Aberrant MT2 positivity distinguishes follicular lymphoma from reactive follicular hyperplasia in B5- and formalin-fixed paraffin sections.

Often, it is difficult to distinguish follicular lymphoma from reactive follicular hyperplasia histologically. Immunotypic evidence of monoclonality cannot be demonstrated routinely or reliably in routine paraffin-embedded sections. To determine whether a panel of monoclonal antibodies reactive with lymphoid cells in paraffin-embedded sections might be useful in distinguishing these confusing proliferations, the authors examined 45 follicular lymphomas and 30 follicular hyperplasia with the following antibodies; L26, B2, MT1, MT2, and UCHL-I. All sections were routine paraffin preparations from formalin- or B5-fixed tissue and were immunostained with the avidin-biotin immunoperoxidase technique. Ninety-two percent of the B5-fixed and 77% of the formalin-fixed lymphomas were MT2 positive. None of the reactive hyperplasias stained positively, and none of the other antibodies demonstrated consistent differences between these benign and malignant proliferations. MT2 marks interfollicular T cells and mantle-zone B cells in normal lymph nodes but does not mark normal germinal centers; this staining pattern is retained in reactive hyperplasia. However, paradoxically, in most follicular lymphomas the neoplastic germinal centers show aberrant MT2 positively. The authors conclude that MT2 may be useful in distinguishing follicular lymphoma from follicular hyperplasia in paraffin sections.     

Distribution and ZAP-70 expression of WHO lymphoma categories in Shanxi, China: a review of 447 cases using a tissue microarray technique.

This study aims to assess the distribution of lymphoma subtypes in Shanxi, China, according to the World Health Organization (WHO) classification, and to compare the relative distribution with other areas of the world. H&E-stained tissue sections from the archives of the Shanxi Tumor Hospital, China, were reviewed and 447 cases with sufficient materials were selected for detailed study. A panel of antibodies and probes was assembled, including antibodies to ALK1, bcl-6, CDs 1alpha, 3, 4, 5, 7, 8, 10, 15, 20, 23, 30, 43, 56, 68, 79alpha, and 99, cyclin D1, EMA, kappa, lambda, LMP1, PAX5, TdT, Vs38C and ZAP70, plus EBER RNA probe by in situ hybridization. The 447 lymphoma cases, subtyped according to the WHO classification, were assembled in triplicate into 11 tissue microarrays and examined with the panel of markers described. Among the 447 cases, 385 (82.6%) were confirmed to be non-Hodgkin lymphomas (NHL) and 62 (13.9%) were Hodgkin lymphomas of classic type (CHL). Of the NHL cases, 68.6% were B-cell lymphomas and 30.6% T/NK-cell lymphomas. Histiocytic neoplasms accounted for only three cases (0.8%). Diffuse large B-cell lymphomas (DLBCL) were the most common subtype (35.1%), followed by peripheral T-cell lymphomas unspecified (PTun, 12.0%), extranodal marginal zone B-cell lymphomas (MALT lymphomas, 11.7%), follicular lymphomas (FL, 8.6%), T-lymphoblastic lymphomas (T-LBL, 7.0%), anaplastic large cell lymphomas (ALCL, 4.2%), B small lymphocytic lymphomas (B SLL, 3.6%), and mantle cell lymphomas (MCL, 2.6%). Of 263 B-cell neoplasms, 105 (39.9%) expressed immunoglobulin light chain, including 52 kappa and 53 lambda, detectable in paraffin sections. The incidence of DLBCL was similar to many Western countries and Asia. The frequency of FL was, however, much lower than the usual pattern in Western countries, although NK/T-cell lymphomas were more common (30.6%), similar to other countries in Asia, including Japan and Korea. With regard to markers of EBV infection, 8 of 385 (2.1%) NHL cases gave positive findings by both in situ hybridization (EBER RNA) and immunohistochemistry (LMP-1), whereas 24 (6.2%) expressed only the EBER and 12 (3.1%) expressed only LMP-1. EBV positivity was found in 24 of 119 (20.2%) T and NK cell lymphomas, in 20 of 263 (7.6%) B cell neoplasms, and in 37 of 62 (59.7%) CHLs. In CHLs there was complete concordance of results by both in situ hybridization (EBER RNA) and immunohistochemistry (LMP-1) procedures. ZAP70 was detected in most T cell-lineage disorders (61.4%) and also in a subset of B small lymphocytic lymphomas (50%). However, ZAP-70 was expressed in a minority of other types of B-cell lymphomas, including precursor B-cell acute lymphoblastic leukemia (25%), diffuse large B-cell lymphoma (26.7%), follicular lymphoma (15.2%), and lymphoplasmacytic lymphoma (9.1%). Immunohistochemical analysis represents an effective method for assessing ZAP-70 expression and reveals that a variety of B-cell malignant neoplasms express ZAP-70, albeit at low frequency.     

Contribution of immunohistochemistry to small B-cell lymphoma classification.

Although the small B-cell lymphomas show major morphologic overlapping, they have been recently shown to be distinct entities with several biologic and clinical differences. Therefore, the utility of a panel of paraffin-reactive antibodies in differentiating these neoplasms was investigated. Using clinical data and morphologic criteria, 134 cases of small B-cell lymphomas were grouped as those with (1) one strongly suggested diagnosis, (2) differential diagnosis between two types of lymphomas, and (3) small B-cell lymphoma without hints for further subclassification. With a panel of antibodies including CD5, CD10, CD23, CD43, bcl-2, and cyclin D1, most but not all cases could be precisely categorized. This panel confirmed the diagnosis in 96.5% of the cases from group 1. In group 2 it confirmed one of the two diagnoses in 81.5% of the cases. In group 3 it established a definitive diagnosis in 55% of the cases. When all groups were considered, a correct diagnosis could be established for 88.1% of cases; for 6.7% of them the authors remained with two possible diagnosis, and the broad "small B-cell lymphoma" was the only diagnosis for 5.2% of cases. CD10 separated most follicular lymphomas from other small B-cell lymphoid neoplasms. CD23 separated small lymphocytic lymphoma/chronic lymphocytic leukemia. Cyclin D1 separated mantle cell lymphoma. The present study selected CD10, CD23, and cyclin D1 as a minimal panel for the classification of small B-cell lymphomas, yielding a final diagnosis in 88.1% of the cases.     

Dendritic reticulum cells and immunophenotype in aspiration biopsies of lymph nodes. Value in the subclassification of non-Hodgkin's lymphomas

Twenty-seven lymph node aspirates were identified for which histologic confirmation of non-Hodgkin's lymphoma was subsequently obtained. Fifteen aspirates interpreted as reactive hyperplasia were also examined. All aspirates were studied by immunoperoxidase on cytospin preparations with the use of antibodies DRC1, kappa, lambda, CD3, CD5, and CD20. The follicular lymphomas could not be identified reliably by morphologic examination of aspirate smears. Clusters of DRC1-positive (DRC1+) cells were present in seven of seven follicular lymphomas, one of one mantle zone lymphoma, and one of seven small lymphocytic lymphomas. Rare DRC1+ cells were present in one of one diffuse mixed and one of seven large cell lymphomas. One lymphoblastic, one Burkitt's, and two diffuse small cleaved cell lymphomas had no DRC1+ cells. None of the seven follicular lymphomas was CD5 positive (CD5+), whereas five of the seven small lymphocytic lymphomas were CD5+. Conversely, all seven follicular lymphomas were CD20-positive (CD20+), but only one of seven small lymphocytic lymphomas was CD20+. Nineteen of the lymphomas, including all 7 of the follicular lymphomas, were either kappa or lambda positive. The other eight lymphomas were T-cell (1), B-cell (1), true histiocytic (1), or "null" cell (5). The reactive aspirates had both kappa- and lambda-positive B-cells. Seven of the 15 had clusters of DRC1+ cells. To further evaluate these antibodies, the authors studied 29 additional, surgically biopsied, non-Hodgkin's lymphomas that had not been aspirated. Similar results were obtained, except that three of five diffuse small cleaved cell lymphomas had DRC1+ cells. DRC1, in conjunction with antibodies to CD5, CD20, kappa, and lambda, helps to distinguish follicular lymphoma from small lymphocytic lymphoma. DRC1 is not useful in separating reactive hyperplasia from follicular lymphoma.     

The differential diagnosis of early gastric mucosa-associated lymphoma: polymerase chain reaction and paraffin section immunophenotyping.

The distinction between benign florid lymphoid hyperplasia and low-grade gastric mucosal-associated lymphoid tissue (MALT) lymphoma may be a challenge. The presence of monoclonal B cells in Helicobacter pylori-chronic active gastritis has suggested that polymerase chain reaction (PCR) data should be viewed with caution. We investigated the reliability of PCR versus immunophenotyping in diagnosing early gastric MALT lymphoma. We studied 1511 biopsies from eight patients with high-grade primary gastric lymphoma, 25 with low-grade MALT lymphoma, 32 with atypical lymphoid infiltrates, and 39 with Helicobacter pylori-chronic active gastritis. Paraffin sections from all cases were stained with antibodies to CD20, CD3, AE1/AE3, kappa and lambda. PCR was performed on paraffin sections using the primer set VH-FR3/J(H). Using histopathology as the gold standard in diagnosis, we confirmed monoclonality in 22 of 25 MALT lymphomas (88%); a clonal band was found in 38% (15 of 39) of patients with chronic active gastritis. An immunophenotype pattern with predominance of CD20-positive cells in lymphocytic infiltrates was associated with monoclonality in 92% of cases. The presence of an enlarged irregular mantle zone was found in both monoclonal and polyclonal areas. An equal prevalence of B and T cells in lymphocytic infiltrates was associated with a polyclonal pattern in 24 of 31 cases (77%). Immunostaining of sIg (kappa and lambda) was difficult in paraffin sections and convincing proof of monoclonality was not obtained. Lymphoepithelial lesions were infrequent in gastric biopsies and their presence was highlighted with keratin stains. Because monoclonal B cells are observed in Helicobacter pylori-associated gastritis, the correct interpretation of clonality by PCR remains unclear. Paraffin section IHC using CD20 and CD3 is especially useful to confirm the diagnosis of gastric MALT lymphoma.     

De novo CD5-positive and Richter's syndrome-associated diffuse large B cell lymphomas are genotypically distinct.

Diffuse large B cell lymphomas (DLBLs) represent a heterogeneous collection of aggressive non-Hodgkin's lymphomas that can arise either de novo or as a result of transformation from chronic lymphocytic leukemia, small lymphocytic lymphoma, follicular lymphomas, or lymphomas of mucosa-associated lymphoid tissue. A small percentage of DLBLs express the CD5 antigen. The majority of these cases have evolved from a pre-existing low grade non-Hodgkin's lymphoma (Richter's syndrome). However, we identified and characterized nine CD5-positive DLBLs in which the patients did not have a previous history or concomitant evidence of chronic lymphocytic leukemia, small lymphocytic lymphoma, follicular lymphoma, or mucosa-associated lymphoid tissue-associated non-Hodgkin's lymphoma, suggesting that they arose de novo. All nine cases expressed CD20 and monotypic immunoglobulin, all eight cases examined expressed CD19, CD22 and CD43, eight of the nine cases expressed HLA-DR, and two of eight cases expressed CD11c. None of the cases expressed CD3, CD10, CD11b, CD21, CD23 or CD30. CD5 expression by these cells was found to be identical to that of CD5-positive B cell chronic lymphocytic leukemia by quantitative polymerase chain reaction analysis of CD5 mRNA. These nine de novo CD5-positive DLBLs exhibited clonal immunoglobulin heavy and light chain gene rearrangements but lacked integration of the Epstein-Barr virus genome and structural alterations of the bcl-1, bcl-2, c-myc, H-ras, K-ras, and N-ras proto-oncogenes and the p53 tumor suppressor gene. However, bcl-6 proto-oncogene rearrangement, which is involved in chromosome band 3q27 aberrations, was found in four cases (44.4%). This is comparable with the frequency of bcl-6 gene rearrangement in CD5-negative DLBL. In contrast, bcl-6 gene rearrangement was absent in six cases of DLBL associated with Richter's syndrome. These findings suggest that de novo CD5-positive DLBLs are genotypically similar to CD5-negative DLBLs and may be pathogenetically distinct from the DLBLs associated with Richter's syndrome.     

根据WHO淋巴造血系统肿瘤新分类对山西省淋巴瘤分布特点的分析

目的根据WHO淋巴造血系统肿瘤新分类标准、分析山西省恶性淋巴瘤的分布特点。方法重新阅读HE切片,选用免疫组织化学ABC法标记间变性淋巴瘤激酶（ALK）1、bcl-6、CD（1α、3、4、5、7、8、10,15、20、23、30、43、56、68、79α和99）、细胞周期蛋白（cyclin）D1、上皮膜抗原（EMA）、IgD,k,λ、潜伏膜抗原（LMP）1、PAX5、末端脱氧核苷酸转移酶（TdT）和Vs38C;原位杂交方法标记EBER RNA。按照WHO淋巴造血系统肿瘤新分类标准,对山西省肿瘤医院存档的447例淋巴瘤组织标本重新分类。结果447例淋巴瘤中,385例（86．1％）为非霍奇金淋巴瘤（NHL）,62例（13．9％）为霍奇金淋巴瘤（HL）。68．3％NHL为B细胞来源,30．6％为T和NK细胞来源,组织细胞来源的肿瘤仅占3例（0．8％）。弥漫大B细胞淋巴瘤（DLBCL）为最常见的类型（35．1％）,其他依次为外周T细胞淋巴瘤、非特殊型（PTun,12．0％）、黏膜相关淋巴组织结外边缘区B细胞淋巴瘤（MALT淋巴瘤,11．7％）,滤泡性淋巴瘤（FL,8．6％）,前体淋巴母细胞性淋巴瘤（T-LBL,7．0％）,间变性大细胞淋巴瘤（ALCL,4．2％）,小淋巴细胞性淋巴瘤（B-SLL,3．6％）和套细胞淋巴瘤（MCL,2．6％）。263例B细胞淋巴瘤105例（39．9％）表达免疫球蛋白轻链,包括52例K和53例λ。263例B细胞淋巴瘤14例表达LMP-1,14例表达EBER;119例T和NK细胞淋巴瘤6例表达LMP-1,19例表达EBER,NHL中LMP-1和EBER表达具有不一致性。62例HL37例（59．7％）一致表达LMP-1和EBER RNA,包括7例富于淋巴细胞型HL、11例混合细胞型HL和19例结节硬化型HL。结论所搜集到的山西省DLBCL的比率类似于美国、澳大利亚、日本和韩国,FL的比率明显低于美国和澳大利亚。     

The utility of CD20 and CD43 in subclassification of low-grade B-cell lymphoma on paraffin sections.

To identify phenotypic differences among the low-grade lympho-proliferative disorders in paraffin-embedded tissue, we studied 49 cases. All 22 follicular small cleaved cell lymphomas (FSC) were CD43 negative and CD20 positive. In contrast, of 20 small lymphocytic lymphomas (SL), 90% were CD20 positive, 85% were CD43 positive, and 75% were positive for both. Of three lymphomas of intermediate differentiation (IDL), two were CD20 positive and two were CD43 positive. All four monocytoid B-cell lymphomas were positive for CD20 and 50% (two cases) were positive for CD43. Some 86% of 14 chronic lymphocytic leukemias (CLL) (on cytospins) were positive for CD43; all nine of the CLL studied for CD20 were positive and 89% (8/9) expressed both antibodies CD5 expression (on frozen sections or cytospin preparations) was compared to CD43 in 21 cases of SL and CLL. Some 77% were positive for both CD5 and CD20. All seven of the CD5-positive SL also expressed CD43. The antibody MT2 was also examined with the following results: FSC, 16/20 (80%) positive; SL, 18/19 (94%) positive; MBC, 3/3 positive; and ILL, 2/3 positive. All 56 cases tested were CD45RO (UCHL1) negative. We conclude that CD43 is expressed on most cases of low-grade lymphoproliferative disorders with the exception of FSC. Its pattern of expression seems similar to CD5; however, unlike CD5, CD43 can be studied in formalin-fixed tissue. MT2 is not helpful in distinguishing among these lesions.     

Large cell anaplastic lymphoma: Evaluation of immunophenotype on paraffin and frozen sections in comparison with ultrastructural features

Summary Eleven cases of large cell anaplastic lymphoma (T typen=5, B typen=4, 0 typen=2) were investigated using electron microscopy and immunophenotyping on formalin-fixed paraffin sections and frozen sections of fresh tissue, to determine whether morphological criteria exist for the discrimination of T, B, and 0 phenotypes. Tumour cell lineage could not be established from ultrastructural features. On paraffin material monoclonal B-cell markers Ki-B5 and L-26 served as reliable tools for recognizing the B phenotype of large cell anaplastic lymphomas (previously determined on fresh material), whereas monoclonal antibodies MT1 (CD43) and UCHL1 (CD45RO) were of limited value in lineage determination.     

Immunohistochemical detection of follicular dendritic cells in the diagnosis of small B-cell lymphomas

Our study included 46 cases of B-chronic lymphocytic leukemia/small lymphocytic lymphoma (B-CLL/SLL), 25 mantle cell lymphomas (MCL), and 40 follicular lymphomas (FL). The lymphomas were diagnosed according to current morphological, immunohistochemical, and in some cases molecular-genetic criteria. The patterns of follicular dendritie cells (FDCs) were studied in paraffin sections using the anti CD21, anti CD23, and CNA.42 antibodies. The differences in staining patterns of FDCs among the studied lymphomas were statistically significant. The absence or small number of FDC clusters are typical of B-CLL/SLL, while FDC meshwork limited to peripheral parts of neoplastic follicles is characteristic for FL. In contrast, MCL is characterized by irregular FDC meshwork or by FDC clusters present in the centres of residual follicles. Thus, we have demonstrated that the patterns of FDCs is an independent diagnostic feature for distinguishing between B-CLL, FL, and MCL.     

The value of immunohistochemistry on paraffin wax embedded tissue sections in the differentiation of small lymphocytic and mantle cell lymphomas.

AIMS: To determine whether immunohistochemistry applied to paraffin wax embedded biopsy tissue can be used to distinguish between B-small lymphocytic lymphoma (B-SLL) and mantle cell lymphoma (MCL). METHODS: Formalin fixed, paraffin wax embedded tissue blocks of 12 cases of B-SLL and 12 cases of MCL were retrieved from the files of the Department of Pathology, Southampton University Hospitals Trust. Following antigen retrieval, where appropriate, sections were stained for CD3, CD5, CD20, CD23, CD43, Cyclin D, PGP9.5, and MIB1 using a streptavidin-biotin complex technique. RESULTS: CD20 stained the neoplastic cells of B-SLL and MCL, and CD3 labelled the reactive T cells in these tumours. In B-SLL, the T cells were generally dispersed among the tumour cells, whereas in MCL they often formed bands around tumour cell nodules. CD5 could be detected on T cells, following antigen retrieval. The level of expression on B cells of B-SLL and MCL was generally too low to allow detection in paraffin wax embedded tissues. CD23 stained B-SLL but not MCL. However, it could be detected in only five of the 12 cases of B-SLL. CD43 could be detected in most cases of B-SLL and MCL. It is not, therefore, of value in distinguishing between these tumours. It will, however, help in the differentiation of B-SLL and MCL from other low grade B cell lymphomas, such as follicle centre cell and marginal zone lymphomas. Cyclin D was expressed in all of the MCL but in none of the B-SLL. PGP9.5 showed reactivity in most cases of MCL and much weaker reactivity in B-SLL. The proliferation indexes of MCL were generally higher than those of B-SLL, as measured by MIB1 labelling. Both tumours, however, showed a wide range of values and considerable overlap. CONCLUSION: Staining for Cyclin D is the most reliable immunohistochemical mean of differentiating between B-SLL an MCL. High levels of PGP9.5, expressed in MCL, may be related to the degradation of Cyclin D by the ubiquitin pathway.     

Composite low grade B-cell lymphomas with two immunophenotypically distinct cell populations are true biclonal lymphomas. A molecular analysis using laser capture microdissection.

Low grade B-cell lymphomas comprise several well defined, clinically and immunophenotypically distinct disease entities. Composite lymphomas showing phenotypic characteristics of more than one of these tumor subtypes in the same site are rare, and both common and separate clonal origins of the two tumor parts have been reported for cases studied by molecular methods. We describe the detailed immunohistochemical and molecular findings in three cases with features of composite low grade B-cell non-Hodgkin's lymphoma (B-NHL). All three neoplasms contained morphologically distinct but interwoven compartments of different cell types, which exhibited discordant expression of several markers, including CD5, CD10, CD43, and cyclin D1. According to their morphology and phenotypes, they were classified as mantle cell lymphoma and follicular lymphoma (Case 1), follicular lymphoma and small lymphocytic lymphoma (Case 2), and mantle cell lymphoma and chronic lymphocytic leukemia/small lymphocytic lymphoma (Case 3). PCR analysis of DNA obtained from whole tissue sections failed to reveal evidence for biclonality in any of the cases. We therefore isolated cell populations with different antigen expression patterns by laser capture microdissection and analyzed them by polymerase chain reaction amplification and sequencing of clonal immunoglobulin heavy chain gene rearrangements and oncogene rearrangements. Sequence analysis revealed unrelated clonal rearrangements in each of the two tumor parts in all three cases, suggesting distinct clonal origins. In addition, Case 1 showed a bcl-2 rearrangement present only in the follicular lymphoma part. Our findings suggest that low grade B-NHL with two distinct morphological and immunophenotypic patterns in the same anatomical site are frequently biclonal. This is in keeping with current classification schemes, which recognize subtypes of low grade B-NHL as separate disease entities. Furthermore, our analysis demonstrates the power of laser capture microdissection in revealing molecular microheterogeneity in complex neoplasms.     

Immunohistochemistry in apparently normal bone marrow trephine specimens from patients with nodal follicular lymphoma.

AIM--To establish the role of immunohistochemistry (using a limited panel of antibodies) in detecting minimal involvement by follicular lymphoma in routinely processed bone marrow trephine specimens, which show no obvious morphological (light microscopic) evidence of lymphoma; to determine whether bcl-2 immunostaining in bone marrow distinguishes between benign and malignant infiltrates in a patient with nodal follicular lymphoma. METHODS--Twenty seven consecutively selected paraffin wax embedded, formalin fixed bone marrow trephine specimens were stained with the following antibodies: anti-bcl-2, anti-CD79a, anti-CD3, and kappa and lambda light chains, using the Streptavidin biotin complex technique. RESULTS--Five of the 27 cases, which showed no evidence of involvement by follicular lymphoma on routine stains, showed monotypic B cells on immunohistochemistry. Two of the cases were diffuse, while the remaining three showed mini-aggregates around bony trabeculae. In all five cases the lymphomatous infiltrates were strongly bcl-2 positive. Reactive B lymphoid nodules did not show the same degree of bcl-2 positivity, and negative cells could be discerned within the reactive nodules. CONCLUSIONS--There is merit in studying so-called negative bone marrows immunohistochemically in order to detect minimal involvement by follicular lymphoma. A limited panel of antibodies including anti-bcl-2, anti-CD79a and anti-CD3 is usually adequate to accomplish this. Strongly bcl-2 positive lymphoid aggregates in the bone marrow of patients with nodal follicular lymphoma are indicative of lymphoma.     

Monoclonal antibodies marking B-cell non-Hodgkin's lymphoma in paraffin-embedded tissue

Traditional methods for the immunophenotypic analysis of the non-Hodgkin's lymphomas require fresh or snap-frozen tissue for flow cytometric or immunohistochemical studies. The monoclonal antibodies LN1, LN2, and L26 have been recently developed to recognize B-cell-specific antigens that survive routine tissue processing and paraffin embedding. In this study, the ability of these three antibodies to mark the neoplastic cells in 160 cases of paraffin-embedded non-Hodgkin's lymphoma relative to frozen section immunophenotype (42 T-cell, 118 B-cell), manner of fixation (B5 versus 10% buffered formalin), and histological subtype was examined. With B5-fixed tissue, the percentages of B-cell lymphoma marking with the antibodies were as follows: L26, 96.6%; LN1, 88.2%; LN2, 93.7%. With formalin-fixed tissue, the percentages of B-cell lymphoma reacting with the antibodies were: L26, 89.1%; LN1, 26.2%; LN2, 57.8%. Each of the antibodies marked a small percentage of paraffin-embedded T-cell lymphomas: L26, 4.7%; LN1, 4.7%; LN2, 7.1%. LN2, and to a lesser extent LN1, stained Reed-Sternberg cells, a feature not seen with L26. Nor did L26 mark nonlymphoid neoplasms, a feature previously reported with LN1 and LN2. Since a high percentage of B-cell lymphomas react with these antibodies and they are relatively specific for B-cells, they should prove highly useful for the evaluation of both diagnostic and experimental pathology specimens. L26 offers the distinct advantage of working well in both B5 and formalin-fixed tissues and seemingly not marking epithelial neoplasms.     

CD43 expression in B cell lymphoma.

AIMS: To determine the expression of CD43 in frozen sections in a range of B cell lymphomas. METHODS: The monoclonal antibody WR14, clustered provisionally in the Fourth Leucocyte Typing Workshop as a CD43 reagent, was investigated by epitope blocking studies on formalin fixed reactive lymph node tissue, using the established CD43 antibody MT1, to validate its use as a CD43 reagent. CD43 expression was studied in 131 immunophenotypically defined B cell lymphomas, including lymphocytic lymphoma (Lc, n = 13), centrocytic lymphoma (Cc, n = 14), and a range of follicle centre cell lymphomas (FCC) including centroblastic/centrocytic follicular (CbCcF, n = 48), centroblastic diffuse (CbD, n = 39), centroblastic/centrocytic diffuse (CbCcD, n = 4), centroblastic follicular and diffuse (Cb FD, n = 3) and centroblastic/centrocytic follicular and diffuse (CbCc FD, n = 1). Nine lymphomas of mucosa associated lymphoid tissue (MALT) were also examined. RESULTS: Epitope blocking studies showed that WR14 is a CD43 reagent that binds to an epitope identical with or close to that recognised by MT1. Eleven of 13 (84%) cases of Lc and 11 of 14 (78%) cases of Cc expressed CD43; 87 of 95 (91%) cases of FCC did not. All eight low grade lymphomas of MALT were negative. One high grade lymphoma, transformed from a low grade MALT lymphoma, was positive for CD43. The expression of CD43 by tumours of B cell lineage was associated with the expression of CD5 (p < 0.001) although either antigen could occasionally be found in the absence of the other. CONCLUSION: CD43 reagents can be used in conjunction with CD5 antibodies for the immunophenotypic discrimination of follicle centre cell lymphomas from non-follicle centre cell lymphomas.     

Diagnostic importance of CD179a/b as markers of precursor B-cell lymphoblastic lymphoma.

Surrogate light chains consisting of VpreB (CD179a) and lambda5 (CD179b) are expressed in precursor B cells lacking a complete form of immunoglobulin and are thought to act as substitutes for conventional light chains. Upon differentiation to immature and mature B cells, CD179a/b disappear and are replaced with conventional light chains. Thus, these molecules may be useful as essential markers of precursor B cells. To examine the expression of the surrogate light-chain components CD179a and CD179b in precursor B-cell lymphoblastic lymphoma, we analyzed tissue sections using immunohistochemistry techniques. Among a number of monoclonal antibodies for the surrogate light chains, VpreB8 and SL11 were found to detect CD179a and CD179b, respectively, in acetone-fixed fresh frozen sections. Moreover, we also observed VpreB8 staining in formalin-fixed, paraffin-embedded sections. Using these antibodies, we found that CD179a/b were specifically expressed in precursor B-cell lymphoblastic lymphomas, but not in mature B-cell lymphomas in childhood. Furthermore, other pediatric tumors that must be included in a differential diagnosis of precursor B-cell lymphoblastic lymphoma, including precursor T-cell lymphoblastic lymphoma, extramedullary myeloid tumors, and Ewing sarcoma, were also negative for both CD179a and CD179b. Our data indicate that CD179a and CD179b may be important markers for the immunophenotypic diagnosis of precursor B-cell lymphoblastic lymphomas.     

bcl-10蛋白异常表达对黏膜相关淋巴组织结外边缘区B细胞淋巴瘤的诊断价值

目的探讨bcl-10蛋白表达对黏膜相关淋巴组织结外边缘区B细胞淋巴瘤（MALT淋巴瘤）的诊断价值。方法收集140例不同部位的MALT淋巴瘤,包括胃38例、眼眶35例、肠16例、皮肤15例、涎腺15例、肺14例、甲状腺3例、其他部位4例。对照：10例扁桃体反应性滤泡增生（RFH）、5例眼眶的淋巴组织增生和143例非MALT淋巴瘤、不同类型的非霍奇金淋巴瘤（NHL）,包括20例NK／T细胞淋巴瘤、20例滤泡性淋巴瘤（FL）、20例间变性大细胞淋巴瘤（ALCL）、20例淋巴结内弥漫大B细胞淋巴瘤（DLBCL）、10例原发胃DLBCL、13例淋巴结边缘区淋巴瘤（NMZL）、12例套细胞淋巴瘤（MCL）、11例脾脏边缘区淋巴瘤（SMZL）、6例血管免疫母细胞性T细胞淋巴瘤（AITL）、6例外周T细胞淋巴瘤（PTCL）、3例B．小淋巴细胞淋巴瘤（B-SLL）、1例淋巴浆细胞性淋巴瘤（LPL）和1例浆细胞瘤。免疫组织化学EnVision法检测bcl-10蛋白;免疫组织化学双标记法检测CD20与bcl-10的共表达。结果在扁桃体RFH中,bel-10蛋白呈中等强度表达于生发中心B细胞质中,套细胞不表达,边缘区细胞和副皮质区T细胞呈弱表达。在眼眶淋巴组织增生中,2例bel-10阴性,3例主要呈淋巴滤泡生发中心B细胞质阳性,与扁桃体RFH的表达类似。在非MALT淋巴瘤的其他类型NHL中,除3例（3／10）原发胃DLBCL呈胞核阳性外,其余均未见胞核表达;在不同NHL中的胞质阳性分别为：结内（12／20）和胃（7／10）DLBCL、FL和ALCL（16／20）、PTCL（5／6）、AILT（6／6）、NMZL（13／13）、SMZL（11／11）、B-SLL（3／3）和浆细胞瘤（1／1）,11例MCL呈胞质可疑阳性,20例NK／T细胞淋巴瘤和1例LPL阴性;在部分淋巴瘤中可见肿瘤性细胞表达而反应性小淋巴细胞不表达：MALT淋巴瘤之bcl-10的总表达率为92．1％（129／140）,其中54．3％（76／140）胞质阳性,37．9％（53／140）胞核阳性;但不同部位之胞核阳性率有所不同。在MALT淋巴瘤中,bcl-10蛋白核强表达最常见于眼眶（25．7％,9／35）;除出现异常bcl-10胞核表达外,约20％有反应性滤泡的病例呈生发中心失表达。双标记显示bcl-10阳性细胞为CD20阳性细胞,但CD20阳性细胞多于bcl-10阳性细胞。结论（1）淋巴细胞增生性病变中bcl-10蛋白普遍表达,细胞质表达可出现在多数NHL和反应性增生中,但在淋巴瘤中呈肿瘤细胞表达而反应性细胞不表达,提示bcl-10异常可能与部分淋巴瘤的形成有关;（2）细胞核内bcl-10异常表达主要见于MALT淋巴瘤;眼眶、肺等部位的胞核强阳性和生发中心阴性的特殊模式,对MALT淋巴瘤的诊断及其与反应性病变的鉴别诊断有一定辅助意义。     

Immunohistochemical determination of CD23 expression in Hodgkin's disease using paraffin sections

The leukocyte antigen CD23 is expressed during B-cell development, and functions as an IgE receptor and a lymphocyte growth factor. We studied the expression of CD23 in paraffin sections of lymphoid tissue using the monoclonal antibody BU38. Fifteen cases of Hodgkin's disease, ten reactive lymph nodes, eight B-cell, and seven T-cell non-Hodgkin's lymphomas were analysed immunohistologically. CD23 positivity was seen on follicular dendritic cells and a small number of lymphocytes in reactive nodes. Thirteen of the 15 cases of Hodgkin's disease showed CD23 expression in both neoplastic cells and reactive lymphocytic infiltrate. The antigen was demonstrated in four of the B-cell and one of the T-cell tumours. CD23 may be important in mediating the mixed cellular infiltrate characteristic of Hodgkin's lymphoma.     

CD40 expression in Hodgkin's disease.

CD40 is a transmembrane protein that belongs to a superfamily of proteins related to nerve growth factor receptor. CD40 is expressed on B cells and some B cell malignancies. It appears to be involved in B cell proliferation and the prevention of apoptosis in germinal center cells, which is accompanied by expression of bcl-2. Its expression is up-regulated by the EBV protein latent membrane protein-1 and cytokines interleukin-4 and interferon-gamma. The expression of CD40 in 37 cases of Hodgkin's disease and 23 cases of non-Hodgkin's lymphoma (11 T cell lymphomas and 12 B cell lymphomas) was examined by paraffin section immunohistochemistry using the BB-20 monoclonal antibody. In 26 of 37 cases of Hodgkin's disease the Reed-Sternberg cells showed strong membrane or cytoplasmic expression of CD40. Only 3 of 23 non-Hodgkin's lymphomas showed any expression of CD40 and then only weakly. There was no correlation between expression of bcl-2 or latent membrane protein-1 with CD40 expression. These results show that there is probable hyperexpression of CD40 in Hodgkin's disease and suggest that dysregulation of CD40 expression may play a role in the pathogenesis of Hodgkin's disease.     

A comprehensive antibody panel for immunohistochemical analysis of formalin-fixed, paraffin-embedded hematopoietic neoplasms of mice: analysis of mouse specific and human antibodies cross-reactive with murine tissue

Immunohistochemistry is an indispensable tool in human pathology enabling immunophenotypic characterization of tumor cells. Immunohistochemical analyses of mouse models of human hematopoietic neoplasias have become an important aspect for comparison of murine entities with their human counterparts. The aim of this study was to establish a diagnostic antibody panel for analysis of murine lymphomas/leukemias, useful in formalin-fixed/paraffin-embedded tissue. Overall, 48 antibodies (4 rabbit monoclonal, 12 rabbit polyclonal, 2 goat polyclonal, 11 rat, and 19 mouse monoclonal), which were either mouse-specific (14) or cross-reactive with murine tissue (34) were tested for staining quality and diagnostic value in 468 murine hematopoietic neoplasms. Specific staining was achieved with 29 antibodies, of which 18 were human antibodies cross-reactive with murine tissue. Only 23 (B220, BCL-2, BCL-6, CD117, CD138 (2x), CD3 (2x), CD43, CD45, CD5, CD79 alpha cy, cyclin D1, Ki-67 (2x), Mac-3, Mac-2, lysozyme, mast cell tryptase, MPO, Pax-5, TdT, and TER-119) were regarded as valuable for diagnostic evaluation. Immunohistochemistry was also established in an automated immunostainer for high throughput analysis. The antibody panel developed is useful for the classification of murine lymphomas and leukemias analyzed, and a valuable tool for human and veterinary pathologists involved in the diagnostic interpretation of murine models of hematopoietic neoplasias.