Assuntos
Leucemia Linfocítica Crônica de Células B/patologia , Receptores de Antígenos de Linfócitos B/análise , Adulto , Idoso , Idoso de 80 Anos ou mais , Sequência de Aminoácidos , Brasil/epidemiologia , Feminino , Humanos , Leucemia Linfocítica Crônica de Células B/epidemiologia , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
In vivo replication of rotaviruses is generally limited to enterocytes. Because of this restriction, most blood circulating rotavirus-specific B cells are hypothesized to originate in Peyer's patches and should express the intestinal homing receptor alpha4beta7. To test this hypothesis in humans, we used a flow cytometry assay that identifies antigen-activated (IgD-) B cells (CD19+) that express surface rotavirus-specific immunoglobulin. With this assay we could detect rotavirus-specific B cells in both children and adults with an acute rotavirus (RV) infection. Staining with an anti-alpha4beta7 monoclonal antibody, we could determine that B cells that express rotavirus-specific surface immunoglobulin predominantly express alpha4beta7. The response of rotavirus-specific antibody-secreting cells in the peripheral blood of children and adults with acute rotavirus infection was also studied by ELISPOT. The antibody-secreting cells of children were mainly of the IgM isotype, while the antibody-secreting cells of adults were predominantly of the IgA and IgG isotype. alpha4beta7+ and alpha4beta7- subsets of peripheral blood mononuclear cells were purified using paramagnetic beads and then tested in the ELISPOT assay. Rotavirus-specific antibody-secreting cells were predominantly present in the alpha4beta7+ subpopulation. The flow cytometry assay we have described will permit future studies to characterize the phenotype of virus-specific B cells and could be useful in the study of the immunogenicity and protective efficacy of RV vaccines and the identification of markers of protective immunity.
Assuntos
Linfócitos B/imunologia , Integrinas/análise , Infecções por Rotavirus/imunologia , Rotavirus/imunologia , Adolescente , Adulto , Idoso , Anticorpos Antivirais/análise , Células Produtoras de Anticorpos/fisiologia , Linfócitos B/química , Diarreia/imunologia , Humanos , Imunofenotipagem , Lactente , Integrinas/fisiologia , Pessoa de Meia-Idade , Receptores de Antígenos de Linfócitos B/análiseRESUMO
We studied the B-1 lymphocyte involvement in host reactions to parasites in the murine model of schistosomiasis. No modifications were observed in the prepostural phase of the disease. From the acute phase on, we observed sequentially an increase of Mac1- B-1 cells in the spleen, followed by their appearance in Peyer's patches and in mesenteric ganglia, suggesting that a fraction of splenic B-1 cells might follow this pathway of migration, acquiring progressively the Mac1 expression. These results are consistent with a primary activation of the splenic B cell compartment, with the subsequent mobilization of B-1 cells into the tissue involved by parasites. Conversely, we found no evidence of an increase of B-1 cells in the peritoneum, nor a mobilization of B-1 cells expressing the peritoneal phenotype (CD5lo, IgMhi) into the tissues involved by infection, despite the general inflammatory reactivity of peritoneal cells. In schistosomiasis, the peritoneal cavity B-1 cells on one side, and those involved in inflammatory reactions to parasites in the spleen, Peyer's patches, and mesenteric ganglia on the other, represent two distinct B-1 lymphocyte pools.
Assuntos
Subpopulações de Linfócitos B/imunologia , Esquistossomose mansoni/imunologia , Animais , Antígenos CD5/análise , Feminino , Gânglios Simpáticos/imunologia , Imunoglobulina M/análise , Linfonodos/imunologia , Contagem de Linfócitos , Masculino , Mesentério/inervação , Camundongos , Camundongos Endogâmicos C3H , Cavidade Peritoneal/citologia , Nódulos Linfáticos Agregados/imunologia , Receptores de Antígenos de Linfócitos B/análise , Baço/imunologiaRESUMO
The study of differentiation antigens of circulating mononuclear cells in 70 patients with primary immunodeficiency (PID) using monoclonal antibodies allowed us to define phenotypic profiles that are characteristic of the different described syndromes. In common variable immunodeficiency we found percentages of lymphocytes within normal ranges, and an altered CD4/CD8 ratio. In sex-linked agammaglobulinemia, absence of B lymphocytes with normal distribution of regulatory populations (CD4/CD8) were found. These results allow us to distinguish two clinically and infectologically similar conditions. In selective IgA deficiency, distribution of lymphocytic populations was normal. In immunodeficiency with hyper IgM, considered up to date as an abnormal maturation of B lymphocytes, we observed a deficiency in cellular immune response, and a phenotypic profile characterized by: decreased number of CD3 cells, inverted CD4/CD8 ratio, and increased CD38 population; this profile being similar to the one that we found in predominantly cellular immunodeficiency. In predominantly cell-mediated immunodeficiency and in those immunodeficiencies associated to other defects (such as: hyper IgE syndrome, Di George syndrome), the most important finding was a significative increase in CD38 population. Although it's not possible to consider on this basis that there is a defect at the thymic level of T-cells maturation, the high levels of circulating CD38 cells were a clear indication of altered cellular immune response in our series of patients. Patients with predominantly cell-mediated immunodeficiency showed the lowest levels of CD4 cells and the corresponding inversion of CD4/CD8 ratio. In Di George syndrome we found a markedly diminished CD8 population that differentiates this entity from the rest of the studied syndromes. In chronic mucocutaneous candidosis distribution of lymphocytic populations was normal, but a significative increase in the percentages of CD11b+ cells was observed. In patients with antibodies deficiency that received substitutive treatment with gammaglobulin we found no variations in lymphocytic populations distribution. In the group of patients with altered cellular immunity treated with thymic hormones, observed phenotypic changes (increase in T-cells population, trend to normalization in CD4/CD8 ratio, and decrease in CD38 population) were transient, and lasted only during the treatment period. We considered that describing these phenotypic profiles is a useful diagnosis tool when evaluating patients with PID, since these profiles are characteristic and very stable.
Assuntos
Síndromes de Imunodeficiência/imunologia , Leucócitos Mononucleares/imunologia , Adulto , Anticorpos Monoclonais , Antígenos CD/sangue , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Síndromes de Imunodeficiência/classificação , Síndromes de Imunodeficiência/diagnóstico , Contagem de Leucócitos , Masculino , Fenótipo , Receptores de Antígenos de Linfócitos B/análise , Formação de RosetaRESUMO
In humans with B-cell malignancies, the presence of monoclonal B lymphocytes (clonal proliferation) can be detected by comparing the fluorescence intensity distributions of lymphocytes stained with anti-kappa and anti-lambda reagents. The sensitivity of previously described single-color immunofluorescence techniques to low levels of clonal excess is limited by background from cytophilic immunoglobulins on non-B cells and by the low proportion of circulating B cells in individuals with minimal disease. We have used two-color immunofluorescence and B-cell gating to develop an improved assay that avoids false positives due to non-B cells, without requiring restrictive light scatter gates that may exclude true positives. This method is sensitive to 0.2% monoclonal B cells admixed with fresh normal lymphocytes, to 0.6% monoclonal B cells admixed with normal lymphocytes that have been stored for up to 72 hours, and readily detects 1% monoclonal cells in patient specimens. The two color B-cell gated assay offers sensitivity equivalent to the single-color assay and improved specificity for detection of low levels of clonal excess.
Assuntos
Linfócitos B/imunologia , Citometria de Fluxo/métodos , Leucemia Linfocítica Crônica de Células B/diagnóstico , Linfócitos B/citologia , Células Clonais , Imunofluorescência , Heparina/farmacologia , Humanos , Cadeias kappa de Imunoglobulina/análise , Cadeias lambda de Imunoglobulina/análise , Leucemia Linfocítica Crônica de Células B/imunologia , Receptores de Antígenos de Linfócitos B/análise , Linfócitos T/imunologiaRESUMO
The association of chronic lymphocytic leukemia (CLL) with serum paraproteinemia (ie, monoclonal immunoglobulin production and secretion) is well known. We, however, could find only three previous reports of CLL where multiple serum paraproteins were encountered. We describe a case of biclonal gammopathy in CLL, involving IgM/kappa and IgM/lambda, with each paraprotein reaching serum levels of approximately 10 g/L (1 g/dL). Using immunohistochemical techniques, we identified two morphologically similar lymphocyte populations, which could be stained for either mu and kappa or mu and lambda. The peripheral blood contained a majority of mu/kappa-containing cells (kappa/lambda = 17.5:1), while the bone marrow only contained a modest excess of cells staining for mu/kappa (kappa/lambda = 2.4:1). The clinical significance and prognosis of biclonal IgM gammopathies is uncertain, since so few cases have been reported. Our patient has now been followed up for more than four years.
Assuntos
Hipergamaglobulinemia/complicações , Imunoglobulina M , Leucemia Linfoide/imunologia , Idoso , Medula Óssea/imunologia , Medula Óssea/patologia , Feminino , Humanos , Hipergamaglobulinemia/imunologia , Cadeias kappa de Imunoglobulina , Cadeias lambda de Imunoglobulina , Leucemia Linfoide/complicações , Leucemia Linfoide/patologia , Receptores de Antígenos de Linfócitos B/análiseRESUMO
Recently, it has been reported that in SJA/9 mice infected with Nippostrongylus brasiliensis there are increased numbers of lymphoid cells positive for surface IgM and IgE (sIgM+ and sIgE+) even though they fail to secrete IgE, that both the sIgM and sIgE on these cells are intrinsic, and that there has been no deletion of genes for the Ig heavy chain constant region in these cells. These observations support a nondeletional model for Ig isotype switching. We have now reexamined the nature of sIgE on sIgE+ spleen and mesenteric lymph node cells of N. brasiliensis-infected SJA/9 mice, and the following observations lead us to believe that this sIgE is cytophilic rather than intrinsic: (i) Only approximately 50% of the N. brasiliensis-infected SJA/9 mice have detectable percentages of sIgE+ lymphoid cells. All mice with detectable sIgE+ lymphocytes have lymphocytes positive for intracytoplasmic IgE (cIgE+) and secrete IgE in vitro, while cIgE+ cells and IgE secretion are absent from N. brasiliensis-infected SJA/9 mice that lack sIgE+ cells. (ii) SJA/9 B lymphocytes have receptors for IgE: expression of these receptors is increased in N. brasiliensis-infected mice that have sIgE+ lymphocytes, but not in infected SJA/9 mice that lack sIgE+ lymphocytes. (iii) Treatment of sIgM+ sIgD+ sIgE+ cells for 1 min with dilute acid removes most sIgE but does not affect expression of sIgM or sIgD. (iv) The removal of mouse IgE from sIgE+ B cells facilitates the binding of exogenous rat IgE. (v) The small amount of sIgE that is reexpressed during a period of in vitro culture after acid treatment is blocked by inclusion of exogenous rat IgE in the culture medium. These observations show that most sIgM+ sIgE+ B cells in N. brasiliensis-infected SJA/9 mice do not express intrinsic sIgE; thus studies using these cells to determine mechanisms of Ig isotype switching are inconclusive.