Circulating immune complexes in chronic hepatitis C

For assessing the role of circulating immune complexes (CIC) in chronic hepatitis C, the relative frequency of CIC was determined in 54 patients with chronic hepatitis C, 15 asymptomatic hepatitis C virus (HCV) carriers, and 54 healthy controls. IgM and IgG containing CIC were studied using both Clq and conglutinin (K) in an immunoglobulin-specific solid-phase enzyme immunoassay. CIC were a common feature of chronic hepatitis C with 96.3% of patients with at least one abnormal test result. The prevalence of elevated IgG-K, IgM-K, IgG-C1q, and IgM-C1q CIC was 70.3%, 50.0%, 64.8%, and 35.1%, respectively. The prevalence of IgG class CIC was higher than IgM class CIC (P = 0.038 for K-CIC and P = 0.01 for C1q-CIC, respectively). There is correlation between IgG-K CIC and IgG-C1q CIC (r = 0.445, P= 0.0021, IgG-K CIC and ISM-Clq CIC (r = 0.348, P = 0.020). IgM-K CIC and aspartic arninotransferase (r = 0.321, P= 0.015). IgM-K CIC and alanine aminotransferase (r =0.301, P = 0.027). Compared to patients with chronic persistent hepatitis and chronic lobular hepatitis, patients with chronic active hepatitis have a higher prevalence of elevated IgG-K CIC (77.2% vs. 40.0%, P = 0.029) and IgM-K CIC (56.8% vs. 20.0%, P = 0.038). The concentration of IgG-K, IgM-K, and IgM-C1q CIC in the former was significantly higher than that in the latter, respectively. In conclusion, IgG class CIC is the major type of CIC in chronic hepatitis C. Conglutinin-binding CIC correlates with more severe tissue damage. CIC may play a role in the pathogenesis of chronic hepatitis C. © 1995 Wiley-Liss, Inc.     

Immunofluorescence studies on the codistribution immune deposits and complement in the thyroid glands of Obese strain (OS) chickens

This study demonstrates immune complexes in thyroid glands of Obese strain (OS) chickens, that consist of thyroglobulin (Tg) and antibodies to Tg. In IIF tests it was shown that these complexes fix complement with an age-dependent increase from 12% in 19-day-old embryos up to 100% in 6-week-old animals. This finding and the observation that the deposition of complement-binding immune complexes precede cellular infiltration of the thyroid gland and correlate with the serum titer of Tg-Ab (as one parameter of the disease) points towards a role as one initial effector mechanism for the development of spontaneous autoimmune thyroiditis (SAT).     

Circulating immune complexes in various thyroid diseases.

In a study of 171 patients with various thyroid diseases, circulating immune complexes (CIC), measured by a C1q solid phase radioassay, were detected in 26% of the patients as compared to 8% of the control subjects. CIC were found in 33--55% of the patients with a well defined thyroid autoimmune disorder (Hashimoto's goitre, asymptomatic thyroiditis, spontaneous myxoedema and Graves' disease) and also in the same proportion of patients with diffuse goitre. CIC were correlated to the presence of serum antibodies to microsomal thyroid antigen but not to their titre. No relationship was observed between CIC and the age or sex of the patients and the presence of exophthalmos, or between CIC and the different thyroid function tests or serum anti-thyroglobulin antibodies. CIC were found in untreated patients as well as in those treated with prednisone, methimazole or thyroxine.     

Thyroid peroxidase and the induction of autoimmune thyroid disease

Animal models of autoimmune thyroid disease are associated with thyroglobulin (Tg) as autoantigen whereas in man the autoimmune response to microsomal antigen/thyroid peroxidase (TPO) appears to play a major role in thyroiditis. Consequently, we have compared the ability of TPO and Tg to induce thyroid autoantibodies and thyroid damage in mice known to be susceptible (CBA/J) or resistant (BALB/c) to thyroiditis induced using murine Tg. Groups of three to five mice were immunized twice using Freund's complete adjuvant with 80-100 micrograms highly purified porcine (p) TPO, pTg, rat (r) Tg, human Tg, bovine serum albumin (BSA) or BSA + 0.2 micrograms pTg (the level of Tg contamination of TPO). Four weeks after immunization with TPO, plasma from CBA/J (but not BALB/c) mice contained IgG class antibodies which bound to TPO-coated tubes in the presence or absence of excess Tg (and could therefore be clearly distinguished from Tg antibodies) but there was no evidence of thyroiditis in either strain of mice. In contrast, in CBA/J mice immunized with rTg and, to a lesser extent in mice that had received pTg, thyroid tissue was infiltrated with lymphoid cells and/or neutrophils and antibodies to pTg (but not pTPO) were present. Our observations demonstrate that induction of TPO antibody alone is insufficient to lead to thyroiditis in CBA/J mice. Further, these studies emphasize the complex interactions between MHC and different thyroid antigens in the processes leading to thyroid destruction.     

Specific increases in urinary excretion of anti-DNA antibodies in lupus mice induced by lysozyme administration: further evidence for DNA-anti-DNA immune complexes in the pathogenesis of nephritis.

We previously reported that lysozyme electrostatically inhibits the fibronectin-mediated DNA binding to the glomerular basement membrane (GBM) and reduces in situ DNA-anti-DNA complex formation in the GBM in NZB/W F1 mice [1]. In this study, we further noticed significant increases in urinary excretion of anti-DNA antibodies and immune complexes (IC) in lysozyme-treated NZB/W F1 mice. Their clearance ratios of IgG anti-DNA antibody to whole IgG were markedly high compared with those of saline-treated animals. A large number of IgG and C3 positive granules were observed in the tubular cells of NZB/W F1 mice treated with lysozyme. On the contrary, nil or only small amounts of anti-DNA antibodies were detected in the urine of NZB/W F1 mice without lysozyme administration despite a large amount of proteinuria, suggesting entrapment of the antibodies in lupus glomeruli. Lysozyme neither inhibited the binding of anti-DNA antibodies to DNA or heparan sulphate nor did it displace anti-DNA antibodies and IC from the kidney homogenates of lupus mice. It thus appears that the inhibition of DNA binding to the GBM due to lysozyme reduced the entrapment of anti-DNA antibodies in the GBM, resulting in urinary excretion of the antibodies.     

Milk whey-specific immune complexes in allergic and non-allergic subjects

We developed an antigen- and isotype-specific ELISA for the rapid detection of native serum immune complexes (IC). It is a sandwich assay, in which a solid phase antigen-specific capture antibody selectively binds the antigen-specific IC via the antigen. The isotype of the bound IC is then identified using an enzyme-labelled indicator antibody. Using this sensitive assay system, we were able to detect native serum milk whey-specific immune complexes (SMIC) of the IgG, IgE and IgA isotypes. Detectable amounts of native serum SMIC of all three isotypes were found in sera of the majority of both atopic and non-atopic subjects. The ELISA was then used to compare the levels of native IgE SMIC in sera of milk RAST positive atopic patients with those found in milk RAST negative atopic patient sera. Milk RAST positive patient sera were found to have significantly higher mean levels (P less than or equal to 0.005) of native IgE SMIC than milk RAST negative sera. Sera of other atopic individuals were also found to contain significantly higher mean levels (P less than or equal to 0.005) of native IgG and IgA SMIC than non-atopic donors. IgE IC may specifically be involved in adverse symptoms seen in milk allergic patients.     

检测HBVDNA/Ig-双特异性循环免疫复合物的免疫捕捉法PCR

目的;建立一种免疫捕捉法ＰＣＲ技术,研究血清免疫复合物中不同Ｉｇ类型抗体结合ＨＢＶ的情况,并初步探讨其意义。方法：以羊抗人μ,γ,α链的ＩｇＧ为捕捉抗体,再利用ＰＣＲ扩增捕捉物中的ＨＢＶＤＮＡ。结果;成功地建立了检测ＨＢＶＤＮＡ／ＩｇＭ,ＩｇＧ和ＩｇＡ－ＴＣＩＣ的免疫捕捉法ＰＣＲ技术。     

Analytical aspects of thyroid antibodies estimation

The search for antibodies that will reliably diagnose, predict and monitor the autoimmune thyroid diseases is a quest that is beset with difficulties. This review will describe the various antigens involved in autoimmune thyroid disease, the development of a humoral response to these antigens and some of the technical difficulties involved in trying to detect and then measure their concentrations.

Multiple antigen configurations of thyroglobulin (TG) are produced when it is iodinated resulting in functionally active but immunologically distinct molecules. Thyroid peroxidase (TPO), originally described as thyroid microsomal antigen, is present on the apical surface of thyroid follicular cells and is the antigen most closely involved in cell-mediated cytotoxicity. Multiple B cell reactive epitopes exist each giving rise to different antibodies. The third antigen is the TSH receptor (TSHR) which is a two subunit glycoprotein. The extracellular A subunit is recognised by thyroid stimulating antibodies whilst those antibodies recognising the B subunit, located much nearer the cell surface, appear to function as blocking antibodies.

The aetiology and mechanics of the autoimmune cellular and antibody responses involves a combination of HLA linkage, genetics and environmental factors to determine the initial and subsequent stages of the development of autoimmune thyroid disease.

Starting off with immunofluorescence or passive tanned red cell agglutination assays, we now favour more sensitive TPO antibody quantitative immunoassays which are standardised using MRC 66/387. The apparent incidence of these antibodies is influenced by the techniques used to detect them and the significance of those positive antibody concentrations detected using assays that report very high incidence rates in the “normal” population remains to be proven using longitudinal studies.

Older immunofluorescence and passive tanned red cell agglutination methods have been improved upon to give the current, competitive and non-competitive immunoassays that are much more sensitive and specific for anti-TG antibodies. However, because a wide-range of methods are still being used in clinical laboratories, the sensitivity and specificity of available methods will vary depending on the method used. There are still assays that are calibrated with purified or crude preparations of TG antibody by pooling patient sera or blood donor material. These various secondary standards are often, but not always, calibrated against the primary standard (MRC 65/93). All requests for TG estimation in thyroid carcinoma patients should have TG antibody estimated at the same time because of the possibility of interference in the tumour marker assay by the antibody.

Two methods are widely used for the estimation of TSHR antibodies. The first involves bioassays based on cultured cells to measure the stimulating class of antibodies and the second involves receptor assays based on ¹²⁵I-labeled TSH. The most widely used assay uses detergent-solubilized porcine TSHR with TSHR antibodies to inhibit the TSHR-¹²⁵I-TSH interaction, and polyethylene glycol to separate receptor-bound and free labelled-TSH by precipitation. TSHR antibody heterogeneity can coexist within an individual patient and change over time is one reason why it has been difficult to develop diagnostically accurate TSHR antibody tests.     

Avidity of thyroglobulin antibody in sera from patients with Hashimoto's thyroiditis with different thyroid functional status

The mechanism of disease progression in Hashimoto's thyroiditis (HT) is still unclear. Thyroglobulin antibody (TgAb) is a diagnostic hallmark of HT. The aim of our study was to evaluate the avidity of TgAb in sera from HT patients with different thyroid functional status. Sera from 50 patients with newly diagnosed HT were collected and divided into three groups according to thyroid function: patients with hypothyroidism (H, n = 18), subclinical hypothyroidism (sH, n = 18) and euthyroidism (Eu, n = 14). Titres and avidity of TgAb were determined by enzyme‐linked immunosorbent assays (ELISAs). Avidity constant (aK) was determined as the reciprocal value of the thyroglobulin molar concentration in the liquid phase resulting in 50% inhibition of TgAb binding to thyroglobulin in solid‐phase ELISAs. The titres and aK of TgAb were performed using log‐transformation, and expressed as lgT and lgaK, respectively. Mean lgT of TgAb in sera was 4·19 ± 0·60 in H, 3·77 ± 0·63 in sH, and 3·29 ± 0·64 in Eu, respectively. The median avidity of TgAb was 2·30 × 10⁹ in H, 8·80 × 10⁸ in sH, 2·00 × 10⁷ in Eu, respectively. lgT and lgaK of TgAb were at significantly lower levels in Eu than in sH and H (P < 0·05). Correlation was found between lgT and lgaK (r = 0·594, P < 0·05). lgaK was also related to TSH (r=0·308, P < 0·05). Our study indicated that patients with high‐avidity TgAb might be at high risk of developing subclinical, even to overt, hypothyroidism.     

Repeated exposure to bacterial lipopolysaccharide interferes with disposal of pathogenic immune complexes in mice.

Patients with systemic lupus erythematosus (SLE) experience clinical flares in association with superimposed bacterial infection. To investigate whether heightened immune phenomena during the course of bacterial infections were related to abnormal disposal of immune complexes, we administered bacterial lipopolysaccharide (LPS) to C57BL/6 mice for 5 weeks. Control mice received vehicle only. We then challenged the mice with a subsaturating dose of radiolabelled immune complexes intravenously and determined the localization of immune complexes in liver, spleen and kidney. In comparison to control mice, mice exposed to LPS developed features of polyclonal B cell activation, autoimmune phenomena, delayed removal of immune complexes from the circulation, diminished liver uptake of immune complexes, and enhanced localization of immune complexes in the kidneys. The findings could not be attributed to biological processes dependent on complement concentration. Instead, interferences with Fc receptor function, or with endocytosis of immune complexes may represent likely possibilities. Thus, clinical flares in patients with SLE, in the presence of a superimposed infection, may result from enhanced localization of immune complexes in organs due to altered mechanisms of their disposal.     

抗HBs-HBsAg复合物诱生体液免疫应答的研究

目的研究抗ＨＢｓ－ＨＢｓＡｇ复合物在ＢＡＬＢ／ｃ小鼠诱生体液免疫应答的特点。方法分别用鼠抗ＨＢｓ－ＨＢｓＡｇ免疫原性复合物（ＩＣ）或单独ＨＢｓＡｇ免疫ＢＡＬＢ／ｃ小鼠（加或不加氢氧化铝），分析其诱生的抗ＨＢｓＩｇＧ效价及ＩｇＧ亚类。结果用ＩＣ加氢氧化铝为佐剂免疫小鼠诱生的抗ＨＢｓ中以ＩｇＧ１亚类为主，而用ＨＢｓＡｇ免疫鼠则以ＩｇＧ２ｂ亚类较高。ＩＣ不加氢氧化铝佐剂诱生的抗ＨＢｓ中ＩｇＧ１及ＩｇＧ２ａ均高于单独ＨＢｓＡｇ免疫鼠。研究还显示，抗ＨＢｓＩｇＧＦｃ段是巨噬细胞（ＭΦ）等抗原提呈细胞摄取ＩＣ的主要途径。结论抗ＨＢｓ－ＨＢｓＡｇ复合物免疫诱生的体液免疫应答较单独ＨＢｓＡｇ免疫强。抗ＨＢｓ主要通过Ｆｃ段的介导作用，改变了机体抗原提呈细胞对ＨＢｓＡｇ的摄取、加工及抗原提呈，并可增强ＨＢｓＡｇ的免疫原性。     

Adrenalectomized mice as an experimental model for the study of the biological activity of immune complexes

Local and systemic reactions to an immune complex formed in vitro can be obtained in adrenalectomized mice. The principles for the composition of the immune complexes giving the appearance of their general (toxic) action and their ability to evoke local reactions are established. Factors inhibiting the anaphylactic reaction (injection of cortisone, antihistamines, general anesthesia) weakened the reaction to the immune complex. The local reaction to the immune complex was diminished by an artificially induced fall in the blood complement level in the animals.Presented by Academician of the Academy of Medical Sciences of the USSR V. I. Ioffe.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 847–850, July, 1976.     

低密度脂蛋白免疫复合物对单核细胞来源巨噬细胞胆固醇代谢和细胞因子分泌的影响

目的：探讨低密度脂蛋白免疫复合物（LDL-IC）对单核细胞来源巨噬细胞胆固醇代谢和细胞因子分泌的影响。 方法： 用胆固醇酶联法测定细胞内胆固醇含量，ELISA法检测培养上清TNFα和IL-1β水平。 结果： LDL-IC组细胞内胆固醇含量及上清TNFα、IL-1β水平均明显高于LDL、IgG-IC及阴性对照组。 结论： LDL-IC可以显著增加细胞内胆固醇含量与培养上清TNFα和IL-1β的水平，提示LDL-IC能通过干扰细胞脂质代谢及细胞因子分泌而在AS中起重要作用。     

The tRNA‐associated dysregulation in immune responses and immune diseases

Transfer RNA (tRNA), often considered as a housekeeping molecule, mainly participates in protein translation by transporting amino acids to the ribosome. Nevertheless, accumulating evidence has shown that tRNAs are closely related to various physiological and pathological processes. The proper functioning of the immune system is the key to human health. The aim of this review is to investigate the relationships between tRNAs and the immune system. We detail the biogenesis and structure of tRNAs and summarize the pathogen tRNA‐mediated infection and host responses. In addition, we address recent advances in different aspects of tRNA‐associated dysregulation in immune responses and immune diseases, such as tRNA molecules, tRNA modifications, tRNA derivatives and tRNA aminoacylation. Therefore, tRNAs play an important role in immune regulation. Although our knowledge of tRNAs in the context of immunity remains, for the most part, unknown, this field deserves in‐depth research to provide new ideas for the treatment of immune diseases.     

Defective prevention of immune precipitation in autoimmune diseases is independent of C4A*Q0

Increased prevalence of C4 null alleles is a common feature of autoimmune diseases. We have shown previously that complement-dependent prevention of immune precipitation (PIP) is defective in patients with systemic lupus erythematosus (SLE), and correlated this defect with C4A*Q0 and low levels of the C4A isotype. To further clarify the role of C4A in the aetiology of SLE, we now extend our studies to other diseases which have been associated with C4A*Q0. The frequency of C4A*Q0 was increased in Icelandic patients with coeliac disease (0.50; P < 0.001), Grave's disease (0.30; P = 0.002) and insulin-dependent diabetes mellitus (0.23; P = 0.04) and in British patients with dermatitis herpetiformis (0.42; P = 0.002) and this was reflected in low levels of C4A. In spite of this, PIP was normal in these patients, and in marked contrast to our previous observations on connective tissue diseases, PIP measurements in these patient groups correlated more strongly with levels of C4B (r = 0.51, P = 0.0000004) than C4A. Patients with increased levels of anti-C1q antibodies had significantly lower PIP than patients without such antibodies (P < 0.01) and a negative association of PIP with anti-C1q antibodies was also reflected in an increased prevalence (P = 0.006) and levels (P = 0.006) of anti-C1q antibodies in patients with subnormal PIP, as well as a negative correlation between PIP and anti-C1q antibodies (r = - 0.25, P = 0.02). These results show that the PIP defect cannot be explained by low levels of C4A alone and suggest that measurements of anti-C1q antibodies may be useful in future studies on the molecular cause of the PIP defect in autoimmune connective tissue disease.     

The selection of antibodies with defined desorption properties from precipitated immune complexes for use in immunoadsorption procedures

A general method for preparing immunosorbents with preselected antibody avidity is described. The method, which is a modification of a method described previously, also includes immunospecific purification of the ligand prior to coupling on the gel matrix. Polyclonal anti-alpha-1-fetoprotein antibodies in precipitated immune complexes were separated according to their avidity (low, intermediate and high) by dissociation with agents of increasing efficiency. After solid-phase coupling the antigen binding activity of the separated antibody preparations was examined according to recovery, capacity and binding strength. Antibodies of intermediate avidity derived from the immune complexes demonstrated optimal properties for preparative affinity chromatography.