Serum Immune Complexes Research Articles

Anti-cytokeratin antibodies in sera of the patients with autoimmune hepatitis.

Antibodies to cytokeratin (CK) are found in some patients with autoimmune hepatitis (AIH). We hypothesized that serum antibodies to CK8, CK18 and CK19 may be formed in patients with AIH. We established an enzyme-linked immunosorbent assay (ELISA) to quantify anti-CK8, anti-CK18 and anti-CK19 antibodies in sera of patients with AIH. In addition, we quantified circulating CK8:anti-CK8 antibody as well as CK18:anti-CK18 antibody immune complexes in patients' sera, by an enzyme-linked immunosorbent assay (ELISA). Furthermore, to evaluate the expression of CK8, CK18 and CK19 in liver tissue, immunohistochemical stainings were performed. Significantly high levels of anti-CK8, anti-CK18 and anti-CK19 antibodies were demonstrated in patients with AIH compared with normal volunteers and patients with chronic active hepatitis C (CH-C). In addition, these antibodies were significantly decreased after steroid treatment. Levels of CK8:anti-CK8 and CK18:anti-CK18 immune complexes in sera of patients with AIH were significantly high compared with those of patients with CH-C and normal volunteers. Immunohistochemically, CK8 or CK18 were absent from some hepatocytes of AIH. CK19 was aberrantly expressed in periportal hepatocytes in patients with AIH, but not CH-C. This is the first study to quantify anti-CK8, anti-CK18, anti-CK19 antibodies and immune complexes in patients with AIH. The clinical significance of anti-CK antibodies and their immune complexes of AIH is also discussed.

Aldosterone and prednisolone control of cochlear function in MRL/MpJ- Fas lpr autoimmune mice

Recently this laboratory showed aldosterone, a mineralocorticoid that only enhances sodium transport, was as effective as the glucocorticoid prednisolone in restoring cochlear function in autoimmune mice. To further test this relationship between sodium transport and autoimmune hearing loss, dosage comparisons were made of prednisolone and aldosterone control of the auditory dysfunction in autoimmune MRL/MpJ- Fas lpr mice. Mice were tested at 2 months of age to establish baseline auditory brainstem response (ABR) thresholds, hematocrit, serum immune complexes, and anti-nuclear antibodies. Mice were then given different doses of prednisolone or aldosterone in their drinking water for 2 months. After the treatment period, most untreated water controls showed elevation of ABR thresholds due to the ongoing autoimmune disease. However, the steroid groups had significantly more mice with improved or unchanged thresholds. Both steroids improved stria vascularis morphology, although aldosterone appeared to be more effective. The immune suppressive prednisolone caused a dose-related improvement in levels of serum immune complexes and hematocrit, hallmarks of systemic autoimmune disease. Aldosterone, which has no immune suppressive function, did not alter systemic disease. The comparable efficacy of prednisolone and aldosterone in restoring auditory function suggests steroid reversal of autoimmune hearing loss in mice is due to increasing stria vascularis sodium transport and not suppression of systemic autoimmune reactions.

Unique immunogenicity of hepatitis B virus DNA vaccine presented by live-attenuated Salmonella typhimurium

A novel vaccine for hepatitis B virus (HBV) was designed by putting a naked DNA vaccine carrying hepatitis B surface antigen (HBsAg) into live-attenuated Salmonella typhimurium. Mucosal immunization by the oral route in mice showed significantly stronger cytotoxic T lymphocyte (CTL) response than recombinant HBsAg vaccination ( P<0.01 at an effector:target ratio of 100:1), while comparable to intramuscular naked DNA immunization at all effector:target ratios. Contrary to previous reports on naked DNA vaccines given intramuscularly, the IgG antibody response induced by the mucosal DNA vaccine is relatively weak when compared to recombinant HBsAg vaccine ( P<0.001 at day 21). These findings are supported by a high interferon-γ but a low interleukin-4 level detected in the supernatant of splenic cell cultures obtained from mucosally immunized mice. As distinct to recombinant HBsAg vaccine which is effective for protection, oral mucosal DNA vaccine should be considered as a candidate for therapeutic immunization in chronic HBV infection, donor immunization before adoptive transfer of HBV-specific CTL to HBsAg positive bone marrow transplant recipients, and immunization of non-responders to recombinant HBsAg vaccine. This strongly cellular and relatively absent humoral response may make this vaccine a better candidate as a therapeutic vaccine for chronic HBV carriers than naked DNA vaccines, as the humoral response is relatively less important for the clearance of HBV from hepatocytes, but its presence may lead to side effects such as serum sickness and immune complex deposition in chronic HBV carriers.

Crescentic glomerulonephritis associated with infective endocarditis: renal recovery after immediate surgical intervention

A 57-year-old man was referred to our hospital because of acute cardiac failure and acute renal insufficiency. Laboratory data showed elevation of serum immune complex levels and antineutrophil cytoplasmic antibody (ANCA) titers, with cytoplasmic pattern (C-ANCA) on indirect immunofluorescence (IIF), and proteinase 3 specificity (PR3-ANCA) on solid-phase enzyme-linked immunosorbent assay (ELISA). Hemodialysis therapy was initiated, and this relieved the symptoms of cardiac failure. Echocardiography revealed three-grade aortic insufficiency and two large floating vegetations on the aortic valve. Considering the risk of embolism, we immediately performed aortic valve replacement and surgically removed the vegetations, subsequently giving antibiotic therapy. Six weeks after the operation, the patient's renal function showed marked improvement and the serological abnormalities, except for ANCA titers, had normalized, resulting in no need for dialysis. A renal biopsy specimen revealed diffuse proliferative glomerulonephritis (GN) with crescents including more than 50% of glomeruli, and granular deposits of IgM, C3, and C1q on immunofluorescence. ANCA titers remained high, but the patient's renal function has been stable, indicating a discrepancy between ANCA titers and his clinical course. In this patient, treatment by immediate surgical intervention, performed during the acute phase with active GN and highly reduced renal function, led to dramatic renal recovery. This case suggests that surgical removal of vegetations in the early stage of crescentic GN may result in a good renal outcome in patients with rapidly progressive GN associated with endocarditis. Although it has been suggested that ANCA may have some relationship to GN in endocarditis, in this patient, its pathogenetic significance is questionable.

Circulating Cytokeratin 8:Anti-Cytokeratin 8 Antibody Immune Complexes in Sera of Patients with Pulmonary Fibrosis

Background: It has been suggested that the humoral immune system plays a role in the pathogenesis of idiopathic pulmonary fibrosis (IPF) and pulmonary fibrosis associated with collagen vascular disorders (PF-CVD). Although circulating immune complexes in patients’ sera have been suggested, none of the antigens have been characterized. Objectives: The purpose of this study is to characterize the antigen of the immune complexes in patients’ sera of pulmonary fibrosis. Methods: As we previously established that one of the antibodies against A549 cells (lung alveolar type II cells) was anti-cytokeratin 8 (CK8), we confirmed the existence of anti-CK8 antibody in patients’ sera by Western immunoblot. In addition, we tried to demonstrate circulating CK8:anti-CK8 immune complexes in patients’ sera by Western immunoblot. Furthermore, we established an enzyme-linked immunosorbent assay to quantitate CK8:anti-CK8 immune complexes. Results: In patients with pulmonary fibrosis, anti-CK8 antibodies were clearly demonstrated in sera by Western immunoblot. In addition, circulating CK8:anti-CK8 immune complexes were also clearly demonstrated by Western immunoblot. It was possible to establish ELISA to quantitate CK8:anti-CK8 immune complexes. If the cutoff value, which was determined based on the highest value of normal volunteers, was introduced, high CK8:anti-CK8 antibody complexes were demonstrated in 9 of 31 patients (29.0%) with IPF and PF-CVD. Conclusions: This is the first study to clarify the antigen of the circulating immune complex in sera of patients with IPF. These results suggest that circulating CK8:anti-CK8 immune complexes may have played a role in the process of lung injury in pulmonary fibrosis.

Anti-modified LDL antibodies, LDL-containing immune complexes, and susceptibility of LDL to in vitro oxidation in patients with type 2 diabetes.

We investigated the hypothesis that modified lipoproteins trigger an immune response leading to the production of autoantibodies and subsequently to the formation of atherogenic immune complexes (IC). We recruited 20 type 2 diabetic patients with macrovascular disease, 14 nondiabetic patients with coronary artery disease (CAD), and 34 healthy control subjects matched for age, sex, and race. Serum antibodies to oxidized and glycated LDL did not differ significantly among the 3 groups. Serum IC contained variable, but not statistically different, amounts of IgG, IgM, and IgA. In contrast, the content of cholesterol in IC isolated from diabetic patients was significantly higher than that in IC isolated from control subjects, and the content of apolipoprotein (apo)-B was significantly higher than that in IC isolated from control subjects and patients with CAD. Cholesteryl ester accumulation in human monocyte-derived macrophages incubated with IC, a measure of the atherogenic potential of IC, was significantly higher in macrophages incubated with red blood cell-adsorbed IC isolated from diabetic patients compared with IC isolated from control subjects (P < 0.03) or from patients with CAD (P < 0.04) and was strongly correlated with the content of apoB (r = 0.68, P < 0.001) and cholesterol (r = 0.61, P < 0.001) in IC. LDL from diabetic patients was more susceptible to oxidation in vitro, was significantly smaller, and contained significantly less alpha-tocopherol than LDL isolated from subjects in the other groups. In addition, the n-3 polyunsaturated fatty acid content of phospholipids and cholesteryl esters in LDL isolated from diabetic patients was significantly increased (P < 0.05) compared with that from patients with CAD or from control subjects. We postulate that LDL size, susceptibility to oxidation, and lipid fatty acid composition may play a critical role in the production of antibodies to oxidized LDL and consequently in the formation of LDL-containing IC in patients with type 2 diabetes.

Autoallergy: A pathogenetic factor in atopic dermatitis?

Long before the discovery of IgE it was reported that human dander extract can elicit immediate-type skin reactions in patients with severe atopy and that this skin sensitivity can be passively transferred with serum. Several recent findings have rekindled the interest in this phenomenon and led to the concept that IgE autoreactivity may play a pathogenetic role in severe and chronic forms of atopy. The elucidation of the nature of several environmental allergens has revealed striking structural and immunologic similarities with human proteins. It was also reported that patients predominantly with severe and chronic manifestations of atopy (eg, atopic dermatitis) contain IgE autoantibodies against a wide variety of proteins expressed in histogenetically unrelated human cell types and tissue specimens. Last, complementary DNAs coding for autoallergens were isolated from human expression complementary DNA libraries and recombinant autoallergens were produced. The autoallergens characterized to date represent mainly intracellular proteins, but some of them could be detected as IgE immune complexes in sera of sensitized patients. We suggest that at least two pathomechanisms could play a role in autoallergy. First, autoallergens may cross-link effector cell-bound IgE autoantibodies and, by release of inflammatory mediators, lead to immediate-type symptoms. Second, IgE-mediated presentation of autoallergens may activate autoreactive T cells to release proinflammatory cytokines, contributing to the magnitude of the allergic tissue reaction. (J Allergy Clin Immunol 2000;105:432-7.)

Mixed Connective Tissue Disease with Multiple Organ Damage. Successful Treatment with Plasmapheresis.

A 24-year-old-woman with mixed connective tissue disease (MCTD) developed multiple organ failure, disseminated intravascular coagulation (DIC), metabolic acidosis, and respiratory and renal failure resulting from visceral vasospasm, so-called visceral Raynaud's phenomenon. After plasmapheresis, the condition of multiple organ failure was markedly improved. The successful treatment with plasmapheresis was dependent upon the removal of immune complexes in serum and improvement of visceral circulation. Thus plasma exchange is recommended as a possible a treatment for multiple organ damage in MCTD.

Immunological characterization of C3H mice congenic for Fas(lprcg), C3h/HeJ-Fas(lprcg)/Fas(lprcg).

Fas(lpr) (lpr) and Fas(lprcg) (lpr(cg)) are allelic mutations of the Fas gene that is involved in apoptosis or programmed cell death. Lpr greatly reduces the expression of functional Fas and lpr(cg) expresses the death domain-disabled, non-functional Fas on the cell surface. C3H/HeJ mice congenic for lpr(cg) (C3H-lpr(cg)) were established and compared with C3H/HeJ-lpr/lpr (C3H-lpr) mice for their immunological and pathological features. Lymphadenopathy, splenomegaly, development of CD4- CD8- B220+ or double-negative (DN) T cells, renal pathology, and lymphoid cell infiltration in the lung and liver were not significantly different between C3H-lpr(cg) and C3H-lpr mice. Noticeably, however, the production of serum immunoglobulin, autoantibodies against double-strand DNA and serum immune complexes were significantly lower in C3H-lpr(cg) than in C3H-lpr mice. The results indicate that the death signal through the death domain of Fas is responsible for lymphoproliferation due to the accumulation of DN T cells and suggest that the region of Fas outside the death domain may be involved in autoantibody production. The newly-developed congenic C3H-lpr(cg) mice will provide a powerful tool for research into the function of Fas apart from apoptosis.

Steroid treatment in young MRL.MpJ- Fas lpr autoimmune mice prevents cochlear dysfunction

Corticosteroid therapy reverses clinical autoimmune sensorineural hearing loss, although little is known of how steroids restore normal auditory function. If suppression of systemic autoimmune processes underlies hearing restoration, then preventing autoimmune symptoms from developing should prevent cochlear dysfunction. MRL.MpJ- Fas lpr autoimmune mice were used to test this potential mechanism by initiating oral prednisolone treatment at 6 weeks of age, prior to autoimmune disease and hearing loss onset. The steroid treatment group was given prednisolone in their drinking water, while untreated controls were given tap water. Treatment continued for 7 months with periodic evaluations of cochlear function with auditory brainstem response (ABR) audiometry. Autoimmune mice given the steroid lived longer and did not develop levels of serum immune complexes seen in their untreated controls. Also, their ABR thresholds remained near normal throughout the 7 months of treatment, while untreated controls showed progressive threshold elevations typical for autoimmune disease. This correlation of suppressed systemic autoimmune activity and maintenance of normal cochlear function identifies one potential mechanism for autoimmune hearing loss and hearing restoration with steroid therapy. The autoimmune mouse should serve as a valuable model for future studies of the cochlear mechanisms responsive to steroid treatment in autoimmune hearing loss.

Steroid-responsive cochlear dysfunction in the MRL/lpr autoimmune mouse

Corticosteroids historically have been used to treat autoimmune sensorineural hearing loss, although little is known of how steroids restore normal inner ear function. Therefore, to identify a potential model for this field of research, this study examined the effects of prednisolone on auditory brain stem response thresholds in the MRL/ lpr mouse model of autoimmune sensorineural hearing loss. Mice treated with prednisolone after auditory threshold elevations demonstrated significant improvement and stabilization of thresholds compared with untreated controls. MRL/ lpr mice treated with steroids before the onset of autoimmune disease and cochlear dysfunction demonstrated decreased serum immune complexes, higher survival rates, and lower auditory thresholds compared with untreated controls. These positive results suggest the autoimmune mouse may be useful for studies of steroid-responsive mechanisms of the cochlea in autoimmune sensorineural hearing loss, as well as any hearing disorder in which steroid therapy is currently used. (Otolaryngol Head Neck Surg 1999;121:344-7.)

Altered expression and action of the low-affinity IgE receptor FcϵRII (CD23) in asthmatic airway smooth muscle

Background: Changes in cell surface expression of certain immunoglobulin Fc receptors have been demonstrated in leukocytes isolated from the lungs of atopic asthmatic individuals. This, together with emerging evidence that Fc receptors can also be expressed and activated in non–bone marrow–derived cell types, including airway smooth muscle (ASM), raises the hypothesis that the atopic asthmatic ASM phenotype is associated with an altered endogenous expression and action of specific Fc receptors present in the ASM itself. Objective: The current study addressed the above hypothesis by examining (1) whether the expression of certain key Fc receptor subtypes for IgE and IgG is altered in ASM tissue isolated from human atopic asthmatic individuals and (2) whether this altered Fc receptor expression is comparably induced in naive human ASM tissue and cultured cells after their passive sensitization with human atopic asthmatic serum or IgE immune complexes. Methods: Messenger RNA and cell surface protein expression of the individual IgG receptor subtypes FcγRI, FcγRII, and FcγRIII, as well as the IgE receptor subtypes FcϵRI and FcϵRII, were examined in human ASM tissue isolated from atopic asthmatic and control (nonatopic/nonasthmatic) individuals. In addition, we examined the effects of passive sensitization of ASM tissue and cultured ASM cells with control serum, atopic asthmatic serum, or exogenously administered IgE immune complexes on Fc receptor expression and action (ie, induction of proinflammatory cytokine release). Results: The observations demonstrate that (1) human ASM tissue expresses messenger RNA and surface protein for FcϵRII, as well as for all the Fcγ receptor subtypes, (2) in contrast to unaltered Fcγ subtype expression, however, relative to control human ASM, FcϵRII is significantly up-regulated in inherently asthmatic ASM tissue, (3) up-regulated expression of FcϵRII represents, at least in part, an inducible phenomenon that is largely attributed to IgE immune complex–coupled activation of the receptor, and (4) the latter action is associated with FcϵRII-induced autologous elaboration of the proinflammatory cytokine, IL-1β, by the atopic sensitized ASM. Conclusion: These observations provide new evidence that human ASM tissue expresses FcϵRII in addition to all 3 subtypes of Fcγ receptors and that the expression of FcϵRII is selectively increased in atopic asthmatic ASM, a phenomenon associated with IgE immune complex/FcϵRII–mediated elaboration of IL-1β by the ASM itself. (J Allergy Clin Immunol 1999;104:575-84.)

Up-regulation of glomerular extracellular matrix and transforming growth factor-βbgr; expression in RF/J mice

RF/J mice were first reported as a murine model of spontaneous glomerulosclerosis by Gude and Lupton in 1960, but the precise histologic characteristics and immunopathological background of this mouse have not been investigated further. Measurements of serum levels of immunoglobulins, anti-single strand DNA (anti-ss-DNA) antibody, complement (C3), and circulating immune complex (IC) were performed. Analyses of glomerular histological and immunopathological lesions in association with the detection of mRNA expression of collagen IV, TGF-beta, matrix protein turnover related enzymes, matrix metalloproteinase-2 (MMP-2), tissue inhibitor of metalloproteinase-2 (TIMP-2) and platelet-derived growth factor (PDGF) were also performed in young (10-week-old) and elderly (60-week-old) RF/J mice with age-matched BALB/C mice as the controls. High levels of serum IgA and IgG from as early as 20 weeks of age were noted in the RF/J mice. Serum anti-ss-DNA antibody of aged RF/J mice increased up to 23% of that of aged MRL-lpr/lpr mice, and serum C3 concentration significantly decreased with age, reaching lower levels than that of BALB/c mice. IgA-IC levels were significantly high compared to BALB/C mice both in the early and late stages of life, whereas IgG-IC levels were high only in mice younger than 20 weeks. Semiquantitative and quantitative analyzes of renal histopathological findings revealed significantly marked and age-related mesangial matrix expansion in RF/J mice, with increasing frequency of global glomerular sclerosis and tubulointerstitial damage. On the other hand, although precise measurements of glomerular cell numbers also showed an apparent augmentation in both young and old RF/J mice compared to BALB/C mice, glomerular cellularity decreased with age in RF/J mice. Immunohistochemical study revealed massive immunoglobulin deposition from a young age in association with significantly higher accumulation of matrix proteins, such as types I and IV collagen and laminin from the early stage of life. In addition, in these glomeruli, transforming growth factor-beta1 (TGF-beta1) was highly expressed both in young and old mice. The mRNA expression of MMP-2 was up-regulated only in the early stage of life. Although PDGF mRNA of RF/J mice was significantly up-regulated in the early stage of life, the differences between the mice disappeared in the late stage of life. These findings suggest that in RF/J mice, an immunopathological background inducing high serum immunoglobulin and IC levels from the early stage of life is closely related to mesangioproliferative glomerular lesions mediated by PDGF, and that development of massive extracellular matrix accumulation in glomeruli was induced by up-regulated expression of TGF-beta with inappropriate regulation of protein turnover-related enzyme production.

A simple and robust method for the complete dissociation of HIV-1 p24 and other antigens from immune complexes in serum and plasma samples

Accuracy of antigen determination in human plasma samples is often adversely affected by immune complex formation between antigens (e.g., HIV-1 p24 protein) and specific antibodies. In this study we describe an optimized method for complete immune complex dissociation (ICD) in plasma. This method is based on heat denaturation of antibodies and utilizes a defined solution of sodium dodecyl sulfate (SDS) and diethylenetriaminepentaacetic acid (DTPA) as diluent. The efficiency of this procedure for ICD was compared with those of published methods, employing heat denaturation alone and acidification. Plasma samples from patients participating in anti-retroviral treatments and samples reconstituted in vitro were treated and analyzed in parallel. HIV-1 p24 antigen was determined by quantitative enzyme-linked immunosorbent assay (ELISA). In 312 samples from 97 patients, antigenemia was found in 44.9% when measured directly and in 87.2% after this treatment. In a subset of 56 samples, 21.4% tested positive prior to treatment, while after either novel treatment, heat denaturation or acidification, these samples tested positive in 80.4%, 62.5% and 60.7%, respectively. In 94% of cases viral RNA was detected. This improved procedure for ICD provides a reliable and convenient method for complete and accurate p24 antigen detection in human plasma and is applicable to commercially available test kits.

Persistent viremia after recovery from self-limited acute hepatitis B.

To define the duration of viremia in the course of acute hepatitis B, we semiquantitatively determined the levels of hepatitis B virus (HBV) DNA in the sera, using polymerase chain reaction (PCR) coupled with Southern blotting, of non-immunocompromised patients with self-limited acute hepatitis B. In the sera of 10 of 11 patients, HBV DNA, which was presumably coated with viral proteins, was detected for a long period after recovery, even at the final observation times, which ranged from 6 to 19 months after disease onset. To characterize the mode of HBV that was present in serum, we immunoprecipitated immune complexes in sera by the addition of anti-human immunoglobulin G (IgG) and determined the levels of HBV DNA separately in the supernatants and pellets. In the acute phase of hepatitis B, high levels of HBV DNA were detected both in the supernatants and pellets at comparative levels. After the convalescent phase, the amount of HBV DNA in the supernatant decreased with respect to that in the pellets. It is notable that, in most cases, serum HBV persisted as a form of immune complex even after the seroconversion to antibody to hepatitis B surface antigen (anti-HBs). These data suggest that the replication of HBV may persist in some organs, most likely in the liver or peripheral blood cells, for a long period after recovery from acute hepatitis B, and the data indicate the possible transmission of HBV from organ transplantation donors who exhibit serological markers of past infection only.

Failure of elevated heat shock protein 70 antibodies to alter cochlear function in mice

Heat shock protein 70 (HSP70) has been suggested as the putative cochlear antigen underlying a proposed autoimmune etiology in certain cases of Meniere's disease and idiopathic hearing loss. To determine if antibodies to this cellular protein are capable of altering cochlear function, BALB/c ( N=3) and CBA/J ( N=9) mice were inoculated with bovine HSP70 by intraperitoneal injections (10 μg in saline) every 10 days for 7 or 10 months, respectively. An equal number of control mice were injected with PBS according to the same schedule. ABR thresholds at 4, 8, 16, and 32 kHz in the HSP70-inoculated mice did not change over the 10 month period and were similar to saline controls. Furthermore, serum immune complexes and antinuclear antibodies did not increase over the inoculation period. ELISA analysis demonstrated the mice created antibodies to the foreign HSP70, but these apparently caused no abnormalities in the auditory or immune systems. It was concluded that foreign HSP70 is antigenic and inoculation with it will raise antibodies, but these antibodies were neither immunopathogenic nor cochleopathic. Therefore, these findings do not support current theories that elevated anti-HSP70 antibodies are the underlying cause of hearing loss in patients with such antibodies present.

IgE /Anti-IgE Immune Complexes in Sera from Patients with Crohn’s Disease Do Not Contain Food-Specific IgE

Background: An association of Crohn’s disease (CD) with food allergy has been discussed, but the role of food-specific IgE has not been clarified yet. Since CD is combined with immune complex formation, we examined in the present study whether anti-IgE autoantibodies in such complexes might hinder the determination of specific IgE. Methods: In order to elucidate the role of food-specific IgE in CD, we tested sera from CD patients (n = 107), healthy controls (n = 65) and allergics subjects (n = 7) for their IgE binding to food antigens (yeast, corn, celeriac, wheat) by an immunodot assay. After determining levels of IgE/IgG anti-IgE immune complexes, we purified them from serum pools of patients with CD, allergic subjects and healthy controls by affinity absorption using a monoclonal anti-IgE antibody. These purified immune complexes were treated by low pH (pH = 4) in order to dissolve them and to increase the detectability of food-specific IgE by RAST and CAP assay. Results: In CD sera no food-specific IgE could be detected, but levels of immune complexes of IgE and IgG anti-IgE autoantibodies were statistically significantly increased compared to healthy controls. pH treatment of purified IgE/IgG anti-IgE immune complexes resulted in a significant increase in specific IgE to yeast, corn, wheat and celeriac detected by RAST, however, only in the serum sample purified from allergic subjects. After pH treatment of CD immune complexes, specific IgE levels remained still very low. Conclusion: Thus, even if IgE seems to represent an autoantigen in CD, it is unlike to specifically participate in the pathophysiology of the putative food adverse reactions.

GPIIIa-(49-66) is a major pathophysiologically relevant antigenic determinant for anti-platelet GPIIIa of HIV-1-related immunologic thrombocytopenia.

High-affinity (Kd = 1 x 10(-9) M) anti-platelet GPIIIa has been isolated from serum immune complexes of immunologic thrombocytopenic HIV-1-infected patients (HIV-1-ITP). Affinity-purified anti-platelet antibody reacted with a recombinant GPIIIa-(1-200) and -(1-66) fusion peptide and with an 18-mer GPIIIa-(49-66) peptide but not with seven other GPIIIa peptides spanning the length of GPIIIa. Most of the anti-platelet antibody ( approximately 85%) could be adsorbed to and eluted from a GPIIIa-(49-66) affinity column. Binding of antibody to platelets could be inhibited by GPIIIa-(49-66) or an equimolar peptide-albumin conjugate (IC50 = 2 microM). Sera from 7 control subjects and 10 classic autoimmune thrombocytopenic patients gave background reactivity with GPIIIa-(49-66). HIV-1-ITP sera from 16 patients reacted with a mean OD 6-fold greater than background (range, 4- to 9-fold). Serum anti-GPIIIa-(49-66) concentration correlated inversely with platelet count, R2 = 0.51, n = 31, P < 0. 0001. Because mouse platelet GPIIIa-(49-66) has 83% homology with human GPIIIa and mouse monocytes contain Fc receptors for the human IgG1-kappa/lambda antibody, we determined the in vivo effect of human anti-GPIIIa on mouse platelets. Affinity-purified antibody, 25-50 microg given i.p., resulted in a precipitous drop in platelet count to 30% of baseline, with nadir at 4 hr and return to normal in 36 hr. No effect was noted with control IgG. Acute thrombocytopenia could be prevented or reversed by the injection of the GPIIIa-(49-66) albumin conjugate at zero time or 2 hr after antibody, respectively, but not with a scrambled peptide-albumin conjugate. Thus HIV-1-ITP patients have high-affinity anti-platelet GPIIIa against a major antigenic determinant, GPIIIa-(49-66), which correlates inversely with platelet count and induces thrombocytopenia in mice.

A study of autoantibodies and circulating immune complexes in mercury-exposed chloralkali workers.

Inorganic mercury may cause immunologically mediated disease: e.g., glomerulonephritis, acrodynia, and contact allergy. Animal models have demonstrated the importance of genetic factors in determining susceptibility and resistance to autoimmunity, as well as the specific manifestation of the autoimmune response. Findings in groups of workers with occupational exposure to inorganic mercury have been inconsistent. To investigate whether an immune response, caused by exposure to inorganic mercury (Hg), could be shown in occupationally exposed workers. Immunoglobulin G (IgG), antinuclear autoantibodies, antibodies against thyroid, stomach or kidney antigens using indirect immunofluorescence, antibodies against glomerular basement membrane using ELISA, and circulating immune complexes in serum, and albumin in urine, were examined in Hg-exposed workers and controls. The two groups, 41 male chloralkali workers exposed to Hg vapour (mean exposure time 9 years) and 41 unexposed controls were age-matched and recruited from the same company. Hg concentrations in whole blood (B-Hg), plasma (P-Hg), and urine (U-Hg) were determined using cold vapor atomic spectrometry. Cross-sectional study. The mean B-Hg, P-Hg and U-Hg levels were 46 nmol/l, 37 nmol/l, and 27 micrograms/g creatinine in the exposed group, and 17 nmol/l, 6.9 nmol/l, and 3.4 micrograms/g creatinine in the referents. No statistically significant differences were found regarding IgG levels, urinary albumin excretion, prevalence of abnormal titers of autoantibodies or circulating immune complexes. There were no statistically significant associations between autoantibodies or immune complexes on the one hand and mercury exposure indices on the other. The results indicate that, if and when lasting autoimmune response occurs at the mercury exposure levels of the present study, it is uncommon. A small fraction of humans may, however, be susceptible to the development of autoimmunity, and there is also a possible "healthy worker" selection. Thus cross-sectional studies of moderate numbers of active workers will have low power to demonstrate autoimmune effects.

Papillitis and vasculitis of the arteria spinalis anterior as complications of hepatitis C reinfection after liver transplantation.

It is well known that hepatitis C virus (HCV)-related chronic liver disease may be associated with various immunological disorders including mixed cryoglobulinemia, which is accompanied by cutaneous vasculitis, arthralgias, membrano-proliferative glomerulonephritis, and neuropathy in association with cryoprecipitable immune complexes in serum. We describe here the first case of central nervous system HCV infection with evidence of the virus in the cerebrospinal fluid in association with cryoglobulinemia in a patient who developed recurrent episodes of papillitis and vasculitis of the arteria spinalis anterior after liver transplantation.