Serum and cerebral spinal fluid complement and serum autoantibodies in systemic lupus erythematosus

Retroviral vector producer cell killing in human serum is mediated by natural antibody and complement: strategies for evading the humoral immune response

The introduction of retroviral vector producer cells (VPC) into tumors as a means of increasing transduction efficiency has recently been employed in human gene therapy trials. However, the fate of these xenogeneic cells in humans is not well understood. In the present study, we used an in vitro model to examine the survival of commonly used VPC lines in serum from humans and various other species. VPC derived from the murine NIH-3T3 cell line, including PA317, Psi CRIP, and GP + E-86, were effectively killed in sera from Old World primates, including human and baboon. Conversely, the same murine cell lines survived exposure to sera from dog, rabbit, rat, and mouse. This pattern of serum killing parallels the occurrence of the anti-alpha-galactosyl natural antibody (Ab) found exclusively in Old World primates. The anti-alpha-galactosyl Ab targets the terminal glycosidic structure Gal alpha 1-3Gal beta 1-4GlcNAc-R (alpha-galactosyl epitope) found on the surface of mammalian cells, excluding Old World primates. All murine-derived VPC tested expressed high levels of the alpha-galactosyl epitope as determined by FACS analysis. VPC killing was complement-mediated, because preincubation of human serum with a functionally blocking anti-C5 mAb completely abolished cell lysis. Furthermore, addition of soluble galactose(alpha 1-3)galactose (Gal alpha 1-3Gal) to human serum or down-regulation of the alpha-galactosyl epitope on the surface of VPC effectively reduced VPC killing, indicating that complement activation by these cells is primarily initiated by natural antibody recognition of the alpha-galactosyl epitope. Finally, VPC incubated with human serum for 8 hr in the presence of complement inhibition continued to produce viable retroviral particles, thus demonstrating a correlation between VPC and particle survival. Taken together, these data suggest that elimination of the alpha-galactosyl epitope or complement blockade may provide a strategy to prolong the survival of VPC and the particles that they produce in vivo.

Neuropsychiatric manifestations of systemic lupus erythematosus

The authors critically review the literature describing the varied neuropsychiatric syndromes associated with systemic lupus erythematosus (SLE). Factors that have complicated the identification and treatment of affective, behavioral, and cognitive disturbances in these patents are identified, and the utility of various diagnostic interventions is examined. Finally, the authors outline the role of the consultation-liaison psychiatrist in the clinical management of the SLE patient with neuropsychiatric disturbances.

Interleukin-1 and interleukin-6 activities are increased in the cerebrospinal fluid of patients with CNS lupus erythematosus and correlate with local late T-cell activation markers

We examined cerebrospinal fluid (CSF) samples from 12 patients with SLE and active central nervous system (CNS) involvement for their levels of the following cytokines: interleukin-1 (IL-1) by means of two different assays--the IL-1 responsive murine cell line LBRM 33-la5 and an ELISA for IL-1 alpha; IL-2 by means of the CTLL cell line responsive to it; and interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF) both determined by a specific ELISA. We found that SLE CSF had significantly higher levels of IL-1 and IL-6 than did those obtained at surgery from eight controls without inflammatory neurologic disease. IL-2 and TNF were not detectable in any of the CSF samples. We also studied the status of activation in CSF T cells using monoclonal antibodies against early (anti-IL-2R (CD25) and anti-transferrin (CD71)), late (anti-T10) and very late (anti-VLA-1) activation antigens, and found increased percentages of T10-bearing (18 +/- 2 vs 3 +/- 0.7%) and VLA-1-bearing T cells (12 +/- 2 vs 0.7 +/- 0.2%) in SLE patients as compared to controls (both P < 0.01). Levels of IL-1 and IL-6 correlated with T10 and those of IL-1 correlated also with VLA-1. Markers of early T-cell activation did not differ in SLE and control CSF. Because of these findings we analysed the effect of recombinant IL-1, IL-6 or normal CSF on normal T cells and found that they did not induce the expression of activation markers.(ABSTRACT TRUNCATED AT 250 WORDS)

The terminal complement complex, C5b-9, a marker of disease activity in patients with systemic lupus erythematosus

Concentrations of the terminal complement complex (TCC), C5b-9, were examined in 120 serum samples from 28 patients with systemic lupus erythematosus. Eleven patients with various manifestations of the disease were followed longitudinally for a 2-year period during active and inactive phases of the disease. In 9 of the 11 patients, elevations in TCC concentrations correlated with disease exacerbations. In many of these patients, C3 and C4 levels remained normal during the study and were less sensitive indicators of disease activity than were TCC concentrations. We believe that measurements of TCC are useful in monitoring patients with rheumatic diseases in which complement activation is a component.

Serum C3 and C4 levels and complement-dependent antibody-mediated cytotoxic activity of islet cell surface antibody in type 1 (insulin-dependent) diabetic children

The role of complement in the pathogenesis of diabetes was studied in 31 Type 1 (insulin-dependent) diabetic children by assaying serum islet cell surface antibody, C3, C4 and serum complement-dependent antibody-mediated cytotoxicity. Nine of 21 islet cell surface antibody-positive children were within 5 months of disease onset and showed significantly lower serum C3 and C4 levels than either 1 year later or the remainder of the islet cell surface antibody-positive children at 6-12 months after disease onset. The overall trend of all islet cell surface antibody-positive diabetic children within 1 year of disease onset was toward increased serum C3 and C4 levels as the disease progressed. Serum C4 concentration and complement-dependent antibody-mediated cytotoxicity which showed an initial negative correlation were uncorrelated 1 year later. Four children who were initially strongly islet cell surface antibody-positive but negative 1 year later also exhibited significantly higher (p less than 0.05) mean serum C4 levels after 1 year. There was a significant decrease in complement-dependent antibody-mediated cytotoxicity when sera from the diabetic children were treated with either ethylene glycol tetra-acetic acid or ethylene diamine tetra-acetic acid. These data strongly suggest that complement-dependent antibody-mediated cytotoxicity induced by the classical complement pathway involving an islet cell surface antibody may play an important role in the pathogenesis of Type 1 diabetes.

Immune responses in the central nervous system

Immune responses occurring within the central nervous system (CNS) have unique features attributable to the cellular and functional organization of the CNS and to the presence of the blood-brain barrier. Immune responses to viral infection of the CNS involve the participation of most immunologically important cells: T and B lymphocytes, monocytes, and natural killer cells. Normally, helper/inducer T lymphocytes are predominant in the cerebrospinal fluid (CSF) and in perivascular cuffs. After stimulation with antigen in tissue, these cells produce lymphokines, which stimulate mast cells to open capillary tight junctions, stimulate proliferation of lymphocytes, and attract monocytes and B lymphocytes. B lymphocytes mature into immunoglobulin-producing cells that secrete antibody locally which appears in the CSF. Cytotoxic/suppressor T lymphocytes, which damage antigen-containing cells, are predominant in immunopathologic reactions. In other situations the immune response targets normal CNS tissue rather than foreign antigens. Two general types of reactions may be seen: (1) vasculitis with destruction of vessel walls and infarction, and (2) perivascular inflammation with demyelination. The former is associated with immune complex deposition, and the cellular infiltrate includes polymorphonuclear leukocytes. The inflammation associated with perivenular demyelination is composed almost exclusively of mononuclear leukocytes. In the diseases for which pathogenetic mechanisms are understood, cells become sensitized to myelin constituents and induce local demyelinating lesions in which the damage is effected by macrophages. It is not clear whether macrophages are directed in this destructive effort by lymphokines or immunoglobulins or both.

Progressive multifocal leukoencephalopathy complicating systemic lupus erythematosus

Two patients with systemic lupus erythematosus who developed progressive multifocal leukoencephalopathy (PML) are described. Although the time of PML onset could not be determined with certainty, it probably developed after steroid-induced immunosuppression. However, high-dose corticosteroids appeared to produce transient amelioration in the neurologic disorder. We suggest that PML is an important addition to the list of conditions to be considered in the differential diagnosis when a patient with systemic lupus erythematosus develops neurologic abnormalities.

Treatment of acute myelopathy in systemic lupus erythematosus with plasma exchange and immunosuppression

Images

Familial hypoplasia of the thenar eminence: a report of three cases

Images

The determination of the complement components C1q, C4 and C3 in serum and cerebrospinal fluid by radioimmunoassay

Non-competitive 2-site radioimmunoassays (RIA) for the determination of the complement proteins C1q, C4 and C3 in cerebrospinal fluid (CSF) are described. The quantitative results of the RIAs were the same as those obtained by other assay methods: radial immunodiffusion and turbidimetry and, in the case of C4, the haemolytic assay. The concentrations of the complement proteins in paired CSF and serum samples from a group of 60 patients were measured, as well as those of albumin and IgG. The ratios (concentration in CSF)/(concentration in serum) of the complement proteins correlated poorly with that of albumin. In contrast, the ratio of IgG was significantly correlated with that of albumin. The ratios of the complement proteins were higher than might be expected on the basis of their molecular masses. This suggests that these proteins may be synthesized within the normal central nervous system.

Radioimmunoassay of the attack complex of complement in serum from patients with systemic lupus erythematosus

We developed a radioimmunoassay to measure the attack complex of complement (SC5b-9) in serum from patients with systemic lupus erythematosus. The radioimmunoassay used a monoclonal antibody to an antigen of C9, which is absent from native C9 but present on SC5b-9. SC5b-9 was detectable in 13 of 63 normal subjects, with a mean value of 0.5 unit (range, 0 to 4.8), and elevated in 13 of 14 patients with active lupus. Analysis of 108 samples from the patients with lupus revealed a mean value of 10.1 units (range, 0 to 35) when the disease was active and 1.0 unit (range, 0 to 433) when it was clinically stable. SC5b-9 was a more sensitive measure of disease activity than C3, C4, or CH50; its specificity was equivalent to that of C3 and C4. SC5b-9 was elevated in serum from 6 of 49 patients with other forms of glomerulonephritis. Our study documents the presence of SC5b-9 in abnormal serum and correlates its elevation with clinical disease activity in patients with active systemic lupus erythematosus.

Measurement of C9 concentrations using an immunochemiluminometric assay

A 2-site immunochemiluminometric assay is described for the measurement of complement component C9 concentrations in biological fluids as an aid in the diagnosis and management of immune-based diseases. The assay utilises 2 monoclonal antibodies one of which is labelled with a chemiluminescent acridinium ester and one of which is covalently coupled to reprecipitated aminoaryl cellulose. The incubation time is 1 h with simultaneous reagent addition. The working range of the assay is 10-2500 micrograms/1 at CVs less than or equal to 10% and the results are in excellent agreement with those of an immunoradiometric assay. The assay exhibits superior performance to other immunochemical and immunoassay techniques and has the advantage of using stable, non-radioactive reagents.

Pretreatment with lipoteichoic acid sensitizes target cells to antibody-dependent cellular cytotoxicity in the presence of anti-lipoteichoic acid antibodies

This study was performed to determine whether antibody-dependent cellular cytotoxicity (ADCC) could be directed against mammalian cells sensitized with spontaneously adhering bacterial substances. 51Cr-labeled SB leukemia cells were incubated with purified S43 group A streptococcal lipoteichoic acid (LTA; 0.001 to 100 micrograms/ml). Purified leukocyte ADCC effector cells were added to the LTA-coated target cells at various effector-to-target ratios (100:1 to 12:1), followed by the addition of rabbit anti-LTA. After incubation for 4 h, target cell lysis was calculated based on the release of label into the medium. As little as 1 ng of LTA per ml was sufficient to sensitize the target cells to ADCC lysis (12%); however, concentrations above 0.1 micrograms/ml generally resulted in 60 to 80% lysis. LTA alone was not cytotoxic to these target cells. Targeting did not occur if effector cells were sensitized or if free LTA was added to the medium. Specificity was demonstrated by cold-target inhibition, which showed that anti-LTA cytotoxicity could be inhibited only by unlabeled, LTA-treated target cells but not by cold SB cells alone. The findings indicate that certain soluble bacterial components, when bound to mammalian cells in the presence of specific antibody, can target ADCC effectors to these cells. This mechanism may be an important factor in the delayed sequelae of bacterial infections.

Immunoradiometric assay for human complement component C9 utilising monoclonal antibodies

A two-site immunoradiometric assay for human C9 has been developed. The assay utilised two non-competing monoclonal antibodies to C9 in a single incubation assay protocol. The detection limit of the assay was 0.1 ng (1.4 X 10(-15) moles) in a sample volume of 100 microliters. Using this assay the C9 concentration in normal human plasma was 60.2 +/- 14.9 mg/l (mean +/- 1 standard deviation, 8.5 X 10(-10) mol/l. Significantly elevated levels were found in the plasma of patients with rheumatoid arthritis (90.4 +/- 19.9 mg/l, mean +/- 1 SD). Measurements of C9 in cerebrospinal fluid and synovial fluid were also performed. The low levels of C9 in cerebrospinal fluid (less than 1 mg/l), undetectable by previously available assay methods, were easily measurable with this highly sensitive assay.

Synthesis of the complement factors C3 and C4 within the central nervous system over the course of aseptic meningitis

The concentrations of complement factors C3 and C4 were quantified by single radial immunodiffusion in unconcentrated cerebrospinal fluid (CSF) and in serum from 38 patients up to 2 months after onset of acute aseptic meningitigs (AM). Elevated absolute concentrations were found in CSF in 26 and 35 patients, respectively, and in serum in 8 and 31, respectively. Elevation of the CSF C3 index, equal to (CSF/serum C3):(CSF/serum albumin), and of the corresponding CSF C4 index were found in 16 and 7 patients, respectively, as evidence of intrathecal synthesis. Only minor differences of the frequencies of elevated CSF C3 and C4 indices were encountered over the course of AM up to 2 months after onset. The occurrence of intrathecal C3 and C4 synthesis in AM is proposed as reflecting activation of hitherto unknown significance within the central nervous system.

Intrathecal IgG synthesis and blood-brain barrier impairment in patients with systemic lupus erythematosus and central nervous system dysfunction

Paired serum and cerebrospinal fluid specimens from 19 patients with SLE and central nervous system dysfunction were studied with respect to cerebrospinal fluid IgG index (a measure of intrathecal IgG synthesis), isoelectric focusing using immunoperoxidase staining techniques to detect oligoclonal IgG, and determination of the cerebrospinal fluid/serum albumin quotient (Q albumin) as a measure of blood-brain barrier integrity. Twenty-five patients without neurologic disease and 70 patients with a variety of non-SLE neurologic disorders were also studied for comparison. Of most interest was the observation that 42 percent of the patients with SLE had cerebrospinal fluid oligoclonal IgG, usually in association with elevation of the cerebrospinal fluid IgG index. In addition, two of the cerebrospinal fluid specimens that exhibited oligoclonal IgG also had increased titers of alpha-interferon. Q albumin was normal (under 9.0) in 12 of 13 patients with SLE, who had seizure, psychosis, or cranial neuropathy as principal central nervous system manifestations (mean +/- SD = 5.3 +/- 2.4), but was significantly elevated (mean +/- SD = 27.4 +/- 18.8, p less than 0.001) in five of six patients with diffuse, major central nervous system injury, for example, encephalopathy with coma, transverse myelopathy, paraparesis. Blood-brain barrier impairment was not correlated either with presence of circulating immune complexes or with other clinical or serologic evidence for extra-central nervous system disease activity. Taken together, the data suggest that, within the limitations of the techniques used, impairment of the blood-brain barrier in SLE may be secondary to the central nervous system lesion, rather than a result of systemic immune complex injury. In addition, substantial evidence is provided for an ongoing humoral immune response within the central nervous system in this disorder, which, in certain patients, may be associated with the production of intrathecal alpha-interferon.

Autoimmune retrobulbar optic neuritis

Three patients, all women, ranging in age from 26 to 44 years, had acute retrobulbar neuritis and laboratory evidence of a collagen vascular disorder. These patients were treated with intravenously administered "pulse" methylprednisolone, and visual acuity recovered in three of four involved eyes. Continued oral administration of prednisone and other immunosuppressive drugs was necessary to maintain vision.

Antibody-independent complement activation by myelin via the classical complement pathway

Murine or rabbit whole brain homogenates were shown to activate human complement via the classical pathway by an antibody-independent reaction. This activity required Ca++ ions. Anticomplementary activity in fractionated murine brain was found to reside in the myelin fraction and in purified myelin. It was absent, however, both from highly purified myelin basic protein (MBP) and from the MBP-free residue. Because purified MBP is a monomer and this protein exists in brain tissue largely as a dimer, the ability of the cross-linked form of MBP to activate complement was investigated. MBP, dimerized with difluorodinitrobenzene, was highly anticomplementary. The murine brain, inactive when taken from the newborn mouse, was shown to first acquire the capacity to activate complement at 7 d after birth. This finding is consistent with the report that the synthesis of myelin protein has been shown to be initiated in murine brain 8 d after birth. Complement activation by MBP could play an important role in the pathological changes observed in neurological disorders.

Neurological complications of connective tissue and other "collagen-vascular" diseases

A variety of neurological complications may occur in the various connective tissue and "collagen-vascular" diseases. Most of these complications are due to vasculitis affecting various sites in the central or peripheral nervous system. While the evidence for definitive vasculitis in SLE is not strong, small vessel damage usually is present in anatomic sites which correlate well with clinical features. Although patients with rheumatoid arthritis also may have vasculitis, neurological complications are usually related to nerve compression by rheumatoid nodules or the arthritic process itself. Considerable controversy exists regarding the accuracy of various diagnostic tests. While corticosteroids are the mainstay of therapy for these conditions, there are no definitive studies proving their efficacy.

Immunologic tests of value in diagnosis. 2. Complement

Laboratory tests are available to assess the function of the complement pathway and to measure levels of individual complement components. The pattern of complement abnormalities is often helpful in suggesting diagnostic possibilities. For example, when when total hemolytic complement, C3, and C4 are all decreased, one of the rheumatoid diseases is likely. In addition, complement levels in spinal and synovial fluid may provide helpful diagnostic clues.

Cold dependent activation of complement in systemic lupus erythematosus. A unique cause for a discrepancy between clinical and laboratory parameters

A 31-year-old woman with systemic lupus erythematosus (SLE) was studied because she developed markedly reduced total hemolytic complement activity at a time when her disease was clinically inactive. Functional assays demonstrated reduced activities of C1, C4, and C2, but normal concentrations of C3 and the terminal (C5-9) components were present. Antigenic concentrations of C1, C4, and C2 were normal. Plasma or serum obtained from blood allowed to clot at 37 degrees C had normal complement activity. Complement activity was depleted when the patient's serum was incubated in the cold. At reduced temperatures, the patient's serum (or purified IgG) depleted complement activity of normal human sera. A second patient with SLE was also demonstrated to have this same phenomenon. Cryoglobulins were not detectable in these patients. These data indicate that in vivo the patients' complement was normal and that the observed in vitro reduction was caused by cold dependent activation of the classical pathway.

The cerebrospinal fluid C4 complement component in different meningeal and neurological diseases

The C4 complement component was measured in CSF from 10 patients without CNS involvement (controls) and 71 with various meningeal and neurological diseases. Serum C4 was also measured in the control group and in 46 of the 71 neurological patients. A significant increase of CSF C4 was observed in all neurological diseases with meningeal involvement independent of the causative agent. Inversely, serum C4 values were within normal limits. Increased CSF C4 with normal serum levels might indicate increased diffusion across the blood-brain barrier, decreased ability for immunocomplex production or increased local production.

Complement activation by Coccidioides immitis: in vitro and clinical studies

Mycelial- or spherule-phase derivatives of Coccidioides immitis caused a decrease in vitro of total hemolytic complement in serum from a nonsensitized person. Activation involved both classic and alternative pathways as shown by deprssion of hemolytic C4 and by generation of products of activation of components C3, C4, and factor B. In addition, functional complement activity or immunoreactive levels of complement components or both were measured in 23 patients with self-limited or disseminated coccidioidomycosis. Low total hemolytic complement was found in nine, usually during the early phase of primary illness, and was transient. Hemolytic C4 was low, and the effect of inulin to decrease complement levels was blunted, suggested both classic and alternative pathways may be deficient. However, associated depression of immunoreactive levels of components assayed (C3, C4, C5, factor B, and properdin) was not consistently found. This disparity raises the possibility of enhanced in vitro inactivation analogous to activation by immune complexes.

Systemic lupus erythematosus presenting as post-partum chorea

A case of systemic lupus erythematosus (SLE) is reported in which chorea was the dominant clinical feature, and which presented following a spontaneous mid-trimester abortion. The diagnosis, natural history and management of this uncommon manifestation of CNS lupus is discussed, as well as the influence of pregnancy on disease activity in SLE.

Spinal cord involvement in systemic lupus erythematosus

A review is made of the literature on central nervous system involvement in systemic lupus erythematosus (CNS-SLE). Particular attention is focused on lupus myelopathy. Referring to two well-documented personal cases, the authors describe the characteristic multisystem involvement, protean clinical pattern, serum and cerebrospinal fluid changes, histoimmunologic findings, response to corticosteroids and immunosuppressive agents and some prognostic features.

The neuropsychiatric disorder in systemic lupus erythematosus: evidence for both vascular and immune mechanisms

As part of a prospective survey of systemic lupus erythematosus (SLE) a detailed collaborative study of the clinical, psychiatric, and laboratory features in 15 patients with nonfocal neuropsychiatric disease has been undertaken. In addition to conventional clinical and psychometric evaluation, electroencephalograph, and cerebrospinal fluid analysis, the study included the assessment of cerebral blood flow with oxygen-15 brain scans and serological testing for the presence of antineuronal and lymphocytotoxic antibodies. Of the 15 patients 12 had psychiatric manifestations, while 13 had various neurological abnormalities. All except 2 episodes of cerebral disease were transient. Striking abnormalities in cerebral blood flow and metabolism were seen in 12 patients, even in the presence of subtle clinical features. Sequential scans showed that improvement in clinical features was accompanied by a reversal of scan abnormalities. All sera contained brain-reactive antibody, either antineuronal IgG antibody (13) or lymphocytotoxic IgM antibody (12) or both (10), though there was an inconsistent association between clinical features and antibody titre. It is suggested that transient disturbances of cerebral vascular function in SLE might allow brain-reactive antibodies from the circulation access to cerebral tissue. In this way the nature of the neuropsychiatric abnormalities would depend on both vascular and immunopathogenic mechanisms.

Central nervous system lupus erythematosus: measurement of cerebrospinal fluid cyclic GMP and other clinical markers of disease activity

Cyclic-GMP (C-GMP), a normal constituent of the central nervous system, was found to be present in increased amounts in the cerebrospinal fluid (CSF) of systemic lupus erythematosus (SLE) patients with active neurologic disease. Twenty-four CSF samples from 17 patients with SLE were evaluated for C-GMP concentration by radioimmunoassay. This study extends our initial observations and examines three groups of SLE patients based on their clinical status at the time of each lumbar puncture: those with active neurologic and psychologic abnormalities (group I), active neurologic abnormalities (group II), and psychologic abnormalities without active neurologic involvement (group III). Groups I and II had mean CSF C-GMP values of 3.1 nM +/- 0.64 (SE) and 4.1 nM +/- 0.10 respectively, which were both significantly higher than the mean for group III (1.2 nM +/- 0.43) (P less than 0.05). Other CSF findings did not display this close correlation with activity of neurologic disease. In 4 SLE patients, significantly higher levels of CSF C-GMP were found on serial sampling during times when neurologic abnormalities were active. Thus elevated CSF C-GMP concentration may be a marker of active neurologic disease in SLE.

Third complement component in cerebrospinal fluid in neuro-Behçet's syndrome. Conversion patterns by crossed immunoelectrophoresis

Thirteen cerebrospinal fluid specimens (CSFs) from 10 patients with neuro-Behçet's syndrome (nB) were examined for the presence of conversion products of C3 protein by means of crossed immunoelectrophoresis. C3 conversion products were found in 4 CSFs from nB patients, and the proportions of the split products to the total immunoprecipitate zones were 17, 34, 61 and 63%, respectively. CSFs with C3 conversion patterns showed higher C3 protein (beta 1C/A) levels compared with those with non-conversion, whereas the differences of C4 protein (beta 1E) levels were unremarkable. CSF with C3 conversion patterns also showed apparent inflammatory characteristics indicating blood-CSF barrier involvement which would be deduced from increased alpha 2-macroglobulin and IgA, both being regarded as sensitive internal barrier parameters: but IgA measurement was much higher than usually expected values. It is suggested that the increase in CSF C3 might be initiated by accelerated consumption of complement through the alternative pathway, leading to hypersynthetic or hyperinflux response in CSF.