

PURPOSE

Small series with limited follow-up have suggested primary follicular lymphoma of the duodenum (FL-D) to be an indolent disease. We report our experience on a large series of patients followed for a median time period of longer than 6 years.

PATIENTS AND METHODS

The study comprised 63 patients with primary FL-D defined as stage I disease. Endoscopy and detailed pathologic work-up was performed at diagnosis and at restaging to monitor the behavior of the neoplastic process.

RESULTS

Histologically, all 63 patients had FL, low grade (1 to 2). Duodenal endosonography demonstrated lesions confined to mucosa/submucosa in 19 of 20 patients. At an overall median follow-up of 77 months (range, 12 to 177 months), only two untreated patients had developed nodal disease, the remaining 61 patients never experienced extrasmall intestinal disease and large cell transformation did not occur at all. Among 24 patients followed by watch and wait strategy, seven showed spontaneous complete regression and 17 had stable disease; radiotherapy resulted in complete regression in all 19 patients; anti-CD20 antibody monotherapy achieved complete regression in four patients and stable disease in one patient. Various chemotherapy protocols in eight patients caused complete regression in all of them, but local relapses occurred in three. No patients required surgery or died of disease.

CONCLUSION

These findings characterize primary FL-D as a remarkably indolent FL variant, which, even left untreated, does not develop tumorous growth, very rarely disseminates (two of 63 patients) and does not transform to high grade disease. A watch and wait approach appears to be the most sensible strategy.

Florid reactive lymphoid hyperplasia of the lower female genital tract (lymphoma-like lesion): a benign condition that frequently harbors clonal immunoglobulin heavy chain gene rearrangements

Lymphoma-like lesions (LLL) of the lower female genital tract are florid reactive inflammatory processes that mainly occur in women in their reproductive years. Histologically, they are characterized by a dense lymphoid infiltrate with admixed large cells that is often suspicious for lymphoma. In contrast to lymphoma, however, they are superficial lesions that typically show surface erosion and a mixed lymphoid infiltrate and do not have evidence of a mass, deep invasion, or prominent sclerosis. With the advent of widespread molecular genetic testing, it would seem that LLLs should be polyclonal helping make the correct diagnosis. However, we have found cases with morphologic and immunophenotypic features of LLLs and evidence of clonal rearrangement of the immunoglobulin heavy chain (IGH) gene, potentially leading to misdiagnosis. We examined the clinicopathologic features and outcome of 12 patients with LLL (9 in the cervix and 3 in the endometrium). The patients ranged in age from 18 to 54 (median 37) years and came to medical attention because of squamous dysplasia (8 patients), vaginal bleeding (3), or adnexal mass (1). One patient had an endocervical polyp, but otherwise none had a discrete mass. The specimens contained a dense, polymorphous inflammatory infiltrate, commonly associated with mucosal erosion. Immunohistochemical studies showed a mixture of B and T cells without immunoglobulin light chain restriction. Four cases (all cervical) had a clonal IGH gene rearrangement by PCR. There was no evidence of lymphoma on staging or on follow-up in any patient, including the 4 patients with clonal IGH rearrangement, after a mean follow-up of 3.5 years (range: 4 mo to 13 y). In summary, we describe 12 patients with LLL of the lower female genital tract. Four of the 9 cases (44%) analyzed by PCR had a clonal IGH gene rearrangement. The clinical and pathologic features of these cases suggest that a clonal IGH rearrangement in this setting does not warrant a diagnosis of lymphoma. Careful correlation of clinical, histologic, immunophenotypic, and genetic features is required to avoid misdiagnosis and inappropriate treatment. Routine microscopic findings and detailed clinical information remain paramount in establishing the correct diagnosis.

Chronic idiopathic myelofibrosis terminating in extramedullary anaplastic plasmacytoma

Chronic idiopathic myelofibrosis (CIMF) is a chronic myeloproliferative disorder (CMPD) with progressive fibrosis and extramedullary hematopoiesis. Similar to other CMPDs, the stem cell in CIMF has the potential to differentiate into myeloid or lymphoid lineages, and thus CIMF can culminate in acute leukemia of myeloid or, rarely, lymphoid lineage. We describe an unusual case of CIMF terminating in extramedullary anaplastic plasmacytoma. The patient was a 61-year-old male with an 11-year history of CIMF. His course was complicated by rapidly growing abdominal and inguinal lymphadenopathy. Lymph node biopsy revealed a diffuse undifferentiated infiltrate in the background of extramedullary hematopoiesis. Flow cytometric and immunohistochemical analysis demonstrated plasma cell-related antigens (CD138, CD38, cytoplasmic kappa light chain), epithelial membrane antigen and CD43 in the tumor cells. The myeloid, B-cell or T-cell markers were negative. A clonal immunoglobulin heavy chain gene rearrangement was identified by polymerase chain reaction. The plasma cell origin was further confirmed by electron microscopic examination, which revealed stacks of rough endoplasmic reticulum. Monoclonal gammopathy may occur in CIMF, and rare cases of simultaneous plasma cell myeloma and CIMF have been reported in the literature. However, to the best of our knowledge, this is the first report of CIMF terminating in extramedullary anaplastic plasmacytoma.

Autoimmune lymphoproliferative syndrome (ALPS) caused by Fas (CD95) mutation mimicking sarcoidosis

Autoimmune lymphoproliferative syndrome (ALPS) is an inherited disorder associated with defects in apoptosis, characterized by childhood onset of lymphadenopathy, splenomegaly, hyperimmunoglobulinemia, and autoimmune disease. ALPS is most frequently associated with a mutation in the cell death receptor Fas (CD95). Very rarely a mutation in caspase 10 is present. An increase of CD4/CD8 double negative T cells in the peripheral blood and lymph nodes is a feature characteristic of ALPS. Additionally, histiocytic proliferations resembling sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) were reported recently in patients with ALPS. In the rare cases with a caspase 10 mutation an accumulation of dendritic cells in lymphoid organs was noted. We describe a different, sarcoidosislike, histiocytic infiltration of lymph nodes that persisted for years in a girl, that was initially supposed to suffer from sarcoidosis, but was eventually diagnosed as ALPS, associated with a missense mutation in the intracellular death domain of Fas. This sarcoidosislike histologic picture extends the spectrum of histiocytic lymph node alterations observed in ALPS and alerts of a potential diagnostic pitfall.

A limited number of IgH-primers binding to framework region 1 is sufficient to detect the majority of mature small B-cell non-Hodgkin lymphomas on formalin-fixed paraffin-embedded tissue by PCR

IGH gene rearrangement analysis by PCR is the widely accepted tool to determine clonality of B-cell lymphoid proliferations on formalin-fixed, paraffin-embedded tissue, but the results are often unsatisfying in terms of sensitivity. This is mainly due to poor quality DNA because of degradation and hence difficulties to amplify products of the needed length. Therefore, most previous attempts to determine clonality have depended on primers binding to framework region 3 thus producing amplification products of relatively short length. In order to improve clonality analyses, we have developed a sensitive monoplex PCR-protocol using primers binding to framework region 1 with extended cycling (42 cycles) and subsequent heteroduplex analysis. For comparison, multiplex reactions with alternative primers binding to framework region 1 according to the BIOMED-2 protocol were analyzed. By the two methods combined, we were able to detect clonality of 94% (16/17) of mature small B-cell non-Hodgkin lymphomas. The results suggest that PCR with primers binding to frame work region 1 may be the method of choice when assessing clonality of mature small B-cell non-Hodgkin lymphomas on formalin-fixed tissue.

Eosinophilia in systemic mastocytosis: clinical and molecular correlates and prognostic significance

BACKGROUND

In a group of patients with systemic mastocytosis (SM), marked and sustained eosinophilia is detectable (SM-eo).

OBJECTIVE

Although the molecular defect has been defined in some cases, little is known about the impact and clinical correlates of eosinophilia.

METHODS

In a cohort of 63 patients with SM, we identified 9 with permanent eosinophilia (>1500/microL). According to the World Health Organization classification, 2 had indolent SM, 1 had smoldering SM, 2 had SM with associated chronic eosinophilic leukemia (SM-CEL), and 4 had aggressive SM.

RESULTS

SM-eo was found to be associated with a significantly reduced probability of overall and event-free survival compared with SM without eosinophilia (P < .05). In the 2 patients with SM-CEL, a CHIC2 deletion was found. By contrast, no KIT mutation at codon 816 was detectable in these patients. In the other patients with SM-eo, KIT D816V was demonstrable. The 2 patients with SM-CEL had cardiomyopathy, whereas other organ systems remained largely unaffected. By contrast, in all other patients with SM-eo, organopathy, if recorded, affected the bone marrow, liver, or/and skeletal system, but not the heart, even when eosinophilia persisted for many years.

CONCLUSIONS

The biochemical basis of eosinophilia in SM is variable and predictive for the type of organopathy.

CLINICAL IMPLICATIONS

In SM eosinophilia is of prognostic significance but is not a final diagnosis and is not invariably associated with cardiomyopathy. The latter might be restricted to cases with an associated primary eosinophilic disorder (SM-CEL).

Composite EBV negative peripheral T-cell lymphoma and diffuse large B-cell lymphoma involving the ileum: a case report and a systematic review of the literature

We report a case of an intestinal peripheral T-cell lymphoma (PTCL) with a concurrent diffuse large B-cell lymphoma (DLBL) involving the ileum and a regional lymph node. The patient presented with an abdominal mass. The terminal ileum showed a diffuse and monotonous population of small CD3-positive T cells. The T-cell receptor gamma (TCRgamma) gene was rearranged by PCR while the immunoglobulin heavy chain (IgH) gene was not. A separate section of the ileum showed a colliding large B-cell proliferation. The regional lymph node showed a diffuse proliferation of large centroblasts positive for CD20 and CD79a admixed with small T cells and showed a rearranged IgH receptor gene without evidence of a clonally rearranged TCRgamma gene. Both the PTCL and DLBL components were negative for EBV. A review and analysis of the pertinent literature describing composite T- and B-cell lymphomas is performed and reported.

Molecular cytogenetic evidence of t(14;18)(IGH;BCL2) in a substantial proportion of primary cutaneous follicle center lymphomas

In contrast to nodal follicular lymphoma, limited data exist on genetic changes in primary cutaneous follicular lymphoma (primary cutaneous follicle center lymphoma according to WHO-EORTC). The detection rate of the BCL2 rearrangement, representing the characteristic t(14;18)(q32;q21) underlying follicular lymphoma, by polymerase chain reaction (PCR) has been reported to vary over a wide range (0%-41%), and only a few cases have been studied by molecular cytogenetic techniques such as fluorescence in situ hybridization (FISH). In this study, 27 primary cutaneous follicle center lymphomas were analyzed by FISH and the results compared with those obtained by PCR. FISH demonstrated translocations affecting the immunoglobulin heavy chain locus (IGH) in 14 of 27 cases (52%): a t(14;18)(q32;q21) involving BCL2 was found in 11 cases (41%), a t(3;14)(q27;q32) affecting BCL6 in 2 cases (7%), and in 1 case the partner gene of IGH could not be identified. Interestingly, PCR did not detect BCL2 rearrangement in any case. These data suggest that the t(14;18)(q32;q21) frequently occurs in primary cutaneous follicular lymphoma. The reason(s) why BCL2 rearrangements escape the detection by PCR is (are) not clear but could be due to BCL2 mutations, breakpoints outside the amplified DNA, or a high load of somatic mutations.

Application of a fluorescent PCR method for molecular diagnosis of posttransplant lymphoproliferative disorders on routine tissue sections

Molecular detection of monoclonality can play an important role in the diagnosis of posttransplantation lymphoproliferative disorders (PTLD). To permit accurate molecular diagnosis of PTLD even on very small amounts of DNA extracted from routinely embedded histologic material, we adapted a commercially available PCR protocol (for FR-1, -2 and -3 regions), originally designed for use on fresh/frozen samples. We applied this approach on routine biopsy/surgical material of 10 PTLD (from nine patients). All three FR regions were always amplified, indicating that the extracted DNA was of medium quality. All five PTLD morphologically classified as lymphomas were monoclonal in at least one FR region. Thus, using the WHO histologic, immunohistochemical, and clinical criteria as the reference standard, the approach provided 100% sensitivity for detection of monoclonal malignancies, supporting the validity of the method. Of five specimens classified morphologically as polymorphic PTLD, three displayed a solitary IgH gene rearrangement peak, consistent with the presence of a monoclonal B-cell population (ie, monoclonal polymorphic PTLD). This rapid and straightforward procedure, which allows identification of a wide range of IgH rearrangements, could facilitate molecular analysis of PTLD in routine practice, while limiting consumption of valuable diagnostic material.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Prognostic significance of molecular staging by PCR-amplification of immunoglobulin gene rearrangements in diffuse large B-cell lymphoma (DLBCL)

The prognostic value of the detection of peripheral blood (PB) and/or bone marrow (BM) involvement by polymerase chain reaction (PCR) amplification of rearranged immunoglobulin heavy chain (IgH) and immunoglobulin kappa light chain (Igkappa) genes was evaluated in 155 patients with diffuse large B-cell lymphomas (DLBCL). Immunoglobulin gene rearrangements (IgR) were detected in 35/155 (23%) patients. The presence of IgR in PB/BM was related to clinical stage (CS I-III vs CS IV; P<0.001), histopathological detection of BM involvement (P<0.001), and the International Prognostic Index (P<0.001). IgR-positive cases had a significantly lower complete remission (CR) rate (18/35, 51%) than IgR-negative patients (85/120, 71%; P=0.042), and a significantly poorer overall survival (OAS) at 5 years (25 vs 66%; P<0.001). There was a significant difference in the estimated OAS at 5 years between patients with negative BM histology and negative PCR results (66%), patients with negative BM histology but positive IgR (37%), and patients with positive BM histology (12%). Our results indicate that molecular methods improve the accuracy of staging in patients with DLBCL and define a group of patients with normal bone marrow histology who have a significantly poorer OAS due to molecular detection of PB/BM involvement.

A single primer pair immunoglobulin polymerase chain reaction assay as a useful tool in fine-needle aspiration biopsy differential diagnosis of lymphoid malignancies

BACKGROUND

Different polymerase chain reaction (PCR) assays have proved to be useful tools for the detection of clonal immunoglobulin heavy chain (IgH) gene rearrangements in frozen or paraffin-embedded tissues. However, the usefulness of a single primer pair PCR assay on fine-needle biopsy aspirates has not been proven yet.

METHODS

The authors conducted a wide prospective study of 148 lymph nodes and extranodal lymphoid infiltrates obtained by fine-needle aspiration biopsy (FNAB). The power of a single primer pair PCR amplification of the hypervariable CDRIII region IgH genes was evaluated using a pair of consensus primers. The PCR cytologic results were compared with the final clinicopathologic diagnosis of each case assessed by combining cytologic and/or immunophenotypic data and histologic features or clinical follow-up.

RESULTS

Among the 139 cases with an evaluable PCR result, 35 of 40 (87%) B-cell non-Hodgkin lymphomas were detected as a monoclonal band. Monoclonal IgH bands also were detected in two of the five (40%) T-cell lymphomas, two of the seven (29%) Hodgkin lymphomas, and 5 of the 87 (6%) reactive lymphoid disorders. These results are similar to those obtained by other authors using seminested PCR or combining different PCR tests in each sample obtained by FNAB or excisional biopsy.

CONCLUSIONS

The results of the current study demonstrate the convenience of a single primer pair PCR amplification over seminested methods in terms of lower cost and workload. The existence of PCR false-negative and false-positive results for lymphoma makes it necessary to combine the information obtained by PCR with cytologic and/or immunophenotypic data to optimize the number of lymphoid malignancies correctly diagnosed by FNAB.

Clonal T cell-mediated cyclic thrombocytopenia

Cyclic thrombocytopenia is a rare disorder characterized by periodic platelet count fluctuations of unknown aetiology. We report on a female patient with cyclic changes of platelet counts ranging from 6 x 10(9)/l to 753 x 10(9)/l in 4-week intervals. Platelet counts were inversely correlated to thrombopoietin levels suggesting production failure. Reticulocyte counts and neutrophil counts showed similar, but less prominent, fluctuations. Clonal T-cell receptor rearrangement was detected in bone marrow samples as well as in peripheral blood. Cell typing of blood lymphocytes revealed a relative increase in CD3+ T cells. Treatment with cyclosporine A resulted in a substantial improvement of platelet counts. Taken together, we provide evidence for clonal T-cell mediated bone marrow failure with cyclic impairment of thrombopoiesis responsive to cyclosporine therapy.

Selection of autologous CD4+ T-cells for adoptive T-cell substitution in patients with CD23+ B-cell CLL

BACKGROUND

B-cell CLL (B-CLL) is accompanied by a progressive decrease in cellular immune functions, and treatment-related immunosuppression can further aggravate T-cell immunodeficiency. To reduce the risks of T-cell depletion, it seems feasible to collect autologous CD4+ cells at an early disease stage and subsequently reinfuse them during periods of profound T-cell depletion.

METHOD

We describe a two-step cell-selection method to obtain highly enriched CD4+ T-cells from leukapheresis compounds of patients with CD23+ B-CLL. The double selection procedure was performed using the CellPro Ceperate device, and consisted of CD4+ selection followed by CD23 purging to further remove contaminating CD23+ B-cells from the CD4+ cell fraction. The results of eight runs performed with leukapheresis material obtained from eight patients with CD23+ B-CLL at different disease stages are presented.

RESULTS

The CD4/CD23 double cell-selection procedure resulted in the purification of > 90% CD4+ cells. Median recovery of CD4+ T lymphocytes after selection was 46%, and was negatively affected by the initial tumor cell load. The final T-cell fraction still contained lymphocytes of the B-CLL clone, as determined by FACS and PCR. The cell-processing procedure had no impact on T-cell function, as assessed by the in vitro production of the cytokine interferon-gamma. Moreover, the selected CD4+ cells retained their capacity to co-stimulate mitogen-induced B-cell IgG production in vitro.

CONCLUSION

The described CD4 selection/CD23 depletion strategy is a suitable approach to obtaining high numbers of functional active autologous CD4+ T cells for adoptive T-cell transfer in patients with CD23+ BCLL.

Simultaneous evaluation of T- and B-cell clonality, t(11;14) and t(14;18), in a single reaction by a four-color multiplex polymerase chain reaction assay and automated high-resolution fragment analysis: a method for the rapid molecular diagnosis of lymphoproliferative disorders applicable to fresh frozen and formalin-fixed, paraffin-embedded tissues, blood, and bone marrow aspirates

Current polymerase chain reaction (PCR) methods for the molecular diagnosis of B- and T-cell lymphomas by determination of clonality of immunoglobulin heavy chain (IgH) and T-cell receptor-gamma rearrangements and by detection of the chromosomal translocations t(14;18) and t(11;14), require several laborious and costly PCR assays for each of these diagnostic tests. We have developed a multiplex PCR assay for the simultaneous determination of B- and T-cell clonality and the detection of the chromosomal translocations t(14;18) and t(11;14) in a single reaction, using four-color fluorescence and automated high-resolution fragment analysis. The 26 primers combined in the multiplex PCR correspond to the sequences of >90% of the 69 variables and 6 join IgH genes and 100% of the T-cell receptor-gamma variables and join genes that could participate in the respective rearrangements. In addition, they detect the major and the minor breakpoint regions of the t(14;18) and the major breakpoint region of the t(11;14), and amplify the beta-globin gene as an internal control. The specificity of the multiplex PCR was confirmed by analysis of 39 T-cell lymphomas and 58 B-cell lymphomas, including 11 mantle cell lymphomas bearing the t(11;14) and 25 follicular lymphomas bearing the t(14;18), with known rearrangements and/or translocations. Fifteen samples of reactive lymphadenitis remained negative.

CD5 expression in a lymphoma of the mucosa-associated lymphoid tissue (MALT)-type as a marker for early dissemination and aggressive clinical behaviour

Mucosa associated lymphoid tissue (MALT) developing in response to chronic infection or autoimmune stimuli has been recognized as a possible site of origin for a distinct type of B-cell lymphoma. While preferentially occurring in the stomach, MALT-type lymphomas can be found in virtually all organs. MALT-type lymphomas normally follow an indolent course, with a tendency to remain localized at their site of origin for a prolonged period of time. Histologically, MALT-type lymphomas are heterogeneous covering a cytological spectrum ranging from centrocyte-like cells to smaller lymphoid cells or monocytoid B-cells. Usually a small number of transformed blasts are also present. Immunohistochemically, the malignant cells express markers of B-cell lineage, but are distinct from follicular lymphomas (which express CD10), mantle cell lymphomas (expressing cyclin D1 and CD5) and small lymphocytic lymphoma, which express CD5 and CD23. In contrast to the usual phenotype CD20+CD10-CD5-Cyclin D1-, scattered reports in the literature have documented expression of CD5 in marginal zone B-cell lymphomas of MALT-type. However, these cases are rare, and aberrant CD5-expression has been thought to be a marker for early dissemination and aggressive behavior in some patients, while other reports have also found CD5 expression in localized indolent MALT-type lymphomas. We report a patient with a CD5+ MALT-type lymphoma following an aggressive clinical course without histological progression who relapsed only 18 months after local radiotherapy at the initial localizations (conjunctiva of the right upper eye lid and hypopharynx), and showed a rapid generalization to the contralateral conjunctiva, mediastinal lymph nodes and the esophagogastric junction. Our case lends further support to the notion that CD5+ MALT-lymphomas arising in the head-and-neck area and/or the ocular adnexa might be characterised by an aggressive clinical course.

IgH, TCR-gamma, and TCR-beta gene rearrangement in 80 B- and T-cell non-Hodgkin's lymphomas: study of the association between proliferation and the so-called "aberrant" patterns

The current study analyzes the rearrangement pattern of immunoglobulin H (IgH), T-cell receptor (TCR)-gamma, and TCR-beta genes in a group of 80 non-Hodgkin's lymphomas (NHL) of different histologic subtypes (43 B-cell and 37 T-cell types). The sensitivity and specificity provided by polymerase chain reaction amplification of these loci are evaluated. The association between the proliferation index and the presence of the so-called "aberrant" or "dual" rearrangements is also considered. Ninety-one percent of B-cell NHL showed IgH gene monoclonality, and 21% also exhibited a monoclonal pattern in one of the TCR genes. Among T-cell NHL, the sensitivity of the study was 65% for the TCR-gamma gene and 46% for the TCR-beta gene. The total sensitivity was 76%, amplifying both loci. IgH gene aberrant rearrangements were observed in 16% of T-cell neoplasms. A substantial percentage of dual rearrangements were detected in precursor and mature B- and T-cell NHL. B-cell NHL showed a tendency toward higher values of proliferation when aberrant rearrangements were present; however, this trend was not significant. Furthermore, in the case of T-cell NHL there was a significant negative association between these two variables.

Long-term clinical and molecular remission after allogeneic stem cell transplantation (SCT) in patients with poor prognosis non-Hodgkin's lymphoma

From 1987 to 1999 35 patients with poor prognosis non-Hodgkin's lymphoma (NHL) underwent allogeneic stem cell transplantation (SCT) at the University Hospitals of Vienna and Graz. Initial biopsy specimens were reclassified according to the Revised European-American Classification of Lymphoid Neoplasms (REAL). All patients surviving 28 days engrafted. Twenty-eight of them (93%) attained clinical remission. At the last follow-up 14 patients were alive and disease-free at a median of 5.0 (range, 2.3-12.9) years after allogeneic SCT. The actuarial overall survival is 35%. Five patients relapsed 1.8 to 27.6 months after transplant, the probability of relapse is 23%. Of the 21 deaths following SCT, seven were due to relapse/refractory disease and 14 due to transplant-related causes. The probability of treatment-related mortality is 48%. After SCT, minimal residual disease (MRD) was monitored by polymerase chain reaction (PCR) in seven patients with a BCL-2/IgH translocation and in 13 with a clonal immunoglobulin heavy chain (IgH) rearrangement. All 20 patients attained clinical remission rapidly and converted to PCR negativity. In the follow-up nine of these patients are in long-term clinical and molecular remission, six PCR-negative patients died of transplant-related causes and five patients relapsed. In summary, allogeneic stem cell transplantation has a curative potential for patients with refractory and recurrent non-Hodgkin's lymphoma. In our series long-term disease-free survival was associated with molecular disease eradication after SCT. Treatment-related mortality rate was high, thus earlier referral of selected patients to allogeneic SCT should be considered.

Epstein-Barr virus-positive aggressive lymphoma as a consequence of immunosuppression after multiple salvage treatments for follicular lymphoma

We report on a patient with follicular non-Hodgkin's lymphoma (NHL) who developed a fatal high-grade Epstein-Barr virus (EBV)-positive NHL after conventional chemotherapies. The sudden onset of the high-grade lymphoma was accompanied by increasing circulating EBV genome copies and was complicated by spontaneous rupture of the spleen. Splenic tissue was diffusely infiltrated by large B cells. In situ hybridization for Epstein-Barr-encoded RNA (EBER) 1-2 was positive in 70% of cells, and molecular analysis revealed the presence of EBV DNA and a monoclonal IgH gene rearrangement. This case shows that the immunosuppression of multiple treatments may induce uncontrolled reactivation of a latent EBV infection, contributing to high-grade transformation in heavily treated lymphoma patients.

Improvement of clonality detection rate in multiple myeloma using fluorescent IgH PCR with different sets of primers

The IgH rearrangement provides a useful marker of clonality in B-cell malignancies and amplification of this rearrangement is the method of choice to monitor the residual tumor cells in multiple myeloma (MM). The critical point of this analysis was the false-negative rate observed at diagnosis in patients presenting tumor cells well above the limit of detection. The aim of this study was therefore to increase the clonality detection rate by IgH polymerase chain reaction (PCR). Bone marrow DNA from 37 MM patients were analyzed at diagnosis. IgH PCR with agarose gel detection was performed between framework regions FR3 and FR1, both in combination with 5 different primers in FR4. Fluorescent IgH PCR with highly resolutive capillary electrophoresis was used to improve the detection and to size clonal PCR products. Sixty-two percent of the clonal rearrangements were initially detected with JHD primer specific to the JH segments 1,2,4,5. The use of JH3 and JH6 homologous primers increased the detection rate to 78%, whereas a consensus JH primer only reached 67% of positivity. The lowest detection rates were obtained with JHExt and JH3 with a detection of respectively 43 and 14%. However, three rearrangements were exclusively amplified by JHExt and two additional cases were detected by JH3. The combined use of primers yielded the best score with 89% of positivity. With Genescan analysis, two additional cases showed a monoclonal rearrangement improving the detection rate to 95%. The use of multiple sets of primers along with a highly sensitive genescan analysis makes possible the follow-up of minimal residual disease for most MM patients.

Limitations of clonality analysis of B cell proliferations using CDR3 polymerase chain reaction

BACKGROUND/AIMS

Detection of clonal immunoglobulin heavy chain (IgH) rearrangements by the polymerase chain reaction (PCR) is an attractive alternative to Southern blotting in lymphoma diagnostics. However, the advantages and limitations of PCR in clonality analysis are still not fully appreciated. In this study, clonality was analysed by means of PCR, focusing in particular on the sample size requirements when studying extremely small samples of polyclonal and monoclonal lesions.

MATERIALS/METHODS

High resolution complementarity determining region 3 (CDR3) PCR was used to investigate the minimum number of cells and the amount of tissue required for the detection of a polyclonal population, both for fresh cells and formalin fixed, paraffin wax embedded tissue. Subsequently, frozen and paraffin wax embedded samples of 76 B cell lymphoproliferative disorders, 43 of which were tested by means of Southern blotting, were analysed to establish the sensitivity of this assay. These specimens included 12 chronic lymphocytic leukaemias (CLLs), nine mantle cell lymphomas (MCLs), 10 follicular lymphomas (FLs), and 45 mucosa associated lymphoid tissue (MALT) lymphomas. The specificity was tested on reactive lymph nodes (n = 19), tonsils (n = 4), peripheral blood lymphocyte fractions (n = 4), and biopsies with gastritis (n = 21).

RESULTS

In reactive tissue, 20 ng of high molecular weight DNA derived from 6.5-9 x 10(3) B cells was sufficient to obtain a polyclonal PCR result. With smaller amounts "pseudoclonality" could be induced. When using paraffin wax blocks, undiluted DNA isolated from tonsillar tissue of at least 1 mm2 was necessary to obtain a polyclonal pattern. The sensitivity required to detect clonality in paraffin wax embedded and frozen tissue by PCR for FL (40% and 60%, respectively) was lower than that for MALT lymphomas (60% and 86%, respectively), CLL (78% and 89%, respectively), and MCL (88% and 100%, respectively). PCR specificity was 96% and 100% for frozen and paraffin wax embedded tissue, respectively.

CONCLUSION

The minimum amount of template for CDR3 PCR is approximately 20 ng of high molecular weight DNA or 1 mm3 of B cell rich paraffin wax embedded normal tonsillar tissue, but care has to be taken to avoid pseudoclonality when low numbers of B cells are present. Duplicate or triplicate tests should be performed to avoid misinterpretation. The specificity of the PCR assay is almost 100%, whereas sensitivity depends on a combination of factors, such as lymphoma type and tissue fixation. Because frozen samples yield better results, obtaining fresh material for the PCR assay is recommended, especially when analysing FL and MALT lymphomas.

Immunoreactivity of B-cell markers (CD79a, L26) in rare cases of extranodal cytotoxic peripheral T- (NK/T-) cell lymphomas

The monoclonal antibodies L26 (CD20) and CD79a are very useful reagents for the immunohistochemical assessment of B-cell lineage in lymphoproliferative disorders. Although very few CD20-positive peripheral T-cell lymphomas (PTL) have been reported, comprehensive analyses of CD79a reactivity in extranodal PTL and NK/T-cell lymphomas have not been performed previously. This study investigated CD79a (clone JCB117) and CD20 reactivity in 94 extranodal non-B-cell lymphomas (enteropathy-type intestinal T-cell lymphoma [n = 52], nasal NK/T-cell lymphoma [n = 11], and primary cutaneous PTL [n = 31]) and in 17 cases of nodal PTL, unspecified. In four cases (enteropathy-type intestinal T-cell lymphoma [n = 3] and nasal NK/T-cell lymphoma [n = 1]), the majority of tumor cells stained for CD79a (all CD20 negative) and one cutaneous PTL, unspecified, was CD20 positive (CD79a negative). Extensive immunophenotyping and polymerase chain reaction-based molecular analyses revealed that all five B-cell marker-positive extranodal lymphomas had a cytotoxic phenotype and did indeed represent monoclonal peripheral T-cell proliferations. To minimize the risk of misinterpretation of lymphoma cell lineage, especially in cases of extranodal, lymphoproliferative disease, we suggest the use of both CD79a and CD20 in combination with a panel of antibodies reactive to T cells, such as betaF1 and CD5, and to T cells and NK cells, such as CD3, CD2, CD56, and TIA-1.