Detectable Surface Immunoglobulin Research Articles

Use of Flow Cytometry to Evaluate the Immunophenotypic Profile of Patients with Chronic Lymphocytic Leukemia from Rio Grande Do Norte State, Brazil

BACKGROUND: Chronic lymphocytic leukemia (B-CLL) is a clonal proliferation of mature B lymphocytes characterized by indolent clinical course. This clonality is characterized biologically by low expression of surface immunoglobulin (sIg) and restriction to a single immunoglobulin light chain associated with high expression of CD5 antigen and positivity to B cell antigen lymphocytes such as CD19, CD20 and CD23 and negativity to FMC7. The immunological profile and morphological analysis of lymphoid cells are the main means for the differential diagnosis of B-CLL from other chronic lymphoproliferative diseases. OBJECTIVE: The aim of this study was to evaluate the expression pattern of a variety of membrane antigens in leukemic cells originating from patients with B-CLL. METHODS: Peripheral blood samples from 80 patients with B-CLL were analyzed by multiparametric flow cytometry and routine hematologic exams, using a panel of monoclonal antibodies (MoAb): CD45/CD14, CD3/CD19/CD45, CD4/CD8/CD3, CD20/CD5/CD3, CD3/CD16-56/CD45, CD2/CD7, FMC7/CD23, CD103/CD22/CD20, HLADR/CD38, CD10/CD19, CD1a, CD11b in addition to IgM/gD, kappa and lambda immunoglobulin light chains to detect surface immunoglobulin and clonal restriction for immunoglobulin light chains. The hematological data were obtained using a hematological analyzer and cytomorphological analysis in blood film stained with Leishman's stain.RESULTS: The study sample consisted of 45 men and 35 women, ages ranging from 55 to 84 years (mean 65 years). Complete white blood cell count ranged from 10.0 to 42.0 x 109/L. (mean 50.0 x 109/L) and lymphocyte count was greater than 5.0 x 109/l in all cases. The neoplastic cells displayed B-CLL phenotype (CD5+/CD19+/CD20+/HLADR+/CD23+) in the vast majority of the cases, associated with failure to stain for T cell markers (CD1a, CD2, CD4, CD3, CD7, CD8), CD103, CD14 and FMC7. Leukemic cells of most patients also expressed low intensity of IgM and IgD, with clonal restricted kappa light chain in the majority of cases (59.7%). CONCLUSIONS: This investigation highlights the importance of immunophenotyping for correct diagnosis of chronic lymphoproliferative syndromes, and the MoAb panel used was sufficient for diagnostic confirmation of B-CLL. DisclosuresNo relevant conflicts of interest to declare.

An Epstein–Barr virus-positive diffuse large B-cell lymphoma presenting as multi-organ failure: A catastrophic lymphomatosis with fulminant visceral organ dissemination resulting in a precipitous death in a 59-year-old female with no identifiable etiology for immunodeficiency

Epstein–Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBV+ DLBCL) of the elderly is an aggressive B-cell neoplasm related to age-associated impaired immunity. We report such a case in a 59-year-old woman with a catastrophic disease course. The patient initially presented with fever, fatigue, malaise and weakness over one-week period. Despite empirical treatment with antibiotics and antiviral agents, she subsequently developed multi-organ failure and coagulopathy. Radiographic imaging revealed hepatomegaly, splenomegaly, pleural effusion, and ascites. Her complete blood cell count showed marked leukocytosis, anemia and thrombocytopenia. Morphologic examination of blood smear demonstrated many abnormal plasmacytoid lymphocytes, and flow cytometric analysis detected an intermediate-large mature B-cell population (69%) without detectable surface immunoglobulin. High copy numbers of EBV genome were detected in the blood by PCR. A diagnosis of EBV+ DLBCL, leukemic phase, was made. Despite aggressive treatment and supportive care, the patient succumbed to multi-organ failure one week after initial presentation. Autopsy demonstrated EBV+ DLBCL infiltration in all the organs examined. This case describes an unusual presentation of EBV+ DLBCL and highlights the necessity of pertinent ancillary tests to avoid delay in the diagnosis and treatment.

FACS analysis of bovine leukemia virus (BLV)-infected cell lines with monoclonal antibodies (mAbs) to B cells and to monocytes/ macrophages

The eighteen monoclonal antibodies (mAbs) to B cells and the fourteen mAbs to accessory cells submitted to the workshop were analysed by FACS on three established, bovine leukemia virus (BLV)-infected bovine cell lines. Several mAbs of previously defined specificity were run in parallel. This analysis allowed us to gain further insight on the precise phenotype of those peculiar cells and to cluster the submitted mAbs according to their staining patterns. The BLV-infected cell lines seemed to belong to the B cell type though some of them lack detectable surface immunoglobulins. Moreover, all lines express the CD5 T cell marker and several myeloid markers.

Studies on the pathogenesis of the erythrocyte destruction associated with the anemia of inflammatory disease.

Density-separated feline RBC were analyzed for surface immunoglobulin and in vitro susceptibility to macrophage phagocytosis before and after introduction of a sterile abscess. Prior to abscess induction, least dense cells did not have detectable surface immunoglobulin G (IgG) as a direct antiglobulin reaction was negative. Two of four intermediate and three of four most dense cell fractions had detectable surface IgG as indicated by a positive direct antiglobulin reaction. On Days 3 and 5 after induction of sterile abscesses all three RBC fractions were positive and the size of the RBC clumps tended to increase. In vitro macrophage phagocytosis of all three RBC fractions increased significantly after abscess induction. The phagocytosis could be partially blocked by preincubation of macrophages with feline IgG.

Equine T lymphocytes express MHC class II antigens.

Six anti-HLA class II mouse monoclonal antibodies (mAbs) were used in conjunction with a rat monoclonal antibody raised against horse lymphocytes to define class II major histocompatibility complex (MHC) molecules in the horse. By utilizing an ELISA assay and complement dependent lymphocytotoxicity assay, five out of the six anti-HLA class II antibodies and the rat anti-horse monoclonal antibody were found to react with a high percentage of peripheral blood lymphocytes. Flow cytometry demonstrated a variable antigen density on peripheral blood lymphocytes and clear evidence for expression by lymphocytes that carried no detectable surface immunoglobulin. None of the antibodies reacted with equine platelets. The mAbs immunoprecipitated an antigenic complex of Mr 29,000-33,000 from horse lymphocytes. It appears that the distribution of MHC class II antigens in the horse is different from that in man but is similar to that in the dog, since MHC class II antigens are expressed on resting peripheral blood lymphocytes which lack membrane-bound immunoglobulins. Correlations between the distribution of MHC class II antigens on lymphocyte subpopulations and their role in immunological phenomena may contribute to our understanding of the functional properties of these molecules.

Two distinct human myeloma cell lines originating from one patient with myeloma.

Two distinct cell lines (OPM-1 and OPM-2) were established from the peripheral blood of a 56-year-old female myeloma patient at the stage of terminal leukemic evolution associated with loss of cytoplasmic immunoglobulin heavy chain (G lambda----lambda). The lines grew in suspension with a doubling time of 36-42 hr and 30-36 hr, respectively. EBNA was absent from both lines. The lines synthesized cytoplasmic lambda-chain, but had no detectable surface immunoglobulins. Fc receptors and complement receptors could not be detected in either line. The lines had very complex chromosomal abnormalities, but the patterns of chromosomes differed greatly between the two lines. The two lines, together with the RPMI 8226 line established by Matsuoka et al. (1967), were analyzed for phenotypic expression as defined by a panel of monoclonal antibodies to B cells (B1, BA-1, BA-2, BA-3, OKIa-1 and OKT10/BMA0100). Neither OPM-1 nor OPM-2 reacted with any of the antibodies tested except OKT10. OPM-1 cells reacted weakly (less than 30%) with OKT10/BMA0100, while OPM-2 cells showed a fluctuating reactivity, ranging from 40 to 80%, with OKT10/BMA0100. In contrast, RPMI 8226 reacted strongly with OKT10 and BA-2. These results demonstrate the presence of phenotypic heterogeneity in all 3 myeloma cell lines, suggesting that the lines might represent different stages of terminal B-cell development.

Establishment of anti-thyroglobulin antibody-producing cell line by EB virus transformation

We established an anti-thyroglobulin antibody-producing cell line using the peripheral lymphocytes from a patient with chronic thyroiditis. The method was based on preselection by "panning", transformation by EB virus and twice clonings by "limiting dilution". The cells of the cloned cell line (Yo3CTX10) had neither E-receptor nor IgG X Fc-receptor but had C3-receptor as shown by rosetting. We could not detect surface immunoglobulin, but we could detect cytoplasmic immunoglobulin (IgG lambda) with FITC-stainings. This cell line has continuously secreted anti-thyroglobulin antibody for 8 months, which was IgG lambda as shown by immunoelectrophoresis and solid phase radioimmunoassay. The pattern obtained using the purified antibody showed two sharp bands (H, L-chains) in SDS polyacrylamide gel electrophoresis, but it showed six sharp bands in isoelectric focusing electrophoresis. Thus we could establish an oligoclonal cell line producing IgG lambda anti-thyroglobulin antibody.

Surface markers and function of circulating thyroid autoantibody-producing cells.

The in vitro synthesis of antithyroglobulin (anti-Tg) and antithyroid microsomal (anti-M) autoantibodies by peripheral blood mononuclear cells (MNC) from patients with autoimmune thyroid diseases was investigated using sensitive immunoradiometric assays. Cultures were carried out in the presence or in the absence of pokeweed mitogen (PWM). Thyroid autoantibodies were undetectable in supernatants of MNC cultures from 9 normal subjects. Supernatants of MNC cultured without PWM had detectable levels of anti-Tg and anti-M in 5 (19.3%) and in 2 (7.7%) of 26 patients with autoimmune thyroid diseases, respectively. In the presence of PWM, a marked increment in the antibody concentrations occurred in all but 1 of these cultures, and the number of positive cultures increased to 13 (50.1%) for anti-Tg and to 15 (57.7%) for anti-M. Studies of MNC fractions depleted of T lymphocytes (non-T cells) were carried out on selected patients showing antibody synthesis only after PWM stimulation. Autoantibody production was not found with non-T cells, but the effect of the mitogen was restored by readdition of T cells. Irradiation (1000 rad) of T cells before coculturing significantly enhanced autoantibody production. With this model no significant functional difference was found between autologous and allogenic T cells from thyroid autoimmune disease patients or from normal subjects. The cells involved in PWM-driven thyroid autoantibody synthesis, as defined by depletion studies, were lymphocytes bearing DR antigens and surface immunoglobulin G (IgG) without detectable surface immunoglobulin M (IgM). Depletion from MNC suspensions of Tg-binding cells abolished PWM-stimulated anti-Tg production, but did not alter the synthesis of anti-M. Further studies were carried out on MNC from a single patient with Hashimoto's thyroiditis, whose non-T cells consistently produced large amounts of anti-M and total IgG in the absence of PWM. The addition of PWM to these unfractionated MNC slightly increased the production of anti-M, but inhibited antibody synthesis after depletion of T lymphocytes. Interestingly, the addition of autologous T lymphocytes to non-T cells inhibited the spontaneous synthesis of anti-M. These data indicate that in vitro synthesis of anti-Tg and anti-M by MNC may be frequently induced by stimulation with PWM in patients with thyroid autoimmune disorders. PWM-stimulated synthesis of thyroid autoantibodies appears to be T-cell dependent and modulated by radiosensitive T lymphocytes. The cells responsible for PWM-dependent thyroid autoantibody synthesis are B lymphocytes with surface membrane IgG and have receptors specific for the autoantigen.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunoglobulin gene rearrangement as a diagnostic criterion of B-cell lymphoma.

We describe the use of the Southern blot hybridization technique to diagnose B-cell lymphoma by detecting clonal immunoglobulin gene rearrangements in lymph node and other biopsy tissues. DNA was isolated from a wide variety of neoplastic and non-neoplastic specimens and analyzed for the presence of rearranged immunoglobulin genes using radiolabeled DNA probes specific for the heavy- and light-chain immunoglobulin constant region genes. Among the specimens examined, clonal immunoglobulin gene rearrangements were found only in biopsy samples of B-cell lymphoma and not in samples containing reactive lymphoid processes or non-B-cell cancers. In lymphomas, the presence of rearrangements for either the kappa or lambda light-chain gene correlated with expression of one or the other of these chains when cellular immunoglobulins could be detected by frozen-section immunophenotyping techniques. The analysis of immunoglobulin gene rearrangements offers several advantages over conventional diagnostic methods for lymphomas, including improved sensitivity in detecting minor populations of neoplastic lymphocytes composing as little as 1% of the total cell population. In addition, clonal immunoglobulin gene rearrangements are demonstrable in a subset of lymphomas that lack detectable surface or cytoplasmic immunoglobulin, thus offering positive evidence for both malignancy and the B-cell origin of these tumors. Our studies indicate that detection of immunoglobulin gene rearrangements is a valuable method for diagnosis and classification of various lymphoproliferative disorders that are difficult to evaluate histologically or that lack distinctive antigenic markers.

Radioautographic studies on the formation and maturation of bone marrow lymphocytes in mice.

DNA labelling by [3H]thymidine and the sandwich radioimmunolabelling method were used to characterize marrow lymphoid cells and to study the kinetics of production and maturation of small lymphocytes in the bone marrow of adult mice. Marrow lymphoid cells consisted of non-proliferating small lymphocytes, 30-40% of which had detectable surface immunoglobulin (SmIg), and proliferating large lymphoid cells lacking SmIg. Double-labelling experiments employing [3H]thymidine in vivo followed by sandwich radioimmunolabelling in vitro indicated that marrow small lymphocytes lack detectable SmIg when they are formed but develop SmIg within the first few days after production. Marrow lymphocytopoiesis includes; (1) proliferation of large lymphoid cells, which are presumptive small lymphocyte progenitors, which have a cell cycle time of 14-15 hr, and (2) a 3-5 day intramyeloid stage when many newly formed small lymphocytes undergo maturational changes towards the B cell lineage.

Studies on the clonal origin of human B cell leukemia using monoclonal anti-idiotype antibodies.

The clonal origin of an IgA1 kappa B cell leukemia in a 71-year-old man (WF) was examined using a monoclonal anti-Id antibody and a panel of monoclonal anti-VH antibodies. Immunofluorescent studies revealed that all surface IgA1 kappa + leukemic cells in WF's blood and 10% of the IgM+ B cells in his bone marrow expressed the WF Id. Three percent of the IgA1 kappa + leukemic cells in blood also expressed gamma-chains in their cytoplasm. Approximately 0.1%, 1%, and 10% of bone marrow mononuclear cells, respectively, expressed mu-chains, gamma-chains, and alpha-chains in their cytoplasm, but no detectable light chains or surface immunoglobulins. These mu, gamma, and alpha-positive cells had the convoluted nucleus and narrow cytoplasm characteristic of normal mu+ pre-B cells. Sequential isotype switching among this unusual pre-B population was indicated by co-expression of mu-chains and alpha-chains by 11% and 63%, respectively, of the gamma pre-B cells. These pre-B cells and the surface alpha-chains and cytoplasmic gamma-chains of the leukemic B cells were reactive with one of four monoclonal anti-VH antibodies. The data suggest malignant transformation of the clone before isotype switching, and also imply light chain precommitment at the pre-B cell level of differentiation.

B-lymphocyte differentiation in Xenopus laevis larvae

Direct immunofluorescence was used to detect the appearance of pre-B cells in different tissues of Xenopus laevis embryos. Cells with intracellular heavy chains belonging to high-molecular-weight immunoglobulin, but devoid of any detectable surface immunoglobulin, were first observed in the liver at stage 46. These cells were also observed in the developing spleen at stage 49 and they were present in these organs up to the beginning of metamorphosis. At stage 58 (climax of metamorphosis) their number dropped to zero. Results of organ culture experiments suggest that the stem cells enter the liver just before stage 39, where they differentiate to become pre-B cells at stage 46.

T cell-mediated cytotoxicity induced by Listeria monocytogenes. III. Phenotypic characteristics of mediator T cells.

Cytotoxic thymus-derived lymphocytes (CTL) generated in vitro by restimulating rat cells with Listeria antigen- (LMA) pulsed syngeneic accessory cells were characterized in respect to their surface membrane markers. LM-dependent CTL were devoid of detectable surface immunoglobulin (Ig) and receptors for the Fc region of rabbit IgG. Experiments with monoclonal antibodies to rat T cell markers revealed that these cytotoxic cells have the phenotypic profile W3/13+, W3/25-, MRC OX 8+. LM-dependent CTL also bind the monoclonal antibody, MRC OX 3, which recognizes an Ia-antigen-like determinant on rat cells. Although LM-dependent CTL lack the W3/25 marker, their generation depends on the cooperative interplay of W3/25+ and W3/25- T cells.

Influence of serum thymic factor (FTS) on radiation-induced leukaemogenesis in thymectomized AKR mice.

The influence of serum thymic factor (FTS) on extrathymic leukaemogenesis induced in thymectomized AKR mice by fractionated sub-lethal irradiation was studied. Thirty-day-old thymectomized mice were submitted to four doses at weekly intervals (1.75 Gy) and thereafter treated with FTS (1 ng) for 9 days. Two groups were restored with either bone marrow or spleen cells prior to FTS treatment. In another group mice were treated with FTS (12 ng) for 1 month after thymectomy and prior to irradiation. Results indicated that primarily irradiation and FTS, and, to a lesser extent, restoration and age of the mice at the time of their first radiation exposure influenced leukaemogenesis. Irradiation increased the spontaneous low incidence of extrathymic leukaemia (5%) up to 50%. Although nothing is yet known about the expression of endogenous retroviruses in thymectomized AKR mice, the possible expression of leukaemogenic recombinants, either identical to or different from mink-cell-focus-inducing viruses (MCF), might explain this enhancing effect of radiation on leukaemogenesis. Mice developed two types of leukaemias: "null" leukaemias whose cells bore no detectable theta antigen or surface immunoglobulin, and B leukaemias. Among the null leukaemias, two kinds could be distinguished: "early" ones which were observed before 450 days, and in which BM and spleen were similarly involved, and "late" ones which displayed the same characteristics as B leukaemias, i.e. delayed appearance (after 450 days) and splenic origin. Although FTS did not modify the overall frequency of leukaemias, it increased significantly the incidence of the "early" null ones. It had no effect on the frequency or the latency of late null and B leukaemias. Any population of theta-negative T cells sensitive to FTS could be an acceptable candidate for "early" null leukaemogenesis. The origin of "late" null leukaemias remains an open question.

Immunoglobulin expression in human lymphoblastoid cell lines with early B cell features.

Immunoglobulin expression was studied by direct immunofluorescence and by biosynthesis experiments in two human cell lines Raji and T 5.1. The basic phenotype of these cells was close to that of pre-B cells: large cells with intracytoplasmic IgM with a predominance of mu chains over light chains and no detectable surface immunoglobulins. The apparent molecular weight of heavy and light chains was abnormally large. Immunoglobulins were secreted at a low rate as pentameric IgM in the T 5.1 line and as subunits and free light chains in the Raji line. Spontaneous variations of this phenotype were observed: the cultured cells acquired mu and lambda chains, then additionally delta chains while they progressively lost detectable cytoplasmic mu chains, thus leading to a mature B cell phenotype. Subsequently, the cells had no detectable surface and cytoplasmic immunoglobulins and then they displayed a pre-B cell phenotype again. Attempts to induce further maturation using various potential inducers were unsuccessful.

Diversity of immunoglobulin expression in leukaemic cells resembling B-lymphocyte precursors.

Approximately 20% of patients with acute lymphocytic leukaemia (ALL) have leukaemic blasts with features of pre-B cells which are the recently characterized precursors of B lymphocytes in normal development (for a review, see ref. 2). Pre-B cells isolated from normal bone marrow or fetal liver, and malignant cells from patients with pre-B cell leukaemia, are rapidly dividing lymphoid cells that contain cytoplasmic immunoglobulin mu heavy chains, but have no detectable surface immunoglobulin. The resemblance of immunoglobulin-containing ALL cells to normal precursors of B lymphocytes and their availability in relatively pure preparations allowed us to explore them as models of early stages in the differentiation of the B-lymphocyte line. We report here observations on the occurrence of intermediate pre-B/B-cell phenotypes, immunoglobulin isotype switching and the asynchrony of immunoglobulin heavy and light chain expression in 30 cases of ALL and 3 cases of chronic myelogenous leukaemia in lymphoblastic crisis (CML-BC).

Sandwich radioimmunolabeling for the study of surface properties of bone marrow lymphocytes

A modification of sandwich radioautographic method was applied to the study of surface immunoglobulin and/or specific antigens on small lymphocytes in mouse and human bone marrow. After incubation of marrow cell suspensions at 37°C, cells were reacted at 0°C for 30 min with graded dilutions of rabbit anti-mouse or anti-human immunoglobulin followed by further reaction with a sheep anti-rabbit immunoglobulin labeled with 125I. Detectable surface immunoglobulin was demonstrated in approximately one-third of mouse marrow lymphocytes and 20–25% of human marrow lymphocytes. The densities of surface immunoglobulin as assessed by grain counts on individual labeled lymphocytes tended to be lower in the marrow than in spleen or peripheral blood. When the same rabbit antiserum was used to compare the sensitivity of the sandwich method with that of the direct radioautography, the former was found sufficiently sensitive to give a plateau level of labeling without seriously increasing background grains. The advantages of the method are discussed with reference to studies on T and B cell specific antigens on human bone marrow lymphocytes.

Stimulation of activated rat T cells in vitro by Listeria monocytogenes antigens

A soluble extract of Listeria monocytogenes bound firmly and in similar amounts to a variety of rat cells. Cells that bound this material differed in their capacity to stimulate the in vitro proliferation of lymphocytes obtained from the thoracic duct of Listeria-immune donors. The capacity of cells to serve as antigen-presenting cells in this system coincided or closely overlapped the expression on these cells of an Ia antigen-like structure. Three lines of evidence indicate that T cells respond to L. monocytogenes antigen: the responder cells are members of a nylon-wool nonadherent population that lacks readily detectable surface immunoglobulin; they express determinants recognized by the W3/25 monoclonal antibody (a surface marker of rat peripheral T cells); and they are stimulated optimally by L. monocytogenes antigen when the latter is displayed on cells that share a haplotype with the responder lymphocytes.

Immunologic characterization of a granulocytic leukemia of inbred strain 13 guinea pigs: presence of Ia-positive myeloblasts

Membrane markers expressed by a transplantable granulocytic leukemia induced in inbred strain 13 guinea pigs by N-nitroso-N-butylurea have been investigated by serologic and immunochemical methods. Although the leukemic myeloblasts have no detectable surface immunoglobulin or Fc receptors, they have been found to synthesize and express membrane antigens encoded for by the I-region of the major histocompatibility complex. Despite the presence of Ia antigens, these cells do not stimulate allogeneic T lymphocytes in the mixed lymphocyte reaction nor are they able to present soluble antigen to immune T cells. The presence of Ia antigens on immature myeloid cells suggests that these proteins may be important in cellular functions beyond those identified in the cellular immune system.

Immunologic Characterization of a Granulocytic Leukemia of Inbred Strain 13 Guinea Pigs: Presence of la-Positive Myeloblasts

Membrane markers expressed by a transplantable granulocytic leukemia induced in inbred strain 13 guinea pigs by N-nitroso-N-butylurea have been investigated by serologic and immunochemical methods. Although the leukemic myeloblasts have no detectable surface immunoglobulin or Fc receptors, they have been found to synthesize and express membrane antigens encoded for by the I-region of the major histocompatibility complex. Despite the presence of Ia antigens, these cells do not stimulate allogeneic T lymphocytes in the mixed lymphocyte reaction nor are they able to present soluble antigen to immune T cells. The presence of Ia antigens on immature myeloid cells suggests that these proteins may be important in cellular functions beyond those identified in the cellular immune system.