RESUMO
Multiple myeloma patients are deficient in normal polyclonal serum immunoglobulins. To determine the reasons for this decrease, we quantitated and compared the number of surface IgM+ B lymphocytes, and the number of B cells susceptible to transformation by Epstein-Barr virus (EBV) with the concentration of IgM in serum. Serum IgM levels varied considerably in individual patients, temporally shifting from undetectable to normal amounts and then dropping again to undetectable levels. A transient rise to normal serum IgM concentrations was seen in 42% of patients assessed at two or more time points. Of 44 patients, 52% showed a lack of correlation between the number of surface IgM+ (sIgM+) B cells and serum IgM concentration. One subset of patients (25%) had detectable to normal numbers of sIgM+ B cells in blood but undetectable levels of serum IgM. Transformation of B cells from these patients indicated a block in IgM secretion that was extrinsic to the B cells that were fully able to transcribe, translate, and secrete IgM after EBV transformation. A second subset of patients (27%) had undetectable numbers of sIgM+ B cells but near normal levels of serum IgM, suggesting abundant secretion by few clones of B cells. Of 18 patients with monoclonal gammopathy of undetermined significance (MGUS), 26% showed a lack of correlation between the numbers of sIgM+ B cells and serum IgM concentration. We suggest that in patients with multiple myeloma, and in some with MGUS, there exists a mechanism(s) extrinsic to the B cell that mediates an arrest in terminal B lymphocyte maturation.
Assuntos
Linfócitos B/imunologia , Imunoglobulina M/metabolismo , Mieloma Múltiplo/imunologia , Diferenciação Celular , Transformação Celular Viral , Células Cultivadas , Herpesvirus Humano 4 , Humanos , Contagem de Leucócitos , Mieloma Múltiplo/patologia , Receptores de Antígenos de Linfócitos B/metabolismoRESUMO
A major problem in the assessment of circulating B lymphocytes in multiple myeloma is the extent to which cells with passively absorbed Ig contribute to the assay. We have analyzed peripheral blood B cell numbers in 51 patients in various treatment categories by using an assay that is not subject to artifacts involving cytophilic Ig. We have defined a B lymphocyte by three different criteria (a) expression of a high surface density of Ig (b) expression of a high density of HLA.DR and (c) expression of a marker exclusive to surface Ig+ B cells. By these criteria, normal individuals have an average of 6% B cells. In multiple myeloma patients, B cell levels in purified mononuclear cell preparations are severely reduced. Untreated patients and the majority of patients on intermittent chemotherapy have 20-600-fold fewer B cells than do normal donors (average = 0.3%). This decrease was even greater in whole blood of patients as compared with normal donors (100-1,000-fold fewer B cells). The number of B cells did not correlate with disease status or paraprotein concentration. We found no evidence to support the idea that B lymphocytes in patients include a substantial monoclonal subset.
Assuntos
Linfócitos B/imunologia , Linfopenia/sangue , Mieloma Múltiplo/sangue , Antígenos HLA-DR , Antígenos de Histocompatibilidade Classe II/análise , Humanos , Idiótipos de Imunoglobulinas/análise , Capeamento Imunológico , Contagem de Leucócitos , Linfopenia/imunologia , Mieloma Múltiplo/imunologia , Receptores de Antígenos de Linfócitos B/análiseRESUMO
Factor XIII A subunit (FXIIIA) is found in plasma, platelets, and monocytes. The hemopoietic contributions to FXIIIA in these components were studied in patients transplanted with marrows from donors with different FXIIIA phenotypes. In three patients with successful engraftment (by DNA genotyping, red cell phenotyping, and cytogenetic studies) platelet and monocyte FXIIIA changed to donor phenotypes with hematologic recovery. Thus, FXIIIA in platelets and monocytes is synthesized de novo and/or from their progenitor cells. Plasma FXIIIA phenotype change after transplantation was more complex. Patient I changed from phenotype 1-1 (one electrophoretically fast band) to 1-2 (three bands) in 115 d; patients 2 and 3 did not change completely from phenotype 1-2 to 1-1 in up to 458 d, but did show enrichment of the fastest band. Thus, while there is a definite contribution of donor hemopoiesis to plasma FXIIIA, another source of recipient FXIIIA appears to be present to delay or prevent the phenotype change.
Assuntos
Transplante de Medula Óssea , Fator XIII/sangue , Hematopoese , Adulto , Plaquetas/análise , Feminino , Humanos , Leucemia Mieloide Aguda/sangue , Leucemia Mieloide Aguda/cirurgia , Leucemia Promielocítica Aguda/sangue , Leucemia Promielocítica Aguda/cirurgia , Masculino , Pessoa de Meia-Idade , Monócitos/análise , Transtornos Mieloproliferativos/sangue , Transtornos Mieloproliferativos/cirurgia , Fenótipo , Plasma/análise , TransglutaminasesRESUMO
A study was performed to determine whether the addition of folinic acid to a combination of methotrexate (MTX) and cyclosporin A (CsA) after allogeneic bone marrow transplantation (BMT) could improve tolerance to the regimen without inhibiting its ability to prevent graft-versus-host disease (GVHD). Sixty-nine adult BMT patients received CsA plus MTX 15 mg/m2 on day 1 and 10 mg/m2 on days +3, +6 and +11. Folinic acid 5 mg was started 24 h after each MTX dose and continued 6 hourly until 12 h before the next dose of MTX. The median age of the group was 37 years and 13 patients (19%) received bone marrow from mismatched and/or unrelated donors. No MTX doses were omitted or modified. Grade II-IV acute GVHD occurred in 18 patients (29%) and chronic GVHD in 35 of 56 (64%) patients at risk. There were no cases of grade > or = III stomatitis. Transplant-related mortality was 7% before 100 days and 20% overall (9% for low risk leukaemia) with a median follow-up of 41 months (range 24-88 months). This regimen of folinic acid rescue may contribute to a well tolerated GVHD prophylaxis protocol with reasonably low BMT-related mortality. Our results suggest that the ability of MTX to prevent acute GVHD is not abrogated by folinic acid given in this way.
Assuntos
Transplante de Medula Óssea , Ciclosporina/uso terapêutico , Doença Enxerto-Hospedeiro/prevenção & controle , Leucovorina/uso terapêutico , Metotrexato/uso terapêutico , Doença Aguda , Administração Oral , Adolescente , Adulto , Doença Crônica , Quimioterapia Combinada , Feminino , Seguimentos , Rejeição de Enxerto , Doença Enxerto-Hospedeiro/mortalidade , Humanos , Leucovorina/administração & dosagem , Leucemia/tratamento farmacológico , Leucemia/terapia , Masculino , Pessoa de Meia-Idade , Transplante HomólogoRESUMO
Twenty patients with Hodgkin's disease which had relapsed at least once after chemotherapy, were treated with melphalan 140-220 mg/m2 i.v. followed by reinfusion of non-cryopreserved autologous bone marrow. Four patients (20%) remain alive and disease-free 28, 45, 52, and 96 months after treatment respectively. There were no treatment-related deaths. This appears to be the only reported series of patients treated with a single agent in this situation. The results are comparable to those achieved by multi-agent regimens with autologous or allogeneic bone marrow transplantation.
Assuntos
Transplante de Medula Óssea , Doença de Hodgkin/terapia , Melfalan/uso terapêutico , Adulto , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Feminino , Doença de Hodgkin/tratamento farmacológico , Humanos , Masculino , Melfalan/administração & dosagem , Melfalan/toxicidade , Pessoa de Meia-Idade , Transplante AutólogoRESUMO
The study purpose was to determine if G-CSF plus dose-intensive cyclophosphamide 5.25 g/m2, etoposide 1.05 g/m2 and cisplatin 105 mg/m2 (DICEP) results in superior autologous blood stem cell mobilization (BSCM) than less intensive chemotherapy. From January 1993 until May 1997, 152 consecutive patients with non-Hodgkin's lymphoma (n = 55), breast cancer (n = 47), Hodgkin's disease (n = 14), multiple myeloma (n = 9), AML (n = 9), or other cancers (n = 18) initially underwent BSCM by one of three methods: Group 1: G-CSF alone x 4 days (n = 30). Group 2: disease-oriented chemotherapy, dosed to avoid blood transfusions, followed by G-CSF starting day 7 or 8, and apheresis day 13 or 14 (n = 82). Group 3: DICEP days 1-3, G-CSF starting day 14, and apheresis planned day 19, 20 or 21 (n = 40). A multivariate analysis was performed to determine which factors independently predicted BSCM. The median peripheral blood CD34+ (PB CD34+) cell count the morning of apheresis linearly correlated with the number of CD34+ cells removed per litre of apheresis that day. The median PB CD34+ cell count and median CD34+ cells x 10(6) removed per litre of apheresis were highest for Group 3, intermediate for Group 2, and lowest for Group 1. By multivariate analysis, mobilization group (3 > 2 > 1), disease other than AML, no prior melphalan or mitomycin-C, and less than two prior chemotherapy regimens predicted better BSCM. Out of 15 Group 3 patients who had infiltrated marrows, 11 had no detectable cancer in marrow and apheresis products after DICEP. These data suggest that DICEP results in superior BSCM than less intensive chemotherapy regimens.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Mobilização de Células-Tronco Hematopoéticas , Adolescente , Adulto , Idoso , Antígenos CD34/sangue , Contagem de Células Sanguíneas , Remoção de Componentes Sanguíneos , Transfusão de Sangue Autóloga , Cisplatino/administração & dosagem , Cisplatino/toxicidade , Ciclofosfamida/administração & dosagem , Ciclofosfamida/toxicidade , Relação Dose-Resposta a Droga , Etoposídeo/administração & dosagem , Etoposídeo/toxicidade , Feminino , Fator Estimulador de Colônias de Granulócitos/toxicidade , Transplante de Células-Tronco Hematopoéticas , Humanos , Masculino , Pessoa de Meia-Idade , Células Neoplásicas Circulantes , Neutropenia/induzido quimicamente , Estudos Retrospectivos , Transplante Autólogo/patologiaRESUMO
We have compared the outcomes of 87 patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) receiving matched sibling transplants with stem cells from peripheral blood (blood cell transplant, BCT) or bone marrow (BMT). In good risk patients (AML in CR1) granulocytes recovered to 0.5 x 10(9)/l a median of 14 days after BCT compared with 19 days after BMT (P < 0.0001). For patients with poor risk disease (AML beyond CR1 and MDS) corresponding figures were 16 vs 26 days (P < 0.0001). Platelet recovery to 20 x 10(9)/l was also faster after BCT (good risk 12 vs 20 days, P < 0.0001; poor risk 17 vs 22 days, P = 0.04). Red cell transfusions were unaffected by cell source, but BCT recipients required less platelet transfusions (good risk 1 vs 5, P = 0.002; poor risk 5 vs 11, P = 0.004). Blood cell transplants resulted in more chronic GVHD (86% vs 48%, P = 0.005) and a significantly higher proportion of recipients with KPS of 80% or less (48% vs 5%, P = 0.004). Disease-free survival at 4 years was 23% for both groups of poor risk patients but outcome in good risk patients was better after BCT (93% vs 62%, P = 0.047) related mainly to less relapse. While disease-free survival may be better after BCT than BMT for AML in CR1, quality of life may be relatively impaired.
Assuntos
Transplante de Medula Óssea/métodos , Transplante de Células-Tronco Hematopoéticas/métodos , Leucemia Mieloide Aguda/terapia , Síndromes Mielodisplásicas/terapia , Adolescente , Adulto , Transfusão de Componentes Sanguíneos , Doadores de Sangue , Criança , Pré-Escolar , Sobrevivência de Enxerto , Doença Enxerto-Hospedeiro , Fator Estimulador de Colônias de Granulócitos/uso terapêutico , Humanos , Pessoa de Meia-Idade , Qualidade de Vida , Recidiva , Relações entre Irmãos , Taxa de Sobrevida , Transplante HomólogoRESUMO
Of three patients with giant lymph node hyperplasia (GLNH) of hyaline vascular type, one had multicentric involvement and systemic symptoms, and had the nephrotic syndrome develop. The two others had localized adenopathy and were asymptomatic. Immunohistochemistry carried out on frozen and paraffin-embedded tissue was uniform in all cases. For the most part this revealed a polyclonal B-cell population and a reactive T-cell population in keeping with reactive follicular hyperplasia. In contrast to the latter, however, was a total absence of Leu-7 (natural killer cell) activity. The significance of this is unclear but may represent an abnormal immunologic response in the face of overwhelming antigenic stimulation. GLNH is a clinically and pathologically heterogeneous disorder, the management of which is dependent on both the clinical presentation of the patient and the histologic appearances of the involved lymph nodes.
Assuntos
Linfonodos/patologia , Adulto , Feminino , Humanos , Hiperplasia/imunologia , Técnicas Imunoenzimáticas , Células Matadoras Naturais/imunologia , Depleção Linfocítica , MasculinoRESUMO
Well-known adverse effects of plasma transfusion include viral transmission, allergic complications, and rare anaphylactic reactions. In making clinical decisions to transfuse plasma, a seldom-considered complication is that of red blood cell (RBC) alloimmunization. The authors report a patient in whom strong IgM and IgG anti-E and weak IgG anti-JKa RBC antibodies developed 15 days after infusion of two units of fresh-frozen plasma for volume expansion. These antibodies are potentially hemolytic. This case underscores the importance of considering risks of plasma infusion. Plasma should not be used casually, especially for indications for which alternate therapies, such as crystalloid and colloid solutions, are available.
Assuntos
Eritrócitos/imunologia , Imunização , Isoanticorpos/análise , Reação Transfusional , Idoso , Feminino , Humanos , Imunoglobulina G/análise , Imunoglobulina G/imunologia , Imunoglobulina M/análise , Imunoglobulina M/imunologia , Isoantígenos/imunologia , Sistema do Grupo Sanguíneo Kidd , Sistema do Grupo Sanguíneo Rh-HrRESUMO
St. Vincent's Hospital and Medical Center of New York has been caring for homebound frail elderly persons since 1973 through a comprehensive network of professional, paraprofessional, and community services that allows many older persons to remain in their homes and communities and avoid institutionalization. The staff consists of physician-nurse-social worker teams that bring to each patient their individual skills as professional practitioners. In addition, working together, they create and attempt to carry out a complete, flexible plan of care. The Chelsea-Village Program (CVP) is open to all persons who the team believes are capable of being maintained independently or who can obtain the necessary additional support of family, friends, or neighbors. The patients, whose average age is 83, are homebound due to orthopedic disorders, arthritis, stroke, chronic cardiac and pulmonary disease, or generalized debility and weakness. St. Vincent's and donations from foundations and individuals fund the program, which is free of charge to its patients. In 1988 about 10 physicians, some in private practice, participated during a typical month; subspecialists have made themselves available; and resident physicians share in the work. The staff has come to understand that human beings are most fulfilled when they are able to use their personal resources in independence and that they must ask the patients for their own definitions of life's goals and serve them as they seek those goals.
Assuntos
Serviços de Assistência Domiciliar/organização & administração , Administração Hospitalar , Hospitais Filantrópicos/organização & administração , Equipe de Assistência ao Paciente , Idoso , Catolicismo , Doença Crônica , Hospitais com mais de 500 Leitos , Humanos , Cidade de Nova Iorque , Participação do PacienteAssuntos
Monossomia/genética , Síndromes Mielodisplásicas/genética , Cromossomo X/genética , Anemia Refratária com Excesso de Blastos/genética , Anemia Refratária com Excesso de Blastos/patologia , Feminino , Humanos , Cariotipagem , Pessoa de Meia-Idade , Monossomia/patologia , Síndromes Mielodisplásicas/patologiaRESUMO
Between 1977 and 1984, 50 patients with Hodgkin's disease underwent a staging laparotomy performed by nine surgeons in a community hospital. Adequate procedures were performed in 80% of cases compared to staging laparotomies done between 1969 and 1976 when only 40% were properly performed. Abdominal lymphangiogram had a false-negative rate of 0 but a false positive rate of 70%. Clinical stage III disease was significantly downstaged at laparotomy (65% of cases). Postoperative complication rate was 4% and there were no operative deaths. A subset of patients not requiring laparotomy have been identified. Because the quality of staging laparotomy and lymphangiography was variable, we encourage all centres treating patients with Hodgkin's disease to review their own experience with these techniques before making individual patient treatment decisions.
Assuntos
Doença de Hodgkin/patologia , Laparotomia , Alberta , Estudos de Avaliação como Assunto , Hospitais Comunitários , Humanos , Metástase Linfática , Linfografia , Estadiamento de Neoplasias , Estudos RetrospectivosRESUMO
Although multiple myeloma is a disease of plasma cells, abnormalities have been detected in both B and T lymphocytes in peripheral blood. Although multiple myeloma patients are deficient in surface Ig (sIg)-positive B lymphocytes, analysis of lymphocytes present in blood indicates an abnormally large pool of circulating pre-B cells. These pre-B cells express BA-1, do not bear sIg, and contain cytoplasmic mu chains. High numbers of pre-B cells occur in 88% of individuals with frank myeloma and in 44% of individuals with monoclonal gammopathy of undetermined significance. Pre-B cells bearing BA-1 differ between patients in their expression of HLA-DR and receptors for peanut agglutinin (PNA). Those pre-B cells in myeloma patients are either BA-1+ PNA- HLA-DR+ (54% of patients) or BA-1+ PNA+ HLA-DR- (30% of patients), or have a mixture of phenotypes (14% of patients). Pre-B cells of the PNA- phenotype are almost always HLA-DR+, and PNA+ pre-B cells are HLA-DR-. Within the same patient, the pre-B cell population varies by both quantitative and qualitative definitions. The number of pre-B cells may increase 460-fold and temporal shifts of surface phenotype from BA-1+ PNA- to BA-1+ PNA+ or vice versa have been detected. These observations indicate an abnormality in the B lymphocyte differentiation pathway leading to pre-B cells in the periphery that vary in number and cell surface phenotype, and that are unable to express sIg.
Assuntos
Linfócitos B/imunologia , Mieloma Múltiplo/imunologia , Anticorpos Monoclonais , Imunofluorescência , Antígenos HLA-DR , Antígenos de Histocompatibilidade Classe II/análise , Humanos , Hipergamaglobulinemia/imunologia , Imunoglobulinas/imunologia , Contagem de Leucócitos , Proteínas de Membrana/imunologia , Pessoa de Meia-Idade , Fenótipo , Receptores Mitogênicos/análiseRESUMO
Patients with multiple myeloma are generally immunodeficient, with pronounced depression in primary antibody responses. We have attempted to delineate the reasons for the humoral immunodeficiency by analyzing the specificity repertoire of the surface immunoglobulin (Ig)-positive B cells in patients with multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS), in comparison with normal donors. B lymphocytes from 26 patients with multiple myeloma, 12 patients with MGUS, and 8 normal donors were transformed with Epstein-Barr virus (EBV) and cultured at limiting dilution for clonal analysis. The Ig secreted by each clone was analyzed for class and anti-tetanus toxoid (TT) specificity to determine the frequencies of IgM, IgG, anti-TT IgM, and anti-TT IgG antibody-secreting clones. Our objective was to establish whether the inability to mount humoral responses to common environmental pathogens was due to a lack of specific B cells or to inhibition of B-cell function. Our results indicate that the quantitative B-cell deficiency in patients was due to a nonrandom loss of selected sets of B cells. Although most patients had a reduced aggregate number of B cells, the number of TT-specific B cells was normal. There was, on average, a threefold increase in the proportion of the B-cell specificity repertoire devoted to recognition of TT. Forty-four percent of the patients with MGUS were also affected. In addition, the TT-specific B cells in multiple myeloma patients were severely compromised in their ability to secrete antibody or to differentiate to antibody-secreting cells in vivo. This arrest in differentiation appears to be extrinsic to the B cells, as they were fully able to secrete anti-TT antibody after transformation and culture in vitro. We postulate the existence of an autoimmune inhibitory network mediating the arrest in B-cell differentiation and the humoral immune deficiency.
Assuntos
Linfócitos B/imunologia , Síndromes de Imunodeficiência/etiologia , Mieloma Múltiplo/imunologia , Diferenciação Celular , Transformação Celular Viral , Herpesvirus Humano 4 , Humanos , Imunoglobulina G/biossíntese , Imunoglobulina M/biossíntese , Mieloma Múltiplo/complicações , Toxoide Tetânico/imunologiaRESUMO
HLA-DR antigens are expressed as differentiation markers in certain human leukemias. To investigate whether DNA methylation plays a role in expression of DR genes in leukemia, we analyzed methylation patterns of the DR-alpha and D/DR-beta genes in the DR antigen-positive and -negative B-cell lines, in normal adults and in chronic lymphocytic leukemia (CLL) patients using Southern blot hybridization of DNA digested with Msp I and Hpa II. The DR-alpha and D/DR-beta genes of a DR antigen positive B-cell line, T5-1, were heavily methylated, while those of DR antigen-negative variant, 6.1.6, were hypomethylated. Blood cells collected from four normal adults contained different levels of DR-alpha and D/DR-beta mRNAs, but their relative amounts were about the same among the individuals. By contrast, the relative amounts of these mRNAs in CLL cells varied widely, indicating aberrant expression of one or both of these genes in CLL. The DR-alpha gene in four normal adults and six CLL patients produced only a 3 kb hybridizable band after Msp I digestion. Normal adult DR-alpha genes were resistant to Hpa II digestion, suggesting that all Hpa II sites are methylated. In contrast, digestion of CLL DNA with Hpa II yielded various bands of larger sizes which differed among the CLL patients, suggesting that Hpa II sites are differentially methylated in the CLL DNA. In the case of D/DR-beta genes, normal adult DNA gave Msp I bands which were slightly polymorphic among four individuals tested. In contrast, CLL DNA showed a high degree of restriction fragment length polymorphism (RFLP) on Msp I digestion. We speculate that the high RFLPs in the CLL DNA may result from differential methylation in CpG clusters in the D/DR-beta genes, and that this characteristic may be of use for diagnosis of CLL.
Assuntos
DNA de Neoplasias/genética , Genes , Antígenos HLA-D/genética , Antígenos HLA-DR/genética , Leucemia Linfoide/imunologia , Adulto , Linfócitos B/imunologia , Linhagem Celular , Humanos , Leucemia Linfoide/genética , Metilação , Hibridização de Ácido Nucleico , RNA Mensageiro/genética , Valores de Referência , Transcrição GênicaRESUMO
A 30-year-old man developed acute myelogenous leukemia nearly 3 years after treatment of Hodgkin's disease with radiation and three chemotherapy combinations. Remission was induced with one cycle of high-dose Ara-C therapy. Three cycles of consolidation chemotherapy were given. The patient then had two autologous bone marrow transplants, the first after conditioning with 5 Gy total body irradiation, the second after Melphalan 140 mg/m2. The procedures were well tolerated, although hematological reconstitution was very slow after the second autotransplant. The patient has been disease-free for over 4 years. Such patients may be more vulnerable to transplant-related complications because of their previous exposure to chemotherapy and radiation, which may damage several organs including the bone marrow. This report demonstrates that patients with secondary acute myelogenous leukemia may tolerate a double autotransplant procedure and achieve durable remissions.
Assuntos
Transplante de Medula Óssea , Doença de Hodgkin/terapia , Leucemia Mieloide Aguda/cirurgia , Adulto , Doença de Hodgkin/complicações , Humanos , Leucemia Mieloide Aguda/etiologia , Masculino , Transplante AutólogoRESUMO
HLA-DR (or Ia-like) antigens which were detergent-solubilized from plasma membranes of leukemic cells of patients with chronic lymphocytic leukemia of the B cell variety were purified by gel filtration, followed by affinity chromatography on Con A-Sepharose. After radioiodination, the DR antigens were immunoprecipitated with specific antisera and analyzed by two-dimensional gel electrophoresis. Repeated mapping revealed several different patterns of DR antigen expression. Most patients (18 out of 42) gave map patterns resembling those obtained from normal peripheral blood B cells. Such maps revealed light (27 kDa) and heavy (33 kDa) DR chains as well as a non-dissociated 60 kDa DR complex. All components, and especially DR light chains, were polymorphic and could be resolved further into several characteristic isoelectric variants. Maps from eleven patients showed decreased levels of 33 and 60 kDa antigen components, while eleven further patients expressed only DR light chains. Two patients lacked detectable DR antigens. Sequential mapping of individual patients indicated that expression of 33 and 60 kDa DR components fluctuates over months. This temporal fluctuation was independent of other B cell markers, including a newly defined group of surface membrane proteins of 28 000 daltons. The patterns are reminiscent of the biochemical dedifferentiation characteristic of immunoglobulin biosynthesis seen in the plasma cell dyscrasias.
Assuntos
Antígenos de Histocompatibilidade Classe II/análise , Leucemia Linfoide/imunologia , Epitopos , Antígenos HLA-DR , Humanos , Imunoglobulinas/biossíntese , Polimorfismo GenéticoRESUMO
Circulating monoclonal B cells in peripheral blood from patients with multiple myeloma or with monoclonal gammopathy of undetermined significance (MGUS) have previously been shown to express CD19, CD20, and PCA-1 and are predominantly CD45R0+, characterizing them as very late stage B cells. This work shows that the abnormal B cells are monoclonal as defined by their exclusive expression of either kappa or lambda light chain mRNA, and that the same type of light chain mRNA is expressed in both bone marrow plasma cells and blood B cells. These abnormal tumour-related circulating B cells express high densities of CD11b, a beta 2-integrin, which is expressed in a conformationally active state as defined by reactivity with monoclonal antibody 7E3. Normal peripheral blood B cells which do not bear CD11b acquire a high density after stimulation with pokeweed mitogen (PWM). At day 4 of culture, the expression of CD11b on normal CD19+ B cells was nearly comparable to that of the circulating myeloma late stage B cells. After PWM stimulation of circulating myeloma B cells the expression of CD11b was gradually lost during 4 days of culture, suggesting that its expression is dynamically regulated. Two patients with no phenotypically abnormal B cells in their blood at diagnosis acquired a large subset of CD11b+ B cells 4 weeks after initiation of chemotherapy. In most patients, a subset of the circulating myeloma B cells express a low density of CD5. The proportion of CD19+ B cells in the bone marrow expressing CD11b was much reduced compared with peripheral blood B cells, and CD11b was not detectable on plasma cells in the bone marrow, suggesting a sequential relationship of the B-cell subsets detected in our population of patients, involving gradual loss of CD11b concurrent with the loss of CD19 during B lineage differentiation. These cells appear to represent a continuously differentiating monoclonal B lineage culminating in the CD11b- plasma cell entrenched in the bone marrow. We speculate that the expression of conformationally active CD11b on the abnormal B cells in peripheral blood mononuclear cells of myeloma patients facilitates transendothelial migration of circulating myeloma B cells to the bone marrow.