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A Carbone

Publications and source records attributed to A Carbone.

At least 19 recordsLinked to original sources
PubMed1992

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

BACKGROUND: Morphologic and immunohistologic studies were performed on a series of 213 lymphoma cases, including CD30-positive anaplastic large cell (ALC) lymphomas (45 cases), other CD30-positive (18 cases) or CD30-negative (72 cases) non-Hodgkin lymphomas (NHL), cases of Hodgkin disease (HD) (73 cases), and an additional 5 cases exhibiting features of both CD30-positive ALC and Hodgkin lymphomas. METHODS: The aim was to assess differential expression by tumor cells of CD30/BerH2, epithelial membrane antigen (EMA), and other monoclonal antibodies, including BNH9, an epithelial and endothelial marker that has been found to be reactive with ALC lymphoma cells. RESULTS: A significantly greater proportion of cases of ALC lymphoma compared with HD exhibited positive results for CD45, EMA, CD45RO, and CD3 in CD30-positive atypical large cells, whereas Reed-Sternberg cells in HD most frequently coexpressed CD15 and CD30 antigens. ALC lymphoma cells reacted with BNH9 MoAb in 10 of the 42 (23.8%) assessable cases, whereas Reed-Sternberg cells reacted with this antibody in 5 of 73 (6.8%) HD cases. Only 3 of 90 (3.3%) NHL cases had positive results for BNH9; they were CD30-negative high-grade or low-grade lymphomas. It was noteworthy that 9 of 10 BNH9-positive ALC lymphomas also were EMA positive. Four of the five cases with morphologic features intermediate between those of HD and ALC lymphoma showed immunohistologic findings (positive results for CD30 and CD15, negative results for EMA, CD45, and BNH9) similar to those frequently observed in the HD cases; conversely, the remaining case showed a profile (positive results for CD30, CD45, and EMA, negative results for CD15) typically observed in ALC lymphomas. CONCLUSIONS: This study suggests that the differential expression of CD45, EMA, and CD15 could be used in the distinction of ALC lymphomas and HD, whereas it seems that BNH9 antibody reactivity may be of diagnostic use only in that it reinforces the diagnostic value of EMA expression in the differentiation of these entities.

Antibodies, Monoclonal↗
PubMed1992

Pathogenesis of human reactive-appearing "non-monomorphous" malignant lymphoproliferative disorders: a hypothesis.

Human reactive-appearing "non-monomorphous" malignant disorders, such as Hodgkin's disease, T-cell-rich B-cell lymphomas and angioimmunoblastic lymphadenopathy display a peculiar and unifying characteristic, which biologically differentiates them from "monomorphous" non-Hodgkin's lymphomas. It consists in the coexistence within the pathologic tissue of a polyclonal, normal-appearing, presumed reactive cellular component, mainly composed of T-lymphocytes together with a clonal cell component constituting a minority of the pathologic mass. To explain the long-lasting coexistence of such polymorphic cell populations in the pathologic tissue of synchronous and metachronous localizations of the disease, it is hypothesized that they are interconnected by "biological interactions" which determine and sustain the pathologic process. Based on the biological characteristics of an experimental model (the follicular center cell "lymphoma" of the SJL murine strain), it is suggested that these human "non-monomorphous" malignant diseases should be regarded as a continuous spectrum of lymphoproliferative disorders sustained by a biological loop which interconnects different cell populations able to stimulate each other for growth.

Animals↗
PubMed1992

Occupation and soft-tissue sarcoma in northeastern Italy.

The influence of occupation and exposure to different agents on the risk of developing soft-tissue sarcoma (STS) was assessed in a case-control study based on 93 cases of STS (53 men and 40 women) and 721 controls (371 men and 350 women), conducted in northeastern Italy. No risk elevation was found in subjects employed in agriculture (odds ratio [OR] for greater than 10 years = 0.8, 95 percent confidence interval [CI] = 0.4-1.5), nor in those who reported exposure to pesticides or herbicides (OR = 0.4, CI = 0.1-1.2). Similarly, neither occupation in the furniture, upholstery, and mechanics industries, nor exposure to livestock or meat processing, wood dust, metal dust, and dyes or paints were associated with STS risk. Workers who reported exposure to chemical agents or to benzene or other solvents for more than 10 years had, respectively, a 1.8-fold (CI = 0.7-4.4) and a 2.2-fold (CI = 0.9-5.5) higher risk of developing STS. Although the small number of STS cases limits the interpretation of the study results, these findings weigh against the hypothesis that pesticides, herbicides, or other exposures related to agriculture, play an important role in the etiology of STS. The direct associations with exposure to chemical agents and benzene or other solvents, albiet not statistically significant, may provide a useful hint for future investigations.

Adolescent↗
PubMed1992

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

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

Adult↗
PubMed1992

B-zone small lymphocytic lymphoma: a morphologic, immunophenotypic, and clinical study with comparison to "well-differentiated" lymphocytic disorders.

The pathologic, immunologic, and clinical features of five cases of B-zone small lymphocytic lymphoma (BZSLL), characterized by a nondestructive growth pattern with a selective and complete replacement of the B-zone areas of lymph nodes, were examined. These findings were compared with those of 13 cases of intermediate differentiated lymphoma/mantle zone lymphoma (ILL/MZL) and 20 cases of typical small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL). B-zone SLL was characterized histologically by a deceptively benign pattern at a low magnification, the lymph node architecture being substantially preserved, in contrast to the ILL/MZL and SLL/CLL cases, in which complete effacement of the normal architecture usually could be observed. Moreover, in BZSLL the cellular population was rather uniform and lacked either a prolymphocytic component or the small-cleaved lymphoid cells often seen in SLL/CLL and ILL/MZL cases, respectively. The phenotypic profile of the BZSLL clonal cell population studied by the immunoperoxidase method and by single- and double-labeling flow cytometric analyses (SIg+, CD19+, CD20+, CD21+, CD22+, CD24+, CD35+, CD37+, CD74+, CD45+, CD45R+, MB2+, HLA-DR+, Leu-8+, CD9+/-, CDw75+/-, CD5-/+, CD23-/+, CD10-, FMC7-, PCA-1-, CD25-, CD38-, CD43-, CD3-) appeared to be fairly homogeneous and sufficiently distinct from that of ILL/MZL, based on the absence of FMC7 and CD38 molecules, and from that of SLL/CLL due to significantly stronger expression of SIgs (P less than .05), the higher reactivity with anti-CD9 and -CD22 antibodies (P less than .05), the lower reactivity with anti-CD5 and -CD23 antibodies (P less than .05), and the absence of CD25 determinants. Several clinical features of patients with BZSLL, including age group, advanced stage disease, and high frequency of bone marrow and peripheral blood involvement, were similar to those found in the other patients with ILL/MZL and SLL/CLL, but none of the BZSLL patients had an absolute lymphocyte count higher than 15.0 x 10(9)/L at presentation. Based on the architectural pattern, cytologic features, immunophenotypes, and hematologic findings, we conclude that BZSLL is an unusual variant of SLL that is primary in the lymph nodes and should be distinguished from ILL/MZL and CLL.

Adult↗
PubMed1992

Superficial extending carcinoma (SEC) of the larynx and hypopharynx.

In this study the histopathological features of an underestimated architectural variety of infiltrating squamous cell carcinoma of the larynx and hypopharynx, operationally termed as "superficial extending carcinoma", are described. Pathologically, the superficial extending carcinoma is a poorly/moderately differentiated infiltrating squamous cell carcinoma showing an entirely or predominant superficial type of growth; deep infiltration was confined to the mucosa or limited to a few underlying glandular and/or muscular laryngopharyngeal structures, regardless of the presence of lymph node metastasis or lymph vessel invasion. As defined above, the superficial extending carcinoma may be regarded, from a pathologic point of view, as a laryngopharyngeal counterpart to "superficial esophageal carcinoma". Studying a series of 88 whole organs serially sectioned laryngopharyngectomy specimens, we found that 6 out of 61 primary laryngeal carcinomas (9.8%) and 6 out of 26 primary hypopharyngeal carcinomas (23%) showed the peculiar architectural features of the superficial extending carcinoma. In 6 cases (2 laryngeal and 4 hypopharyngeal) the tumor was entirely intramucosal or early infiltrated the underlying muscle or gland structures. In the remaining 6 cases (4 laryngeal and 2 hypopharyngeal tumor) a superficial extending carcinoma was found to be associated with a deeply infiltrating squamous cell carcinoma of the "classic" type. Features useful to histopathologic diagnosis of superficial extending carcinoma and to its differentiation from preneoplastic and other neoplastic lesions of the laryngopharyngeal mucosa are emphasized. The possible association of superficial extending carcinoma with multiple synchronous and metachronous neoplastic lesions in the upper aerodigestive tract and the frequent underestimation of its real extension may have important clinical implications.

Adult↗
PubMed1992

"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.

Female↗
PubMed1992

Follicular lymphoma of compartmentalized small cleaved center cells and mantle zone lymphocytes. Evidence for a common derivation.

The authors have observed a unique case of follicular lymphoma in which the central zones of neoplastic nodules were composed predominantly of small cleaved cells (SCC) that were surrounded by small lymphoid cells proliferating in wide mantles as in mantle zone (MZ) lymphoma. The central SCC component displayed a follicular SCC lymphoma-like phenotype (IgD-, CD10+, CD5-, CD68-), whereas the neoplastic cells of the peripheral zones had an MZ lymphoma-like phenotypic profile (IgD+, CD10-, CD5+, CD68+). In extranodal involved tissues, either follicular or diffuse (leukemic-like) patterns of lymphoma infiltration were noted. Flow cytometric analyses showed in the bone marrow or the peripheral blood two leukemic B cell populations, one mimicking the phenotypic profile (IgM+, IgD+, CD5+, CD10-, Leu8-) of small lymphoid cells with MZ-like features, and the other with phenotypic features (IgM+, IgD-, CD5+, CD10+, Leu8+) intermediate between those of MZ-like cells and those of the SCC component (follicular center-like) detected in the lymph node. Immunomagnetic sorting and gene rearrangement studies indicated that both CD10+ and CD10- B lymphocytes and lymph node neoplastic B cells shared the same clonal origin. This unusual follicular lymphoma can be viewed as the result of the proliferation of a single follicular progenitor capable of differentiating toward both a germinal center and an MZ phenotype. The simultaneous presence in the same patient of at least three neoplastic B-cell populations at different maturation stages, encompassing follicular center and MZ phenotypes, and showing the same clonal derivation, indicates a close lineage relationship between follicular SCC and MZ lymphomas.

Aged↗
PubMed1992

The value of immunohistochemistry in the diagnosis of soft tissue sarcomas.

Histological classification of soft tissue sarcomas can be made by light microscopy alone for those tumors with unique appearances, while a significant proportion of sarcomas require the implementation of electron microscopy or immunohistochemistry to obtain a final diagnostic classification. Immunostaining methods are particularly valuable in certain classes of sarcomas such as epithelioid sarcomas, malignant schwannomas, hemangiosarcomas, clear cell sarcomas, rhabdomyosarcomas, pleomorphic liposarcomas, leiomyosarcomas and synovial sarcomas through documentation of their cellular products. Immunohistochemistry is not a substitute for skilled interpretation of conventionally stained microscopic specimens; however, the availability of more specific determinants in the soft tissue neoplasms will expand the value of this approach in this area of diagnostic pathology.

Humans↗
PubMed1992

Radiation therapy and conservative surgery for soft tissue sarcomas of the extremities, torso and head and neck.

Between May 1985 and July 1990, 45 patients (pts.) with primary (39) or recurrent (6) soft tissue sarcomas of the extremities (82%), torso (11%) and head and neck (7%) were treated with radiation therapy and conservative surgery. Seven pts. not amenable to conservative surgery underwent preoperative radiation therapy whereas 38 pts. underwent local excision and post-operative radiation therapy. Out of the 38 pts. managed by postoperative radiation, 24 (63%) showed negative surgical margins and 14 (37%) positive margins, their tumor being adjacent to vital structures. Preoperative radiation allowed conservative surgery in all 7 pts. with initially inoperable tumor; surgical margins were negative in 5 and positive in 2 pts. Twenty-six pts. (58%) had tumor greater than or equal to 5 cm (5-24) and 19 (42%) less than 5 cm (2.5-4.5) in diameter. High grade tumors (G2-G3) were reported in 41 pts. (90%). In pts. treated postoperatively the radiation dose was 64-66 Gy/32-33 fractions and the pts. treated preoperatively received a dose of 50 Gy/25 fractions. Median follow-up was 33 months and all pts. had a minimum follow-up of 12 months (12-72). Three pts. (6.5%) had local failure and 9 (20%) developed distant metastases with local tumor control. All distant metastases occurred in AJC stage IIIB, 9/18 (50%), with an increased frequency by tumor size. Overall local control and disease free survival rates at 5 years (product-limit method) were 93% and 73%, respectively. An evident decrease in disease-free survival rate (33%) was noted for stage IIIB pts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Hodgkin's disease in 92 patients with HIV infection: the Italian experience. GICAT (Italian Cooperative Group on AIDS & Tumors).

Ninety-two cases of Hodgkin's disease (HD) in patients with HIV infection have been collected by the Italian Cooperative Group on AIDS and Tumors (G.I.C.A.T.). In accordance with the epidemiology of HIV infection in Italy, 82% were intravenous drug users (IVDU), 8% homosexual men, 5% IVDU+homosexuals and 5% heterosexuals. At diagnosis of HD, 16% had AIDS, 20% AIDS related complex (ARC), 33% persistent generalized lymphadenopathy (PGL) and 31% were asymptomatic. Fifty-three percent of the patients had stage IV disease and 70% mixed cellularity and lymphocytic depletion. Forty-six patients were treated with MOPP or MOPP [symbol: see text] ABVD +/- radiotherapy (zidovudine was not given) with complete remission (CR) in 54% and partial remission (PR) in 46% of the patients. Fifty-six percent of these patients developed opportunistic infections (OI) during therapy or follow-up. Sixteen patients were treated with epirubicin, bleomycin and vinblastine (EBV) and concomitant zidovudine, with CR in 44% and PR in 38%. However, only one of these patients developed OI during therapy or follow-up. The clinico-pathological features and natural history of HD in HIV setting are peculiar and quite distinct from those observed in HD in the general population. Better combined chemotherapy and antiretroviral therapy is needed in order to ameliorate the CR rate and decrease the OI in patients with HIV infection and HD.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Prospective study with combined low-dose chemotherapy and zidovudine in 37 patients with poor-prognosis AIDS-related non-Hodgkin's lymphoma. French-Italian Cooperative Study Group.

The French-Italian Cooperative Study Group included patients with poor-prognosis AIDS-related non-Hodgkin's lymphoma (NHL), defined as those with performance status (PS) > or = 3 and/or opportunistic infections (OI), in a prospective study with a 50% reduced-dose combination chemotherapy regimen: CHVmP-Vincristine-bleo (cyclophosphamide 300 mg/m2 i.v. day 1, doxorubicin 25 mg/m2 i.v. day 1, teniposide 30 mg/m2 i.v. day 1, prednisone 20 mg/m2 per os days 1-5, vincristine 2 mg i.v. day 15, and bleomycin 10 mg i.v. day 15), given every 21 days for eight cycles, and concomitant zidovudine 500 mg per os per day. The aims of this combined treatment were to reduce bone marrow toxicity and infectious complications related to chemotherapy (with a low-dose chemotherapy regimen), and to control the HIV and related infectious complications (with zidovudine therapy). Thirty-seven patients entered this prospective study. At the time of the NHL diagnosis, 41% of the patients had asymptomatic HIV infection, 27% had ARC and 32% had already had CDC-defined diagnoses of AIDS. The median CD4+ cell count was 35 mm3. Only 29 patients are evaluable for response, since 8 received only one cycle of chemotherapy. Fifteen of 29 (52%) patients obtained objective responses, with only 4 (14%) achieving complete remissions (CR) of 1, 4, 14 and 29+ months. Three (16%) CRs were achieved in 19 evaluable patients included in the study because of poor PS, and only one CR was observed in 10 evaluable patients with histories of OI, either alone or with poor PS. The most common side effect was bone marrow toxicity with 2 related toxic deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Association of Epstein-Barr virus genome with mixed cellularity and cellular phase nodular sclerosis Hodgkin's disease subtypes.

Association of Epstein-Barr virus (EBV) genome with Hodgkin's disease (HD) histological subtypes was investigated using the polymerase chain reaction (PCR). A highly significant association of EBV genome with the mixed cellularity (MC) subtype (10 positive out of 15 cases; 66%) was observed, suggesting a possible etiopathogenetic role of EBV in the induction of this subset. By contrast, a markedly lower frequency of association with EBV genome was found in nodular sclerosis (NS) (12 positive out of 46 cases; 26%) and in nodular lymphocytic predominance (NLP) (0 positive out of 5 cases) HD subtypes. In addition, in the NS series, the presence of EBV genome was mainly restricted to the 'cellular phase' NS subset. This finding strengthens the possibility, suggested by clinico-pathological features and survival rates, that 'cellular phase NS' is a disease more akin to MC than to typical NS HD.

Genome, Viral↗
PubMed1992

Unique genotypic features of infant acute lymphoblastic leukaemia at presentation and at relapse.

Acute lymphoblastic leukaemia (ALL) of infants aged less than 1 year represents a group of patients with peculiar biological features, poor response to therapy and unfavourable prognosis. In order better to characterize this type of leukaemia, we have investigated the immunoglobulin (Ig) and T-cell receptor (TCR) genes configuration of 21 infants with ALL, and compared the genotypic features with the phenotypic and karyotypic data, as well as with the clinical outcome. All cases had a pre-B phenotype; 12 (57%) of them were pre-pre-B ALL (CD10-, CD19+). Six of the 16 cases evaluated (38%) displayed chromosomal abnormalities; five had the typical translocation t(4;11)(q21;23). Eleven cases presented with a white blood cell count greater than 100 x 10(9)/l. The clinical course was unfavourable in 14 patients. The genotype of this group of ALL revealed several peculiarities. (1) Of the 21 cases, six (29%) displayed a multiple rearrangement pattern at the IgH locus. (2) In three cases (15%), the light chain genes were rearranged. (3) The TCR beta and gamma genes were rearranged in only one case (one case at the TCR beta and one at the TCR gamma locus). (4) The TCR delta chain was rearranged in eight cases (40%) and rarely deleted; the rearrangements observed were those most frequently observed in B cell-precursor ALL. Two cases were evaluated both at presentation and at relapse. While the immunophenotype had remained unmodified, comparison of Ig heavy chain gene rearrangements revealed clonal variations in both cases. Taken together, these findings further underline the biological peculiarities of infant ALL compared to ALL which occurs in older children and in adults, and stress the need of differentiated and aggressive therapeutic approach for these patients.

Antigens, Neoplasm↗
PubMed1992

Phenotypic and genotypic switch in Philadelphia-positive, BCR-positive blast crisis of chronic myeloid leukemia.

We report a case of Ph1-positive, bcr-positive chronic myeloid leukemia blast crisis (CML-BC) which at presentation showed a mixed myeloid/B-lymphoid immunophenotype along with TdT positivity and, at the molecular level, an oligoclonal rearrangement of the immunoglobulin heavy chain (IgH) gene region. After obtaining a successful remission, at the time of relapse the patient underwent a phenotypic and genotypic switch from mixed to myeloid phenotype, characterized by the loss of the lymphoid markers and TdT expression and by a germline configuration of the IgH gene region. The same bcr rearrangement was, however, found in both phases of the disease, supporting the suggestion of a true phenotypic and genotypic conversion. This report confirms that the neoplastic event in CML may take place at an early multipotent stem-cell level, prior to a well-defined phenotypic and genotypic lineage expression. Moreover, it is suggested that different factors (chemotherapy? growth factors?) may have either eradicated the bcr+/IgH+ clone and promoted the growth of bcr+/IgH- leukemic cells or, alternatively, supported the lymphoid differentiation program and induced a myeloid lineage shift.

Adult↗
PubMed1992

Constitutive production of tumor necrosis factor-alpha in hairy cell leukemia: possible role in the pathogenesis of the cytopenia(s) and effect of treatment with interferon-alpha.

PURPOSE: In view of the pleomorphic role cytokines play in human lymphoproliferative disorders, we investigated the possible involvement of tumor necrosis factor-alpha (TNF) in hairy cell leukemia (HCL). PATIENTS AND METHODS: The levels of TNF were measured in the serum of untreated patients, and in the culture supernatants of unstimulated and stimulated enriched hairy cells (HC). Furthermore, the presence of TNF mRNA transcripts in HC was analyzed. The possibility that HC could inhibit the in vitro growth of normal erythroid progenitors via the release of TNF was also investigated. Finally, in an attempt to correlate the circulating levels of TNF with the course of the disease, these were retested during and after treatment with interferon-alpha (IFN). RESULTS: Significantly increased levels of TNF were found in the sera of untreated HCL patients compared with normal control sera were seen from patients with other diseases (P less than .001), with values greater than 10 pg/mL in 21 of 42 samples tested. A significant decrease (P less than .01) of TNF levels was recorded following IFN-2a administration in 16 cases with detectable pretreatment serum levels of TNF. In two cases, an increase in TNF values was associated with persistence or progression of disease. The likelihood that the circulating levels of TNF were caused by the pathologic cells is supported by the evidence that purified HC may release TNF spontaneously. The values can be markedly increased following in vitro activation with the phorbol ester 12-0-tetradecanoylphorbol-13 acetate (PMA), with B-cell growth factor (BCGF), and, to a further extent, with the combination of PMA and BCGF. Furthermore, the constitutive mRNA for TNF was found in seven of eight HC samples analyzed. Although supernatants of enriched HC, were capable of reducing the growth of normal bone marrow erythroid progenitors by 50%, duplicate experiments using an anti-TNF antibody produced an almost complete disappearance of the inhibitory effect. CONCLUSION: The results of this study suggest that TNF plays an important role in the pathogenesis of the cytopenia(s) characteristically associated with HCL.

Adult↗
PubMed1992

Characterization of EBV-positive lymphoblastoid cell lines obtained from HIV seropositive patients with or without lymphomas.

Epstein-Barr-virus- (EBV-) positive lymphoblastoid cell lines (LCLs) spontaneously arising in vitro were obtained from the peripheral blood of six HIV-seropositive patients and from the peripheral blood and the bone marrow of one patient (LAM) with AIDS and lymphoma. The LCLs from HIV-seropositive patients had phenotypic, cytogenetic, and biological characteristics indistinguishable from those of normal LCLs obtained by infecting B cells with EBV in vitro. The LCLs from LAM patient comprised composite cell populations. Cloning analysis and cell fractionation procedures showed that, beside normal EBV-infected cells, these lines contained a malignant subset population characterized by c-myc rearrangement, abnormal karyotype, and a surface phenotype similar to that of Burkitt's lymphoma cells. Analyses of Ig heavy chain and c-myc oncogene loci showed that these malignant cells were the progeny of a single precursor. Nevertheless, these cells had heterogeneous EBV-fused termini, a finding which indicates that EBV infection followed c-myc rearrangement.

Blotting, Southern↗