S-100 protein, fibronectin, and laminin immunostaining in lymphomas of follicular center cell origin

Methods of Simultaneous Visualization of Cytoplasmic Enzyme Reactivity and Cell Surface Antigens (by Cytochemistry Combined with Immunocytochemistry) in Individual Hematopoietic and Lymphoid Cells

Enzyme cytochemistry alone, and more recently, immunocytohistochemistry have been satisfactorily used by hematologists and hematopathologists for the study, diagnosis and classification of human hematological and lymphoproliferative disorders. To enhance the potential of these techniques, the possibility of combining immunocytohistochemical techniques with enzyme cytohistochemistry with simultaneous visualization of both reaction products has been examined by some investigators. This approach has been applied to normal, reactive and neoplastic material using mainly cell suspensions and frozen sections, with the aim of improving cell identification in specimens containing different cell types, of determining the cytochemical profiles of well-defined lymphocyte subpopulations and of establishing the cell surface phe-notypes of cells that are positive for certain enzymes. In this paper, published reports on this subject are reviewed and compared with the experience of our study group.

Significance of S-100 Protein Immunostaining in the Immunohistological Analysis of Normal and Neoplastic Lymphoid Tissues - An Appraisal

S-100 protein is a heterogeneous fraction of dimeric polypeptides (alpha and beta subunits) that can exist in different combination forms within the various tissues. Concerning the S-100 protein immunodetection within lymphoid tissue, the heterogeneity of the S-100 antigen, the tissue quality (frozen or paraffin-embedded after treatment with different fixatives) and the treatment of the tissue with different immunostaining methods and antibodies of different nature, all make for inconsistent results obtained in the immunohistological studies reported in the literature. Most of the S-100-positive cells of the lymphoreticular system are dendritic cells involved in the immune response (interdigitating reticulum cells, Langerhans cells, and follicular dendritic reticulum cells), other S-100-positive cells belonging to the mononuclear/phagocytic system. S-100 protein immunostaining may be used as a helpful immunohistological diagnostic clue to certain malignancies of the immune system (follicular center cell lymphomas) on the basis of their specifically related dendritic cell microenvironment. In addition to monoclonal antibodies for the immunophenotypic characterization of dendritic cells and macrophages and to enzyme reactions, the combined use of anti-S-100 antibodies specific for each of the S-100 protein subunits, tested with sensitive procedures, would be a very useful tool in the attempt to classify the proliferative disorders of dendritic cells and macrophages.

The utility of immunohistochemistry for the identification of hematopoietic and lymphoid cells in normal tissues and interpretation of proliferative and inflammatory lesions of mice and rats

Expression of antigens in cells and tissues can be readily studied immunohistochemically with the use of antibodies. A panel of antibodies to cell-specific markers can be used to diagnose lesions, including tumors, in the hematopoietic and lymphoid systems. This review discusses the use of readily available antibodies and procedures to identify antigens expressed in normal tissues and in proliferative and inflammatory lesions in formalin-fixed, paraffin-embedded (FFPE) murine specimens.

Immunohistochemical analysis for CD21, CD35, Caldesmon and S100 protein on dendritic cells types in oral lymphomas

Objective:

Follicular dendritic cells (FDCs) and interdigitating dendritic cells (IDCs) are dendritic cells found in lymphoid follicles, reactive follicles and in lymphomas. The goal of this study was to evaluate the presence and distribution of FDCs and IDCs in oral lymphomas.

Material and Methods:

Immunohistochemistry reactions were applied to 50 oral lymphomas using the antibodies anti-CD21, anti-CD35 and anti-caldesmon to FDCs, and anti-S100 protein to IDCs. Caldesmon+/FDCs and S100+/IDCs were quantified in Imagelab® software.

Results:

FDCs revealed by CD21 and CD35 were positively stained in two cases of diffuse large B-cell lymphoma, one MALT lymphoma, and in one case of mantle cell lymphoma. FDCs were immunopositive to caldesmon in all cases, as well as IDCs to S100 protein. Burkitt lymphoma presented a lower amount of caldesmon+/FDCs and S100+/IDCs than diffuse large B-cell lymphoma and plasmablastic lymphoma of the oral mucosa type.

Conclusions:

The microenvironment determined by neoplastic lymphoid cells in oral lymphomas is responsible by the development and expression of dendritic cells types.

Differentially expressed cytosolic proteins in human leukemia and lymphoma cell lines correlate with lineages and functions

Identification of cytosolic proteins differentially expressed between types of leukemia and lymphoma may provide a molecular basis for classification and understanding their cellular properties. Two-dimensional fluorescence difference gel electrophoresis (DIGE) and mass spectrometry have been used to identify proteins that are differentially expressed in cytosolic extracts from four human leukemia and lymphoma cell lines: HL-60 (acute promyelocytic leukemia), MEC1 (B-cell chronic lymphocytic leukemia), CCRF-CEM (T-cell acute lymphoblastic leukemia) and Raji (B-cell Burkitt's lymphoma). A total of 247 differentially expressed proteins were identified between the four cell lines. Analysis of the data by principal component analysis identified 22 protein spots (17 different protein species) differentially expressed at more than a 95% variance level between these cell lines. Several of these proteins were differentially expressed in only one cell line: HL-60 (myeloperoxidase, phosphoprotein 32 family member A, ras related protein Rab-11B, protein disulfide-isomerase, ran-specific GTPase-activating protein, nucleophosmin and S-100 calcium binding protein A4), and Raji (ezrin). Several of these proteins were differentially expressed in two cell lines: Raji and MEC1 (C-1-tetrahydrofolate synthase, elongation factor 2, alpha- and beta-tubulin, transgelin-2 and stathmin). MEC1 and CCRF-CEM (gamma-enolase), HL-60 and CCRF-CEM (ubiquitin-conjugating enzyme E2 N). The differentially expressed proteins identified in these four cell lines correlate with cellular properties and provide insights into the molecular basis of these malignancies.

Tumour responding accessory cells in testicular seminoma: an immunohistochemical study

AIM

To investigate the role of accessory cells (and other chronic inflammatory cells) in the host immune response to testicular seminoma by defining their immunophenotypic characteristics and topographical arrangement.

METHODS AND RESULTS

A panel of antibodies applicable to paraffin-embedded tissues was employed to characterize the host chronic inflammatory response in eight cases of classical testicular seminoma. The antibodies were directed against CD45RO, CD20, CD68, acid cysteine proteinase inhibitor (ACPI), MAC387, muramidase (MUR), S100 protein, Factor XIIIa, CD21 and HLA Class II. In all cases the majority of the inflammatory cells were T-lymphocytes situated mainly in areas of apparent tumour destruction. Large numbers of macrophages/dendritic cells which had not been evident by conventional light microscopy were also demonstrated. In particular, an immunophenotypically distinct population of accessory cells showing a specific pattern of distribution was revealed. It clearly rimmed islands of tumour and showed strong positive staining for CD68, MAC387 and HLA Class II.

CONCLUSION

The study has identified an immunophenotypically distinct population of accessory cells showing a characteristic topographical arrangement. It is proposed that it represents a subpopulation of macrophages which are responding directly to the tumour and are likely to play a part in influencing tumour dynamics.

The accessory cell populations in ulcerative colitis: a comparison between the colon and appendix in colitis and acute appendicitis

We present an immunohistochemical study of accessory cells in acute appendicitis and ulcerative colitis (UC). By comparing these two diseases, it is possible to distinguish between changes associated with inflammatory bowel disease and those resulting from nonspecific intestinal inflammation. Nine total colectomy specimens from patients with UC, in which the appendix was also involved, were compared with nine cases of acute appendicitis. Accessory cells were stained for CD68 (PGMI), ACPI (acid cysteine proteinase inhibitor), S100 protein, MAC387 (calgranulin), CD1a, factor XIIIa, and WR18 (HLA class II). In ulcerative colitis, but not acute appendicitis, there was extension of a network of S100 positive dendritic cells into the crptal mucosa, and these S100-positive dendritic cells were closely aligned with the epithelium. The epithelium in UC, but not in acute appendicitis, showed intense upregulation of HLA class II, and this was particularly marked at the crypt bases. Dendritic, MAC387-positive cells were seen only in UC. In both diseases there were abundant ACPI-positive accessory cells in the cryptal areas, a population normally restricted to the dome areas. Factor XIIIa- and PGM1-positive cells, although abundant in both conditions, had distributions similar to those that we had previously shown in normal controls. No CD1a-positive cells were identified in either UC or acute appendicitis. We hypothesize that S100 identifies a subpopulation of activated macrophages. The concentration of this subpopulation, in close contact with the epithelium, which also shows altered expression of HLA class II antigens, suggests that a component of the immune response is targeting this area in UC. In addition, we also suggest that the identification of MAC387-positive dendritic cells in UC reflects increased macrophage turnover in inflammatory bowel disease.

A study of accessory cells in the acquired lymphoid tissue of helicobacter gastritis

This paper presents a description of the patterns of distribution of accessory cells in helicobacter gastritis and low-grade gastric MALT lymphomas. The use of gastric resection specimens afforded abundant, well-orientated lymphoid tissue. Fifteen cases were selected from patients with MALT lymphomas, three with gastritis alone, and six histologically normal controls. A panel of antibodies working in paraffin-embedded tissue, identifying differing accessory cells, was used. These comprised antibodies to HLA class II (WR18), acid cysteine proteinase inhibitor (ACPI), CD68 (PGM1), Factor XIIIa, S100 protein, CD23 (BU38), CD106 (V-CAM1), CD55 (BRIC 128), and CD21 (1F8). CD68-positive macrophages in the gastritis cases were abundant in the superficial mucosa. Factor XIIIa also identified dendritic cells at deeper sites but these were absent from both the acquired and the neoplastic lymphoid tissue. Antibodies to both S100 protein and ACPI stained dendritic cells localized to areas within and adjacent to the lymphoid tissue only. S100 protein-positive cells were concentrated in close contact with glandular epithelium immediately above the germinal centres, while ACPI-positive dendritic cells were identified, especially around the more blastic reactive follicles, in the intervening space between the germinal centres and the overlying epithelium. Similar patterns of organization were also seen in the areas of mucosal lymphoma. The follicular dendritic markers revealed overlapping but distinct sub-populations within the germinal centres which appeared to alter depending on the activity of the germinal centres. While both ACPI and CD55 stained the germinal centre dendritic reticulum cell networks only, CD21 and CD106 also stained the mantle dendritic cells. The proportion staining with CD23, which stains dendritic reticulum cells within the centrocyte-rich areas of the germinal centres only, was greatest in the more quiescent germinal centres. Similar patterns of staining were also seen in germinal centres within the gastric MALT lymphomas. It is proposed that the sub-populations of dendritic cells staining with S100 protein and ACPI may facilitate helicobacter antigen delivery to the germinal centres. The follicular dendritic cells then promote a sustained B-cell response to the luminal pathogen.

Angiogenesis spectrum in the stroma of B-cell non-Hodgkin's lymphomas. An immunohistochemical and ultrastructural study

Samples of lymph nodes from 88 patients with B-cell non-Hodgkin's lymphoma (B-NHL) grouped by the Working Formulation (WF) and from 15 patients with benign lymphadenopathies were investigated immunohistochemically and ultrastructurally for changes in angiogenesis and stromal distribution of two subendothelial basement membrane (BM) components, namely laminin and type IV collagen. The microvessel number was usually low in lymphadenopathies, and increased significantly in low-grade B-NHL. Intermediate-grade tumors displayed a further significant increase that was mainly due to their diffuse subtypes rather than to the follicular subtype. High-grade B-NHL showed the highest counts. By contrast with the lymphadenopathies studied, the stroma of B-NHL reacted intensely with both BM components, whose linear co-expression was significantly associated with low-grade and follicular intermediate-grade B-NHL, while expression of laminin alone in a granular pattern was detected in diffuse intermediate-grade and high-grade tumors. Ultrastructural analysis revealed immature vessels more frequently in diffuse intermediate-grade, and in high-grade B-NHL. These in situ data suggest that angiogenesis occurring in B-NHL increases along their progression path, and emphasize the importance of angiogenesis as an epigenetic phenomenon of B-NHL progression.

Distribution of extracellular matrix components and their receptors in human lymphoid tissue and B-cell non-Hodgkin lymphomas

In this study the distribution patterns of various extracellular matrix components and their receptors (i.e. beta 1 integrins) in B-cell non-Hodgkin lymphomas were examined and compared to those in reactive lymphoid tissue. Neoplastic follicles within follicular lymphomas showed similar patterns to that observed in reactive follicles, which appeared to be strongly associated with the presence of follicular dendritic cells. Diffuse lymphomas of low and intermediate malignancy grade revealed features comparable to those of interfollicular areas of reactive lymphoid tissue, irrespective to which compartment the tumour cells were related. Highly malignant lymphomas, however, displayed unique extracellular matrix configurations, resulting from active matrix degradation by macrophages; this may support rapid tumour growth. Extranodal lymphomas showed virtually the same matrix patterns as their nodal counterparts, suggesting that (malignant) lymphoid cells generate (at least partly) their own specific microenvironment. In reactive lymphoid tissue beta 1 integrins were mainly found on resident cells and except for alpha 4, alpha 5 (and beta 1) the lymphoid cells expressed very little, if any, beta 1 integrins. In comparison, expression of these integrins on lymphoma cells was reduced (follicular lymphomas) or could not be detected at all (diffusely growing lymphomas); this might contribute to the growth pattern and metastatic properties of the tumours.

Leiomyomatosis with vascular invasion. A unified pathogenesis regarding leiomyoma with vascular microinvasion, benign metastasizing leiomyoma and intravenous leiomyomatosis

Three uterine leiomyomas with vascular invasion (LWVI), two of which were associated with pulmonary leiomyomatous nodules, and a case of intravenous leiomyomatosis (IVL) invading the vena cava and extending to the right atrium, are described. Despite their histological benignity, these lesions have a strong tendency to metastasize and are closely related to the so-called benign metastasizing leiomyoma (BML). From a clinical point of view, the pulmonary nodules of LWVI are stable or slowly-growing. The IVL was a "worm-like" tumour that presented as a cardiac mass. On the basis of their histological and immunohistological features, a unified histogenetic view of LWVI, IVL and BML of the uterus is proposed. LWVI and BML may be the same pathological entity and microscopic vascular invasion may represent the metastatic mechanism of BML. Alternatively, LWVI may be the initial stage of IVL. In rare instances, IVL may be associated with distant parenchymal (pulmonary) metastases. LWVI seems to be the precursor of both BML and IVL.

Extrapulmonary small cell carcinoma: a single-institution experience and review of the literature

BACKGROUND

Small cell carcinoma (SCC) is a distinct pathologic entity that may also occur in extrapulmonary sites. In this report the retrospective results of multimodal therapy of primitive extrapulmonary (E) SCC, in a single institution series, are presented.

METHODS

Twenty-four patients (pts) with ESCC were referred to the Centro di Riferimento Oncologico, Aviano, Italy, from 1986 to 1992. Clinico-therapeutic findings were evaluated in 20 pts. Their ages ranged from 20 to 87, with a median of 60.5 years. Primary tumor sites were urinary bladder (5 pts), prostate (4 pts), larynx (3 pts), kidney (2 pts), ovary, skin, oropharynx, trachea, uterine cervix, ethmoid, and stomach (1 pt each); lymph node metastases of unknown origin were observed in 3 pts. More than 50% of pts presented extensive disease.

RESULTS

Histologically, 16 cases were pure ESCCs and 8 cases were combined, 4 of them with adenocarcinoma, 2 with transitional cell carcinoma, and 2 with squamous cell carcinoma. Immunohistochemical studies, performed in 7 cases, demonstrated the epithelial nature of these tumors. The cisplatin-VP16 (PE) regimen was used in 13 pts, and 9 of them (69%) obtained objective responses after chemotherapy (CT) alone, with 3 complete remissions (CR) and 6 partial remissions (PR). Median CR and PR duration was 13+ and 24 months, respectively. Radiotherapy was performed in 7/13 pts after induction CT and before consolidation CT. The objective response rate was 100%, with 6 CR and 1 PR. No severe toxic side effects and no toxic deaths were reported. A patient treated with surgery alone for a urinary bladder tumor showed continuous long-term survival, while 1 of 2 pts treated with radiotherapy alone obtained PR.

CONCLUSIONS

The PE regimen has an activity similar to the one observed in pulmonary SCC.

Ileal lymphoma in swine

Eleven cases of alimentary lymphoma affecting the ileum were observed among 26 cases of swine lymphoma detected by meat inspection in Kochi, Japan. The ileal lymphomas were located in the Peyer's patches, along with early involvement of regional lymph nodes, and showed a characteristic pattern of follicular invasion leading to diffuse growth. Following the National Cancer Institute Working Formulation, 10 neoplasms were classified as diffuse, large, noncleaved cell lymphomas and one neoplasm was a diffuse, mixed, small to large cell lymphoma. Both types of lymphoma featured numerous intermingled "starry sky" histiocytes. The lymphoma cells tended to infiltrate into the muscular layer of the ileum in an "Indian file" pattern. Two cases also showed transserosal metastasis into the abdomen and leukemic change. The lymphoma cells showed membrane positivity for alkaline phosphatase and diffuse cytoplasmic staining for acid phosphatase and non-specific esterase. Monoclonal intracytoplasmic immunoglobulins were demonstrated in nine neoplasms (IgM-lambda in seven, IgG-lambda in one, and IgG-kappa in one). In the areas of follicular invasion, an attenuated network of follicular dendritic cells was visualized via an antiserum against the beta subunit of S-100 protein. Ultrastructurally, strands of dilatated rough endoplasmic reticulum and scattered or clustered dense bodies were noted. When compared with feline and human alimentary lymphoma, including Burkitt's lymphoma, the present neoplasms possessed distinctive features, such as originating in Peyer's patches, transserosal metastasis, and predominantly large B cell type with IgM-lambda type immunoglobulin expression, although some features were similar.

Mixed renal tumor with carcinomatous and fibroleiomyomatous components, associated with angiomyolipoma in the same kidney

A 54-year-old woman, without the stigmas of tuberous sclerosis, underwent radical nephrectomy for simultaneous occurrence of an Angiomyolipoma (AML) and a carcinomatous and fibroleiomyomatous mixed tumor in the same kidney, diagnosed by computerized tomography, selective renal arteriography and anatomopathological examination. The peculiar findings of the mixed neoplasia, characterized by a mixture of carcinomatous and fibroleiomuscular components are stressed. The latter component is considered to be a proliferative element interacting with the carcinomatous one. After review of the pertinent literature, this is the first example of an association of AML and renal cell carcinoma (RCC) in which the RCC is constituted by a mixture of carcinomatous and fibroleiomyomatous cells.

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.

"Lipoleiomyoma with metaplastic cartilage" (benign mesenchymoma) of the uterine cervix

Benign mesenchymoma (BM) is an uncommon tumor containing two or more differentiated mesenchymal elements in addition to fibrous tissue. A case of BM of the uterine cervix in a 51-year-old woman is reported. This tumor, which we designated "lipoleiomyoma with metaplastic cartilage" because of its morphological features, apparently represents the first documented example of BM of the cervix.

Immunohistochemical characterization of Ki-M6 monoclonal antibody in Bouin-fixed, paraffin-embedded sections of normal and neoplastic human tissues

A monoclonal antibody (Ki-M6) against the CD 68 antigen, which labels cells of the monocyte/macrophage system, was tested on Bouin-fixed, paraffin-embedded samples of normal, reactive and neoplastic tissues by an avidin-biotin-peroxidase complex method, with the aim of establishing its value in diagnostic pathology. In normal human tissues, Ki-M6 reactivity was confined to the so-called resident macrophages populating normal organs under physiological conditions. Moreover, restricted reactivity against cells of macrophage lineage was observed in reactive and inflammatory lesions. Granulocytes, monocyte/macrophage-related immune accessory cells, and other analysed normal tissue structures did not reveal any reactivity. Ki-M6 was strongly reactive with the cases of benign (4/4) and malignant (15/15) fibrous histiocytomas, in addition to the true histiocytic lymphomas (3/3). Cases of granular cell tumour (2/3) showed strong reactivity with Ki-M6, whereas only few immunoreactive cells, with weak staining, were seen in the other Ki-M6-positive neoplasms [neurofibroma (3/3), benign schwannoma (1/2), ganglioneuroma (1/1), malignant schwannoma (5/9), melanoma (9/28), dermatofibrosarcoma protuberans (1/1), myelomonocytic leukaemia (3/3)]. Among the epithelial malignancies tested (47 cases), Ki-M6 was positive only in renal cell carcinoma (11/14). Malignant lymphomas of the Hodgkin (56 cases) and non-Hodgkin type (67 cases) were uniformly non-reactive. From these data, Ki-M6 appears to be an excellent marker of monocyte/macrophage-related cells and appears to be a reliable indicator for fibrous histiocytomas and true histiocytic malignancies. The availability of this additional antibody capable of staining routinely processed tissue is of practical interest.

Histopathologic, immunophenotypic, and genotypic analysis of Ki-1 anaplastic large cell lymphomas that express histiocyte-associated antigens

CD30/Ki-1 antigen expression in 243 cases of malignant lymphomas was examined using Ber-H2 monoclonal antibody. Among them 20 cases were categorized as Ki-1 anaplastic large cell lymphoma. In two of these cases histiocyte-associated markers were also expressed. In these cases histopathologic and extensive in situ immunophenotypic analyses were used with genotypic studies in the determination of cell lineage. A sinusoid histologic pattern of involvement with partial lymph node infiltration by pleomorphic neoplastic cells was noticed in the nodes from both patients. Solid areas of node replacement resembling metastatic carcinoma were seen in Patient 1. Immunohistologically, tumor cells of both cases were positive for CD30, CD25, CD71, LN3 (HLA-DR), EMA, CD45, CD74, vimentin, alpha-1-antichymotrypsin, and CD68. Patient 1 was also CD45RO+, CD43+, whereas Patient 2 was positive for alpha-1-antitrypsin and CD4 tumor cells. Genotypic studies revealed that TCR beta and TCR gamma chain genes were clonally rearranged in Patient 1, whereas no rearrangements were detected in Patient 2. This study supports the view that some Ki-1 anaplastic large cell lymphomas may express multiple histiocyte-associated antigens and confirms that this group of neoplasms have immunophenotypic heterogeneity. The results of genotypic analyses used with immunophenotyping does not exclude that the tumor cells in these cases may be of true histiocytic origin despite the Ki-1-positive phenotype.

Non-Hodgkin's lymphoma in the elderly. I. Pathologic features at presentation

The pathologic findings of 118 patients aged 70 years or older with non-Hodgkin's lymphoma (NHL) are reported. These patients formed 27.2% of 433 consecutive cases of NHL seen in a single institution over a 5-year period. Thirty-one of 433 NHL cases were histologically not classified, whereas the remaining 402 could be classified according to the International Working Formulation (WF) of NHL for clinical usage. Immunophenotypic analyses were carried out in 112 NHL cases; of this group 28 were NHL in elderly patients. Of the 95 elderly NHL that could be classified in the histologic categories of the WF 28 cases were in the low-grade, 41 in the intermediate-grade, and 26 in the high-grade categories. Eighty-one cases had diffuse histologic types and 14 had follicular/nodular histologic types. Thirty-five cases were of the G (diffuse large cell) + H (large cell, immunoblastic) categories. No significant differences in the prevalence of the different subtypes were observed among patients younger or older than 70 years. Immunohistologically, most NHL cases in the elderly expressed B-cell phenotype. Sixty-two NHL in the elderly were extranodal at presentation. The results of this study indicate that elderly patients form a relevant proportion of patients developing NHL and thereby present a very difficult management problem. The pathologic features of NHL in the elderly does not differ significantly from those of their younger counterparts, although an increase in diffuse versus follicular histologic patterns, and in extranodal versus nodal disease was observed with advancing age.

Vimentin immunostaining in fibroblastic reticulum cells within human reactive and neoplastic lymphoid follicles

We analyzed the distribution of fibroblastic reticulum cells (FRCs), stationary cells of lymphoid tissues, as visualized by the anti-vimentin (V9) monoclonal antibody in human reactive and neoplastic lymphoid follicles, by using immunoenzymatic and immunofluorescence methods on fixed and paraffin-embedded tissue sections from 37 lymphoid specimens with reactive disorders and 10 specimens with nodular/follicular non-Hodgkin's lymphomas (NHLs). The pattern of distribution of the vimentin-positive (VIM+) FRCs was compared with that of follicular dendritic reticulum cells (DRCs) as visualized by anti-S-100 protein antibody. Elongate VIM+ FRCs intimately attached to reticulum fibers were randomly distributed in the paracortical and interfollicular areas of lymph nodes, whereas they were recognized specifically in the mantle zones of the secondary follicles, mostly in the outer margins. Germinal centers were consistently devoid of VIM+ FRCs. Comparative analysis on serial sections as well as paired immunoperoxidase and double immunofluorescence studies demonstrated that there was a sharp difference between the patterns of intrafollicular distribution of VIM+ FRCs and S-100 protein-positive (S-100+) DRCs without juxtaposition, the FRCs being confined to the mantle zones. In the 10 nodular/follicular NHLs VIM+ FRCs could be observed in the thinned mantles of neoplastic nodules displaying a corona-like pattern that accentuated the boundaries of the nodules. The results of this study support the view that the intrafollicular distribution of VIM+ FRCs is specific for the mantle zone. The different microenvironmental organization within the follicles of VIM+ FRCs and S-100+ DRCs suggests that FRCs or at least VIM+ FRCs are stationary cells strictly related to the mantle zone microenvironment, where they may play a role in supposed sustentacular and immunologic functions similar to that of DRCs in the germinal center microenvironment.

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

Selective involvement of the B-cell compartment of lymph node by B-cell malignant lymphomas is an occasional finding related to early phases of lymph node infiltration. The authors have observed a unique case of diffuse small lymphocytic lymphoma that consisted of immunohistologically and genotypically proven B-clonal population exhibiting a repetitive pattern of infiltration in three lymph node samples obtained from the patient during a 9-year period. This pattern consisted of a selective and complete replacement of the B-areas with disappearance of follicles and widening of the medullary cords, an expanded T-zone showing features consistent with dermatopathic lymphadenitis and well-preserved sinuses. Clinically, multiple involved sites at presentation (lymph nodes, spleen, skin, bone marrow, and peripheral blood) and during the 9-year follow-up (testis) were detected, and the disease was associated with a relative indolent course like other low-grade lymphomas. The phenotypic profile of lymphoma cells studied by immunoperoxidase method, and by single-labeling and double-labeling flow cytometric analyses (SIg+, K+, LN2+, MB1+, MB2+, HLA-DR+, CD 9+, CD19+, CD 20+, CD 21+, CD 22+, CD 24+, Leu 8+, CD 5-, CD 10-, CD 11b-, CD 11c-, CD 25-, CD 38-, PCA-1-, FMC-7-, CD 23-) was consistent with a B-cell proliferation at an intermediate stage of differentiation but distinct from other well-defined B-cell neoplasms. Whether such unique B-zone pattern was due to an intrinsic property of this lymphoma or it is to be related to the coexisting reactive T-zone expansion remains controversial.

Immunohistocytochemical correlation of DAP IV-CD 26 reactivity with immunologic markers of lymphocyte activation in human lymphoid tissues

The topographic distribution of the dipeptidylaminopeptidase IV (DAP IV-CD 26) and II (DAP II) positive T-cell population in six reactive lymph nodes and seven follicular B-cell non-Hodgkin's lymphomas (NHL) was analysed with regard to the distribution of activated T-cells, as visualized by a panel of monoclonal antibodies including Tac-CD 25, HLA-DR, OKT 9-CD 71, ICAM-1-CD 54, LFA-1-CD 11a. For comparative studies serial frozen sections of the lymph nodes were tested by enzyme histochemistry and immunohistochemistry. In addition, cell suspensions obtained from 10 B-NHL and interleukin-2 (IL-2) activated T-cells were investigated by a combined cytochemical and immunological method for simultaneous visualization of DAP IV-CD 26 cytoplasmic activity and surface immunostaining for markers of lymphocyte activation. Both in reactive and lymphomatous lymph nodes the topographic distribution of DAP IV-CD 26+ and DAP II+ lymphocytes was rather similar to that of Tac-CD 25+ lymphocytes. On the contrary, the DAP IV-CD 26 and DAP II distribution pattern substantially differed from that of the other immunologic markers. In a cell suspension of IL-2 activated T-cells, more than 80% of the cells with a blastic morphology were DAP IV-CD 26+; DAP IV-CD 26+ cells coexpressing Tac-CD 25, OKT 9-CD 71, HLA-DR positivity, relative to the total number of DAP IV-CD 26 positive cells, were 90.5%, 70.5% and 87% respectively. Only small (not activated) lymphocytes expressed a focal cytoplasmic DAP II positivity. In cell suspensions from 10 cases of B-NHL the mean percentage of DAP IV-CD 26+ Tac-CD 25+ cells was 75.8. Only a small number of DAP IV-CD 26+ cells coexpressed HLA-DR, the mean percentage being 9.6. The results support the view that DAP IV-CD 26 may be considered as a marker of lymphocyte activation; this marker seems to be restricted to T lymphocytes that reside in the T dependent areas of reactive lymph nodes and to non malignant T-cells surrounding neoplastic follicles of follicular NHL.

Dendritic reticulum cell-related immunostaining for laminin in follicular and diffuse B-cell lymphomas

We performed a comparative immunohistocytochemical study of the distribution patterns of laminin and follicular dendritic reticulum cells (DRCs) within their follicular microenvironment in both nodular or diffuse B-cell non Hodgkin's lymphomas (NHLs). Twenty nine cases of immunophenotypically diagnosed B-cell NHLs (19 of follicular center cell origin-FCCL- and 10 of the diffuse well differentiated lymphocytic type-WDLL-) and five reactive lymph nodes with follicular hyperplasia were analyzed by immunoperoxidase and immunofluorescence techniques. Serial frozen sections and cytospin preparations were tested either with single antibodies anti laminin and DRC-1, or paired reagents in double labeling immunofluorescence. Our results indicated consistently that within both the reactive germinal centers and the neoplastic nodules of FCCL laminin immunostaining visualized a punctate-granular pattern apart from the linear vascular basement membrane positivity. Double immunofluorescence assay demonstrated that there was a close parallelism between this laminin staining pattern and DRC-1 distribution showing a well developed DRCs meshwork; in the diffuse tumour areas of both FCCL and WDLL, laminin immunoreactivity was found only in those cases in which nests of DRCs were observed. Double immunofluorescence studies performed on cytospin preparations demonstrated that the groups of cells containing DRC-1 positive cells, contained a positivity for laminin, although within the cell the staining for DRC-1 was intense and diffuse, while that for laminin was granular and more sparse. Our results suggested that these laminin and DRC-1 positive reactive sites may be present on the same cells. Since the reduction in number or loss of both DRCs and their related immunostaining for laminin within the microenvironment was consistently associated with a loss of nodularity by lymphoma cells, whereas nodularity in reactive and neoplastic conditions was associated with a rich DRCs meshwork and the related laminin immunostaining, a trapping function of DRCs exercised in the presence of laminin should be considered.

Anti-vimentin antibody reactivity with Reed-Sternberg cells of Hodgkin's disease

There are few data on the reactivity of Reed-Sternberg (RS) cells with antibodies against vimentin. In a preliminary survey of biopsy specimens from 16 cases of Hodgkin's disease (HD), we found that the antivimentin (V9) monoclonal antibody stained RS cells in 6 cases. We therefore examined vimentin expression on RS cells immunohistologically in 38 Bouin-fixed and paraffin-embedded lymph nodes with HD [lymphocyte predominance (LP) 4; nodular sclerosis (NS) 23; mixed cellularity (MC) 7; lymphocyte depletion (LD) 4]. The results were correlated with the histopathological features, the immunohistological phenotype of the RS cells, and the findings obtained from molecular genetics studies (available in 13 cases). RS cells were found to express strong and diffuse cytoplasmic staining for vimentin in 13 cases, all of the NS subtype. No differences in antigenic expression on RS cells were found between the vimentin-positive and negative cases within the NS subtype. DNA analysis revealed no B- or T-cell clonal populations in the tested samples. The results indicated that RS cells were immunostained by anti-vimentin (V9) antibody with a relatively high frequency, but only in the NS subtype of HD. This subtype, however, was heterogeneous according to vimentin immunostaining on RS cells. The significance of this finding concerning the RS cell origin in this subset is discussed.

Basement membrane components in lymphoid follicles: immunohistochemical demonstration and relationship to the follicular dendritic cell network

We analyzed the distribution of two basement membrane components, laminin and type IV collagen, in human reactive and neoplastic lymphoid follicles by using immunoenzymatic and immunofluorescence methods on serial frozen sections from 11 reactive lymph nodes, three palatine tonsils, and 11 immunophenotypically defined B cell non-Hodgkin's lymphomas. The patterns of distribution of these two antigens were compared with that of follicular dendritic reticulum cells (DRCs) as visualized by anti-DRC-1 and anti-desmoplakin 1 and 2 antibodies. Immunostaining for laminin and type IV collagen produced overlapping results. Germinal centers contained some vascular and fiber-like linear staining, but the most striking feature was the presence of a large amount of punctate-granular staining. This staining was present throughout the entire area of most of the germinal centers, although often more densely in the central areas. The stronger punctate-granular staining for laminin, type IV collagen, and desmoplakin 1 and 2 corresponded to the more densely stained areas for DRC-1. Double immunofluorescence assay demonstrated that there was a close similarity between the punctate-granular staining pattern of laminin and the dendritic network of DRC-1-positive cells. In the nine B cell lymphomas of follicular center origin in which DRCs were present, although distributed in different patterns, immunostaining for laminin and type IV collagen could be observed only in those areas showing immunoreactivity for DRC-1. The results of this study suggest that the punctate-granular staining pattern for laminin and type IV collagen is specific for the follicle. This finding may be strictly related to the follicular microenvironment because the pattern of distribution displayed by laminin and type IV collagen seems to be spatially related to the staining pattern of DRCs, as visualized by the anti-DRC-1 and desmoplakins antibodies, both in reactive and neoplastic conditions.

The dendritic reticulum cell pattern in B cell lymphomas of the small cleaved, mixed, and large cell types: an immunohistochemical study of 48 cases

An immunohistochemical study was designed to study the dendritic reticulum cell (DRC) patterns in 48 cases of B cell non-Hodgkin's lymphomas of the small cleaved, mixed, and large cell types, both follicular (20 cases) and diffuse (28 cases), in order to evaluate the possible influence of DRCs on homing and the differentiation of neoplastic B cells. Three DRC patterns were observed. In the follicular lymphomas, DRCs constituted nodular networks of variable density. In the diffuse lymphomas, DRCs were present either as isolated and scattered cells (17 cases) or constituted irregular meshworks of variable sizes (11 cases). These DRC patterns correlate with B cell immunophenotypes. Like follicular lymphomas, and unlike diffuse lymphomas without DRC networks, diffuse lymphomas with DRC networks constantly expressed the pan B antigens and one marker characteristic of normal germinal center cells, CD21 antigen, the C3d receptor. The finding of organized DRC networks in a significant number of diffuse lymphomas does not substantiate the hypothesis that DRCs may play a role in the homing of neoplastic B cells. The correlations observed between DRC patterns and B cell immunophenotypes suggest that the persistence and/or the development of DRC networks within follicular center cell-type lymphomas are related to the degree of functional differentiation of neoplastic B cells.

Characterization of extracellular matrix in non-Hodgkin's lymphomas

Basement membrane proteins laminin, type IV collagen and aminoterminal propeptide of type III collagen (type III pN-collagen) are important components of extracellular matrix of normal lymph nodes; they are present in reticular fibres and in the walls of blood vessels and sinuses. We have studied the distribution of these proteins in 45 cases of non-Hodgkin's lymphomas representing different types of Kiel classification. Light microscopic immunohistochemistry was used on sections from formalin fixed, paraffin embedded biopsy specimens. Reticular cells were identified by using antibodies against S-100 protein, a marker for dendritic and interdigitating reticulum cells, and against cystatin A for the demonstration of follicular dendritic reticulum cells. The findings of the immunohistochemical stainings were generally similar in the different lymphoma types. Thus the method for the demonstration of extracellular matrix proteins could not give obvious aid for lymphoma classification. BM stainings proved to be efficient in the demonstration of sinuses. Marginal and medullary sinuses of the nodal cases were either totally or partly spared and open also in the cases in which there was extracapsular growth. The fibre content was variable, but generally the distribution of all the three extracellular matrix proteins was comparable with each other and mainly corresponded with the pattern seen in conventional Gomori's reticulin stain. This also holds for the tumor tissue infiltrated through the capsule and for extranodal cases. Areas of sclerosis of some cases contained only type III pN-collagen. Reticular fibres were at places seen to be closely associated with cells of spindle or dendritic shape. A few reticulum cells could be found to show cytoplasmic staining for laminin, type IV collagen and type III pN collagen. This finding suggests that the cells are synthetizing these proteins. The amount of cells staining for cystatin A or S-100 protein did not generally correlate with the amount of fibres, and most of the stained cells were not closely associated with fibres. The results show that in non-Hodgkin's lymphomas basement membrane proteins and type III pN-collagen are important components of reticular fibres. Results also indirectly support the main role of fibroblastic reticulum cells in the production of the fibres.

Dendritic reticulum cell pattern as a microenvironmental indicator for a distinct origin of lymphoma of follicular mantle cells

Follicular dendritic reticulum cells (DRCs) are known to be normally present in primary follicles and both follicular centres and mantle zones of secondary follicles of peripheral lymphoid tissue. Involved frozen biopsy tissue specimens from eight cases of intermediate lymphocytic lymphoma/mantle zone lymphoma (ILL/MZL); eight cases of follicular centre cell lymphomas (FCCL) of the centroblastic/centrocytic type; and seven cases of well-differentiated lymphocytic lymphoma (WDLL) consistent with chronic lymphocytic leukaemia (CLL) were analysed immunohistologically with R4/23 (DRC-1) monoclonal antibody reactive with 'bystander' DRCs. As opposed to FCCL and most WDLL/CLL cases, the DRCs consistently formed a loose, ill-defined meshwork with a radiating or blurred outline in all MZL cases and one ILL. On the basis of the observed findings as well as from those reported in literature, the hypothesis is proposed that ILL/MZL originates from the follicular mantle zone and represents a distinct lymphoma entity owing to its peculiar immunostaining pattern of DRCs that allows it to be separated from both FCCL and WDLL/CLL. Moreover, the absence of DRCs in the microenvironment of other B-cell malignancies such as prolymphocytic leukaemia and hairy cell leukaemia, analogously with most CLL cases, would speak in favour of their different--possibly extrafollicular--compartment of origin within lymphoid tissue.

Expression of Leu-8 surface antigen in B-cell lymphomas. Correlation with other B-cell markers

Using in situ immunohistological analysis, expression of Leu-8 and its correlation with other B-cell markers were investigated in 21 selected lymphomas of different categories, each one expressing its own typical immunophenotype. These categories included eight follicular centroblastic/centrocytic (CB/CC) lymphomas, eight intermediately differentiated lymphocytic lymphomas (ILL)/mantle zone lymphomas (MZL), and five lymphocytic lymphomas (LL) associated with chronic lymphocytic leukaemia (CLL). Four reactive lymph nodes and three tonsils were also studied using double immunolabelling procedures. Cell suspensions were also performed in three CB/CC and four ILL/MZL cases. Leu-8 was consistently expressed in ILL/MZL and LL but it was absent in most (7/8) CB/CC lymphomas. In reactive tissues, the Leu-8-positive B cells were strictly confined to the mantle zones. A close association emerged between Leu-1 (CD5) and Leu-8, both being present in ILL/MZL and LL but absent in CB/CC. A consistent lack of association was found between Leu-8 or CD5 antigens and common acute lymphoblastic leukaemia antigen (CD10) and BA-2 (CD9) antigen, whereas Leu-8 and CD5 were strictly associated with surface IgD. Reactivity with Leu-8 provides a means of distinguishing between CB/CC and ILL/MZL. Furthermore, shared immunoreactivity for Leu-8 in ILL/MZL and LL may represent a potential clue to the still uncertain cellular derivation of LL/B-CLL.

Heterogeneous immunostaining patterns of follicular dendritic reticulum cells in human lymphoid tissue with selected antibodies reactive with different cell lineages

A comparative immunohistologic study of the cell density and distribution pattern of follicular dendritic reticulum cells (DRCs) within their follicular microenvironments (germinal centers and mantle zones) was performed by immunoperoxidase technique with a selected panel of antibodies either operationally specific for DRCs (DRC-1) or reported as having additional immunoreactivity with DRCs (antibodies to B- and T-cells, leukocytes, monocytes/macrophages, desmosomal components, and S-100 protein). Twenty-five biopsy specimens, including reactive lymph nodes and tonsils as well as normal spleen tissue, were analyzed. Serial frozen sections were tested either with single antibodies or paired monoclonal reagents in double-labeling procedures. Our results consistently indicated that DRCs positive for Leu M3 and BA-2 antibodies were confined to the central portion of germinal centers, whereas DRCs immunoreactive for S-100 protein and desmoplakin 1 and 2 were localized mostly in the central and pericentral portion of germinal centers. All the DRCs extending from the central portion of germinal centers to the mantle zones were labeled with DRC-1 and, unexpectedly, with OKB7 antibodies. Other immunostainings, such as those for HLA-DR antigens, common leukocyte antigen, and Leu 3a, were not contributory in defining topographic differences of DRCs within the follicle. The consistent heterogeneity of the labeling patterns appears to suggest a possible in situ immunophenotypic grouping of DRCs, and the concept of their possible heterogeneity appears to be corroborated.

Heterogeneous in situ immunophenotyping of follicular dendritic reticulum cells in malignant lymphomas of B-cell origin

The phenotype of follicular dendritic reticulum cells (DRC) was analyzed with monoclonal antibodies (DRC-1, OKB7, BA-2, Leu-M3, and antidesmoplakin 1 and 2) in 28 frozen biopsy specimens of both morphologically and phenotypically analyzed B-cell lymphomas and 21 normal or reactive controls. The former included 15 follicular center cell lymphomas (FCCL), four intermediately differentiated lymphocytic lymphomas (ILL), four mantle zone lymphomas (MZL), and five well-differentiated lymphocytic lymphomas (WDLL). In controls, DRC-1+ and OKB7+ DRC were localized in both follicular centers (FC) and mantle zones (MZ), but BA-2+ and Leu-M3+ DRC were confined to FC only. FCCL were usually accompanied by DRC-1+, OKB7+, and BA-2+ DRC, and either lost or maintained positively with Leu-M3 from case to case. By contrast, MZL consistently lacked BA-2+ and Leu-M3+ DRC, and was associated with DRC-1+ and OKB7+ DRC only. Desmoplakin-positive DRC occurred in variable proportions in both FCCL and MZL. As opposed to FCCL and MZL, all WDLL and all but one of the ILL (associated only with DRC-1+, OKB7+, and desmoplakin+ DRC) did not show any DRC as identifiable with the antibody panel used. Remarkably, the difference in the distribution of BA-2+ and Leu-M3+ DRC in the normal FC and MZ appears to be maintained in their neoplastic counterparts (FCCL and MZL) also. Such a difference represents an example of the possible interactions between lymphoma cells of different phenotype and their microenvironment, as portrayed by phenotypically heterogeneous DRC.