Small noncleaved follicular center cell lymphoma: Burkitt's and non-Burkitt's variants in the US. II. Pathologic and immunologic features

The morphologic criteria for the two variants of small noncleaved follicular center cell (SNC FCC) lymphoma in the Lukes-Collins classification, Burkitt's (BL) and non-Burkitt's variants (NBL), were evaluated and related to the results of multiparameter laboratory and clinical studies. Forty-two patients were studied: 25 cases were classified as BL according to World Health Organization (WHO) criteria. Seventeen cases were classified as NBL on the basis of greater variability in nuclear size and shape, more prominent nucleoli, and greater variation in the amount of cytoplasm. Neoplastic follicles were present in three cases of BL and two of NBL, indicating an FCC origin for this lymphoma. Electron microscopic examination confirmed the light microscopic features. Immunoglobulin (Ig) monoclonality, as demonstrated by immunofluorescence (surface Ig) and/or immunoperoxidase staining for cytoplasmic immunoglobulin (CIg), was demonstrated in 21 of 24 (87.5%) of BL and 13 of 16 (71%) of NBL. Clinically, BL presented more frequently in extranodal sites and with gastrointestinal involvement than NBL. Bone marrow involvement was more common in NBL patients. Both groups had advanced stage disease at diagnosis. The median survival was 10.5 months in BL and 7.7 months in NBL. The results of this study indicate that BL and NBL are biologically related variants of SNC FCC lymphoma but have different presentations, which may be clinically significant.

Mechanism of the t(14;18) chromosomal translocation: structural analysis of both derivative 14 and 18 reciprocal partners

To elucidate the mechanism of the t(14;18)(q32;q21) chromosomal translocation found in follicular lymphoma, we examined the structure of both derivative (der) chromosomal breakpoints as well as their germ-line predecessors. We noted that chromosome segment 18q21 was juxtaposed with immunoglobulin heavy (H) chain gene diversity (DH) regions on all five der(18) chromosomes we examined, and we confirmed the juncture with immunoglobulin H-chain gene joining (JH) regions on the der(14) chromosome. However, the t(14;18) was not fully reciprocal in that chromosome 14 DNA between the DH and JH regions was deleted. Furthermore, extra nucleotides, reminiscent of "N" segments, were present at the der(14) and possibly der(18) junctions. This indicates that despite the mature B-cell phenotype of follicular lymphoma, the t(14;18) occurs during attempted DH-JH joining, the earliest event in immunoglobulin rearrangement in a pre-B-cell. Our detailed analysis of the germ-line 18q21 region indicated that most breakpoints clustered within a 150-base-pair major breakpoint region. However, we found no evidence for evolutionarily conserved immunoglobulin-like recombinational signals at 18q21, arguing against a role for immunoglobulin recombinase in chromosome 18 breakage. Instead, a direct repeat duplication of chromosome 18 sequences was discovered at both chromosomal junctures, typical of the repair of a naturally occurring staggered double-stranded DNA break. These results prompt a translocation model with illegitimate pairing of a staggered double-stranded DNA break at 18q21 and an immunoglobulin endonuclease-mediated break at 14q32 and with N-segment addition, repair, and ligation to generate der(14) and der(18) chromosomes.

Initial experience in treating human lymphoma with a chimeric univalent derivative of monoclonal anti-idiotype antibody

Murine monoclonal anti-idiotype antibody was raised against the surface IgM on the neoplastic cells of a patient with widespread follicular lymphoma. For therapy, a chimeric antibody derivative, FabIgG, was constructed by thioether-linking Fab'gamma, from the monoclonal antibody, to human normal IgG. FabIgG is univalent and thereby avoids rapid antigenic modulation. Its human IgG component is intended to optimize recruitment of effectors and metabolic survival while minimizing immunogenicity. Four intravenous (IV) infusions of 380 to 580 mg of anti-idiotype FabIgG were given over a period of 11 weeks. There was no significant toxicity. On each occasion, the antibody disappeared from the plasma with a half-life (t1/2) of less than 24 hours. The brief survival was evidently due to uptake by tumor, as infused control FabIgG, containing Fab'gamma from an irrelevant antibody, yielded a plasma t1/2 of greater than 10 days. With each therapeutic infusion, there was a fall in the number of circulating neoplastic cells over a 24-hour period. The numbers were largely replenished over the next week, but a net fall became discernible over the entire period of treatment. Four days after each infusion, nodal masses were swollen and tender, subsiding over approximately 8 days. At the end of the treatments, the blood lymphocyte count and nodal and splenic swellings continued to subside, so that by 6 weeks a partial remission with removal of greater than 50% of tumor was judged to have occurred. We did not detect any qualitative change in surface idiotype nor any antibody response to the infused Ig.

Diffuse large cell lymphomas of follicular center cell origin presenting in the skin. A clinicopathologic and immunologic study of 16 patients

This report describes the clinical, histologic, and immunologic characteristics of 16 diffuse large cell lymphomas of follicular center cell origin with only skin lesions at presentation. These patients presented with nodular and tumorous skin lesions, which in 10 of 16 cases were confined to a circumscribed area on the trunk. Four patients, all elderly women, presented with skin tumors on the lower legs. Histologically, these 16 lymphomas showed nonepidermotropic diffuse dermal infiltrates, mainly consisting of large follicular center cells, with a variable admixture of small cleaved cells, immunoblasts, T-lymphocytes, and macrophages. The relative numbers of large cleaved and large noncleaved cells, respectively, varied considerably in these lymphomas. Immunophenotypically, almost all lymphomas expressed monotypic surface immunoglobulins and HLA-DR antigens, whereas all lymphomas were reactive with B-cell-associated monoclonal antisera B1, Leu-14, and/or To15. Three of four elderly female patients presenting with disease on the lower legs died. Of the 12 other patients, 11 are currently alive and in complete remission, which suggests a favorable prognosis for this type of cutaneous large cell lymphoma.

Cutaneous follicular lymphoma

Fifteen cases of cutaneous follicular lymphoma were evaluated clinically, histologically, and immunologically. Nine of the patients presented with skin disease alone, which showed a predilection for the scalp and forehead. The six remaining cases had either concurrent or secondary cutaneous involvement. All of the cases had a nodular configuration which was evident histologically or immunologically. In many cases, the diagnostic microscopic fields were in the deep dermis or subcutis, with nonspecific inflammation in the superficial dermis. The cases consisted of five small cleaved, seven mixed, and three large cell follicular lymphomas. A senior dermatopathologist diagnosed four of the 15 cases as benign, indicating the difficulty of diagnosis by morphology alone when the biopsy is small or the inflammatory component is prominent. This underscores the importance of large, deep biopsies for accurate histologic diagnosis. Immunological studies confirmed the B cell lineage of these lesions. An unexpectedly high proportion of immunoglobulin-negative cases (eight cases) was found, especially among the primary cutaneous follicular lymphomas (six of nine cases). Immunoglobulin-expressing cases exhibited monotypic immunoglobulin light-chain staining of tumor cells. In all cases, the dendritic reticulum cell network within lymphoma follicles lacked the polytypic immunoglobulin complexes characteristic of reactive follicles. As described previously for follicular lymphomas in lymph nodes, many cases exhibited polytypic follicular mantle zones similar to reactive follicles. The low-grade nature of these lymphomas was supported by clinical follow-up. We conclude that given adequate sampling, cutaneous follicular lymphomas can usually be diagnosed by histologic criteria similar to those used for lymph nodes; however, immunohistologic studies are an important adjunct.

Immunologic induction of malignant lymphoma: graft-vs-host reaction-induced B cell lymphomas contain integrations of predominantly ecotropic murine leukemia proviruses

The induction of a graft-vs-host reaction in (BALB/c X A)F1 mice by i.v. injection with BALB/c lymphoid cells leads to a lymphoid hyperplasia that may progress to malignant lymphoma. In the present paper, the following aspects of graft-vs-host-reaction lymphomagenesis were studied: 1) the cellular requirements for the induction of lymphomas, 2) their cellular origin, and 3) the role of murine leukemia viruses. The development of graft-vs-host-reaction lymphomas was found to be mediated by donor T cells and to require the presence of histoincompatibility between donor and host. Histologically, the vast majority of these lymphomas were either of follicular center cell or of immunoblastic type, whereas immunoperoxidase studies showed that they were virtually all B cell derived. Most of the lymphomas were of host origin. In the DNA of approximately 80% of the lymphomas, integrated murine leukemia virus proviruses were detected. In the B cell lymphoma DNA, integrated ecotropic proviruses prevailed, but recombinant murine leukemia virus and/or deleted murine leukemia virus genomes were also detected in some tumor DNA.

Nodular lymphomas: current concepts

The past several years have witnessed innovative approaches to clinical management as well as significant insights into the basic biology of the nodular lymphomas. Clinical studies have explored two apparently widely disparate approaches to the treatment of patients with nodular lymphoma. On the one hand, withholding initial therapy (watch and wait) has proved to be a viable option in the management of some patients. This approach has provided information regarding the natural history of disease, such as the relative incidence of spontaneous tumor regression vs. histologic transformation to more aggressive forms of lymphoma. Alternatively, recent data also suggest that the administration of intensive chemotherapy, shown to induce long-term remissions in a high percentage of patients with diffuse aggressive lymphomas, may also produce a significant number of durable remissions in at least certain histologic subtypes of nodular lymphomas. Clinical studies which attempt to achieve a synthesis of the above two approaches are currently in progress. Advances in immunology and molecular biology have also found application in the study of nodular lymphoma. Monoclonal antibodies have been employed diagnostically, as, for example, in detecting small numbers of persistent abnormal lymphoid clones in patients in apparent remission, and therapeutically, as exemplified by the clinical use in vivo of monoclonal antibodies directed against unique idiotypic determinants expressed by surface immunoglobulin on the malignant B lymphocytes. The demonstration of the immunoglobulin gene rearrangements in nodular lymphoma cells has established a more definitive criterion for their phenotypic characterization. Finally, molecular cloning of the breakpoint of the t(14; 18) chromosome translocation frequently found in nodular lymphoma cells has led to the identification of a potential new transforming gene which could be activated as a direct consequence of its rearrangement in proximity to the immunoglobulin in heavy chain gene locus.

Mantle-zone lymphoma. A pattern produced by lymphomas of more than one cell type

We analyzed the distribution and immunologic phenotype of the neoplastic cells in eight cases of mantle-zone lymphoma. Although in all the cases the follicle centers appeared reactive on routine histologic examination, polyclonal staining for immunoglobulin was found in the follicle centers in only five of the eight cases; in the other three cases the follicle centers were monoclonal. In three cases, the immunologic phenotype was that of centrocytic (diffuse small cleaved cell) lymphoma: IgM+IgD+B1+B2+Ia+Tl+. In one case the phenotype was that of a follicular (centroblastic/centrocytic) lymphoma: IgG+B1+B2+Ia+CALLA+. In the other four cases, the phenotype was IgM+B1+B2+ or B2-Ia+; this phenotype can be seen in diverse B cell lymphomas. The phenotype of normal mantle-zone cells (IgM+IgD+B1+B2+Ia+) was not reproduced by any of the lymphomas. A mantle-zone pattern may be produced by either follicular or diffuse lymphomas of predominantly small cleaved cell type, and does not indicate an origin from the cells of the normal mantle zone.

A case of swine follicular lymphoma with intracytoplasmic immunoglobulin inclusions

A case of swine follicular lymphoma with Russell body-type inclusions is described in a 4-year-old pig. Distinct neoplastic follicles were observed in various lymph nodes and contained many cells with Russell body-type inclusions that were positive for IgM and corresponded to dilated cisternae of the RER. Desmosome-connected dendritic reticulum cells and neoplastic cells with desmosome-like structures demonstrated the germinal centre origin of this tumour. Although such cases have been reported in man, this is the first recorded case of swine follicular lymphoma showing this feature. The histological similarity of swine follicular lymphoma with Russell body-type inclusions to that of man is discussed, as is the relationship between reactive follicular hyperplasia and follicular lymphoma.

B- and T-cell subsets in follicular centroblastic/centrocytic (cleaved follicular center cell) lymphoma: an immunohistologic analysis of 26 lymph nodes and three spleens

Follicular centroblastic/centrocytic (CB/cc/F), or cleaved follicular center cell, lymphomas are known to contain admixtures of B cells and, often, numerous T cells. To analyze the presence and distribution of B and T cells and their subsets in CB/cc/F lymphomas, 26 lymph nodes and three spleens (from 24 patients) were studied with a panel of monoclonal antibodies and peanut lectin by the avidin-biotin immunoperoxidase technique on frozen sections. Immunoglobulin studies revealed monoclonal neoplastic follicles in most cases, although cells of the nondominant light chain were occasionally present. Rarely, the follicles showed both kappa and lambda light chains or were immunoglobulin-negative. Although monoclonal mantles were observed in only one case, more than half of the nodes demonstrated monoclonal interfollicular infiltrates. In most cases the phenotype of the follicular cells was similar to that of the predominant cells in the normal follicles. Interfollicular lymphomatous cells had variable phenotypes that, unlike the normal situation, sometimes resembled those in the follicles. Phenotypic variation was present within single neoplastic clones and sometimes suggested more mantle-like differentiation. Phenotypic changes were also observed in repeat biopsies. T cells, usually predominantly of the T-helper phenotype, were present in variable numbers in all cases. Although present in the neoplastic follicles, they were usually more common in the interfollicular areas. Six nodes and two spleens had definite rims composed predominantly of T cells around neoplastic follicles. Apparently "activated" (Tac-positive) T cells were often present and showed accentuation around the follicles in some cases. Thus, CB/cc/F lymphoma is a malignant lymphoma that closely resembles follicular hyperplasia but that also has distinctive features.

Distribution of HNK-1+ cells in malignant lymphomas

HNK-1, a murine monoclonal antibody, is known to react with most of the natural killer (NK) and killer (K) cells in peripheral blood. Cells reacting with this antibody (HNK-1+ cells) were studied on tissue sections of ninety two cases of malignant lymphomas (MLs) by using immunoperoxidase technique, in an attempt to elucidate the role of this type of cells in MLs. Follicular lymphomas were found to be highly infiltrated with HNK-1+ cells. The mode of infiltration in follicular lymphomas is just like in normal germinal centers. Many cases of diffuse lymphomas with cleaved nuclei, indicative of diffuse B-cell lymphomas of follicular center cell origin, as well as diffuse ML with heavy fibrosis (sclerosis) or histiocytic reaction, were also found to be infiltrated with abundant HNK-1+ cells. Meanwhile, other types of B-cell ML and all types of T-cell ML, as well as Hodgkin's disease, were shown to be very poor in HNK-1+ cell reaction. From a prognostic viewpoint, the low grade malignancy group in the NCI Working Formulation or Kiel Classification was found to be infiltrated with significantly much more HNK-1+ cells as compared to the high grade malignancy group. The significance of these findings are discussed, with the stress on the possible suppressive function of HNK-1+ cells on proliferation and differentiation of follicular center cell type B-cell MLs.

Neoplastic B cells with cerebriform nuclei in follicular lymphomas

Three cases of follicular lymphoma in which the follicular center cells exhibited pronounced nuclear irregularities, i.e., convoluted and cerebriform shapes, are described. The cytoplasm in B5-fixed sections was scanty to abundant and showed pale to clear staining, with interlocking cell borders. Although the architectural pattern in these cases suggested B-cell lymphoma, the cytologic features suggested a T-cell phenotype. Immunologic studies of frozen sections by immunohistochemical techniques in all three cases, as well as cell suspension studies in two cases, showed that the follicular center cells, including those with convoluted and cerebriform nuclei, were clearly monoclonal B cells, as evidenced by the presence of only one immunoglobulin light chain on the surfaces. The results of this study suggest that the follicular architectural pattern is a more reliable predictor of the immunologic phenotype than are the cytologic features.

Unusual nonimmunoglobulin-containing inclusions in a case of follicular large cell lymphoma

Intracytoplasmic inclusion bodies were found in a case of follicular large cell lymphoma. They did not react with anti-immunoglobulin antisera and showed no enzyme reactivity. On electron microscopy the inclusions consisted of loosely packed fibrillar material not surrounded by a membrane or by rough endoplasmic reticulum. They were found only in the large lymphomatous cells. Immunocytochemistry showed a reactivity of these cells with anti-HLA-Dr and the OKT10 monoclonal antibodies. The nature of the inclusions remains unknown. They differ significantly from those described in the literature in cases of B-cell lymphoproliferative disorders.

Intracellular J chains in lymphoproliferative diseases

The presence of J or joining chains has been studied in formol-paraffin tissue sections from various lymphoproliferative diseases. The percentages of J chain positivity in 56 cases of multiple myeloma, in 41 of immunocytic malignant lymphoma and 35 of immunoblastic malignant lymphoma were 58.9, 70.7 and 37.1%, respectively. The ratio of kappa to lambda chain types of the monotypic Ig-s was the lowest in multiple myeloma, intermediate in immunocytic and highest in immunoblastic malignant lymphoma (ml). In 8 cases (one local immature plasmocytoma, one non-secretory multiple myeloma, one immunocytic, 4 immunoblastic and one centroblastic malignant lymphoma), only J chains were present in the tumour cells--"J chain disease". A significant difference in survival of J chain positive (26.8 months) and negative (17.7 months) multiple myeloma cases was observed. Myeloma kidney lesions were slightly more frequent in J chain negative cases. In lymphoproliferative disease J chain seems to be associated with early events of Ig synthesis. On the other hand, in two cases with biclonal Ig-s, the IgM positive immunoblastic ml cells and inclusions and the IgA positive multiple myeloma cells and inclusions were J chain positive. The IgG positive cells in both tumours and the IgG positive inclusions in the immunoblastic tumour were negative for J chains.

Reactivity of Leu 1 and T101 monoclonal antibodies with B cell lymphomas (correlations with other immunological markers)

The reactivity of Leu 1/T101 monoclonal antibodies (MoAb) was studied in a series of 69 lymphomas with B cell differentiation and was correlated with other cell markers. A three step immunoperoxidase technique on frozen sections was used to test a panel of 20 MoAb: anti-human Ig (heavy and light chains), To 15 (Pan B cells), Leu 1, T101, Leu 4, Leu 3a, Leu 5, OKT 8, OKT 6, Leu 7, anti-CALLA (IOT 5), Leu 10, anti-HLA-DR, OKM 1 and anti-dendritic reticulum cells (R 4/23). T101/Leu 1 antigen was detected in 24 cases: CLL (11 of 11), diffuse centrocytic lymphomas (four of 11), follicular lymphomas (none of 12), follicular and diffuse lymphomas (seven of 10) and one unclassified low grade lymphoma. This antigen was observed in only one high grade malignant lymphoma. In follicular lymphomas, two results deserve attention: (1) T101+ lymphomas showed most frequently IgM+, IgD+ surface Ig. Inversely, T101 unreactive lymphomas displayed IgM+, IgD+ phenotype. (2) Tp67 antigen (T101, Leu 1) and CALLA (GP 100) were found to be mutually exclusive in these lymphomas. These results suggest that follicular lymphomas could be derived from two distinct germinal center cell populations: IgM+ Ig'D-, Calla+, Leu 1-/T101- and IgM+, IgD+, CALLA-, Leu+/T101+.

Large cell lymphomas. I. Differential diagnosis of centroblastic and B-immunoblastic subtypes by morphometry on histologic preparations

Thirty-three large cell lymphomas, 18 centroblastic or large noncleaved follicle center cell lymphomas and 15 B-immunoblastic lymphomas, diagnosed by morphology and marker studies, were studied with morphometry. The following parameters were studied: nuclear and nucleolar area, nuclear shape, cytoplasm-to-nucleus ratio, number of nucleoli per nuclear cross section, location of the nucleolus within the nucleus as expressed by the relative nucleolar eccentricity (rNE), and the percentage of morphometrically defined immunoblasts. Mean values and standard deviations (SDs) were calculated and statistically analyzed. The two groups differed significantly in their nucleolar area (mean and SD), cytoplasm-to-nucleus ratio (mean), number of nucleoli per nuclear cross section (mean and SD), rNE (mean), and percentage of immunoblasts. Using nonlinear discriminant analysis, the possibility of classifying individual cases with the studied parameters was investigated. Twenty-nine cases were reliably classified (88%); three were classified correctly, but with less than a 95% certainty, and 1 case was misclassified. The results indicate a spectrum ranging from centroblastic to B-immunoblastic lymphoma. Transition forms occur and can be accurately defined with morphometry.

Identification of two major B cell forms of nodular mixed lymphoma

To resolve the controversy over the immunologic nature of nodular mixed lymphoma (NM), we examined nine cases of NM for surface antigens using both tissue section and cell suspension methods. These were contrasted with 12 cases of nodular poorly differentiated lymphocytic lymphoma. We found two major B cell types of NM, those with monoclonal immunoglobulin (SIg+)-positive nodules with an SIg+B1+B2+Ia+T- phenotype (four cases) and those with nodules devoid of immunoglobulin with an SIg-B1+B2-Ia+T- phenotype (five cases). Our SIg+ NM cases appear similar to nodular poorly differentiated lymphocytic lymphoma (SIg+B1+B2+Ia+T-), except suspension assay indicates fewer SIg+ cells in NM. In our SIg- NM cases, the neoplastic nodules consistently expressed B1 and Ia-like antigens and lacked T cells, indicating a B cell neoplasm similar to many large cell lymphomas. By demonstrating a B cell antigen in SIg- nodules, we substantially resolve the controversial NM cases previously called "null" or T cell. The two distinct immunotypes indicate the complexity of B cell antigenic expression in NM and might also explain the variable response to therapy in NM described in previous studies. Finally, we describe NM cases with the simultaneous occurrence of several stages of B cell differentiation. This suggests that some NM cases are not frozen in a single stage of B cell development but may express a range of B cell antigens. NM, then, may be a paradigm of variable, simultaneous B cell maturation.

Immunohistologic characterization of two malignant lymphomas of germinal center type (centroblastic/centrocytic and centrocytic) with monoclonal antibodies. Follicular and diffuse lymphomas of small-cleaved-cell type are related but distinct entities

The relationship between follicular lymphomas and diffuse lymphomas of small-cleaved-cell type was investigated with the use of a panel of antibodies against B-cell differentiation antigens. Follicular lymphomas, regardless of histologic subtype, were immunologically homogeneous: Ig+ B1+ B2+ CALLA+ Ia+. Two cases were Ig-negative, and 4 were CALLA-negative. Diffuse small-cleaved-cell (centrocytic) lymphomas were more heterogeneous. The majority were Ig+ B1+ B2+ Ia+ T1+ CALLA-. A minority were B2-negative, T1-negative, or CALLA-positive. An increased frequency of Ig heavy chain class switching and loss of T1 antigen suggest that follicular lymphomas are at a later stage of differentiation than most centrocytic lymphomas. The differences in immunologic phenotype provide further justification for a classification that distinguishes between follicular and diffuse lymphomas of small-cleaved-cell types. The expression of Ig, Ia, B1, and B2 on neoplastic follicular center cells correlates with expression of these antigens on normal B cells. In addition, anti-B2 appears to stain a nonlymphoid dendritic cell present in normal germinal centers and in both follicular and diffuse germinal center cell lymphomas in this study. In follicular lymphomas, the dendritic pattern was similar to that of normal follicles, while in centrocytic lymphomas a more irregular dendritic pattern was seen. Dendritic staining was seen in both nodal and extranodal lymphomas, suggesting that these nonlymphoid cells either migrate with neoplastic B cells or are present in a variety of normal tissues.

Clinical relevance of immunologic phenotype in diffuse large cell lymphoma

The immunologic phenotypes of 78 diffuse large cell lymphomas were determined by an immunoperoxidase technique using a panel of monoclonal antibodies. The phenotypes were correlated with clinical and morphological parameters by univariate and multivariate analysis. Forty-one lymphomas (53%) expressed immunoglobulin (Ig+). Of the 37 cases that did not express immunoglobulin (Ig-), 9 expressed T cell antigens. Although the T cell phenotypes were antigenically heterogeneous, all cases represented mature T cell phenotypes. The majority of the remaining 28 cases expressed the B cell-associated antigen, B1. At 5 yr, actuarial survival for the Ig- patients was 63%, compared with 15% for the Ig+ patients. A significantly greater proportion of patients with Ig+ lymphomas were over the age of 65 at diagnosis. All of the 9 patients with marrow involvement were Ig+. Multiple factors were analyzed by the Cox regression procedure for their impact on survival, including antigenic profile, histologic grade, morphological classification, and numerous clinical parameters previously recognized to be of prognostic significance. In this analysis, stage, age greater than 65 yr, systemic symptoms, and marrow involvement had the greatest influence on survival. The survival difference between Ig- and Ig+ patients is explained by a higher proportion of Ig+ patients with these unfavorable prognostic factors. With our current immunologic methods, retrospective cell phenotyping analysis has not provided independent prognostic significance in diffuse large cell lymphoma. A prospective evaluation of similarly treated patients is needed to characterize the influence of phenotype fully and to determine its potential usefulness for therapy.

Multiinstitution study of non-Hodgkin's lymphomas using frozen section immunoperoxidase: the Southeastern Cancer Study Group experience

This report describes the experience of the Southeastern Cancer Study Group (SECSG) with a transport medium used for immunologic phenotyping of non-Hodgkin's lymphomas. In a 2-mo pilot study, portions of 53 specimens of non-Hodgkin's lymphoma from four member institutions of the SECSG and affiliated community hospitals were sent by regular mail to a central laboratory. Immunologic phenotyping was carried out using a frozen section immunoperoxidase technique. In 48 of the cases, a clear-cut immunologic phenotype was obtained. Thirty-four tumors were of B cell origin and 7 had T cell markers. Six of the remaining lymphomas had neither B nor T cell markers, and the seventh had both. In 12 cases, phenotyping was also carried out at the originating institution using conventional cell suspension techniques; agreement between the two methods was excellent. The immunologic results were correlated with histopathologic diagnosis standardized using the Working Formulation for non-Hodgkin's lymphomas. It was found that the low grade tumors were all B cell, but that the intermediate grade tumors were very heterogeneous immunologically. About one-fourth of the diffuse, intermediate grade or miscellaneous tumors had T cell markers. Our results indicate that immunologic phenotyping may be performed satisfactorily on transported material, making multiinstitution studies on the prognostic significance of immunologic phenotype in non-Hodgkin's lymphomas feasible.

Low-grade lymphomas. Expression of developmentally regulated B-cell antigens

A series of low-grade B-cell lymphomas was analyzed for a battery of immunologic determinants by flow cytometry and immunohistochemistry. Histologically distinctive subclasses of these lymphomas, well-differentiated lymphocytic (WDL), intermediately differentiated lymphocytic (IDL), and follicular center cell (FCC) lymphoma, were found to be readily distinguishable by their expression of immunologic determinants that are known to be developmentally regulated in normal B cells. Although all cases expressed monoclonal surface immunoglobulin (sIg), HLA-DR, and the surface membrane proteins recognized by antibodies B1 (p32) and BA1, staining with other monoclonal antibodies revealed unique immunologic phenotypes for each subclass: WDL p65 (Leu 1)+, p24 (BA2)-; IDL p65+, p24+; FCC p65-, p24-. Additionally, the fluorescence intensities (number of determinants per cell) obtained for sIg, BA-1, and B1, but not HLA-DR, were significantly different among the three lymphoma subclasses. The relative fluorescence intensities of each of these three markers followed the same pattern: FCC greater than IDL greater than WDL. Taken together, these distinguishing features suggest that low-grade B-cell lymphomas represent arrested, and possibly sequential, stages of B-cell differentiation.

Small noncleaved follicular center cell (FCC) lymphoma: Burkitt and non-Burkitt variants in the United States. I. Clinical features

With the understanding that Burkitt's lymphoma was of follicular center cell (FCC) derivation, Lukes and Collins classified the tumor, descriptively, as small noncleaved FCC lymphoma. Two subtypes were described: Burkitt and non-Burkitt. Attempting to define the clinicopathologic features of the subtypes, we studied 42 patients: 25 Burkitt and 17 non-Burkitt. Histologically, the Burkitt tumor demonstrated remarkable uniformity of nuclear size and contour, whereas the non-Burkitt variant had greater variability. Immunoglobulin monoclonality was demonstrated in 83% of Burkitt and 81% of non-Burkitt cases. Burkitt patients tended to be younger. Gastrointestinal disease was seen in 15 Burkitt and only four non-Burkitt patients (P less than 0.05). Disseminated disease was found in the majority of both variants. Marrow involvement was demonstrated in 4.5% of Burkitt and 37.5% of non-Burkitt patients (P less than 0.05). Median survival of Burkitt patients was 10.5 months versus 7.7 months in the non-Burkitt group. The authors believe that significant biologic differences between the variants have been demonstrated, which may be of potential value to the clinician.

Middle Eastern intestinal lymphoma: a morphological and immunohistochemical study

A total of 31 cases of Middle Eastern gastrointestinal lymphoma (from Mosul, Iraq) has been analysed by conventional histology, and also by immunoperoxidase staining of trypsinised paraffin sections with anti-Ig and anti-J chain antisera. Histologically these neoplasms fell into three categories: undifferentiated lymphoma of Burkitt type (8 cases); follicle centre cell (FCC) lymphoma, resembling European lymphomas of FCC origin (15 cases); and Mediterranean lymphoma (MTL) (3 cases). Immunohistological staining of the FCC neoplasms showed that these tumours resembled their European counterpart in that cytoplasmic Ig and J chain could be demonstrated in a proportion of cases. However there was a striking difference in that alpha chain alone, light chain alone, or J chain alone were detected in several cases (in contrast to the predominance of mu plus kappa or lambda light chains found in European cases). Furthermore, prominent intracellular inclusions of alpha chains were found in two cases. Staining of the MTL cases revealed that the characteristic mucosal plasma cell infiltrate was positive for alpha chain (weakly) and J chain (strongly) but that the invasive cells which morphologically resembled FCCs were negative for both constituents. It is argued that these three histological categories constitute the major types of gastrointestinal lymphoma in the Middle East; and that in MTL the invasive lymphoma is of FCC type.