Malignant lymphomas of the nasal cavity and Waldeyer's ring--clinicopathologic and immunohistochemical study.

The clinicopathologic and immunohistochemical finding of 10 cases of nasal non-Hodgkin's lymphoma (NHL) and 23 cases of Waldeyer's ring NHL were studied. Immunohistochemically, nasal NHL expressed T-cell markers exclusively, whereas the NHL of Waldeyer's ring were of both T-cell (56.5%) and B-cell lineages (43.5%). Angioinvasiveness by tumor cells was exclusively noted in the T-lineage lymphomas. Epithelial hyperplasia, epitheliotropism by tumor cells, and extensive invasion of adjacent normal tissue were more prominent in T-cell lymphomas than in B-cell lymphomas. T-lineage lymphomas showed distant extranodal spread pattern involving the skin, soft tissue, stomach, spleen, and the liver, whereas B-lineage lymphomas tended to localize in the lymph nodes. The survival rate of Nasal NHL was similar to that of Waldeyer's ring NHL. Although not statistically significant because of small sample numbers, immunophenotype, histologic groups of monomorphic lymphoma, and stage had prognostic importance. In general, T-lineage lymphomas presented with a higher stage than B-lineage lymphomas (p < 0.05)-and overall survival was poor. Stage I disease showed a much more favorable prognosis than stage II disease. Monomorphic lymphomas had a shorter survival than polymorphic reticulosis (PR) or lymphomas with features of PR. This result in conjunction with the morphologic transition between them suggested that monomorphic lymphoma may represent the most advanced stage in the spectrum of PR, lymphoma with features of PR, and monomorphic lymphoma.     

Low-grade B-cell lymphoma of mucosa-associated lymphoid tissue type in Waldeyer's ring

Amongst a total of 329 cases of low-grade B-cell lymphoma of Waldeyer's ring, we identified 12 cases that corresponded histomorphologically to low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. These lymphomas are characterized by an extrafollicular growth pattern, often with a marginal zone-like arrangement, and by the centrocyte-like morphology of the tumour cells. They have not been described previously in this location. They predominantly affected the palatine tonsil. Ten cases were primary lymphomas of Waldeyer's ring. In two cases there was a simultaneous high-grade component. Two cases showed regional spread to cervical lymph nodes, but there was no widespread nodal involvement at the time of diagnosis. Immunohistochemically, all cases displayed B-cell markers and light chain restriction. Tropism of tumour cells for the epithelium was a consistent finding. In two cases involvement of Waldeyer's ring was secondary; in one of them the primary tumour was a gastric low-grade B-cell lymphoma of MALT type and in the other a high-grade B-cell non-Hodgkin's lymphoma of the stomach. These findings indicate that low-grade B-cell lymphomas of MALT type occurring in Waldeyer's ring should be included amongst the tumours of the MALT system. We surmise that in Waldeyer's ring such tumours are derived from the marginal zone, as has already been postulated for similar gastric tumours.     

Immunohistochemical analysis of peripheral T-cell lymphoma in Japanese patients

The authors immunohistochemically analyzed the phenotype of 40 cases of peripheral T-cell lymphoma, including 12 adult T-cell leukemia/lymphoma (ATL) cases. Molecular genetic analysis of the T-cell receptor beta-chain and immunoglobulin heavy chain genes were also applied to cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like lymphoma and so-called Lennert's lymphoma. Twenty non-ATL lymphomas expressed a helper/inducer phenotype, whereas only one extranodal case expressed a suppressor/cytotoxic phenotype. Three cases had a CD4-CD8- phenotype, and two cases a CD4+CD8+phenotype. No specific relationship between morphologic characteristics (LSG classification) and phenotype was found among non-ATL lymphomas. Six of eight AILD-like lymphomas had a helper/inducer phenotype. Monoclonality of neoplastic T-cells was demonstrated in six of the seven cases of AILD-like lymphoma by molecular genetic analysis. Two cases of Lennert's lymphoma also showed a helper/inducer phenotype and rearrangement of the T-cell receptor beta-chain gene. Serologically defined ATL cases had a helper/inducer phenotype except in one case that expressed both CD4 and CD8. None of the ATL cases had the CD7 antigen in this study using WT 1 as a CD7 antibody, which is in contrast with the non-ATL lymphomas in which 13 of 25 cases expressed CD7. CD25, strongly detectable in all ATL cases, was negative or weakly expressed in non-ATL lymphomas. These facts suggest that non-ATL and ATL are in the different biologic state, probably resulting from the integration of human T-cell leukemia virus type I (HTLV-I), although both are derived from helper/inducer T-cells.     

Aberrant expression of T-cell-associated antigens on B-cell non-Hodgkin lymphomas

We describe 9 well-characterized cases of B-cell non-Hodgkin lymphoma (NHL) that showed aberrant expression of T-cell-associated antigens by 2-color flow cytometry. Cases were as follows: chronic lymphocytic leukemia/small lymphocytic lymphoma, 4; follicle center cell lymphoma, 2; mantle cell lymphoma, 1; and diffuse large B-cell lymphoma, 2. CD2 was the most commonly expressed antigen (5 cases). CD8 and CD7 were identified in 2 cases each, including 1 case that expressed both CD7 and CD4. The disease course and response to treatment were compatible with the type and stage of lymphoma. No unusually aggressive behavior was noted in any case. A control group of 59 cases of benign lymph nodes analyzed during the same period showed no aberrant expression of T-cell-associated antigens; thus, such expression is not a feature of benign lymphoid proliferations. Study of these B-cell lymphomas may prove invaluable to study aberrant activation of silent or repressed T-cell differentiation genes. CD2-expressing B-cell NHLs may represent clonal expansion of CD2+ B lymphocytes that normally constitute a small fraction of peripheral B lymphocytes and should not be confused with composite B- and T-cell lymphomas. Unless aggressive behavior is noted consistently, no aggressive treatment is justified.     

Rare expression of T-cell markers in classical Hodgkin's lymphoma.

Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphoma are primarily of B-cell origin, although there are instances of T-cell antigen expression suggesting T-cell origin. We comprehensively analyzed expression of various T-cell antigens in 259 classical Hodgkin's lymphoma cases using the tissue microarray technique. Expression of the T-cell antigens CD2, CD3, CD4, CD5, CD7 and CD8 was assessed by immunohistochemistry. Hodgkin's and Reed-Sternberg cells of T-cell marker-positive cases were microdissected and analyzed by a multiplex polymerase chain reaction for clonal immunoglobulin heavy chain- and T-cell receptor gamma gene rearrangements. In all, 12 cases (5%) expressed at least one T-cell marker in the following order: CD2 in 11 cases, CD4 in five, CD3 in two, and CD5 and CD8 in one case each; there were no CD7-positive cases, and five cases (2%) expressed more than one T-cell antigen. In positive cases, a mean fraction of 40% of the Hodgkin's and Reed-Sternberg cells (range 20-100%) expressed the analyzed T-cell markers. Two cases (<1%) evidenced clonal T-cell receptor gamma gene rearrangement. Phenotypic expression of T-cell antigens in Hodgkin's and Reed-Sternberg cells of classical Hodgkin's lymphoma is rare (5%), while genotypically, less than 1% of classical Hodgkin's lymphomas are of possible T-cell origin. Therefore, T-cell antigen expression on Hodgkin's and Reed-Sternberg cells is aberrant in the majority of cases and only infrequently classical Hodgkin's lymphomas are of T-cell origin.     

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.     

T-cell lymphoma presenting in the breast: a histologic, immunophenotypic and molecular genetic study of four cases.

Primary non-Hodgkin's lymphoma of the breast is uncommon. Most primary breast lymphomas are of B-cell phenotype, with only rare cases showing a T-cell phenotype. In this study, we report the clinicopathologic features of four cases of T-cell lymphoma in the breast. The patients all were female with a mean age of 48 years (range, 13 to 77 years). All cases showed immunoreactivity in paraffin-embedded tissue for T-cell markers CD3, CD45RO, and CD43. beta F1 was positive in three of four cases. The four cases were further subclassified as anaplastic large cell lymphoma (CD30 positive) of T-immunophenotype; natural killer/T-cell lymphoma; peripheral T-cell (CD4 positive), large cell type; and peripheral T-cell (CD8 positive, T-cell intracellular antigen positive), medium cell type. Three of the four cases were monoclonal for T-cell receptor beta and/or T-cell receptor gamma. The one case of natural killer/T-cell lymphoma was negative for monoclonality with both T-cell receptor beta and gamma by molecular diagnostic studies. In all cases, IgH was negative. Follow-up was obtained in three cases. Two patients died within less than 1 year after the diagnosis. The third patient died within 18 months of the diagnosis. Our results suggest an aggressive clinical course for T-cell lymphomas that present in the breast.     

Histological and immunohistochemical studies on primary gastrointestinal lymphomas.

To study the characteristics and histogenesis of the malignant lymphomas derived from the gastrointestinal mucosa, histologic and immunohistochemical analyses were performed on a series of 28 malignant lymphomas of the gastrointestinal tract. By cytomorphologic classification, there were two small lymphocytic lymphomas, one small cleaved cell lymphoma, two mixed small cleaved and large cell lymphomas, 17 large cell lymphomas, one small noncleaved cell lymphoma, three immunoblastic lymphomas, and two lymphoblastic lymphomas. This distribution of histologic types was compatible with that of nodal lymphoma. The lymphomas with poor prognostic histology (23 cases) outnumbered those with favorable prognosis (five cases). Three of 28 cases (one in the stomach and two in the small intestine) had cytologic features consistent with centrocytoid cell lymphoma of the mucosa associated lymphoid tissue and were large cell lymphomas. Immunophenotypically, 23 cases expressed B-cell markers (82.1%) and three cases reacted with T-cell markers. Two cases did not react with either T-cell or B-cell markers. True histiocytic lymphomas were not identified. Gastric lymphomas (nine cases) and colorectal lymphomas (three cases) were of B-lymphocyte origin whereas T-cell lymphomas were noted in the small intestine (two cases) and ileocecal region (one case). Three cases of centrocytoid lymphoma were of B-lymphocyte origin. Histologically B-cell lineage lymphomas were evenly distributed on various histologic subtypes but all T-lineage lymphomas belonged to the large cell type. The two cases with undetermined phenotype were lymphoblastic lymphomas histologically. This study showed that the primary GIT lymphomas, mostly of B-cell lineage, were not cytomorphologically distinctive from the nodal lymphomas.(ABSTRACT TRUNCATED AT 250 WORDS)     

Primary gastric T-cell lymphoma of suppressor-cytotoxic (CD8+) phenotype: discordant expression of T-cell receptor subunit beta F1, CD7, and CD3 antigens.

Primary gastric T-cell lymphomas are rare neoplasms, and all but one of the previously phenotyped cases have shown a helper-inducer phenotype. The present case is the second reported case of a primary gastric T-cell lymphoma of suppressor-cytotoxic phenotype. The tumor histology was similar to that described in some forms of node-based peripheral T-cell lymphomas. Phenotypic analysis revealed low expression of pan-T marker CD7, reduced expression of CD3, but higher density and frequency of expression of CD8 antigens that could be predicted on the basis of the pan-T markers. Natural killer cell (NK) related markers CD16, HNK-1 and NKH-1 were not expressed by the neoplastic cells. T-cell receptor (TCR) beta subunit expression was detected on fewer cells than would have been predicted on the basis of CD3 and CD8 expression, and TCR delta chain expression was undetectable.     

Ploidy, proliferative activity, cluster differentiation antigen expression and clinical remission in highgrade non-Hodgkin''s lymphoma

Using a large range of monoclonal antibodies to specific cluster differentiation antigens the phenotypes of a series of high-grade non-Hodgkin's lymphomas of B- and T-cell type were investigated. Cell ploidy and proliferative fraction were assessed by fluorescent staining of DNA and flow cytometry and data on the incidence of complete clinical remission were obtained. With the exception of some lymphoblastic lymphomas, high-grade B-cell lymphomas normally expressed the pan B-cell antigens CD19 and CD22 but only immunoblastic lymphomas consistently expressed the pan B marker CD20. Variable, generally weak expression of CD21 was observed whilst CD23 expression was most prevalent in rapidly proliferative cases and in Burkitt's and centroblastic lymphomas. A rapidly proliferative, multilobated B-cell lymphoma displayed phenotypic properties intermediate between centroblastic and immunoblastic lymphomas. The T-cell lymphomas generally showed low proliferative activity and expression of CD4 prevailed over CD8. Most cases also showed CD2 and CD5 positivity with some also showing CD3 and CD7 expression. Patients with rapidly proliferative diploid or DNA aneuploid tumours obtained complete remission more readily than patients with lowly proliferative diploid tumours. An excess of early deaths occurred among T-cell cases.     

B-cell and T-cell lymphomas of the breast: clinical--pathological features of 53 cases

Breast involvement by non-Hodgkin lymphomas is rare. We studied the morphological, immunophenotypical, and clinical features of 53 cases of malignant lymphomas involving the breast in a population of Brazilian patients. Most of the cases were of B-cell phenotype. Four of the patients with primary breast lymphomas had T-cell lymphomas, 3 had CD30-positive anaplastic large cell lymphomas, and 1 had panniculitis-like T-cell lymphoma. Most patients presented with an incidental breast mass. Secondary breast lymphoma was seen in 19 patients and most commonly occurred as part of widespread nodal disease. Two patients presented with bilateral breast involvement. The most prevalent histological subtype was also diffuse large B-cell lymphoma, followed by follicular lymphoma. This study shows that the broad morphological and immunophenotypical spectrum of malignant lymphoma of the breast occurring in a large series of Brazilian patients has many similarities with that seen in Western countries, with a higher proportion of high-grade lymphomas in both primary and secondary cases.     

Specific phenotyping of T-cell proliferations in formalin-fixed paraffin-embedded tissues. Use of antibodies to the T-cell receptor beta F1.

Antibody beta F1 to a common framework determinant of the beta subunit of the T-cell receptor (TCR) was used as a specific phenotypic marker for T-cell differentiation in malignant lymphomas. Sensitivity of immunoperoxidase staining in paraffin sections was enhanced by pronase pretreatment, overnight incubation of primary antibody in Tween 20, and use of streptavidin horseradish peroxidase complexes to amplify the reaction. All 43 cases of B-cell lymphoma were negative for TCR. Reed Sternberg (RS) cells in 3 of 20 cases of Hodgkin's disease exhibited cell membrane staining for TCR (all nodular sclerosis type), further evidence that some RS cells may be T-cell derived. Twenty-nine of 44 cases of T-cell lymphoma expressed TCR (66%). These included 11 of 12 cases of peripheral T-cell lymphoma (PTCL) of small and mixed cell type, 8 of 9 cases of lymphoepithelioid cell (Lennert's) lymphoma, and 2 of 4 cases of T-cell lymphoblastic lymphoma. Loss of immunoreactivity for TCR occurred in lymphomas of large or activated T-cell type, including 7 of 9 cases of T-cell immunoblastic lymphoma and 3 of 4 cases of large cell PTCL. Antibody beta F1 is a specific and relatively sensitive marker of T-cell phenotype in formalin-fixed paraffin sections of malignant lymphomas.     

Lymphoma of the breast. A clinicopathologic study of primary and secondary cases

BACKGROUND: Primary lymphomas of the breast are rare, accounting for 1.7% to 2.2% of extranodal lymphomas and 0.38% to 0.7% of all non-Hodgkin lymphomas. Although secondary breast lymphomas are also rare, they represent the largest group of metastatic tumors of the breast. OBJECTIVES: To investigate the clinicopathologic and immunophenotypic characteristics of breast lymphomas, the relative frequency of primary and secondary mammary lymphomas, and in selected cases, the role of gene rearrangement analysis in diagnosis and staging of these lymphomas. RESULTS: We conducted a retrospective review of 22 cases of breast lymphoma diagnosed at William Beaumont Hospital, Royal Oak, Mich, during a 30-year period (1963-1994). Eleven of the 22 cases fulfilled the criteria for primary breast lymphoma; these cases represented 0.6% of all non-Hodgkin lymphomas seen in our hospital. Of the 11 cases, 5 were diffuse large B-cell lymphomas, 2 were follicle center lymphomas, 2 were marginal zone B-cell lymphomas (mucosa-associated lymphoid tissue type), 1 was a lymphoplasmacytoid lymphoma, and 1 was a peripheral B-cell neoplasm, unclassified. Using a panel of immunohistochemical stains (CD45RO, CD45RA, CD43, CD3, CD20, CD30, CD68, and HLA-DR), 8 cases demonstrated unequivocal B-cell phenotype and 3 cases had equivocal or weak staining patterns for B-cell markers. We identified no cases of T-cell lymphoma. Of 7 cases that had bone marrow biopsies for staging, 3 were positive morphologically for bone marrow involvement. Molecular analysis of B- and T-cell gene rearrangement was used to exclude bone marrow involvement in one case with bone marrow lymphoid aggregates and to confirm negativity in a case that was morphologically negative. Of the 11 secondary breast lymphomas, 5 were diffuse large B-cell lymphomas; 1 was diffuse large B-cell, primary mediastinal subtype; and 5 were follicle center lymphomas. CONCLUSIONS: Breast lymphomas represented 1.2% of all non-Hodgkin lymphomas in this study; the frequency of primary and secondary cases was equal. In both groups, right breast lesions were predominant, and the most frequent morphologic type was diffuse large B-cell lymphoma. Gene rearrangement analysis is helpful in selected cases to rule out bone marrow involvement, especially in older patients, in whom lymphoid aggregates are common.     

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.     

CD40 ligand is constitutively expressed in a subset of T cell lymphomas and on the microenvironmental reactive T cells of follicular lymphomas and Hodgkin's disease.

Although CD40 has been extensively studied in B- and T-cell non-Hodgkin's lymphomas (NHLs)/leukemias, and more recently in Hodgkin's disease (HD), little is known about the expression of its ligand (CD40L) in lymphoproliferative disorders other than T-cell NHLs/leukemias. A series of 121 lymphoma/leukemia samples, including 35 cases of HD, 34 T-cell and 39 B-cells NHLs, 2 cases of adult T-cell leukemia/lymphoma, and 11 cases of T-cell acute lymphoblastic leukemia, were evaluated for CD40L expression by immunostaining of frozen tissue sections and flow cytometry with the anti-CD40L monoclonal antibody M90. CD40L was constitutively expressed by neoplastic cells in 15 of 36 (42%) T-cell NHLs/adult T-cell leukemia/lymphomas, almost invariably those displaying the CD4+/CD8- phenotype, whereas no CD40L-expressing tumor cells could be found in B-cell NHL and HD. Among T-cell acute lymphoblastic leukemias, CD40L was detected only on 2 cases displaying a stem-cell-like phenotype. In follicular B-cell lymphomas a large number of CD40L-expressing CD3+/CD4+ T lymphocytes were found admixed with tumor cells within the neoplastic follicles and in their surrounding areas. In the nonfollicular B-cell lymphomas, CD40L-positive CD3+/CD4+ T lymphocytes were few or absent. In all HD subtypes other than the nodular lymphocytic predominance, CD40L-expressing CD3+/CD4+ T lymphocytes were numerous in the HD-involved areas and were mainly located in close proximity to the Reed-Sternberg cells. Our data indicate that in human lymphomas CD40L is preferentially expressed by a restricted subset of T-cell lymphomas, mostly with CD4 immunophenotype. Finally, we have provided morphological evidence that CD40L may play an important role in the cell contact-dependent interaction of tumor B-cells (CD40+) within the neoplastic follicles or Reed-Sternberg cells (CD40+) in HD-involved areas and the microenvironmental CD3+/CD4+/CD40L+ T lymphocytes.     

Large cell lymphoma of bone. A report of three cases of B-cell origin

Clinicopathological and immunohistological features of three cases of large cell lymphoma of bone are reported. On histological grounds, all the cases were diagnosed as histiocytic lymphomas (Rappaport) or primary centroblastic lymphomas, polymorphic subtype (Kiel). On immunophenotyping, malignant cells strongly reacted with the anti-leucocyte antibodies PD7/26 and ROS-220C, thereby indicating their lymphomatous nature, and expressed the B-cell antigens CD19 and CD22. Further studies are warranted to determine whether the B-cell phenotype observed in our cases is typical of the majority of primary large cell lymphomas of bone. Immunohistological analysis with monoclonal antibodies is expected to be of great value not only in defining the immunological phenotype of this rare pathological entity, but also in differentiating it from other neoplasms that involve the skeleton, either primarily or secondarily.     

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.     

HLA-DR expression in B-cell non-Hodgkin's malignant lymphomas: a multiparameter flow cytometry study

Ten cases of reactive follicular hyperplasia and 31 cases of B-cell non-Hodgkin's malignant lymphoma were studied using multiparameter flow cytometry. A bimodal distribution for HLA-DR expression, but not for surface immunoglobulin or B cell-specific antigens CD19 and CD20, was observed commonly in mixed cell type and infrequently in non-mixed cell type B-cell malignant lymphomas. On the basis of HLA-DR distribution alone, 31 cases of B-cell malignant lymphomas of low, intermediate, and high grades could be separated into mixed and non-mixed cell types, with only two misclassifications (P = 0.0001). Exceptionally, one case of malignant lymphoma, follicular and diffuse, mixed-cell type had a unimodal HLA-DR distribution, and one case of malignant lymphoma, diffuse, large noncleaved cell type had a bimodal HLA-DR distribution. In all cases of malignant lymphoma, follicular, mixed-cell type studied, low HLA-DR was correlated with small cells, and high HLA-DR was correlated with large cells. In contrast, HLA-DR expression and cell size were not as directly correlated in cases of malignant lymphoma, diffuse, mixed-cell type. These observations suggest that most, but not all, cases of B-cell malignant lymphomas of the mixed cell type can be separated from other B-cell lymphomas on the basis of HLA-DR distribution.