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Biomedical subjects

R M Blaese

Publications and source records attributed to R M Blaese.

At least 127 records · Page 7Linked to original sources
PubMed1986

Patients with Wiskott-Aldrich syndrome have normal IgG2 levels.

The Wiskott-Aldrich Syndrome (WAS) in humans has a number of similarities to the immunodeficiencies found in CBA/N mice, including X-chromosome-linked inheritance, inability to produce antibodies to various carbohydrate antigens, susceptibility to various bacterial infections, and an imbalance in B lymphocyte subpopulations. Moreover, in both man and mice, IgG antibodies to polysaccharides are predominantly, but not exclusively, restricted to a single IgG subclass--IgG2 in man, and IgG3 in the mouse. Because CBA/N mice have a deficiency of IgG3 antibodies and because human IgG2 subclass deficiencies have been generally associated with inability to produce antibodies to carbohydrate antigens, it would seem likely that patients with WAS would have greatly reduced levels of IgG2. Quite to the contrary, the data presented here demonstrate that WAS patients have normal levels of the different IgG subclasses, including IgG2. Thus, inability to produce antibodies to carbohydrates is not always associated with IgG2 subclass deficiency.

ABO Blood-Group System↗
PubMed1986

The role of nonactivated and interferon-gamma activated monocytes in regulating normal and SLE patient B cell responses to TNP-Brucella abortus.

We have previously characterized the human B cell response to trinitrophenol (TNP)-Brucella abortus (Ba) response as being T cell independent. In this report we examine the role of monocytes in the TNP-Ba antibody response of human peripheral blood mononuclear cells (PBMC). Depletion of monocytes by sequential adherence to plastic and Sephadex G-10 passage did not result in decreased plaque-forming cell responses to TNP-Ba, suggesting that monocytes were not required. On the contrary monocytes were probably inhibitory because their removal resulted in enhanced responses. This was confirmed by showing that adding monocytes back reconstituted the inhibition. When interferon-gamma (IFN-gamma), a potent activator of monocytes, was added to TNP-Ba-driven PBMC cultures, marked inhibition (greater than 90%) of the responses ensued. This IFN-gamma-mediated suppression was monocyte dependent because it was completely abrogated by monocyte, but not T cell depletion. Previously, we described a concanavalin A (Con A), T cell inhibition pathway of the TNP-Ba response. Both the Con A and IFN-gamma pathways were tested for their ability to inhibit systemic lupus erythematosus (SLE) patient responses to TNP-Ba. The B cell response of SLE patients was inhibitable by both pathways. In all of the patients, the inhibition was complete (greater than 95%) when IFN-gamma was added to the cultures. In the presence of Con A, greater than 95% inhibition was observed in six of 10 patients, the remainder being inhibited to a lesser extent. Thus the hyperactive B cells from SLE patients can be down-regulated, particularly in the presence of IFN-gamma.

B-Lymphocytes↗
PubMed1985

Cellular distribution of a human I-A-like (DS/DC) antigen on normal and neoplastic lymphoid cells.

Previous biochemical studies have shown that B cell specific, monoclonal antibody, McAb 33.1, reacts with a class II antigen that represents a human analogue of murine I-A (DS/DC) antigens (J. Exp. Med. 158:1924, 1983). McAb 33.1 recognizes a polymorphic human B lymphocyte specific antigen present on mu+, B1+ peripheral B cells, B lymphoid cell lines, activated B cells, and neoplastic B lymphoid cells. Of 100 HLA-D/DR typed EBV-transformed lymphoblastoid cell lines tested, only those from DR3,3 and DR7,7 individuals failed to react with McAb 33.1. The 33.1 antigen is present at lower concentrations on B cells from blood, tonsil, spleen, and lymph node when compared to B cell lines. By contrast, the antigen is not detectable on blood T lymphocytes, T cell lines, or mitogen activated T cells and it is absent on monocytes of some individuals or is present only on a minor subpopulation (approximately 20%). McAb 33.1 should facilitate the functional, structure, and molecular dissection of the human Ia system.

Animals↗
PubMed1985

Malignant lymphoma in patients with the Wiskott-Aldrich syndrome.

The type and incidence of malignant lymphoma developing in patients with the Wiskott-Aldrich syndrome being followed at the National Cancer Institute (NCI) between the years 1966 and 1982 was evaluated. Histologic material from lymphoid tissue was available for review on 24 of the 50 Wiskott-Aldrich patients followed by the Metabolism Branch of the NCI. In 17 patients, specimens were obtained by biopsy performed for diagnosis of lymphoid mass lesions, and in 16 patients autopsy specimens were reviewed. In 9 of the 24 patients a diagnosis of malignant lymphoma was made. A distinct preponderance of non-Hodgkin's lymphoma (NHL) over Hodgkin's disease (HD) with a ratio 8:1 was observed, and the overall incidence of malignant lymphoma in all 50 patients was 18%. The most common histologic subtype of NHL was large cell immunoblastic. In all but one patient the diagnosis of lymphoma was made antemortem, most often presenting in extranodal sites or the brain. Involvement of peripheral lymph nodes was conspicuous by its absence. Immunoperoxidase staining for kappa and lambda chain immunoglobulin and lysozyme was negative in the four cases studied, failing to provide supportive evidence for a B-cell or true histiocytic origin for the tumor cells. Histologic subtypes of lymphoma commonly observed in childhood, such as Burkitt's lymphoma and lymphoblastic lymphoma, were not observed. Despite treatment with combination chemotherapy in some patients, there were no long-term remissions and median survival was less than one year following the diagnosis of lymphoma.

Adolescent↗
PubMed1985

Immunostimulation by cytomegalovirus (CMV): helper T cell-dependent activation of immunoglobulin production in vitro by lymphocytes from CMV-immune donors.

Cytomegalovirus (CMV) is the cause of a number of different diseases ranging from self-limited benign infections in healthy adults to life threatening illnesses among immunocompromised hosts and newborns. Suppression of cell-mediated immunity is often found in cases of acute CMV infection, and in addition, the virus may also be a potent stimulant of lymphoid cells in vivo. We studied cellular proliferation and immunoglobulin (Ig) production induced by CMV to determine its effect on human lymphocytes in vitro. The CMV that was added to cultures of lymphocytes from CMV-seronegative donors failed to induce either significant cellular proliferation or Ig production. By contrast, CMV-stimulated cultures from CMV-seropositive donors induced both prominent cellular proliferation and Ig production. B cell differentiation into Ig-secreting cells required the presence of T cells, and this T cell help was sensitive to irradiation with 2000 rad and to treatment with cyclosporin A. When T cells were depleted of OKT4+ cells with monoclonal antibody and complement, the co-cultured B cells failed to produce Ig, whereas the depletion of OKT8+ cells had no effect on the Ig-secreting cell response. Inactivation of CMV before culture did not result in a reduction of either cellular proliferation or Ig production. Thus, infection of target cells is not required for in vitro lymphocyte activation by CMV. These results demonstrate that CMV is a potent activator of B cells inducing Ig production in vitro, and that this process requires the presence of virus-specific memory T cells.

Adult↗
PubMed1985

Characteristic T cell dysfunction in patients with chronic active Epstein-Barr virus infection (chronic infectious mononucleosis).

We evaluated immune functions in 16 patients with chronic active Epstein-Barr virus (EBV) infection (chronic infectious mononucleosis). Chronic infectious mononucleosis is an illness characterized primarily by chronic and occasionally disabling fatigue and other constitutional complaints, only sometimes beginning with an episode of acute infectious mononucleosis, and associated with an abnormal pattern of serum antibodies to EBV. In these patients, the frequency of circulating EBV-infected B cells that manifested spontaneous outgrowth in vitro was comparable to that found in EBV-seropositive normals, and the levels of EBV-specific suppressor activity were also normal. Upon stimulation with polyclonal activators, unseparated cells from these patients produced a relatively normal number of immunoglobulin-secreting cells. However, when purified T cells from these patients were mixed with normal mononuclear cells in co-culture, immunoglobulin production was strikingly suppressed. The degree of this T cell suppression correlated directly with the abnormally elevated titer of antibody to the early antigens of EBV. Interestingly, during normal convalescence from acute EBV-induced infectious mononucleosis a period is also seen during which T cells suppress the response of allogeneic but not autologous cells. Thus, from an immunologic viewpoint, patients with chronic active EBV infection appear "frozen" in a state typically found only briefly during the convalescence from acute EBV infection.

Adolescent↗
PubMed1985

Relationship between immunoglobulin production and immortalization by Epstein Barr virus.

After infection with Epstein Barr virus (EBV), human B lymphocytes actively secrete immunoglobulin (Ig) and are immortalized to become long-term cell lines. In these studies, we investigated the relationship between these virally induced processes utilizing limiting dilution culture techniques, and asked whether all B cells stimulated by EBV to secrete Ig are also immortalized. The activation of B cells by EBV resulting in Ig production and immortalization involved a single precursor cell, required live viral particles, and was independent of immunity to EBV by the lymphocyte donor. However, the precursor frequency of B cells activated to secrete Ig (mean 4.7%) was higher than the precursor frequency of B cells activated to long-term in vitro growth (mean 2.1%). When examined at a single cell level, it appeared that although the vast majority of the immortalized B cells also secrete Ig, only approximately 50% of the B cell precursors induced by EBV to secrete Ig go on to form long-term cell lines. In addition, although immortalized B cell clones producing all major classes of Ig were detected, IgM-committed precursors were more likely to become immortal than were precursors committed to IgG or IgA production. In contrast to these findings in B cells freshly infected with EBV, Ig production was almost always associated with evidence of long-term growth when B cells from previously established EBV-induced B cell lines were tested in identical limiting dilution cultures. Thus, after infection with EBV, human B cells can either become transiently activated to proliferate and to secrete Ig, or become transformed into long-term cell lines most of which produce Ig.

Adult↗
PubMed1985

Defective allosuppression in patients with ataxia-telangiectasia.

We describe a novel in vitro assay system that detects the generation of suppressor T cells after exposure of human lymphocytes to class I alloantigens. We have used this system to study immune functions in a group of seven patients with ataxia-telangiectasia (AT). Normal T lymphocytes exposed to cells differing at the A and B locus histocompatibility locus antigens (HLA) become activated for suppression of Epstein-Barr virus (EBV)-induced immunoglobulin (Ig) production. In contrast to the normal, T cells from patients with AT demonstrate no inhibitory effect after allostimulation. These data indicate that patients with AT have a profound defect involving responses to class I antigens of the major histocompatibility complex (MHC).

Adolescent↗
PubMed1985

Platelet-associated immunoglobulin, platelet size, and the effect of splenectomy in the Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome (WAS) thrombocytopenia is frequently improved by splenectomy, although the mechanism of the thrombocytopenia and its resolution are unknown. Previous studies in two patients have shown that mean platelet volume, which is characteristically reduced in WAS, increased along with platelet count postsplenectomy. Additional studies in a limited number of patients have also demonstrated that platelet-associated immunoglobulin G (PAIgG) is elevated presplenectomy, but to date no postsplenectomy data have been reported. The present study was performed to more fully evaluate the effect of splenectomy on platelet volume and PAIgG in WAS. Before splenectomy, mean platelet volume was reduced but platelet size was broadly distributed with substantial overlap of the normal range. PAIgG was significantly elevated in 13 of 14 presplenectomy WAS patients (means = 78.9 fg per platelet) and fell to normal levels postoperatively (means = 4.0 fg per platelet). Platelet count and clinical status improved postsplenectomy, and mean platelet volume and platelet volume distribution returned to the normal range. WAS subjects who relapsed with recurrent thrombocytopenia redeveloped elevated PAIgG but maintained normal platelet size. The spleen appears to play a critical role in a process that may be immunologically mediated and results in reduced platelet size.

Blood Platelets↗
PubMed1984

Purification and characterization of a mannose-containing disaccharide obtained from human pregnancy urine. A new immunoregulatory saccharide.

Endogenous mammalian lectin-like sugar-binding molecules have been previously described that have immunoregulatory properties. Further, the addition of defined simple saccharides to lymphocyte cultures has been shown to inhibit a variety of in vitro lymphocyte functions, presumably because these sugars are able to compete with the binding of endogenous lectins to critical membrane receptors. In this report, we describe the isolation and characterization of a D-mannose-containing disaccharide in human pregnancy urine that inhibits the proliferative response of human T lymphocytes. The inhibitory disaccharide was purified to homogeneity by sequential steps including affinity chromatography on immobilized concanavalin A and molecular sizing on Sephadex G-75 and then Fractogel 40S columns, with final purification on high-performance thin-layer chromatography. By mass spectrometry of the purified material as its permethylated derivative, the deduced structure of this compound was alpha-D-Manp 1-6-D-Man. To confirm that this disaccharide was in fact immunosuppressive, an identical disaccharide was prepared by sequential digestion of yeast cell wall polysaccharide. The urinary and yeast disaccharides had identical immunosuppressive properties. It has been previously reported that D-mannose is inhibitory for antigen-specific proliferative assays in the range of 10-50 mM. The purified alpha-D-Manp 1-6-D-Man disaccharide was inhibitory at 100-fold-lower concentrations. Further, while D-mannose inhibits T cell proliferation when added at anytime up to 24 h before harvest of a 6-d lymphocyte culture, alpha-D-Manp 1-6-D-Man disaccharide was inhibitory only if added at the initiation of culture and had no inhibitory effect if added just 24 h later. These data support the concept that simple sugar compounds can exhibit marked immunoregulatory activity in vitro. The impact of these molecules on the regulation of immune responses in vivo is unknown, as is their precise mechanism of action, but structural and chemical identification should now permit a detailed analysis of these issues.

Chromatography, Affinity↗
PubMed1984

Abnormally elevated frequency of Epstein-Barr virus-infected B cells in the blood of patients with rheumatoid arthritis.

Patients with rheumatoid arthritis (RA) are known to have in vitro regulatory T cell abnormalities relating to Epstein-Barr virus (EBV). In this report, we asked whether patients with RA have more circulating EBV-infected B cells than normals. To address this question, we determined the frequency of spontaneously transforming B cells in the peripheral blood of 18 normals, 15 patients with RA, and 8 patients with systemic lupus erythematosus (SLE). The mean frequency of spontaneously transforming B cells in RA patients was 10.1/10(6) B cells, which was significantly greater than that of the normal controls, 2.8/10(6) B cells (P less than 0.005). The group of patients with SLE did not differ from the normals (P greater than 0.4). In further studies undertaken to investigate as to whether RA B cells are more easily transformed by EBV than normal B cells, we determined that the frequencies of transforming B cells in the presence of exogenous EBV were similar in RA patients and normals. Lymphocytes obtained from patients with RA demonstrate a profound T cell defect in their EBV-specific suppression, as measured in vitro; there was no direct correlation, however, between this in vitro T cell abnormality and the number of circulating EBV-infected B cells. Thus, patients with RA, as a group, have abnormally elevated numbers of circulating EBV-infected B cells, and this abnormality most likely derives from a complex dysregulation of the defense mechanisms for infection with EBV.

Adult↗
PubMed1984

Pure red blood cell aplasia associated with chronic Epstein-Barr virus infection: evidence for T cell-mediated suppression of erythroid colony forming units.

A prominent T cell suppressor response is known to develop and inhibit the polyclonal B cell activation induced by Epstein-Barr virus infection. Exuberant T suppressor cell activity suppressing erythropoiesis has been demonstrated in certain cases of pure red blood cell aplasia. We studied a 19-year-old man who developed pure red cell aplasia after Epstein-Barr virus infection. Over a 70-week period, lymphocyte function and serologic evidence for chronic Epstein-Barr virus infection was demonstrated. On two separate occasions, no evidence for serum inhibition of bone marrow erythroid colony formation in methylcellulose was observed. Growth of granulocyte-macrophage progenitors from the patient's bone marrow was normal. The patient's bone marrow cultures yielded 81.6 +/- 11.2 erythroid colony-forming units per 10(5) bone marrow mononuclear cells, which was approximately 50% of levels in normal control bone marrow. Culture of peripheral blood mononuclear cells for erythroid burst-forming units revealed minimal growth (less than 1% of control values). Depletion of bone marrow T cells by E-rosetting resulted in a threefold increase in erythroid colony-forming units in the patient's bone marrow but no significant increase from control bone marrow. In the patient, addition of bone marrow T cells but not peripheral blood T cells significantly suppressed autologous erythroid colony-forming unit proliferation from T cell-depleted bone marrow. These results suggest that the pure red cell aplasia associated with chronic Epstein-Barr virus infection in this case was caused by bone marrow T cell-mediated suppression of erythroid colony-forming unit proliferation.

Adult↗
PubMed1984

Newborn and Wiskott-Aldrich patient B cells can be activated by TNP-Brucella abortus: evidence that TNP-Brucella abortus behaves as a T-independent type 1 antigen in humans.

TNP-Brucella abortus (TNP-Ba) has been classified as a T-independent type 1 (TI-1) antigen in the mouse on the basis that it activates neonatal and CBA/N (X-linked immunodeficient) murine B cells in contrast to T-independent type 2 (TI-2) antigens. Therefore, it was of interest to determine whether human newborn and X-linked Wiskott-Aldrich syndrome B cells could be triggered by TNP-Ba. Previous studies had shown that human B cells from both these latter sources were relatively insensitive to stimulation with T-dependent and polysaccharide antigens (TI-2 in mouse). In this study, we show that TNP-Ba can trigger human cord blood B cells to differentiate into anti-TNP plaque-forming cells (PFC) in a hapten-specific and T-independent manner. The dose response and kinetics were similar to those previously seen with adult cells. The newborn responses, however, were lower than adult PFC responses. Precursor frequency and clone size analyses revealed that this lower response was not due to newborn cells containing fewer precursors but was the result of a reduced ability of these anti-TNP clones to expand. The ability of TNP-Ba to activate immature newborn B cells implies that this antigen can be used to assess B cell function in very young children. It also implies that TNP-Ba behaves as a TI-1 antigen in humans as well as in mice. This was supported by the finding that B cells from Wiskott-Aldrich patients, which were unreactive to polysaccharide antigens, were generally responsive to TNP-Ba. Therefore, it would appear that human newborn and Wiskott-Aldrich patients do possess a functionally competent B cell subset possibly equivalent to Lyb-5- immature murine B cells.

Antibodies, Bacterial↗
PubMed1983

T cell-replacing factor for glucocorticosteroid-induced immunoglobulin production. A unique steroid-dependent cytokine.

Glucocorticosteroids (GCS) added to otherwise unstimulated cultures of human peripheral blood mononuclear cells (PBMC) induce the synthesis and secretion of all classes of immunoglobulin. The magnitude of this response is similar to that seen with other polyclonal B cell activators such as pokeweed mitogen (PWM), and like that of PWM, the steroid effect is dependent on both T cells and monocytes. To determine the cellular target for GCS in these cultures, separated populations of T cells and non-T cells were preincubated with steroids and then recombined. No immunoglobulin was produced in any of these preincubation experiments. As a different approach to this question, supernatants were collected from various cell populations following stimulation with PWM, concanavalin A (Con A), phytohemagglutinin (PHA), alloantigens, or GCS. These supernatants were tested for their effects on GCS-induced Ig production by B cells. Supernatants from 3-d cultures of unstimulated, as well as GCS-treated, PBMC contained a T cell-replacing factor that permitted T-depleted PBMC to produce Ig upon steroid stimulation. This supernatant factor (TRF-S) could be produced in the absence of steroid stimulation, but both the factor and GCS were necessary for the induction of Ig synthesis. Production of the TRF-S required the presence of both T cells and adherent cells in culture and was found in the highest concentrations at 3-4 d of culture. Supernatants from cultures stimulated with PWM, PHA, Con A, and alloantigens did not contain detectable TRF-S activity, and TRF-S was unable to replace helper T cells for PWM-induced Ig production. TRF-S required the presence of adherent cells in the T cell-depleted responder population for its action. Further, it was effective in inducing Ig production along with GCS in the presence of a sufficient concentration of cyclosporin A to block all T cell helper activity for primary responses of PBMC to PWM or GCS. TRF-S was inactivated by trypsin treatment, heating to 56 degrees C, freezing, lyophilization, and storage at 4 degrees C for greater than 3 wk. Its molecular weight is probably 10,000 daltons or more, since TRF-S activity is not rapidly dialyzable. These experiments indicate that GCS-induced Ig production by human B cells does not require the presence of intact T cells in the cultures and therefore the steroids are not exerting their influence directly on T suppressor or T helper cells. Furthermore, they demonstrate a previously unrecognized cytokine that induces the differentiation of human B cells to Ig production in the presence of GCS.

B-Lymphocytes↗