Association between endogenously activated T cells and immunoglobulin-secreting B cells in patients with active systemic lupus erythematosus

Hepatocyte growth factor prevents lupus nephritis in a murine lupus model of chronic graft-versus-host disease

Chronic graft-versus-host disease (GVHD) induced in (C57BL/6 x DBA/2) F1 (BDF1) mice by the injection of DBA/2 mouse spleen cells represents histopathological changes associated with systemic lupus erythematosus (SLE), primary biliary cirrhosis (PBC) and Sjogren's syndrome (SS), as indicated by glomerulonephritis, lymphocyte infiltration into the periportal area of the liver and salivary glands. We determined the therapeutic effect of hepatocyte growth factor (HGF) gene transfection on lupus using this chronic GVHD model. Chronic GVHD mice were injected in the gluteal muscle with either HVJ liposomes containing 8 microg of the human HGF expression vector (HGF-HVJ liposomes) or mock vector (untreated control). Gene transfer was repeated at 2-week intervals during 12 weeks. HGF gene transfection effectively prevented the proteinuria and histopathological changes associated with glomerulonephritis. While liver and salivary gland sections from untreated GVHD mice showed prominent PBC- and SS-like changes, HGF gene transfection reduced these histopathological changes. HGF gene transfection greatly reduced the number of splenic B cells, host B cell major histocompatibility complex class II expression, and serum levels of IgG and anti-DNA antibodies. IL-4 mRNA expression in the spleen, liver, and kidneys was significantly decreased by HGF gene transfection. CD28 expression on DBA/2 CD4+ T cells was decreased by the addition of recombinant HGF in vitro. Furthermore, IL-4 production by DBA/2 CD4+ T cells stimulated by irradiated BDF1 dendritic cells was significantly inhibited by the addition of recombinant HGF in vitro. These results suggest that HGF gene transfection inhibited T helper 2 immune responses and reduced lupus nephritis, autoimmune sialoadenitis, and cholangitis in chronic GVHD mice. HGF may represent a novel strategy for the treatment of SLE, SS and PBC.

Production of pathogenic antibodies: cognate interactions between autoimmune T and B cells

A select population of autoimmune T-helper (T(H)) cells drive the production of pathogenic anti-DNA autoantibodies in SLE. These T(H) cells recognize nucleosomal peptides that are processed and presented by the anti-DNA B cells that they help. The critical peptide epitopes for the T(H) cells reside in the core histones of the nucleosome particle. Remarkably, the nucleosomal peptide epitopes do not obey the rule of MHC-restriction; they can be promiscuously presented and recognized in the context of diverse MHC alleles. Such promiscuous antigens, called pantigens, are also recognized by autoimmune T cells, in a degenerate fashion, and this promiscuous recognition is conferred by the lupus TCR alpha chains. High-affinity interactions between the lupus TCRs and MHC-nucleosomal peptide complex due to reciprocally charged residues probably overcome the requirement for MHC restriction. These studies open up the possibility of developing 'universally' tolerogenic epitopes for therapy of lupus in humans despite their diversity of HLA alleles. The results also have profound implications regarding the selection of autoimmune T cells in the lupus-prone thymus and their expansion in the periphery. Furthermore, the T(H) cells, as well as B cells of lupus, have a regulatory defect causing markedly increased and prolonged expression of CD40 ligand (CD40L), which mediates abnormal co-stimulatory signals to autoimmune B cells, sustaining the production of pathogenic autoantibodies. These observations suggest a new paradigm for B cell hyperactivity in lupus and provide alternative targets for immunotherapy. Indeed, giving only three injections of anti-CD40L antibody in a one-week period to mice with manifest lupus selectively blocks the pathogenic autoimmune response and delays the development of lupus nephritis by one year (equivalent to three decades in humans). Thus, possession of promiscuous, high-affinity receptors and prolonged expression of CD40L by lupus T cells probably lowers activation threshold, leading to an autoimmune response against nucleosomes derived from apoptotic cells that are normally ignored by the immune system.

Decreased T cell response to anti-CD2 in systemic lupus erythematosus and reversal by anti-CD28: evidence for impaired T cell-accessory cell interaction

OBJECTIVE

To assess the ability of T cells from patients with systemic lupus erythematosus (SLE) to respond to a mitogenic combination of anti-CD2 monoclonal antibodies (MAb), and to learn the molecular basis of the documented defect.

METHODS

Peripheral blood mononuclear cell (PBMC) populations from individuals with SLE and paired controls were stimulated in vitro with anti-CD2, and the proliferative response was compared with that evoked by stimulation with phytohemagglutinin (PHA) and anti-CD3. Surface markers on lymphocyte populations were assessed by flow cytometry after staining with specific MAb.

RESULTS

The proliferative response to anti-CD2 was decreased to a greater extent than was the response to anti-CD3 or PHA in SLE patients. This defect was found in approximately one-half of the patients examined, was not associated with disease activity, and was maintained upon repeated testing. Since either monocytes or resting B cells can serve as accessory cells for T cells following activation by anti-CD2, we examined the T cell response after depletion of adherent cells. In approximately two-thirds of the individuals with a decreased response, depletion of monocytes or substitution of monocytes with allogeneic, resting B cells from normal donors corrected the defect. The addition to PBMC of anti-CD28, but not of a neutralizing antibody to interleukin-10, largely reversed the anti-CD2 proliferative defect. Significantly fewer CD8+ T cells expressed CD28 in SLE, and this defect was also documented, to a lesser extent, in CD4+ cells.

CONCLUSION

This study provides evidence that some functional T cell defects in SLE may be due, at least in part, to decreased CD28-mediated costimulatory activity following the interaction of T cells with conventional accessory cells.

T- and B-cell abnormalities in systemic lupus

A wealth of T- and B-cell abnormalities has been described in systemic lupus erythematosus (SLE). In general, T and B cells manifest evidence of intense in vivo activation, yet perform poorly when tested for in vitro responsiveness to exogenous antigen. The immune system behaves as if its commitment to self-responsiveness overrides the normal capacity to respond to immunogenic challenges. Many immunoregulatory abnormalities have been characterized, but their relation to disease remains controversial. Although a widely accepted unifying hypothesis for the vigorous autoantibody production and associated immune deficiency of SLE is lacking, it seems certain that the profound abnormalities of T and B cells in SLE are intertwined with the fundamental cause of this illness.

Deficient interleukin-2 responsiveness of T lymphocytes from patients with primary biliary cirrhosis

There is increasing evidence that primary biliary cirrhosis is associated with an alteration of the immune system. Although the cause remains unknown, it has been suggested that the immune system of patients with primary biliary cirrhosis is involved in the pathogenesis of their disease. We have investigated the T-cell function in patients with primary biliary cirrhosis and have found defective phytohemagglutinin-induced T-cell mitogenesis. Likewise, their blastogenic response to CD3 monoclonal antibody was also depressed, although the DNA synthesis induced by stimulation with phorbol esters (12-O-tetradecanoil-phorbol-13-acetate) plus ionophore (ionomycin) was normal. These alterations could not be ascribed either to a decreased synthesis of interleukin-2 or to a defective expression of interleukin-2 receptor after cellular activation. Moreover, this defective proliferative response of T lymphocytes was observed even in the presence of saturating concentrations of exogenous interleukin-2. These results represent evidence of the deficiency in the interleukin-2-dependent pathway found in T lymphocytes from patients with primary biliary cirrhosis.

Heterogeneity of RNP and Sm autoantigens in relation to the cell sources and the activated state of the cells

The extracts of rabbit thymus (RTE), HeLa cells, human histiocytic lymphoma cell line U-937, human promyelocytic cell line HL-60, Ehrlich ascites tumor cells (EACs), and peripheral white blood cells (WBCs) were tested for their composition, molecular weight, and amount of Sm and RNP autoantigens on immunoblotting. The molecular weight of the so-called 68 kDa U1 RNP antigen, which is associated with mixed connective tissue disease (MCTD), was 64.5 kDa in RTE, 62.5 kDa in HeLa cells and HL-60 cells, and 59 kDa in WBCs. Surprisingly, in both WBCs and U-937 cells, the main protein band bearing the 68 kDa U1 RNP antigenic determinants was 30.5 kDa in molecular weight, which was confirmed using antibodies purified by affinity chromatography. After stimulation with phytohemagglutinin (PHA), there was in the human lymphocytes a diminished amount of the 30.5 kDa protein and simultaneously an increased synthesis of several proteins of higher molecular weight, especially the 57 kDa protein bearing the 68 kDa antigenic determinants. The concentrations of the A, B/B', C, D, and E proteins also increased with PHA stimulation. Our results indicate that the expression of Sm and RNP autoantigens may depend on the cell source as well as the activated state of cells. These differences should be taken into consideration in the detection of anti-RNP and anti-Sm antibodies by immunoblotting.

Lupus nephritis at the University Hospital of the West Indies, Kingston, Jamaica: a 10-year experience

The case records of 75 patients who had systemic lupus erythematosus (SLE) and renal involvement on renal histology were reviewed. There were 70 females and 5 males, with a ratio of 14:1. The majority of the patients were in their second and third decades of life. SLE nephritis was distinctly uncommon in patients below 10 years of age and above 50 years of age. In nearly 80% of the patients, SLE nephritis was diagnosed within the year prior to presentation. The most common presenting clinical features were arthritis in 78% and a rash in 48%. The two most common renal features were proteinuria in 60% and renal failure in 55%. Of these patients, 20%, 12%, 48%, and 17% fell into Class II (mesangial GN), Class III (focal GN), Class IV (diffuse GN), and Class V (membranous GN), respectively, when the renal histological abnormalities were categorized according to the World Health Organization classification. The remaining 3% of patients had sclerosis and as a result were unclassifiable. The two major clinical manifestations in the Class IV patients were an acute nephritis syndrome in 83% and renal failure in 61%. The nephrotic syndrome was seen in 62% of Class V (membranous GN) cases. There was 100% survival in Classes II (mesangial GN) and V (membranous GN), and 62% percent in Classes III (focal GN) and IV (diffuse GN) combined.

Nature of IgG anti-lymphocyte autoantibody-reactive molecules shed from activated T cells in systemic lupus erythematosus

Shedding of cell-surface antigens that react with anti-lymphocyte autoantibodies in systemic lupus erythematosus (SLE) is well-recognized, but the nature of such molecules is unknown. The present investigation demonstrates the rapid shedding of three IgG antibody target molecules of Mr 55,000, 37,000, and approximately 32,000 from the surface of mitogen-activated peripheral T cells during brief incubation at 37 degrees C. Sera lacking IgG anti-lymphocyte antibodies stained none of the three antigens. Absorption of antibody-positive sera with viable HSB-2 cells, a primitive T-cell line lacking HLA antigens and many CD antigens characteristic of mature peripheral T cells, eliminated staining of the shed molecules. These data delineate the number and estimated molecular mass of anti-lymphocyte autoantibody target molecules that are shed from the surface of T cells, and provide further insight into potential mechanisms by which anti-lymphocyte antibodies contribute to the pathogenesis of SLE and related disorders.

The B-cell activation pathway in human systemic lupus erythematosus: imbalanced in vitro production of lymphokines and association with serum analytical findings

Recent knowledge of B-lymphocyte physiology has clarified the role of T cell-derived lymphokines in clonal proliferation and differentiation of B-cell responses. Lymphokine production was analyzed in 19 systemic lupus erythematosus (SLE) patients and sex- and age-matched controls in relation to clinical activity and steroid treatment. When in vitro production of interleukin-2 (IL-2) and B-cell growth factor (BCGF) was tested, both activities were found to be diminished in the group of patients (P less than 0.01), while B-cell differentiation factor (BCDF) activity was higher in this group with respect to normal controls (P less than 0.01). Interestingly enough, this in vitro BCDF synthesis was positively correlated with clinical activity regardless of low-dose steroid treatment. A correlation was also found between BCDF production and the levels of IgG (r = 0.64, P less than 0.01), anti-DNA antibodies (r = 0.52, P less than 0.05), and the IgG/IgM ratio (r = 0.7, P less than 0.01) in serum. Implications of these abnormal T-lymphocyte functions in SLE with respect to in vivo B-cell function are discussed.

Clinical and immunologic effects of monthly administration of intravenous cyclophosphamide in severe systemic lupus erythematosus

Severe systemic lupus erythematosus affecting the kidney or central nervous system may lead to organ failure or death despite treatment with high doses of corticosteroids. To evaluate the clinical and immunologic effects of intravenous cyclophosphamide in this setting, we treated nine patients with monthly intravenous infusions of cyclophosphamide for six months. A comparison of characteristics at entry and follow-up revealed improvements (by paired t-test) in creatinine clearance (66 vs. 96 ml per minute, P less than 0.001); 24-hour urinary protein level (4.11 vs. 0.90 g, P less than 0.05), Farr anti-DNA titer (43 vs. 8.5 percent, P less than 0.01); complement components C3 (894 vs. 1150 mg per liter, P less than 0.05), C4 (154 vs. 222 mg per liter, P less than 0.05), and total complement activity (CH50) (88.7 vs. 113.4 IU, P less than 0.05); and Westergren erythrocyte sedimentation rate (60.2 vs. 34.4 mm per hour, P less than 0.0005). Other manifestations of lupus improved markedly in most cases, despite a reduction in the mean daily dose of prednisone, from 45 mg at entry to 17 mg at follow-up (P less than 0.01). The numbers of lymphocytes positive for T3, T4, T8, and B1 declined progressively during treatment. At follow-up, persistent decreases were observed in the T-lymphocyte subsets, whereas the absolute number of B lymphocytes had returned to levels near base line. T-cell proliferative responses at follow-up were not significantly different from entry values, except that the response to mitogenic anti-T11 (CD2) antibodies was decreased (P less than 0.01). Our data indicate that monthly intravenous administration of cyclophosphamide was associated with a substantial amelioration of severe systemic lupus, in conjunction with discrete changes in T-lymphocyte markers and T-cell function. This was a preliminary, uncontrolled study, but the results warrant further investigation of this form of treatment.

The influence of interferon-gamma, interleukin-2, prostaglandin E2, and cyclosporine on the polyclonal and anti-DNA antibody secretion in lymphocyte cultures derived from patients with systemic lupus erythematosus

The influence of various immunoregulatory substances was studied in lymphocyte cultures derived from patients suffering from systemic lupus erythematosus (SLE) by using the model of spontaneous secretion of polyclonal immunoglobulin G (IgG)/immunoglobulin M (IgM) and anti-DNA autoantibodies. Compared with healthy donors, lymphocytes derived from patients with active SLE disease showed an elevated secretion of total IgG as well as anti-DNA-IgG in vitro, which was associated with an increase in the proportion of activated (HLA-class II +) T cells in their peripheral blood. Recombinant interferon-gamma increases the total IgG/IgM as well as anti-DNA-IgG/IgM secretion, which suggests that it has a possible role in the pathogenesis of SLE disease. Recombinant interleukin-2 and prostaglandin E2 normalize the high, spontaneous total IgG secretion, but elevate anti-DNA-IgG/IgM secretion. These results suggest that autoreactive B-cell clones are regulated differently in SLE patients. Cyclosporine inhibits total IgG/IgM secretion in all patients and anti-DNA-IgG/IgM secretion in six of eight patients. The possible therapeutic use of such immunomodulatory substances in SLE disease is discussed.

Increased proto-oncogene expression in peripheral blood lymphocytes from patients with systemic lupus erythematosus and other autoimmune diseases

Using RNA hybridization techniques, we examined the expression of proto-oncogenes associated with lymphocyte activation in vitro in patients with systemic lupus erythematosus and other autoimmune diseases. T and B lymphocytes from these patients were found to have significantly increased expression of c-myc, c-myb, and c-raf RNA when compared with those of normal individuals. Among the mononuclear cell subpopulations, B lymphocytes expressed higher levels of RNA for these proto-oncogenes compared with the T lymphocytes. Since prompt expression of these and other proto-oncogenes occurs in fibroblasts and lymphocytes following mitogenic stimulation, we propose that the present findings reflect the pathologically activated state of various lymphocytic subpopulations which is observed in systemic lupus erythematosus and in other autoimmune diseases. Endogenous and exogenous factors which lead to the expression of autoimmunity might share the induction of proto-oncogene expression as a common pathogenetic step.

Cell-mediated immunity in rheumatic disease

Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis are the three most common systemic rheumatic diseases in which disordered immune function is thought to play a pathogenetic role. Each disease has different and characteristic abnormalities of the cellular immune system. In rheumatoid arthritis the identified abnormalities of immunoregulation are largely limited to specific antigens: Epstein-Barr virus and collagen. Systemic lupus erythematosus is characterized by exuberant B-cell activity with exaggerated humoral response, a diversity of autoantibodies, non-antigen-specific loss of suppressor cell function, and general suppression of cell-mediated immunity. In systemic sclerosis systemic defects of cellular and humoral immune function are mild, but the release of lymphokines and monokines at sites of inflammatory lesions is thought to be important in the pathogenesis of the disease. Similar immune cell-connetive tissue cell interactions are probably important in the propagation of rheumatoid synovitis. Thus, despite the many shared clinical and serologic features of these diseases as well as the presence of many patients who have clinically overlapping features of more than one of these entities, the immune defects and the immunopathogenesis of these disorders appear to be distinct.

Studies of the pathogenesis of angioimmunoblastic lymphadenopathy

We studied the immune functions of two patients with angioimmunoblastic lymphadenopathy (AILD) in an attempt to determine whether the B cells were primarily hyperactive or, rather, if T cell abnormalities might underlie the B cell hyperactivity observed in these patients. We found that the B cells of the AILD patients did not proliferate spontaneously, nor were they induced to proliferate excessively by fresh normal T cells. In contrast, AILD T cells induced both autologous and allogeneic B cells to proliferate and to differentiate into Ig secreting cells. Spontaneous culture supernates of T cells obtained from each patient induced substantial proliferation of B cells (B cell-activating activity) as well as proliferation in a standard costimulatory assay (B cell growth factor activity). The culture supernate of a T cell line, which was established from one patient, showed both activities. The T cell line supernate also induced Ig production by staphylococcal A Cowan-activated B cells. None of these properties of AILD T cells was found among 10 normal controls. The addition of AILD T cells to autologous or allogeneic B cells in the presence of pokeweed mitogen (PWM) led to marked suppression of both proliferation and Ig production. This was true even in the presence of fresh normal T cells. Pretreatment studies showed that suppressor cells were induced by the interaction of AILD T cells with PWM-activated B cells. The present study suggests that the B cell hyperactivity observed in AILD patients might in part be due to excessive T cell effects on B cells. In addition, our results may help clarify the paradoxical impaired responsiveness to in vitro stimulation with PWM by active B cells from patients with autoimmune diseases.

Correction of interleukin-2 production in patients with systemic lupus erythematosus by removal of spontaneously activated suppressor cells

Interleukin-2 (IL-2) production in vitro is depressed in systemic lupus erythematosus (SLE) patients. It is not known whether this abnormality is caused by a defect in the producer lymphocytes or by excessive suppression. We report that removal of OKT8 (Leu 2a)+ cells increased the IL-2 production by in vitro-stimulated lymphocytes to normal or above normal levels in 19 of 21 SLE patients. This increase was more apparent in those patients with clinically inactive disease and/or receiving less than 7.5 mg of prednisone. Removal of OKT8+ cells from normals did not significantly increase IL-2 activity. SLE, but not normal, OKT8+ cells decreased IL-2 production when added back to autologous OKT8-depleted cells. In some experiments, OKT8+ cells from normal donors also suppressed IL-2 production in SLE. This result suggests that the defect in IL-2 production is complex and may involve multiple cell interactions. Three lines of evidence suggest that the SLE OKT8+ cells actively inhibit the production of IL-2 rather than passively absorb this lymphokine: (a) only 3.2% of SLE lymphocytes expressed IL-2 receptors as detected with anti-Tac; (b) freshly prepared SLE lymphocytes did not absorb IL-2; and (c) cell-free supernatants from SLE OKT8+ cells inhibited IL-2 production, but not IL-2 activity. Double-labeling studies by flow cytometry revealed that 19.3% of SLE OKT8+ cells were also Ia-positive, and approximately 33% co-expressed the natural killer cell marker, HNK-1 (Leu 7). Removal of Leu 7+ cells also significantly elevated IL-2 production in SLE. These studies suggest that one or more circulating mononuclear cell subsets in SLE patients can suppress IL-2 production and that one subset may possibly belong to a non-T, non-B "third mononuclear population."

Inhibition of soluble antigen-induced T cell proliferation by warm-reactive antibodies to activated T cells in systemic lupus erythematosus

One of the fundamental immunologic characteristics of systemic lupus erythematosus (SLE) is a depressed T cell proliferative response to various specific and nonspecific stimuli. Both intrinsic cellular defect(s) and inhibitory influences of humoral factors, e.g., antilymphocyte autoantibodies or immune complexes, have been postulated to underly this functional abnormality. Because patient serum can induce SLE-like T cell dysfunction in normal cells, an extrinsic mechanism is probably responsible, but the nature and site of action of this humoral activity has not been defined. This laboratory recently described a novel antibody specific for activated T cells in SLE, which raised the possibility that suppression of T cell proliferation by SLE serum involved antibodies directed to surface determinants expressed during the process of activation. In experiments to examine this concept further, relatively warm-reactive antibodies to T cell blasts were found to inhibit strongly the well-characterized T cell response to tetanus toxoid. These antibodies were distinct from conventional cold-reactive IgM antibodies to resting T cells, which exhibited little inhibitory activity. Inhibition involved noncytotoxic effects on early activation events at the level of the responding T cell, which markedly reduced the expression of receptors for interleukin 2. Inhibitory effects on antigen-pulsed macrophages or on T cells already committed to proliferate were not demonstrable. Anti-T blast antibodies were characteristic of active SLE and were detected only occasionally in patients with inactive disease or non-SLE rheumatic disorders. Although the exact antigenic specificity was not identified, considerable evidence was obtained against the presence of antibodies to Ia and certain other surface determinants of functional relevance. Our observations concerning the suppressive effects of anti-T blast antibodies in SLE serum on the T cell response to tetanus toxoid should provide new insight into mechanisms of in vivo T cell dysfunction in this and other immunologic disorders.

Class II major histocompatibility antigens and the etiology of systemic lupus erythematosus

It is hypothesized that the underlying immunoregulatory dysfunction in systemic lupus erythematosus (SLE) is altered recognition by T cells of self class II major histocompatibility antigens (Ia). The resultant cellular autoreactivity would directly cause certain of the immunopathological manifestations of SLE. The perception by T cells of self non-MHC antigens in the context of altered Ia on antigen presenting cells would also stimulate specific help for autoantibody production. Autoimmunity induced by the graft-versus-host reaction is an experimental model that illustrates this potential mechanism (A. G. Rolink, S. T. Pals, and E. Gleichmann, J. Exp. Med. 157, 755, 1983; R. A. Eisenberg, S. Y. Craven, and P. L. Cohen, Arth. Rheum. 26, S19, 1983).