Expression of vimentin and epithelial membrane antigen in human malignant lymphomas

Immunoreactivity with monoclonal antibodies against the intermediate filament protein, vimentin, and epithelial membrane antigen (EMA) was examined in 330 cases of lymphoma (317 non-Hodgkin's and 13 Hodgkin's lymphomas), 12 reactive lymph nodes and mononuclear cells of the peripheral blood using either indirect immunoperoxidase staining or the avidin-biotin immunoperoxidase complex technique. The cell origin of each tumor was established using a panel of monoclonal antibodies against lymphocyte differentiation antigens. There were 41 T-cell, 247 B-cell and 29 undetermined lymphomas, and 13 cases of Hodgkin's disease in the series. Vimentin was expressed in 24 T-cell lymphomas (58.5%) and 60 B-cell lymphomas (24.2%). This difference in frequency was statistically significant. Vimentin expression in follicular lymphomas was less frequent than in diffuse B-cell lymphomas. In diffuse lymphomas, small and medium cell types were more reactive with anti-vimentin than large cell types. Reed-Sternberg cells (R-S cells) in Hodgkin's disease were positive for vimentin in 11 cases (84.6%). The frequency of EMA reactivity in lymphomas was low, particularly in T-cell lymphomas. No positive cases were found among follicular lymphomas. In diffuse non-Hodgkin's lymphomas, EMA was expressed only in mixed and large cell types, but never in smaller ones. In conclusion, monoclonal antibodies against vimentin and EMA appear to be of limited usefulness for the diagnosis of non-Hodgkin's lymphomas, but anti-vimentin antibody may be used as an adjunct to the diagnosis of R-S cells in Hodgkin's disease.     

Monoclonal antibodies reactive in routinely processed tissue sections of malignant lymphoma, with emphasis on T-cell lymphomas

The immunoreactivity of eight monoclonal antibodies was evaluated on 45 routinely processed lymphomas (22 T-cell lymphomas, 11 B-cell lymphomas, and 12 cases of Hodgkin's disease). Two antibodies reactive with leukocyte common (T200) antigens (PD7/26 and 2B11) stained most of the B- and T-cell lymphomas but did not stain the Reed-Sternberg cells and variants in Hodgkin's disease. Two antibodies known to stain B cells (LN-1 and LN-2) reacted with some of the B-cell lymphomas, but LN-2 also reacted with the neoplastic cells in six of 22 T-cell lymphomas and with the Reed-Sternberg variants in eight of 12 cases of Hodgkin's disease. The granulocyte antibody anti-Leu M1 reacted with most cases of Hodgkin's disease but also reacted with two of 11 B-cell non-Hodgkin's lymphomas. An antibody to epithelial membrane antigen (anti-EMA) stained some cases of T-cell lymphoma, B-cell lymphoma, and Hodgkin's disease. Leu 7 was expressed in one T-cell lymphoma and in one case of Hodgkin's disease. A novel antibody reactive with T cells (L60) stained all cases of T-cell lymphoma but also stained some cases of B-cell lymphoma and one case of Hodgkin's disease. We conclude that none of these antibodies, when used alone on routinely fixed paraffin-embedded material, is completely sensitive and specific for T-cell lymphoma, B-cell lymphoma, or Hodgkin's disease. However, a panel of antibodies is useful in distinguishing Hodgkin's disease from non-Hodgkin's lymphoma and in suggesting the B- or T-cell phenotype of non-Hodgkin's lymphomas.     

A novel monoclonal antibody (FUN-1) identifies an activation antigen in cells of the B-cell lineage and Reed—Sternberg cells

The characterization of a new monoclonal antibody (MoAb) recognizing a human B-cell activation antigen, designated FUN-1, is described in this paper. Immunoprecipitation revealed that FUN-1 recognizes an antigen with a molecular weight (MW) of 75 kD. FUN-1 reacts with pokeweed mitogen-activated B lymphocytes and monocytes of peripheral blood, but not with unstimulated lymphocytes or granulocytes. It also reacts with large lymphoid cells in germinal centres, Epstein–Barr virus-transformed B cell lines, large B-cell lymphomas, Ki-1-positive anaplastic largecell lymphomas, and Reed–Sternberg cells of Hodgkin's disease, but not with Concanavalin A-activated T cells, acute lymphoblastic leukaemias, T-cell lymphomas, or low-grade B-cell leukaemias. These findings indicate that FUN-1 recognizes a previously unreported B-cell activation antigen. This MoAb appears to be useful for the study of maturation and differentiation in the B-cell lineage as well as for the immunohistochemical diagnosis of B-cell lymphomas and Hodgkin's disease.     

Coexpression of epithelial membrane antigen (EMA), Ki-1, and interleukin-2 receptor by anaplastic large cell lymphomas. Diagnostic value in so-called malignant histiocytosis

A group of 63 cases of anaplastic large cell lymphomas (variants of diffuse large cell lymphomas often diagnosed as "malignant histiocytosis") was characterized on both morphologic criteria and expression of epithelial membrane antigen (EMA) and Ki-1 antigen (CD30). On the basis of the reactivity of these tumors with anti-EMA and anti-Ki-1 antibodies, four subtypes could be distinguished. In the majority of cases (n = 49), neoplastic cells coexpressed EMA and Ki-1 antigens. Nineteen of these cases were tested for IL-2R, and all were positive (Type I, EMA+, Ki-1+, IL-2R+). In the second group (n = 5), the neoplastic cells expressed EMA but not the Ki-1 antigen. These cases were not tested for the presence of IL-2R (Type II, EMA+, Ki-1-, IL-2R?). There were tumors with similar morphology expressing only Ki-1 antigen (Type III, EMA-, Ki-1+, IL-2R-) or negative for both EMA and Ki-1 antigens (Type IV, EMA-, Ki-1-, IL-2R-). EMA appeared to occur predominantly on activated cells, as has been previously shown for Ki-1 antigen. Analysis using monoclonal antibodies to T-cell, B-cell, or macrophage-associated differentiation antigens showed that these tumors were heterogeneous in terms of cell lineage. Tumors coexpressing EMA, Ki-1, and IL-2R (Type I), were most commonly of T-cell origin (n = 12); the remainder in this type expressed B-cell markers (n = 4), a mixed B/T phenotype (n = 2), or no clear phenotype (n = 9). By contrast, tumors of Types II, III, and IV were mainly from B-cell origin (n = 6) or showed a mixed B/T phenotype (n = 1). Despite the fact that a significant proportion of these cases were initially classified morphologically as "malignant histiocytosis," only 3 of the 63 cases were possibly of histiocytic origin. These results confirm that true malignant histiocytosis is rare and that most tumors with histologic features currently regarded as being consistent with this diagnosis are lymphocytic in origin and express activation antigens such as EMA, Ki-1 antigen, and IL-2R.     

Malignant lymphomas of true histiocytic origin. A clinical, histological, immunophenotypic and genotypic study

The clinical, histological, immunophenotypic and genotypic properties of four cases of lymphoma of true histiocytic origin are described. The cases were identified by typing 925 non-Hodgkin's lymphomas by immunophenotypic and/or genotypic techniques, and they all presented with skin lesions. The histological and immunophenotypic examination showed dense, diffuse infiltrates of markedly pleomorphic mononuclear cells that were positive for macrophage-associated markers, and negative for B-cell, T-cell and myeloid cell-associated antigens. Staining for Ki-1 and epithelial membrane antigen was also negative. Gene rearrangements studies were performed in three cases, and all of these showed germline configuration of both T-cell receptor and immunoglobulin genes. In all cases, the clinical course was aggressive with rapid and widespread dissemination to internal organs, poor response to conventional chemotherapy, and short survival times (0.5 to 14 months). This suggests that although true histiocytic tumours are very rare, their recognition may be important for clinical and/or prognostic reasons.     

Study of vimentin expression in non-Hodgkin's lymphoma using paraffin sections.

Human non-Hodgkin's lymphomas were studied by means of an avidin-biotin complex immunoperoxidase method using several monoclonal antibodies against the intermediate filament protein, vimentin. The study cases were 61 B-cell lymphomas (including 2 plasmacytomas) and 30 T-cell lymphomas (including 8 cases of mycosis fungoides). Twelve of the 61 B-cell lymphomas were positive for vimentin, and were composed of extrafollicular-center cells such as immunoblastic and plasmacytoid cells. On the other hand, lymphomas of follicular center cell origin were negative for vimentin. All cases of T-cell lymphoma except for 14 (all of 9 AILD-type lymphomas, all of 4 lymphoblastic lymphomas and one diffuse mixed small/large lymphoma) were positive for vimentin. Although vimentin expression appeared to be influenced by various conditions such as the proportion of T- and B-cell subsets, or B-cell proliferation rate, follicular center cells were constantly negative for vimentin.     

CD30 distribution. Immunohistochemical study on formaldehyde-fixed, paraffin-embedded Hodgkin's and non-Hodgkin's lymphomas.

Two hundred Hodgkin's and non-Hodgkin's lymphomas were immunohistochemically studied for the presence of the CD30 (Ki-1) activation antigen using a monoclonal antibody BerH2 on paraffin-embedded, formaldehyde-fixed tissue. Immunohistochemistry was performed by using the avidin-biotin complex technique and was preceded by enzymatic digestion with pepsin (0.05% for 20 minutes). Ninety percent (56/64) of cases of Hodgkin's disease, other than lymphocyte predominance type, showed positive tumor cells, although the positivity was often focal. In contrast, lymphocyte predominance type showed CD30 in only two of nine cases. CD30 was commonly seen in non-Hodgkin's lymphomas. Five of 37 large-cell lymphomas showed extensive CD30 positivity and morphologically represented large-cell anaplastic lymphomas ("Ki-1 lymphomas"). Apart from this, occasional CD30-positive cells were seen in nine of 32 large-cell non-Hodgkin's lymphomas. About half of the nodular small cleaved-cell lymphomas contained CD30-positive cells, two of them showing large numbers of positive cells both within and outside the nodules. Lymphocytic lymphoma sometimes (6/17) showed a few CD30-positive cells. Peripheral T-cell lymphomas showed positive cells in three of eight cases. The positive cases were one lymphoma with small groups of epithelioid cells (Lennert's lymphoma) and two immunoblastic lymphadenopathylike peripheral T-cell lymphomas. The results show that CD30 is more widespread than originally thought in non-Hodgkin's lymphomas and that especially nodular small cleaved-cell lymphomas often contain positive cells. These findings have to be considered in the immunohistochemical differential diagnosis of lymphomas. Obviously, CD30 alone cannot be used to differentiate between Hodgkin's and non-Hodgkin's lymphomas. The CD30-positive cells in non-Hodgkin's lymphoma may represent a link between Hodgkin's and non-Hodgkin's lymphomas.     

My4 antibody staining of non-Hodgkin's lymphomas.

The My4 antibody, one of a number of monoclonal antibodies that react with the CD14 antigen, was originally reported to weakly stain monocytes, macrophages, and granulocytes. However, recent studies have shown that the My4 antibody also stains normal peripheral blood B lymphocytes and some subtypes of B-cell non-Hodgkin's lymphoma. Thus, the authors have studied a large series of non-Hodgkin's lymphomas stained with the My4 antibody. In frozen sections of reactive lymph node biopsy specimens, the My4 antibody strongly stained mantle zone B lymphocytes and weakly reacted with dendritic reticulum cells and histiocytes. In a series of 245 non-Hodgkin's lymphomas, the My4 antibody stained 111 (45%) cases: 108 of 189 (57%) B-cell lymphomas, 3 of 50 (6%) T-cell lymphomas, and 0 of 6 null cell lymphomas. My4-positive B-cell lymphomas occurred in all histologic subtypes with the exception of small noncleaved cell lymphomas. Follicular lymphomas were most often My4 positive (82%). My4 antibody staining showed no correlation with Working Formulation grade. All three My4-positive T-cell lymphomas had a mature T-cell phenotype. Seventy-six of the 111 (68%) My4-positive lymphomas were also analyzed with at least one other anti-CD14 antibody, either Mo2 and/or Leu-M3. In all cases the antigens that react with Mo2 and Leu-M3 were not expressed. Thus, the staining of reactive and neoplastic B cells by My4 appears to be unique to this antibody and is not a feature of all anti-CD14 antibodies.     

Expression of Vimentin and Epithelial Membrane Antigen in Human Malignant Lymphomas

Immunoreactivity with monoclonal antibodies against the intermediate filament protein, vimentin, and epithelial membrane antigen (EMA) was examined in 330 cases of lymphoma (317 non-Hodgkin's and 13 Hodgkin's lymphomas), 12 reactive lymph nodes and mononuclear cells of the peripheral blood using either indirect immunoperox-idase staining or the avidin-biotin immunoperoxidase complex technique. The cell origin of each tumor was established using a panel of monoclonal antibodies against lymphocyte differentiation antigens. There were 41 T cell, 247 B cell and 29 undetermined lymphomas, and 13 cases of Hodgkin's disease in the series. Vimentin was expressed in 24 T-cell lymphomas (58.5%) and 60 B cell lymphomas (24.2%). This difference in frequency was statistically significant. Vimentin expression in follicular lymphomas was less frequent than in diffuse B-cell lymphomas. In diffuse lymphomas, small and medium cell types were more reactive with anti-vimentin than large cell types. Reed-Sternberg cells (R-S cells) in Hodgkin's disease were positive for vimentin in 11 cases (84.6%). The frequency of EMA reactivity in lymphomas was low, particularly in T cell lymphomas. No positive cases were found among follicular lymphomas. In diffuse non Hodgkin's lymphomas, EMA was expressed only in mixed and large cell types, but never in smaller ones. In conclusion, monoclonal antibodies against vimentin and EMA appear to be of limited usefulness for the diagnosis of non Hodgkin's lymphomas, but anti vimentin antibody may be used as an adjunct to the diagnosis of R-S cells in Hodgkin's disease.     

Immunohistochemical, molecular, and cytogenetic analysis of a consecutive series of 20 peripheral T-cell lymphomas and lymphomas of uncertain lineage, including 12 Ki-1 positive lymphomas

Although several independent series of non-Hodgkin's lymphomas (NHLs) have been subjected to cytogenetic studies or analyses of lineages by assaying for clonal immunophenotypes and clonal rearrangements affecting immunoglobulin (IG) and T-cell receptor (TCR) genes, no published reports exist of series of non-B-cell NHLs on which cytogenetic, immunohistochemical, and IG and TCR gene rearrangement studies have been undertaken together. Among 343 NHLs ascertained prospectively between January 1984 and December 1988 at the Memorial Sloan-Kettering Cancer Center, 278 cases with clonal chromosome abnormalities were identified. Of the latter, 20 were non-B-cell NHLs, which in turn comprised 15 peripheral T-cell lymphomas (PTCLs) and 5 lymphomas of uncertain lineage (LULs). The LULs either were biogenotypic, had discordant immunophenotype and immunogenotype, or showed no evidence of B-cell, T-cell, or histiocytic derivation. Of the 15 PTCLs, eight expressed the Ki-1 antigen and four of these had translocations involving the band 5q35 [t(5q35)]. Of the five LULs, four expressed the Ki-1 antigen and one of these had a translocation involving band 5q35. Previous studies have associated t(5q35) with Ki-1 positive NHLs characterized histologically by a pleomorphic diffuse large cell morphology. In our series of 12 Ki-positive non-B-cell NHLs, five (42%) had a 5q35 translocation. They were histologically indistinguishable from the subset without the translocation. The frequent lineage uncertainty exhibited by Ki-1 positive NHLs of similar histology and cytogenetic abnormalities suggests their derivation from an early uncommitted lymphoid cells.     

Immunophenotyping of non-Hodgkin''s lymphomas using a panel of antibodies on paraffin-embedded tissues.

The use of monoclonal and polyclonal antibodies for the immunophenotyping of non-Hodgkin's lymphomas in paraffin-embedded tissue has been limited by the fact that most antigens on lymphoid cells are denatured by histologic fixation, dehydration, and embedment. In this article the authors have analyzed a small panel of antibodies which represent exceptions to this rule, in that they identify denaturation-resistant determinants on leukocyte antigens in paraffin-embedded tissue. Monoclonal antibodies L26 [corrected] and 4KB5 label preferentially B cells, monoclonal antibody UCHL1 stains predominantly T cells, and monoclonal antibody MAC 387 reacts with granulocytes and some macrophages. A polyclonal antiserum raised against purified CD3 (T3) antigen, a T-cell-specific molecule, was also employed. This antibody panel was used to immunophenotype routinely processed tissue biopsy specimens from 61 non-Hodgkin's lymphomas (all of which had been previously phenotyped in cryostat sections). The lineage of the neoplastic cells was correctly identified in 32 of 34 (94%) cases of B-cell lymphoma, in 19 of 19 (100%) cases of T-cell neoplasm, and in 2 of 4 (50%) cases of histiocytic malignancy. It is concluded that this combination of antibodies is helpful in immunophenotyping non-Hodgkin's lymphomas when only paraffin-embedded tissue sections are available, although additional reagents of higher specificity are required to improve the identification of lymphomas.     

Immunohistological analysis of the immunoreactivity of normal lymphoid cells and lymphomas with the monoclonal antibody OPD4

OPD4 is a recently described monoclonal antibody that recognizes a fixation-resistant 200 kD antigen restricted to a subset of T cells. Immunolabelling with OPD4 in paraffin sections of normal lymphoid tissues and cases of malignant lymphoma was compared with that of other antibodies in common use, including the T-cell restricted antibodies MT1 and UCHL1 and the B-cell restricted antibodies MB1, F8-11-13, and L26. OPD4 showed similar immunoreactivity to UCHL1 in normal tissues. OPD4 did not stain Reed-Sternberg cells in Hodgkin's disease. In non-Hodgkin's lymphomas, OPD4, like UCHL1, reacted with only 2/22 B-cell lymphomas. OPD4 was, however, less useful as a marker of T-cell lymphomas, staining only 11/32 cases, while UCHL1 stained 22/32 cases. We conclude that OPD4 is not a useful antibody for the routine diagnosis of T-cell lymphoma.     

Monoclonal antibody HML-1 reactivity with adult T-cell leukaemia/lymphoma and other lymphomas

Human T-cell leukaemia/lymphoma virus type 1 (HTLV-1), a causative virus of adult T-cell leukaemia/lymphoma (ATLL), is known to be transmitted by breast-feeding. Using a monoclonal antibody HML-1 which labels human intestinal intra-epithelial T lymphocytes, we have immunohistochemically examined ATLL tissues in order to evaluate the possibility that HTLV-1 infected intestinal T cells are the origin of ATLL cells. Previously this antibody was reported to react with intestinal T-cell malignant lymphomas but not with peripheral tumours, or any B-cell lymphomas. We investigated 181 patients with malignant lymphomas and found that 19 out of 113 ATLLs were positive for HML-1. T-cell malignant lymphomas excluding ATLL also reacted with HML-1 (7/24), but all the B-cell lymphomas 0/33) and non-neoplastic lymph node and skin lesions (0/10) were negative for HML-1. In patients with ATLL and other T-cell malignant lymphomas, the positivity level of HML-1 was relatively higher in stomach (3/7) and tonsil (2/6) than that in lymph nodes (15/100) and skin (8/47). We observed one HML-1 positive ATLL patient with tumour formation in the skin and lymphadenopathy and marked infiltration of the large intestine but minimal involvement of other organs. Although HML-1 was frequently expressed in gastric infiltration of ATLL, the level of positivity was too low in lymph nodes to support the hypothesis that HTLV-1 infected intestinal T cells are the origin of ATLL cells. Some of the HML-1 positive ATLL cases co-expressed CD30. Furthermore, three of six cases of Ki-1 lymphoma (large anaplastic cell lymphoma) were positive for HML-1. We conclude that expression of HML-1 in ATLL reflects an activated state of the lymphoma cells, but not the intestinal origin of ATLL cells.     

Methods in pathology. Identification of T-cell lymphomas in paraffin-embedded tissues using polyclonal anti-CD3 antibody: comparison with frozen section immunophenotyping and genotypic analysis.

While L26 (CD20) is now well established as a B-cell marker of high specificity for use in paraffin-embedded tissues, paraffin-reactive T-cell antibodies (UCHL1, MT1, Leu-22, DF-T1, and MT2) have not shown comparable lineage specificity. A new commercially available polyclonal antibody directed against a synthetic peptide sequence of the CD3 (T-cell) antigen has recently become available for use on paraffin sections. In order to evaluate the utility of this antibody, we studied CD3 expression in conjunction with L26 and leukocyte common antigen (LCA) in 15 T-cell and 20 B-cell non-Hodgkin's lymphomas (NHL), all genotypically confirmed by DNA hybridization and immunophenotyped by immunoperoxidase studies in frozen tissue. Ten of 15 T-cell NHLs (67%) showed unequivocal immunolabeling of neoplastic cells with anti-CD3 in paraffin-embedded tissue. Of the five negative cases, three were lymphoblastic lymphomas, and two were peripheral (postthymic) lymphomas (one anaplastic large cell, Ki-1 positive and one large cell, immunoblastic). CD3 expression was identical in paraffin and cryostat sections (100% concordance). Twenty of 20 B-cell NHLs were positive with L26 and LCA but were negative with anti-CD3. Other neoplasms examined, including three granulocytic sarcomas and 45 nonhematopoietic tumors, were similarly negative with anti-CD3. We conclude that polyclonal anti-CD3 is a sensitive and highly specific T-cell marker in paraffin-embedded tissue and, when used in conjunction with LCA and L26, that it can determine cell lineage in the majority of non-Hodgkin's lymphomas.     

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.     

Primary non-Hodgkin's lymphoma of the intestine: a morphological, immunohistochemical and clinical study of 31 Chinese cases

Thirty-one cases of primary non-Hodgkin's lymphoma of the intestine were investigated. Twenty-one were of B-cell and 10 of T-cell origin. The B-cell lymphomas comprised two cases of low-grade B-cell lymphoma of mucosaassociated lymphoid tissue (MALT), one of centroblastic/centrocytic type, three of high-grade B-cell lymphoma coexisting with a low-grade B-cell lymphoma of MALT, nine of centroblastic, three of immunoblastic and three of Burkitt type. Of the T-cell lymphomas, eight were of pleomorphic medium-to large-sized cell type and two of large cell anaplastic type. All the B-cell lymphomas expressed CD20 (L26) and/or Ki-B5; in six there was monotypic immunoglobulin light chain restriction. Membrane positivity for CD45RO (UCHL1) was observed in the 10 cases of T-cell lymphoma, but the tumour cells did not express monocyte-macrophage markers. Clinically, the patients with T-cell lymphomas were usually young males with constitutional symptoms and their prognosis was significantly worse than those of patients with intestinal B-cell lymphoma.     

Sinonasal non-Hodgkin's lymphomas and Wegener's granulomatosis: A clinicopathological study

Summary Reports of sinonasal non-Hodgkin's lymphomas, analysed with monoclonal antibodies, are scarce, and differentiation of these lymphomas from Wegener's granulomatosis can be difficult. In this study, we investigated histopathologically and immunohistologically 20 cases of non-Hodgkin's lymphoma, primary in the sinonasal region, and sinonasal biopsies from 11 patients with Wegener's granulomatosis. All T-cell lymphomas (n=7) and plasmacytomas (n=4) were stage I at clinical presentation, while all B-cell lymphomas (n=9) presented at higher stages. T-cell lymphomas tended to be more frequent in the nasal cavity and paranasal sinuses; B-cell lymphomas more often presented in the nasopharynx. Remarkably, 1 B-cell lymphoma expressed MT1, and 1 T-cell lymphoma expressed L26 (CD 20). The follow-up of 2 patients with a clinical diagnosis of Wegener's granulomatosis was suggestive of non-Hodgkin's lymphoma. Retrospective immunohistochemical analysis revealed that the original histological diagnosis of non-specific inflammation had to be changed to T-cell lymphoma, pleomorphic small cell type. We conclude that a biopsy from the sinonasal region with a dense inflammatory infiltrate, consisting predominantly of Tlymphocytes, renders a diagnosis of Wegener's granulomatosis unlikely and is at least suspicious of T-cell lymphoma. Immunohistochemical analysis is warranted for this type of biopsy.     

Ki-1 lymphomas in childhood: Immunohistochemical analysis and the significance of epithelial membrane antigen (EMA) as a new marker

Summary Two cases of Ki-1 lymphomas in childhood were analyzed immunohistochemically and immunoelectron microscopically. They expressed Hodgkin's disease associated antigen, Ki-1, interleukin-2 receptor (IL2R), OKT9, and HLA-DR. Histologically, the tumour cells were large in size with abundant cytoplasm and atypical nuclei. Lymph node involvement was characterized by parafollicular and marginal sinus infiltration. These features were identical to those reported in Ki-1 lymphomas. Electron microscopically tumour cells had abundant cytoplasmic organelles with pleomorphic nuclei but had no specific granules. Some tumour cells had marked interdigitation of cell membrane. Immunoelectron microscopically Ki-1 was positive on cell membrane. Tumour cells had no T-cell or B-cell antigens except for Leu-3 (T4). Unexpectedly they expressed epithelial membrane antigen (EMA) strongly. EMA was positive on cell membrane and in the cytoplasm. EMA was detected effectively in paraffin-embedded sections. Among the malignant lymphomas in childhood tested, two cases were EMA-positive. The pattern of EMA-reactivity and the histology were very similar to Ki-1 lymphomas. These results strongly suggest that Ki-1 lymphomas in childhood may arise from non-lymphoid haematopoietic cells and that EMA can be used as a new marker to distingish certain type of Ki-1 lymphomas in childhood.     

Non-Hodgkin's lymphomas of the gastrointestinal tract. An evaluation of paraffin section immunostaining.

Although the gastrointestinal (GI) tract is the most common site of primary extranodal lymphomas, the lineage of these tumors has been controversial. The authors used paraffin-reactive antibodies detecting markers of B-, T-, histiocytic, and epithelial cells to study 34 non-Hodgkin's lymphomas of the GI tract for which unequivocal frozen-section immunophenotypine was available as a control to determine whether these antibodies are reliable in the study of these tumors. Frozen-section studies revealed 31 tumors of B-cell origin and three T-cell tumors. Paraffin-reactive antibodies confirmed B-cell lineage in 28 of the 31 cases, with equivocal results in the remaining three. Only one of the T-cell lymphomas was identified in paraffin studies. Our results indicate that paraffin-reactive antibodies can reliably identify most B-cell lymphomas in the GI tract but may be unreliable in the detection of lymphomas of T-cell origin.     

An immunocytochemical study of T-cell lymphomas using monoclonal and polyclonal antibodies effective in routinely fixed wax embedded tissues

Formalin fixed and paraffin wax embedded tissue from 24 cases of T-cell lymphoma diagnosed using immunocytochemistry on cryostat sections was examined using a panel of eight monoclonal and three polyclonal antisera. The monoclonal antibodies UCHL1 and MT1 proved to be comparable and reliable markers of neoplastic cells in T-cell lymphomas. The B-cell specific marker, MB1, strongly stained all cells in two cases of pleomorphic large cell T-cell lymphoma, large cells in two cases of pleomorphic mixed medium and large cell lymphoma, and isolated clusters of blast cells in four cases of T-zone and angioimmunoblastic lymphadenopathy-like T-cell lymphoma. The cells stained by MB1 expressed T suppressor/cytotoxic surface markers on frozen section. Epithelial membrane antigen, as detected by a polyclonal anti-EMA and the monoclonal antibody HMFG2, was expressed in 36% of tumours especially those of monomorphic large cell and pleomorphic large cell phenotype. Single granules or finely dispersed cytoplasmic granularity was seen in four tumours using the anti-granulocyte reagent Leu M1. Tumour cells in one case stained in a pattern identical to Reed-Sternberg cells in Hodgkin's disease. Granular alpha-1-antitrypsin staining was found in 10 cases of pleomorphic large cell and monomorphic large cell lymphoma. No staining was observed using anti-lysozyme or the monoclonal macrophage specific marker Mac411. Monomorphic and pleomorphic large cell lymphomas tended to show a common immunophenotype with the majority of cells co-expressing alpha-1-antitrypsin HLA-DR and epithelial membrane antigen. Scattered large transformed blast cells in cases of angioimmunoblastic lymphadenopathy-like T-cell lymphomas and T-zone lymphomas shared a similar immunophenotype with the large cell lymphomas. Using a panel of monoclonal antibodies effective in paraffin embedded tissue, diagnostically useful staining profiles which correlate with the morphological phenotype can be established in T-cell lymphomas.