Ill-defined germinal centers and severely reduced plasma cells are histological hallmarks of lymphadenopathy in patients with common variable immunodeficiency

Given the severely reduced numbers of circulating class-switched memory B cells and plasmablasts in patients with common variable immunodeficiency (CVID) the germinal center (GC) reaction as the source of both populations is expected to be disturbed in many CVID patients. Therefore immunohistochemical studies were performed on lymph node (LN) biopsies from ten CVID patients with benign lymphoproliferation. According to the Sander classification the majority of patients presented with reactive lymphoid hyperplasia (7/10), 6/10 showed granulomatous inflammation. All cases showed some normal GCs but in 9/10 these concurred to a varying degree with hyperplastic, ill-defined GCs in the same LN. The percentage of ill-defined GCs correlated significantly with the percentage of circulating CD21(low) B cells suggesting a common origin of both immune reactions. In 9/10 CVID LNs significantly higher numbers of infiltrating CD8+ T cells were found in GCs of CVID patients compared to controls, but no HHV-8 and only in 2/10 LNs EBV infection was detected. Class switched plasma cells (PCs) were severely reduced in 8/10 LNs and if present, rarely found in the medulla of the LN. Based on the presence of large GCs in all examined patients, the reduction of circulating memory B cells and PCs points towards a failure of GC output rather than GC formation in CVID patients with lymphadenopathy.

Homozygous loss of ICOS is associated with adult-onset common variable immunodeficiency

No genetic defect is known to cause common variable immunodeficiency (CVID), a heterogeneous human disorder leading to adult-onset panhypogammaglobulinemia. In a search for CVID candidate proteins, we found four of 32 patients to lack ICOS, the "inducible costimulator" on activated T cells, due to an inherited homozygous deletion in the ICOS gene. T cells from these individuals were normal with regard to subset distribution, activation, cytokine production and proliferation. In contrast, naive, switched and memory B cells were reduced. The phenotype of human ICOS deficiency, which differs in key aspects from that of the ICOS-/- mouse, suggests a critical involvement of ICOS in T cell help for late B cell differentiation, class-switching and memory B cell generation.

Expansion of CD19(hi)CD21(lo/neg) B cells in common variable immunodeficiency (CVID) patients with autoimmune cytopenia

Common variable immunodeficiency (CVID) is characterized by a severe hypogammaglobulinemia. While the clinical picture is dominated by recurrent respiratory and gastrointestinal infections, a subgroup of up to 30% of the patients develops additional autoimmune phenomena, including thrombocytopenia and autoimmune hemolytic anemia. So far no classification allowed a prediction of the coincidence of immunodeficiency and autoimmunity. Here, we propose the size of the peripheral CD19(hi)CD2(lo/neg) B cell pool as a marker for CVID patients with autoimmune cytopenia and splenomegaly. Interestingly similar B cell populations are also found in patients with SLE and may not only be an epiphenomenon of the disease.

Severe deficiency of switched memory B cells (CD27(+)IgM(-)IgD(-)) in subgroups of patients with common variable immunodeficiency: a new approach to classify a heterogeneous disease

Hypogammaglobulinemia is the hallmark of common variable immunodeficiency (CVID) syndrome, a heterogeneous disorder predisposing patients to recurrent bacterial infections. In this study, we investigated the peripheral B-cell compartment of 30 well-characterized CVID patients in comparison to 22 healthy controls. Flow cytometric analysis of peripheral blood lymphocytes revealed a reduction of class-switched CD27(+)IgM(-)IgD(-) memory B cells below 0.4% in 77% of our patients (group I), while this B-cell subpopulation exceeded 0.5% in all healthy donors and in 23% of CVID patients (group II). These results correlate well with the capacity of peripheral blood lymphocytes to produce immunoglobulins in vitro upon stimulation with Staphylococcus aureus Cowan I (SAC) plus interleukin-2 because the production of immunoglobulin G in vitro is entirely dependent on the presence of switched memory B cells. The subdivision of group I into patients with an increased proportion of CD21(-) peripheral B cells (> 20%; group Ia) and patients with normal percentages of CD21(-) B cells (< 20%; group Ib) revealed a significant clustering of patients with splenomegaly and autoimmune cytopenias in group Ia. Based on these observations, we propose a fast and reliable new classification for CVID patients by flow cytometric quantification of class-switched memory and immature B cells in the peripheral blood of patients. Our results point toward defects at various stages of B-cell differentiation in CVID subgroups and support the value of a B-cell-oriented classification principle. A consensus on this new classification system will hopefully provide a tool for rapidly defining homogeneous subgroups of CVID for functional studies and genetic linkage analysis.

Presence of IgE antibodies to bovine serum albumin in a patient developing anaphylaxis after vaccination with human peptide-pulsed dendritic cells

Dendritic cells are professional antigen-presenting cells that can be generated in vitro either from monocytes or from CD34+ peripheral blood progenitor cells by using recombinant cytokines. These cells have potential implications for immunotherapeutic approaches in the treatment of cancer and other diseases. We have conducted a phase I study in melanoma patients using peptide-pulsed dendritic cells cultured in medium supplemented with 10% fetal calf serum (FCS) and a cocktail of cytokines. Peptide-pulsed dendritic cells were injected intravenously at 2-week intervals. Here we report on a case of type I hypersensitivity anaphylactic reaction after repetitive vaccination with autologous peptide-pulsed cells. Pre-vaccination and post-vaccination serum samples were evaluated for the presence of antibodies to FCS and bovine serum albumin (BSA). A retrospective study in 7 patients vaccinated with FCS-cultured dendritic cells demonstrated the presence of IgG and IgM antibodies to FCS and BSA after vaccination in 6 out of 7 patients. However, IgE antibodies were absent in all patients with the exception of the patient developing anaphylaxis. The patient's serum was demonstrated to contain a strong IgE response directed against BSA. In contrast, 2 patients vaccinated with dendritic cells cultured under serum-free conditions developed no antibodies to FCS and BSA after repetitive vaccination. We suggest that patients can be sensitized with an IgE response against BSA leading to anaphylactic reactions. On the basis of these data, dendritic cells cultured in autologous serum or under serum-free conditions are recommended for therapeutic applications in vivo.

Transient CD80 expression defect in a patient with variable immunodeficiency and cyclic neutropenia

CD80 expression on stimulated B cells of 9 common variable immunodeficiency (CVID) patients and 10 healthy control individuals was examined. Here we report on an exceptional CVID patient with recurrent episodes of cyclic neutropenia, skin vasculitis and recurrent infections associated with a transient, but reproducible CD80 expression defect on stimulated B cells. Concomitantly serum Ig levels were markedly reduced and B cell counts were low. Interestingly, after recovery from an episode of neutropenia and vasculitis we observed an improvement of the CD80 expression as well as an increase in the number of B cells and a recovery of IgM and IgG production in vivo and in vitro.

Severe combined immunodeficiency due to defective binding of the nuclear factor of activated T cells in T lymphocytes of two male siblings

Peripheral blood lymphocytes (PBL) and alloreactive T cell lines of two male infants born to consanguinous parents and presenting with severe combined immunodeficiency (SCID) showed a pronounced deficiency in T cell activation. Although phenotypically normal, the proliferative response of the childrens' T cells was strongly reduced but could be improved by the addition of interleukin-2 (IL-2). Furthermore both childrens' T cells were unable to produce the cytokines IL-2, interferon-gamma (IFN-gamma), IL-4 and tumor necrosis factor-alpha (TNF-alpha). This multiple cytokine production deficiency could not be restored by IL-2 or co-stimulatory signals provided by antigen-presenting cells (APC). Moreover, mRNA for IL-2 and IFN-gamma could not be detected. In contrast, expression of the activation-dependent cell surface markers CD25 and CD69 was within normal limits. To determine whether the functional defect of the patients' T cells was due to the absence or abnormal binding of transcription factors involved in cytokine gene expression, electrophoretic mobility shift assays were used to examine the DNA binding of AP-1, Oct, CREB, SP1, NF-kappa B and the nuclear factor of activated T cells (NF-AT) to their respective response elements in the promoter of the IL-2 gene. Whereas AP-1, NF-kappa B, Oct, CREB and SP1 displayed normal binding activities in nuclear extracts, the binding of NF-AT to its IL-2 promoter response element was barely detectable both before and after T cell stimulation. Our results strongly suggest that this NF-AT/DNA binding defect is responsible for the multiple cytokine deficiency and the SCID phenotype observed in the two infant brothers.

Two novel cationic staphylococcal proteins induce IL-2 secretion, proliferation and immunoglobulin synthesis in peripheral blood mononuclear cells (PBMC) of both healthy controls and patients with common variable immunodeficiency (CVID)

Two cationic proteins, a neutral phosphatase (NP-tase) and a 70-kD protein (p70) were isolated from Staphylococcus aureus by ion exchange chromatography. We compared their properties to those of the well established B cell mitogen of whole, fixed Staph. aureus strain Cowan I cells (SAC). Both purified proteins were able to induce immunoglobulin synthesis in PBMC cultures of healthy donors. NP-tase and p70 also induced immunoglobulin synthesis of PBMC from those patients with CVID who were also responsive to SAC plus IL-2 stimulation. Immunoglobulin synthesis in response to NP-tase and to p70 was time- and dose-dependent and could be inhibited by addition of specific antibodies against the proteins. In contrast to SAC, no addition of exogenous IL-2 was necessary to obtain maximal immunoglobulin synthesis induced by NP-tase or p70. However, neither protein was able to induce immunoglobulin synthesis in B cell-enriched cultures. High amounts of IL-2 were found in supernatants of PBMC from healthy donors following stimulation with low concentrations of NP-tase or p70, and this was associated with vigorous lymphocyte proliferation. Both proteins behave like typical antigens, and not like lectins or superantigens, since an NP-tase-stimulated T cell line showed an antigen-specific, MHC-restricted secondary response. In addition, no preferential T cell receptor V beta chain usage was found with eight V beta-specific MoAb. It is likely that the two proteins induce antigen-specific T cell activation, which is then followed by polyclonal activation of B cells via CD40 receptors and cytokine release.

Monocyte differentiation and accessory function: different effects on the proliferative responses of an autoreactive T cell clone as compared to alloreactive or antigen-specific T cell lines and primary mixed lymphocyte cultures

An autoreactive T cell clone derived from a patient with reactive arthritis, two alloreactive T cell lines, two antigen-specific T cell lines and allogeneic resting T cells were analyzed for their responses to monocytes and macrophages derived from monocytes by in vitro differentiation. The autoreactive T cell clone strongly proliferated in response to fresh monocytes and to macrophages derived from a 7 day culture, but only poorly to monocytes cultured for 2 days. In contrast, alloreactive and antigen-specific T cell lines proliferated to all stimulatory cells equally well. Finally, primary mixed lymphocyte reactions could be stimulated by both fresh and 2-day cultured monocytes, but not by in vitro derived macrophages. The impaired response of the autoreactive T cell clone to 2-day cultured monocytes could not be attributed to reduced expression of several well-defined surface molecules nor to induction of nonresponsiveness. Neither allogeneic monocytes nor cytokines (IL-1, IL-2, IL-4, IL-6) could correct the defective response of the autoreactive T cell clone. However, preculture of monocytes in the presence of interferon-gamma, IL-1, IL-4 or IL-6 retained their stimulatory capacity. Our interpretation of the selectively impaired response of the autoreactive T cell clone is that it most likely recognizes a differentiation-dependent monocyte/macrophage-specific peptide.

[Preliminary results in a placebo-controlled, double-blind crossover clinical trial with human interleukin-2 (n-IL-2) in patients with variable immunodeficiency syndrome (CVID)]

Ten CVID patients with an in vitro defect for IL-2-synthesis were treated for 12 months in a placebo-controlled double-blind crossover therapy study with human natural IL-2 s.c. There were no severe side effects of n-IL-2 recorded. Serum levels of soluble IL-2 receptors were unaffected by the therapy. Serum IL-2 levels were only measurable in single patients during the therapy phase. Since verum and placebo groups did not differ with respect to requirement for intravenous gammaglobulin substitutions, n-IL-2 therapy was uneffective in switching on IgG synthesis in vivo. Nevertheless, there was an elevation in vitro of IgM synthesis in 5 patients and of IgG synthesis in 4 patients during n-IL-2 therapy after stimulation of patients' lymphocytes with staphylococcus aureus Cowan I (SAC) plus n-IL-2 or with Pokeweed Mitogen (PWM) without n-IL-2. Additionally, an elevated IL-2-synthesis in vitro was recorded after OKT3 stimulation for 3 CVID patients. There was a significant reduction of severe infections from 25 during the first 6 months of the study to 7 infections during the following 6 months, in the group of patients which received n-IL-2 first. In the second group, which received placebo first, there were no significant differences between placebo and n-IL-2 therapy phase detectable (25 infections during the first 6 months of the study and 24 severe infections in the second phase).(ABSTRACT TRUNCATED AT 250 WORDS)

Possible role of IL-2 deficiency for hypogammaglobulinaemia in patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) patients are unable to produce specific immunoglobulins after antigen contact in vivo. The aim of this study was to investigate whether in some cases of CVID a decreased de novo synthesis of IL-2 might be the cause of immunodeficiency and whether this deficiency can be corrected by IL-2 supplementation in vitro. Mononuclear cells from 17 CVID patients and from 10 healthy controls were cultured with monoclonal anti-CD3 antibody OKT3, pokeweed mitogen (PWM) or tetanus toxoid (TT) to stimulate IL-2 synthesis. In parallel, in vitro IgG and IgM synthesis was stimulated with Staphylococcus aureus Cowan I (SAC), PWM or TT in the presence or absence of IL-2. While lymphocytes of 11 out of 17 patients produced low to normal amounts of IL-2 upon stimulation with anti-CD3, only three patients showed low IL-2 production in response to PWM and five in response to TT. Regarding immunoglobulin synthesis in vitro, five patients completely failed to produce IgM or IgG upon stimulation with PWM, SAC or TT irrespective of the addition of IL-2. By contrast, four patients did not show any defect in vitro and synthesized normal amounts of IgM and IgG with any of the three stimuli. Finally, eight patients could be reconstituted for PWM-, SAC- and TT-induced IgM and/or IgG synthesis in vitro, by adding IL-2 to the culture system. This enhancing effect of IL-2 could be blocked by adding anti-IL-2 receptor antibodies to the cultures. Our findings indicate that a defective IL-2 synthesis after antigen stimulation may be one reason for the impaired immunoglobulin production in some cases of CVID.

[Effects of IL-2 and IL-6 on the immunoglobulin synthesis of lymphocytes from CVID patients]

Peripheral blood lymphocytes from five hypogammaglobulinemic patients suffering from common variable immunodeficiency (CVID) were stimulated with Staphylococcus aureus Cowan I (SAC) and pokeweed mitogen (PWM). The assays were substituted with interleukin-2 (IL-2) and interleukin-6 (IL-6) in different combinations. In three patients who were deficient for IgM in vivo a combination of SAC and IL-2 induced a normal IgM synthesis in vitro. In these patients a deficient IL-2 synthesis is probably the cause of CVID. In only one patient a "class switch" from IgM to IgG was detectable. Stimulation with PWM which is T-cell-dependent induced in one out of the five patients a normal IgM synthesis. Another CVID patient showed no defect in IgM or IgG synthesis in vitro. With these in vitro assays it seems possible to identify CVID patients who might profit from a therapy with human IL-2 in vivo.

Autoreactive T cells in rheumatic disease. II. Function and specificity of an autoreactive T helper cell clone established from a HLA-B27+ reactive arthritis

T cell lines were established by limiting dilution of peripheral blood (PBL) and synovial fluid lymphocytes (SFL) of a patient with HLA-B27+ reactive arthritis. Among these cell lines, the CD4 phenotype was dominant. Functionally, the majority of these cell lines exhibited helper activity for the immunoglobulin production by autologous B cells and proliferated in response to autologous mononuclear cells. In most cases, this autoreactive response was associated with alloreactivity. Only one cell line, the autoreactive CD4+ T cell clone, UA-S2, which was derived from the synovial fluid, proliferated in a highly specific manner in response to a determinant associated with MHC class II products present on autologous mononuclear cells. The restriction element was shown to be associated with DR molecules by inhibition experiments with monoclonal antibodies. Within the patient's family, the capacity of mononuclear cells to stimulate a proliferative response of UA-S2 segregated together with the HLA haplotype A2 or 32, B27, Cw1, DRw11 which was contributed by the patient's mother. UA-S2 proved to be a functional helper T cell clone. In the absence of additional antigen or mitogen, it induced IgG and IgM synthesis of autologous and family members' B cells. This helper activity of UA-S2 showed the same MHC restriction as the proliferative response. Although the patient's father also typed DRw11, this haplotype was not recognized by UA-S2. It is suggested that this autoreactive T cell clone detects a microheterogeneity of the serologically defined DRw11 haplotype. Indeed, typing of the patient's family members with cellular reagents established a difference between the two DRw11 haplotypes.

Quantitative absorption of interleukin-2 by peripheral blood and synovial fluid lymphocytes from patients with rheumatoid arthritis

Peripheral blood (PBL) and synovial fluid lymphocytes (SFL) from 18 patients with definite rheumatoid arthritis (RA) and from one patient with Reiter's disease (RD) were examined for their capacity to absorb quantitatively interleukin-2 (IL-2) from a standardized, lectin-free IL-2 source. For comparison normal ConA blasts and PBL from various inflammatory and noninflammatory diseases as well as from healthy control persons were studied. IL-2 activity was quantitated by measuring 3H-thymidine-2-deoxyriboside uptake in the IL-2 dependent murine T cell line CTL6. ConA blasts exhibited a high IL-2 absorption capacity and served as a positive control for calibrating the absorption assay. In a population of normal PBL at least 5-10% of ConA blasts were required to detect IL-2 absorption. Significant absorption was assumed if more than 50% of IL-2 activity was removed from 200 microliters of a lectin-free IL-2 standard following incubation with 5 X 10(6) lymphoid cells for 2 h at 4 degrees C; this criterion was fulfilled with 8 out of 20 SFL and 4 out of 14 PBL preparations from RA patients. As a rule SFL absorbed more IL-2 than PBL. Control PBL did not absorb significant quantities of IL-2. PBL from the RD patient apparently produced an IL-2 inhibitor during incubation with the IL-2 standard. IL-2 absorption by ConA blasts and SFL was fully inhibited by preincubation of the absorbing cells with monoclonal anti-TAC antibody, a reagent known to react with the human IL-2 receptor. The results are discussed in view of current concepts of antigen/mitogen induced T cell activation.

[Terminal B-cell maturation and immunoglobulin synthesis in vitro in primary and secondary immune deficiencies]

Peripheral blood lymphocytes (PBL) from patients with various forms of primary and secondary immunodeficiencies and from 30 healthy control persons were examined for their capacity to show terminal B-cell maturation and immunoglobulin (Ig) synthesis in vitro following pokeweed mitogen (PWM) stimulation. PBL were cultured for 9 days with or without PWM and the percentages of B-cells or plasma cells with strongly positive cytoplasmic Ig (CIg+) were determined by indirect immunofluorescence on methanol fixed cytocentrifuged lymphocyte smears. In addition, newly synthesized IgA, IgG and IgM was measured in the cell free culture supernatant by means of a sensitive microplate ELISA. In 29 out of 30 control cultures the proportion of CIg+-cells increased markedly following 9-day stimulation with PWM. CIg+-cells and newly synthesized Ig were significantly correlated. In a group of 18 patients with common variable immunodeficiency (CVID) maturation to CIg+-cells was greatly impaired and the in vitro production of IgA and IgG was reduced. Two infants with severe combined immunodeficiency (SCID) failed to produce Ig prior to and following haplo-identical bone marrow transplantation despite the presence of immature B-cells. A heterogeneous group of secondary immunodeficiencies showed different forms of an impaired terminal B-cell maturation and a reduced capacity to synthesize Ig in vitro. The described PWM culture techniques in combination with the evaluation of CIg+-cells and the measurement of newly synthesized Ig in the culture supernatant proved to be a reliable in vitro correlate for terminal B-cell maturation and represent an important tool for the classification of humoral immunodeficiencies.