Antigenic phenotypes of hairy cell leukemia and monocytoid B-cell lymphoma: an immunohistochemical evaluation of 66 cases.

Using a large panel of antibodies on multi-tumor block sections of routinely processed, paraffin-embedded fixed tissue, we compared the antigenic phenotype of 42 clinically, morphologically, and immunologically well-characterized cases of hairy cell leukemia (HCL) with 24 cases of monocytoid B-cell lymphoma (MBCL) selected from the Monocytoid B-Cell Lymphoma Registry at the City of Hope National Medical Center. The predominant antigenic phenotype of hairy cells was CD45 (leukocyte common antigen)+, CD45Ra (4KB5, MB1, MT2)+, L26+, CDw75 (LN1)+, CD74 (LN2)+, LN3+, MB2+, CD45RO (UCHL1)-, MT1-, CD15 (Leu-M1)-, neuron-specific enolase (NSE)-, epithelial membrane antigen-, and CD30 (Ber-H2)-. The immunophenotype of neoplastic monocytoid B lymphocytes was essentially identical to that of the hairy cells, with one exception: the neoplastic monocytoid B lymphocytes were stained by epithelial membrane antigen in seven cases. An interesting observation was the staining by anti-muscle-specific actin of the neoplastic cells of MBCL in 53% of cases, but of none of the cases of HCL. The results of our study (1) indicate that HCL and MBCL can be immunophenotyped reliably on fixed tissue samples, (2) further confirm the proposed lineage relationship between these two lymphoproliferative disorders, and (3) indicate that decalcification of bone marrow biopsies does not adversely affect the immunoreactivity of hematopoietic-associated antigens.     

Use of monoclonal antibodies for the typing of malignant lymphomas in routinely processed biopsy samples

Eight antibodies (UCHL1 (CD45RO), MT1 (CD43), MT2 (CD45R), 4KB5 (CD45R), MB1 (CD45R), MB2, L26 (CD20) and LN1 (CDw75)) have been examined for reactivity with routine specimens of normal and hyperplastic lymphoid organs (n = 6), non-Hodgkin's lymphomas (n = 62), Hodgkin's disease (n = 27) and non-lymphoid malignancies (n = 9). In normal and hyperplastic lymphoid organs, UCHL1 and MT1 stained predominantly T cells; 4KB5, MB1, MB2, L26 and LN1 stained predominantly B cells; and MT2 reacted with a subset of B and T cells. The lineage of the neoplastic cells was correctly identified in 24 of 28 (86%) peripheral T-cell lymphomas; and in 31 of 35 (88%) B-cell malignancies. In two cases of lymphocyte-predominant Hodgkin's disease, the Hodgkin's and Reed-Sternberg (H&RS) cells were 4KB5+, L26+ and/or LN1+. The H&Rs cells in nodular sclerosis and mixed cellularity Hodgkin's disease were positive with 4KB5 in 17 of 25 cases. Antibodies UCHL1, MT1, MB1, MB2, L26 and LN1 also labelled some H&RS cells, but in a much smaller proportion of the cases. In three of nine non-lymphoid neoplasms, UCHL1 and MB2 showed a staining of the neoplastic cells, but the staining was cytoplasmic rather than membrane-associated. The remaining antibodies were unreactive with the non-lymphoid malignancies. It is concluded that many non-Hodgkin's lymphomas can be typed in routine specimens, and that antibodies UCHL1, MT1, L26 and LN1 are especially useful in this respect. The antibodies do not provide a means of distinguishing between non-Hodgkin's lymphomas and Hodgkin's disease.     

Monoclonal antibody Leu-22 (L60) permits the demonstration of some neoplastic T cells in routinely fixed and paraffin-embedded tissue sections

Monoclonal antibody Leu-22 (L60) detects a T cell-associated antigen which is stably expressed in routinely fixed and paraffin-embedded tissue sections. We investigated the utility of monoclonal antibody Leu-22 to immunophenotype routinely processed lymphoid neoplasms by determining its reactivity in 105 archival pathologic specimens of lymphoid neoplasia that had been previously immunophenotyped by standard cell suspension and frozen tissue section techniques. Monoclonal antibody Leu-22 reacted with 69% of T cell non-Hodgkin's lymphomas (NHLs), including cases belonging to each of the major clinicopathologic categories, and with 22% of B cell NHLs, but did not react with the Reed-Sternberg (RS) cells of Hodgkin's disease (HD). We concluded that monoclonal antibody Leu-22 reacts preferentially but not exclusively with T cell NHLs. Therefore, we performed parallel analyses of the same 105 cases with monoclonal antibodies leukocyte common antigen (LCA), Leu-M1, LN1, and LN2, which detect various paraffin-resistant antigens, and of 80 of these cases with monoclonal antibody UCHL1, which detects a paraffin-resistant T cell-associated antigen. UCHL1 reacted with 61% of the T cell NHLs studied. Sixty-nine percent of T cell NHLs expressed the LCA+, Leu-22+ or Leu-M1+, LN1- phenotype and 47% of B cell NHLs expressed the LCA+, Leu-22-, Leu-M1-, LN1+ phenotype. These phenotypes had a false-positive rate of only 7%. The substitution of UCHL1 for Leu-22 or the combined use of UCHL1 and Leu-22 in this panel did not improve our ability to correctly predict the T cell phenotype of these lymphoid neoplasms. LN1 and LN2 reacted with 13% and 56% of T cell NHLs, respectively, and LN2 reacted with RS cells in 85% of cases of HD. In summary, our results demonstrate that the judicious use of monoclonal antibody Leu-22 in combination with other selected commercially available monoclonal antibodies permits the determination of the B cell or T cell origin of a high proportion of NHLs, and is helpful in the differential diagnosis between HD and NHL among cases that have been routinely fixed and paraffin-embedded.     

Monomorphic lymphomas arising in patients with Hodgkin's disease. Correlation of morphologic, immunophenotypic, and molecular genetic findings in 12 cases

Patients with Hodgkin's Disease (HD) occasionally develop monomorphic lymphomas in which mononuclear cells, usually large in size, grow in sheets, and in which there are few reacting cells or classic Reed-Sternberg (RS) cells. Twelve patients of this type were reviewed to determine the nature of the monomorphic growth. Paraffin-embedded tissue sections from the original diagnostic HD and the monomorphic growths were stained for Leu-M1 (CD15), leukocyte common antigen (LCA, CD45), pan B-cell markers LN1, LN2, and L26, and pan T-cell marker UCHL1 (CD45R) reactive in paraffin-embedded tissues. Cases were included only if the original diagnostic material had the classic histopathologic features of HD, if there was a separate monomorphic growth (in place or time), and if sufficient materials from both phases were available for study. Original diagnoses of HD included nodular sclerosing (NS; 8 cases); lymphocyte predominant (LP; 2 cases); mixed cellularity (MC; 1 case); and lymphocyte depleted (LD: 1 case) types. RS cells in the eight cases of NS HD and one case of MC HD were generally Leu-M1 and LN2 positive, and L26, LN1, UCHL1, and LCA negative. RS cells in one case of NS HD were LCA positive in addition to Leu-M1, LN1, and LN2. Two cases of NS HD showed L26 positive RS cells. Conversely, RS cells and lymphocytic-histiocytic (L and H) variants in the cases of LP HD were Leu-M1 and LN2 negative, and LCA and LN1 positive. The one case of LD HD possessed RS cells that were negative for Leu-M1, but positive for LCA, L26, LN1, and LN2. In seven cases (4 NS, 2 LP, 1 LD) the monomorphic growths possessed a B-cell phenotype (LCA, L26, and LN1 positive; Leu-M1 and UCHL1 negative). In the remaining cases (4 NS, 1 MC), the monomorphic growths were Leu-M1 positive, and displayed phenotypes similar to the RS cells of the original NS HD. Southern blot analysis was performed on the monomorphic components of five cases and showed some form of immunoglobulin gene rearrangement in each (4 cases: rearranged heavy chain-joining region gene; 1 case: rearranged Mu chain-constant region gene). Two of these cases expressed L26 and LN1 in the monomorphic phases. Despite apparent immunoglobulin gene rearrangement, one case expressed T-cell antigens Leu-4 (CD3) and Leu-1 (CD5), in addition to Leu-M1 (CD15).(ABSTRACT TRUNCATED AT 400 WORDS)     

Demonstration of lymphoid antigens in decalcified bone marrow trephines.

A panel of antibodies recognising lymphoid and epithelial antigens in formalin fixed, paraffin embedded sections was applied to a series of 54 bone marrow trephines decalcified by formic or edetic acids. Normal trephines and cases infiltrated by myeloid, lymphoid, and epithelial tumours were included. Patterns of reactivity were distinct and allowed the different diseases to be distinguished. All lymphoid tumours expressed leucocyte common antigen, with B cell tumours staining with MB1 and MB2, and T cell tumours staining with MT1 and UCHL1. T cell acute lymphoblastic leukaemia (ALL)/lymphoblastic lymphoma all stained with MT1, but some were negative with UCHL1. B cell ALL/lymphoblastic lymphoma also stained with MT1, but could be distinguished by its reactivity with MB1 and MB2. Reed-Sternberg cells did not stain with any reagent. Normal and neoplastic myeloid cells stained with MT1. Carcinomas stained with CAM 5.2 but were negative for lymphoid markers except MB2 staining in some cases. A case of neuroblastoma could be distinguished from ALL/lymphoblastic lymphoma by its lack of reactivity with all antileucocyte antibodies and its staining with antineurone specific enolase. Although not ideal, if used together, this panel of reagents may usefully be applied to routinely fixed and processed, decalcified bone marrow trephines.     

Immunohistochemical examination of routinely processed bone marrow biopsies.

Immunohistochemistry was performed on paraffin sections of 169 bone marrow biopsies fixed in a buffered methanol-formalin solution and decalcified with EDTA. The biopsies included specimens with normal hematopoiesis, and specimens that were affected by various hematological disorders as well as some metastatic carcinomas. The results demonstrate that a wide spectrum of antigens was preserved in routinely processed bone marrow biopsies, even after long-term fixation up to 12 days. Markers for granulopoietic cells were lysozyme, elastase, DAKO-M 1, and MT 1. Megakaryopoiesis was stained with glycoprotein IIIa, von Willebrand factor, and Ulex europaeus agglutinin (UEA), and erythropoiesis with LN 1. Normal lymphocytes as well as lymphoma cells of all non-Hodgkin's lymphomas tested were positive for leukocyte common antigen (LCA), and at variable degree, for MB 1, 4 KB 5, LN 1, LN 2, UCHL 1, or MT 1. Reed-Sternberg and Hodgkin's cells in Hodgkin's lymphomas were reactive with Ber-H 2, LN 2 and Dako-M 1. In plasma cell disorders, staining for immunoglobulin light chains gave best results. Metastatic carcinomas showed predominantly staining with EMA, and KL 1. A selected panel of specific cell markers is proposed, which proved to be helpful in routine bone marrow diagnosis in most cases.     

Paraffin section immunohistochemistry. I. Non-Hodgkin''s lymphoma

Reagents that recognize antigens on lymphoid cells in fixed and wax-embedded sections have been applied to a series of cases of non-Hodgkin's lymphomas. The panel consisted of MB1, 4KB5 (CD45r), LN1, L26 and MB2 which recognize antigens expressed predominantly on B-lymphocytes; UCHL1 and MT1 which recognize antigens expressed on T-lymphocytes and myeloid cells; antibodies recognizing the non-lineage antigens LeuM1 (CD15), BerH2 (CD30), anti-EMA; anti-lysozyme and MAC 387 which detect antigens present on some macrophages; and finally TAL1B5 (class II MHC), CAM 5.2 (low molecular weight cytokeratin) and PD7/26 + 2B11(CD45). Two hundred and four cases of non-Hodgkin's lymphoma have been studied, of which 158 had been fully characterized on frozen sections. The series was biased towards high-grade (n = 108) and T-cell (n = 44) tumours and these were largely prospectively accrued. It was found that discrimination between B-cell and T-cell lymphomas can be reliably achieved using these reagents and that a small panel (CD45, L26, MB2, MT1, UCHL1) is adequate for this purpose. Using the full range of reagents it is not possible to subdivide cases into groups that correspond with morphological subtypes of lymphoma. Although paraffin section immunohistochemistry is of value, the diagnosis of lymphoproliferative disorders must still be based upon the assessment of well fixed, carefully prepared tissue sections using conventional tinctorial methods.     

Analysis of epithelial and lymphoid phenotypic markers in relation to growth pattern of colorectal adenomas.

The relationship of villous to tubular adenomas is poorly understood and often difficult to characterize morphologically. A villous growth pattern in colorectal adenomas has been associated with a higher frequency of high-grade dysplasia. We compared phenotypic markers using immunoperoxidase techniques in paired samples of villous (75% to 100% villous) and pure tubular adenomas matched for size and degree of dysplasia, which were selected by review of 1,000 polyps from our files. The following monoclonal antibodies were used: CAM 5.2 and AE1/AE3 to cytokeratins; B18, D14, B7.1, and B7.8 to four distinct carcinoembryonic antigen epitopes; Leu-M1 and LN3 to HLA-DR antigen; LN2 to invariant chain class II major histocompatibility complex; LN1 and MB2 to B-cell markers; UCHL1 and MT1 to T-cell markers; Leu-7 to natural killer cells; Mac 387 to macrophages; S-100 to Langerhans-type cells; and a polyclonal antibody to secretory component. LN3 reactivity correlated with villous morphology and secretory component correlated with tubular morphology. Combined HLA-DR and secretory component expression discriminated between tubular and villous growth patterns in 12 of 15 pairs of adenomas (P less than .001). LN2 was expressed more frequently than LN3, but did not correlate with growth pattern. Neuroendocrine cells (Leu-7) were more frequent in tubular adenomas. Carcinoembryonic antigen epitopes did not relate to growth pattern. We did not confirm previously reported differences in cytokeratin expression. We concluded that among the markers tested, HLA-DR expression, which may have an immunologic basis, is most characteristic of colorectal adenomas that exhibit a villous growth pattern.     

Methods in pathology. Immunophenotype of hairy cell leukemia in paraffin sections

The immunophenotype of hairy cell leukemia (HCL) was investigated using 20 routinely fixed paraffin-embedded tissue sections (12 bone marrows, six spleens, one liver, one lymph node) from 12 patients known to have this disease. A panel of antibodies was used, including anti-leukocyte common antigen (anti-LCA), B-lineage antibodies (LN2, MB2, L26), T-lineage reagents (MT1, UCHL1), monocytic (anti-cathepsin B) and myelomonocytic (anti-lysosyme, Mac 387) antibodies, and other less lineage-specific markers (anti-S-100, anti-alpha-1-antichymotrypsin (anti-alpha 1-ACT), anti-alpha 1-antitrypsin (anti-alpha 1-AT), anti-vimentin). Anti-LCA stained hairy cells in seven of the 12 bone marrows and consistently recognized hairy cells in the spleen, liver, and lymph nodes. Hairy cells generally reacted with B-lineage antibodies and were not labeled by T-lineage markers. No reactivity was noted with myelomonocytic antibodies, anti-S-100, anti-alpha 1-ACT, or anti-alpha 1-AT. Vimentin was expressed in the majority of cases. Tartrate-resistant acid phosphatase reactivity was demonstrated in three of the 20 routinely processed tissue sections. These data suggest that immunohistochemical studies of hairy cell leukemia in routinely processed tissue may be useful in diagnostic hematopathology and surgical pathology.     

Detailed phenotypic analysis of B-cell lymphoma using a panel of antibodies reactive in routinely fixed wax-embedded tissue.

Sixty-three well characterized B-cell lymphomas, with diagnoses previously established by conventional cryostat immunocytochemistry or limited paraffin immunocytochemistry, were studied. The tumors encompassed most of the Kiel subtypes and included the newly recognized entity, sclerosing mediastinal B-cell lymphoma. by the avidin-biotin peroxidase complex technique, each tumor was stained with a panel of monoclonal and polyclonal antibodies reactive in routinely fixed wax-embedded tissues. The panel included four reagents recognizing probable T-cell and B-cell restricted leukocyte common moieties (UCHL1, MT1, MB1, 4KB5), three antibodies to B-cell-related antigens (KiB3, MB2, LN1), and one to a macrophage-related antigen (Mac411). Other antibodies employed included anti-mu chain, anti-kappa, anti-lambda, and seven antibodies to non-phenotype-associated antigens, including HLA-DR (TAL-1B5, LN3, LN2, MB3), CD15 (C3D-1), and CD30 (BER-H2). Monotypic surface or perinuclear space and cytoplasmic immunoglobulin were detected in 80% of cases. Distinctive immunocytochemical profiles were demonstrable in many tumor categories by means of the panel of antibodies, thus facilitating the differential diagnosis of tumors of similar morphology. These results, together with our work on T-cell lymphoma in paraffin sections, show that accurate phenotypic analysis of lymphoma is now possible in routinely processed tissues.     

A panel of antibodies for the immunostaining of Bouin's fixed bone marrow trephine biopsies.

AIMS: To assess a panel of antibodies on Bouin's fixed bone marrow trephine (BMT) biopsies. These biopsies are widely used in routine diagnosis of various haematological malignancies and may be the sole material available in many centres; however, information regarding the immunostaining of this material is lacking. METHODS: Biopsies were taken from 72 patients presenting with various haematological malignancies (leukaemia, 38; lymphoma, 14; multiple myeloma, 20). A panel of antibodies was assessed on Bouin's fixed BMT biopsies by the alkaline phosphatase-antialkaline phosphatase method. RESULTS: Three B (MB2, LN-2, Ki-B5) and two T cell lineage antibodies (UCHL-1, CD3-r) reliably identified lymphoid cells, while MPO-r, Leu-M1/CD15, and KP-1/CD68 recognised cells from the myeloid or histiocytic/macrophage series. Reed-Sternberg cells were stained by LN-2, Leu-M1, and CD30. Antibodies specific for plasma cells (VS38) and hairy cells (DBA.44) gave a variable pattern of staining. Among the proliferation markers, proliferative cell nuclear antigen but not Ki-67 related antibodies were effective. CONCLUSION: This study presents a panel of antibodies with reactivity not restricted to common fixatives that are also suitable for Bouin's fixed BMT biopsies.     

Central nervous system lymphomas. Immunohistochemical and clinicopathologic study of 26 autopsy cases

Twenty-six malignant lymphomas involving the central nervous system were studied. Eleven were primary (P) and 15 were systemic (S). Eight cases (3 P, 5 S) occurred in immunocompromised patients. Age at presentation in immunocompromised patients was typically younger than in the nonimmunocompromised patients. Presenting complaints of central nervous system involvement included headache, seizures, personality changes, memory lapses, ataxia, cranial nerve symptoms, and impaired consciousness. Cerebrospinal fluid involvement was seen only in 3 S cases. In 8 of the P cases, the diagnosis was first established at autopsy; in 6 of the S cases, central nervous system involvement was first documented at autopsy. Survival was longer in treated patients than in those who received no therapy (5 months in P cases and 9.3 months in S cases; 2.3 months without therapy). Regardless of therapy, the average survival of immunocompromised patients was 2.4 months. The majority of cases were multifocal. Of the P cases, 1 was of low histologic grade, 9 were of intermediate grade, and 1 was of high grade. Of the S cases, 5 were of low grade, 9 were of intermediate grade, and 1 was of high grade. Immunophenotypic studies were performed on formalin-fixed, paraffin-embedded tissue with antisera against common leukocyte antigen (all reactive), B-cell markers (L26, MB2, LN1, and LN2), T-cell markers (UCHL1 and MT1), Leu-M1, Leu-7, and HLA-DR (LN3). Two S cases were of T-cell phenotype; all others were of B-cell derivation. Eleven cases were HLA-DR positive (all of B-cell phenotype). One T-cell lymphoma was reactive for Leu-7. All cases were nonreactive for Leu-M1. All cases in immunosuppressed patients and all P cases were of B-cell phenotype.     

Immunohistochemical evaluation of neoplasms in bone marrow biopsies using monoclonal antibodies reactive in paraffin-embedded tissue

A panel of commercially available monoclonal antibodies (MoAbs) including LN1, LN2, MB2, L26, Leu M1, UCHL1, MT1 and L60 was used to evaluate a diverse group of neoplastic processes in 256 Zenker's-fixed, decalcified, paraffin-embedded bone marrow biopsies using the ABC immunoperoxidase technique. LN2 and MB2 were useful in delineating the extent of B-cell lymphoproliferative processes and in identifying interstitial patterns of involvement. The combined application of LN2, MB2 and UCHL1 had utility in differentiating B-cell from T-cell lymphoproliferative processes; in no instance was reactivity with LN2 observed in T-cell processes. The combined application of these three MoAbs was also used in differentiating benign reactive lymphoid aggregates from focal malignant B-cell proliferations. LN2 exhibited positivity with the Reed-Sternberg cells (RSC) of Hodgkin's Disease (HD) and significantly aided in the identification of these cells. Staining of RSC with Leu M1 was inconsistent and was observed in only 50% of cases of HD. Use of the entire panel of MoAbs together with more recently available reagents such as Cathepsin G, MAC 387 and neutrophil elastase was essential in optimally evaluating a particular lesion; none of these MoAbs used singly reliably differentiated myeloid from lymphoid, hematopoietic from metastatic, or reactive from malignant processes.     

Differential antigen preservation during tissue autolysis.

Immediate fixation or snap freezing of tissue is ordinarily done to maximize antigen preservation for immunocytochemistry; however, delay in tissue allocation or spontaneous lymph node infarction can render tissue suboptimal for immunostaining. To test the effects of tissue autolysis/necrosis on the preservation of various lymphoid, epithelial, and mesenchymal markers, two lymph nodes (one with reactive lymphoid hyperplasia and one with metastatic ductal breast carcinoma) were evaluated for immunocytochemically demonstrated antigen preservation at 0-, 4-, 8-, 12-, 24-, 48-, and 72-hour intervals of autolysis at 37 degrees C. All specimens were stained by frozen section and formalin-fixed paraffin section immunocytochemical reactions with antibodies against CLA (CD45), UCHL-1 (CD45RO), L-26, kappa, lambda, anti-epithelial keratins (AE-1 and AE-3), epithelial membrane antigen, and vimentin. Frozen sections were additionally stained for Leu-1 (CD5), Leu-2a (CD8), Leu-3a+b (CD4), Leu-4 (CD3), and Leu-14 (CD22). The most resilient lymphoid antigen preservation was observed with CLA and UCHL-1, both exhibiting immunoreactivity at 72 hours in both frozen and fixed preparations. L-26 showed similar reactivity in frozen sections, but detectable antigen was observed only up to 24 hours in formalin-fixed tissue. Leu-2a proved to be the most labile antigen, persisting for only 12 hours in frozen sections. The epithelial markers epithelial membrane antigen and AE-1 exhibited excellent antigenic preservation in both frozen and fixed preparations; AE-3 persisted well in frozen section but was not demonstrated in fixed tissue. Vimentin immunoreactivity was vastly superior in frozen, as compared with fixed, tissue sections. Most antigens showed remarkable preservation despite morphologic degradation; however, differential antigenic resilience was demonstrated. Knowledge of this variation in antigen decay is critical for evaluation of immunoperoxidase phenotypic studies of autolyzed or necrotic tissue.     

Leu-22 (L60). A more sensitive marker than UCHL1 for peripheral T-cell lymphomas, particularly large-cell types

Paraffin-embedded sections of 77 peripheral T-cell lymphomas (PTCLs) were stained with several monoclonal antibodies, including the preferential T-cell markers Leu-22 (L60[CD43]) and UCHL1 (CD45RO). The staining characteristics of L60 and UCHL1 were compared to determine the value of each in the immunophenotypic analysis of PTCLs. Lineage specificity was evaluated among 39 B-cell lymphomas and 33 cases of Hodgkin's disease (HD). L60 and/or UCHL1 stained 95% of PTCLs, whereas L60 and UCHL1 alone stained 90% and 69% of cases, respectively. L60 demonstrated significantly greater numbers of immunopositive tumor cells than UCHL1 in 37% of the PTCL cases, principally because of enhanced marking of large, neoplastic cells. UCHL1 was a better marker in only 10% of the PTCL cases. L60 stained 33% of B-cell lymphomas, usually small lymphocytic or lymphoplasmacytic types. UCHL1 stained only 8% of B-cell lymphomas, all large-cell types. L60 and UCHL1 stained Reed-Sternberg cells and variants in three cases of nodular sclerosing HD. These results suggest that both L60 and UCHL1 are useful markers of PTCLs in routinely processed tissue. L60 is a more sensitive marker of large neoplastic T-cells than UCHL1 but is less lineage-specific. These antibodies are most effective when used as part of a panel of monoclonal antibodies.     

Immunophenotyping of non-Hodgkin's lymphomas in paraffin-embedded tissue sections. A comparison with genotypic analysis.

Several monoclonal antibodies (MoAbs) are now available for immunophenotyping non-Hodgkin's lymphomas (NHLs) in paraffin-embedded tissue sections. To determine the reliability of these reagents in predicting the genotype, 44 cases of NHL were studied with the alkaline phosphatase-anti-alkaline phosphatase technique with the use of the following MoAbs: leukocyte common antigen (CD45), Mac 387, L26, 4KB5, MB1, MB2, LN2, UCHL1, MT1, and MT2. The lineage of the neoplastic cells was determined in all cases by gene rearrangement studies for immunoglobulin heavy chain and for the T-cell receptor beta-chain. Genotypic results showed B-cell lineage in 33 cases (75%), T-cell lineage in 6 cases (14%), and mixed or undetermined lineage in 5 cases (11%). A concordance of lineage assignment by paraffin section immunophenotyping with gene rearrangement studies was observed in 37 of 39 (95%) lymphomas with an unequivocally defined genotype. MoAb L26 was the most sensitive in detecting B-cell genotype; MoAbs MT1 and UCHL1 were the most sensitive and specific, respectively, in detecting T-cell genotype. The authors conclude that lineage assignment of NHLs in paraffin sections is reflective of the corresponding genotype when an appropriate panel of MoAbs is used.     

Immunophenotypic analysis of acute lymphoblastic leukemia using routinely processed bone marrow specimens

Monoclonal antibodies have been recently developed that react with antigens expressed on T and B lymphocytes in routinely processed, paraffin-embedded lymphoid tissues. In this study, we assessed bone marrow clot and/or core biopsy sections of 19 cases of acute lymphoblastic leukemia (ALL) using routinely decalcified, B5- or formalin-fixed, paraffin-embedded sections and a panel of monoclonal antibodies, including LN1, LN2, L26, Leu-22, UCHL-1, and LCA. Each case had been previously phenotyped using freshly obtained aspirate material and a standard immunophenotypic protocol. Our results demonstrate the utility of the LN2 antibody in differentiating between precursor B-cell (pre-B) and precursor T-cell ALL. The LN2 antibody stained 11 of 12 cases of pre-B ALL and did not react with any of the seven T-cell ALLs. The other antibodies tested were less helpful. The Leu-22 antibody stained both pre-B and T-cell ALLs, while the results with UCHL-1 revealed peculiar nuclear staining of pre-B and T-cell ALLs; this we attributed to processing artifact. The L26 antibody reacted with only one case of pre-B ALL (also CD20 antigen positive), while the LN1 antibody did not react with any pre-B ALLs. Neither L26 nor LN1 stained any cases of T-cell ALL. The LCA antibody stained in only four (21%) of 19 cases, two pre-B and two T-cell ALLs. The results also suggest that this panel of antibodies may be useful in differentiating ALL from mature B-cell and T-cell lymphomas involving the bone marrow.     

New marker of B lymphocytes, MB2: comparison with other lymphocyte subset markers active in conventionally processed tissue sections.

The use of the murine monoclonal antibody MB2 for identifying B lymphocytes in routinely processed tissue was evaluated and contrasted with the use of the monoclonal antibody UCHL1 for identifying T cells. One hundred and sixty eight surgical biopsy specimens were immunostained with these antibodies, including a wide range of normal and neoplastic non-lymphoid tissues, as well as normal lymphoreticular tissues and lymphomas. Sixty four non-Hodgkin's lymphomas were also examined, of which 51 had been previously phenotypically defined. In selected cases the results were compared with those obtained using two other monoclonal antibodies MB1 and MT1, used for identifying B and T cells, respectively, in paraffin sections. MB1 stained a smaller proportion of B cell tumours than MB2 and staining was, in general, weaker, except in one case of centroblastic lymphoma. MT1 immunoreactivity was comparable with that of UCHL1, except in one case of T lymphoblastic lymphoma (MT1 positive, UCHL1 negative). None of the antibodies is ideal, but, if used as a panel, they permit the separation of B cells and T cells in paraffin sections.     

Acute myeloid leukemia: immunohistologic findings in paraffin-embedded bone marrow biopsy specimens.

Immunohistochemical investigations were performed on decalcified, paraffin-embedded iliac crest trephine biopsy specimens from 30 cases of acute myeloid leukemia (AML, as defined by the FAB classification) with antibodies against B cells (L26, 4KB5, MB1, Ki-B3), T cells (UCHL1, MT1), myeloid/histiocytic cells (anti-neutrophil elastase, MAC387, anti-S-100 protein, anti-alpha 1-antichymotrypsin, DAKO-M1), natural killer/killer cells (anti-Leu-7), and megakaryocytes (anti-factor VIII-related antigen). (1) The blast cells of all the cases reacted with from at least two to at most eight different antibodies. Each antibody reacted with blast cells in a minimum of two (maximum 30) cases. (2) MT1, Ki-B3, anti-alpha 1-antichymotrypsin anti-neutrophil elastase, anti-S-100 protein, and MAC387 stained blast cells in more than 50% of the cases; MB1, L26, UCHL1, 4KB5, and DAKO-M1 in 20% to 50% of the cases; and anti-Leu-7 and anti-factor VIII-related antigen in less than 20% of the cases. (3) In the majority of cases many T lymphocytes, a small-to-moderate number of B lymphocytes, and a few Leu-7-positive lymphoid cells were intermingled with the blast cells. In some cases, especially where only a minor proportion of the blast cells was immunostained, it was nearly impossible to distinguish the lymphocytes of the tumor's stromal reaction from small blast cells. Thus, AML exhibits a heterogeneous immunophenotype in trephine biopsy specimens. Immunohistologic diagnosis of this disease in such specimens may be extremely difficult. Since staining of the blast cells with one or more of the antibodies generally used to define B cells, T cells, or their neoplastic derivatives is not uncommon, misinterpretation as non-Hodgkin's lymphoma of high-grade malignancy could easily occur. These findings also suggest that mixed-type (hybrid) acute leukemias with coexpression of myeloid and lymphoid cell markers could be more common than generally realized.     

The demonstration of B-cell, T-cell and myeloid antigens in paraffin sections

The monoclonal antibodies MB1 and MT1, which detect B cells and T cells respectively, have been applied to human lymphoid tissues. The distribution of staining within paraffin sections was compared with that observed using frozen sections and was found to be identical. The antibodies were then applied to paraffin sections of 19 B-cell lymphomas and 10 T-cell lesions in which full immunophenotyping had been performed. The B lymphomas all consisted of a large majority of MB1 positive cells with a variable infiltrate of small MT1 positive lymphocytes. The T cell lesions consisted of MT1 positive cells with few MB1 positive cells except in residual B cell areas of lymph nodes. In paraffin sections from cases of Hodgkin's disease anti-Leu M1 identified Reed-Sternberg cells and their variants and MB1 and MT1 showed a similar distribution of B cells and T cells to that demonstrated in previous studies using frozen sections. The results show that MB1 and MT1 are useful markers for B and T cells in routinely fixed paraffin embedded tissue. In conjunction with anti-Leu M1 they provide a valuable panel of antisera for the examination of lymph nodes and other biopsies when frozen tissue is not available.