Report of an unusual small lymphocytic B-cell lymphoma selectively involving the B-zone of lymph node

KP1 (CD68)-positive large cell lymphomas: a histopathologic and immunophenotypic characterization of 12 cases

CD68/KP1 antigen expression in a series of 298 non-Hodgkin's lymphoma (NHL) cases, including 41 cases of CD30/Ki-1-positive anaplastic large cell (Ki-1+ ALC) lymphomas, was examined. Among the cases in this series, 12 large cell NHLs, including five centroblastic (G group according to the Working Formulation) NHLs, three immunoblastic (H group) NHLs, and four Ki-1+ ALC lymphomas, were found to express KP1. By extensive immunophenotypic analysis and in situ hybridization, KP1-positive large cell lymphomas of the G and H groups were assigned a B-cell phenotype. The pattern of KP1 staining usually consisted of localized small to medium-sized cytoplasmic dots; only two cases showed diffuse fine granular reactivity. In two of the four Ki-1+ ALC lymphomas tumor cells failed to express a B- or T-cell phenotype and stained positively for lysozyme, whereas in the other two cases they showed a hybrid T/histiocytic, phenotypic profile. KP1 staining of Ki-1+ ALC lymphoma cells was usually intense and showed a diffuse granular cytoplasmic pattern; tumor cells also expressed the CD13 antigen and showed strong reactivity with the anti-CD68 EBM11 antibody. Our results suggest that certain subsets of large "blastic" B-cell lymphomas may simultaneously express the CD68/KP1 histiocyte-specific marker and other myeloid-associated antigens, indicating the necessity of using a multiparameter approach in the determination of cell lineage. Moreover, this study, which demonstrates that the expression of CD68/KP1 and CD30 antigens is not mutually exclusive, supports the view that a fraction of cases diagnosed as Ki-1+ ALC lymphomas (at least those with KP1 expression along with the lack of B- or T-antigen expression) represent true histiocytic lymphomas despite the Ki-1+ phenotype.

Differential expression of cell adhesion molecules in B-zone small lymphocytic lymphoma and other well-differentiated lymphocytic disorders

BACKGROUND

Cell adhesion molecules (CAM) may determine the patterns of growth and dissemination of lymphoproliferative disorders.

METHODS

The authors have studied, by flow cytometric and immunohistochemical examination, the expression of several CAM, mediating cell-cell and cell-microenvironment interactions, on B-zone small lymphocytic lymphoma (BZSLL) and other B-cell low-grade non-Hodgkin lymphomas (NHL), including intermediate lymphocytic/mantle zone lymphoma (ILL/MZL), small lymphocytic lymphoma (SLL), and chronic lymphocytic leukemia (CLL).

RESULTS

Relevant differences in the "adhesion phenotype" of BZSLL compared with other low-grade NHL examined were evidenced. Cells from BZSLL displayed a higher rate of expression and/or a stronger intensity of LFA-1, LFA-3, ICAM-1, and BL-CAM and a lower density of H-CAM and LAM-1 homing receptors, as opposed to SLL or CLL. A lower intensity of H-CAM along with a stronger expression of LFA-1, LFA-3, ICAM-1, and BL-CAM were also detected by comparing BZSLL with ILL/MZL: Malignant cells from BZSLL expressed Leu-CAMb determinants in three cases. BZSLL cells lacked VLA-alpha 5-integrins as opposed to CLL lymphocytes and displayed a stronger reactivity with anti-VLA-alpha 4 antibodies with respect to ILL/MZL and CLL. beta 1-integrins were consistently detected on BZSLL lymphocytes as opposed to ILL/MZL:

CONCLUSIONS

These data suggest that the adhesion phenotype of BZSLL, by favoring homotypic and heterotypic adhesive interactions of tumor cells, might account at least in part for the peculiar intranodal compartmentalization leading to a deceptively benign (reactive) histologic appearance, and for the smoldering clinical course of this lymphoma. The pattern of CAM expression detected by the authors on malignant lymphocytes also is suggestive for a cellular origin of BZSLL from a rare subset of interfollicular or external mantle B-lymphocytes.

Co-expression of Epstein-Barr virus latent membrane protein and vimentin in "aggressive" histological subtypes of Hodgkin's disease

The presence of Epstein-Barr virus (EBV) genome in Hodgkin's and Reed-Sternberg (HRS) cells, as detected using in situ hybridization (ISH) with biotinylated BamHI "V" probes, along with the expression of EBV-encoded latent membrane protein (LMP) and vimentin was examined in paraffin-embedded sections of 39 immunomorphologically characterized cases of Hodgkin's disease (HD). ISH demonstrated EBV in HRS cells in 15 of 39 cases, whereas LMP expression was detected in 11 of 39 cases, only in the presence of EBV genome detection. With the exception of 1 case, in which HRS cells expressed B-cell-associated antigens, the LMP-positive cases included specimens in which HRS cells were of non-B, non-T phenotype. LMP expression showed a stronger association with lymphocyte depletion (LD) (3/3) and mixed cellularity (MC) (6/11) than with lymphocyte predominance (0/5) or nodular sclerosis (2/20) subtypes. Vimentin expression on HRS cells was found in all the LMP-expressing cases and only in a fraction (13/28) of LMP-negative cases. This study supports the view that HD represents a heterogeneous group of diseases also in terms of EBV association, LMP expression being strongly related to the "aggressive" LD and MC histological subtypes. In light of the supposed interactions between vimentin and LMP, their co-expression on HRS cells, as detected in this study, provides further evidence for a significant role of EBV in the development of a proportion of HD cases.

The nonlymphoid microenvironment of reactive follicles and lymphomas of follicular origin as defined by immunohistology on paraffin-embedded tissues

Twenty-five reactive lymph nodes, 10 palatine tonsils, and 72 B-cell non-Hodgkin's lymphomas (NHLs) of supposed follicular origin were investigated in an immunohistologic study of fixed, paraffin-embedded tissues using a panel of monoclonal antibodies reactive with antigens resistant against fixation and paraffin-embedding techniques together with polyclonal antibodies. The results concerning the microenvironmental organization of reactive lymphoid follicles confirmed that the distribution of CD21+ and CD23+ dendritic reticulum cells, vimentin+ fibroblastic reticulum cells, and CD68+ tingible-body macrophages is heterogeneous with reference to their immunostaining patterns and topographic localization within the germinal center and mantle zone. Moreover, a close microenvironmental similarity between the follicular lymphomas of supposed germinal center or mantle zone origin and their normal counterparts was noted. The study of the microenvironment of the B-zone small lymphocytic lymphoma cases, showing the same distribution patterns for the nonlymphoid cells as seen in mantle zone lymphomas, corroborated the supposed follicular origin of this unusual variant of small lymphocytic lymphoma. In conclusion, this study shows that monoclonal antibodies recognizing CD21, CD23, and CD68 antigens may be valuable additions to vimentin, S-100 protein, laminin, and type IV collagen antibodies for investigating the microenvironmental organization of lymphoid tissues in both normal and neoplastic conditions.

Immunohistochemistry of Hodgkin and non-Hodgkin lymphomas with emphasis on the diagnostic significance of the BNH9 antibody reactivity with anaplastic large cell (CD30 positive) lymphomas

BACKGROUND

Morphologic and immunohistologic studies were performed on a series of 213 lymphoma cases, including CD30-positive anaplastic large cell (ALC) lymphomas (45 cases), other CD30-positive (18 cases) or CD30-negative (72 cases) non-Hodgkin lymphomas (NHL), cases of Hodgkin disease (HD) (73 cases), and an additional 5 cases exhibiting features of both CD30-positive ALC and Hodgkin lymphomas.

METHODS

The aim was to assess differential expression by tumor cells of CD30/BerH2, epithelial membrane antigen (EMA), and other monoclonal antibodies, including BNH9, an epithelial and endothelial marker that has been found to be reactive with ALC lymphoma cells.

RESULTS

A significantly greater proportion of cases of ALC lymphoma compared with HD exhibited positive results for CD45, EMA, CD45RO, and CD3 in CD30-positive atypical large cells, whereas Reed-Sternberg cells in HD most frequently coexpressed CD15 and CD30 antigens. ALC lymphoma cells reacted with BNH9 MoAb in 10 of the 42 (23.8%) assessable cases, whereas Reed-Sternberg cells reacted with this antibody in 5 of 73 (6.8%) HD cases. Only 3 of 90 (3.3%) NHL cases had positive results for BNH9; they were CD30-negative high-grade or low-grade lymphomas. It was noteworthy that 9 of 10 BNH9-positive ALC lymphomas also were EMA positive. Four of the five cases with morphologic features intermediate between those of HD and ALC lymphoma showed immunohistologic findings (positive results for CD30 and CD15, negative results for EMA, CD45, and BNH9) similar to those frequently observed in the HD cases; conversely, the remaining case showed a profile (positive results for CD30, CD45, and EMA, negative results for CD15) typically observed in ALC lymphomas.

CONCLUSIONS

This study suggests that the differential expression of CD45, EMA, and CD15 could be used in the distinction of ALC lymphomas and HD, whereas it seems that BNH9 antibody reactivity may be of diagnostic use only in that it reinforces the diagnostic value of EMA expression in the differentiation of these entities.

Paraffin section immunohistochemistry in the diagnosis of Hodgkin's disease and anaplastic large cell (CD30+) lymphomas

Morphological and immunohistological studies were carried out on a series of 137 lymphomas including CD30+ anaplastic large cell (ALC) lymphomas (48 cases) and non-lymphocyte predominant Hodgkin's disease (HD) (89 cases), with the aim of assessing in situ expression of a combination of antibodies including anti-CD30/BerH2, epithelial membrane antigen (EMA), CD15 and CD45, in addition to other monoclonal antibodies suitable for paraffin tissues. A greater proportion of cases of ALC lymphomas than of HD exhibited positivity for CD45 (91.7% vs 17.6%), EMA (56.2% vs 4.5%), CD43 (53.6% vs 13.1%) and CD45RO (39.5% vs 3.5%), whereas Reed-Sternberg (RS) cells in HD most frequently expressed CD15 (93.2% vs 20.8%) antigen. Moreover, in 35 of 48 (72.9%) ALC lymphomas tumour cells expressed the CD30+, CD45+, CD15-, EMA- or + phenotypic profile, while in the same percentage (62/85) of HD cases RS cells were found to express the CD30+, CD45-, CD15+, EMA- profile. This study suggests that the differential expression of CD45, EMA, and CD15 may be used in the separation of ALC lymphomas and HD. However, co-expression of CD30, CD45 and CD15 antigens by RS cells in HD (14/85 cases, 16.5% in this series) and by tumour cells in ALC lymphomas (9/48 cases, 18.7% in this series) may be encountered in a non-negligible fraction of cases.

Phorbol ester induced osteoclast-like differentiation of a novel human leukemic cell line (FLG 29.1)

Studies on human osteoclast formation have been hampered by lack of a defined isolated progenitor cell population. We describe here the establishment of a human leukemic cell line (designated FLG 29.1) from bone marrow of a patient with acute monoblastic leukemia. The cultured cells are predominantly undifferentiated leukemic blasts, but addition of 12-o-tetradecanoylphorbol 13-acetate (TPA; 0.1 microM) induces irreversible differentiation into adherent, non-dividing, multinucleated cells. TPA-treated cells bear surface antigens typical of fetal osteoclasts, degrade 45Ca-labeled devitalized bone particles, display tartrate-resistant acid phosphatase in both mononuclear and multinuclear cells and receptors for calcitonin. Calcitonin increases intracellular cAMP accumulation in TPA-treated cells. TPA-treated cells show some ultrastructural features of osteoclasts as evidenced by transmission EM. These results indicate that FLG 29.1 cells may represent an osteoclast committed cell population, which upon induction with TPA acquire some morphological, phenotypical, and functional features of differentiated osteoclasts.