Hypercatabolism of normal IgG; an unexplained immunoglobulin abnormality in the connective tissue diseases

The metabolism of radioiodinated IgG was studied in a series of 42 patients with connective tissue diseases (16 systemic lupus erythematosus, nine rheumatoid arthritis, five polymyositis, five vasculitis, and seven miscellaneous diagnoses). Fractional catabolic rates were increased and survival half-lives were shortened in all diagnostic categories indicating hypercatabolism of IgG. This hypercatabolism was masked by increased IgG synthesis, resulting in elevated serum concentrations of IgG in patients with systemic lupus erythematosus and rheumatoid arthritis and in generally normal concentrations in the others.The metabolism of iodinated IgM was also studied in eight patients with systemic lupus erythematosus, in seven with rheumatoid arthritis, and in 12 controls. The fractional catabolic rates were normal in both groups of patients. Serum concentrations of both IgM and IgA were moderately elevated in all diagnostic categories. Serum albumin metabolism was entirely normal in the nine subjects studied who were not receiving corticosteroids; in three who were receiving them, moderate hypercatabolism was observed.The hypercatabolism of IgG could not be accounted for by factors previously known to alter IgG metabolism. It was not observed in 15 patients with other chronic, inflammatory diseases and was not explained by concomitant administration of adrenal corticosteroids to some patients. Identical results were obtained whether the IgG was obtained from a patient himself or from a normal donor, demonstrating that the hypercatabolism is a host defect and not an abnormality of the protein. Thus, patients with connective tissue disease of several different diagnostic categories have been shown to have an unexplained immunoglobulin abnormality: they catabolize normal IgG at an accelerated rate.     

Antibody-dependent cell-mediated cytotoxicity in selected autoimmune diseases.

Antibody-dependent cell-mediated cytotoxicity mediated by peripheral blood lymphocytes was studied in patients with systemic lupus erythematosus, polyarteritis nodosa. Sjogren's syndrome, and rheumatoid arthritis. The target cells were chicken erythrocytes coated with rabbit anti-chicken erythrocyte antibody. Antibody-dependent cell-mediated cytotoxic activity was normal in Sjogren's syndrome and rheumatoid arthritis but significantly decreased (P is less than 0.001) in active systemic lupus erythematosus and in two patients with polyarteritis nodosa. A partial regeneration of antibody-dependent cell-mediated cytotoxic activity was obtained by treatment with pronase and DNase followed by overnight incubation. Sera from patients with systemic lupus erythematosus inhibited antibody-dependent cell-mediated cytotoxic activity of normal lymphocytes. The inhibitory activity was studied by specific immunoadsorption and sucrose density geadient ultracentrifugation. Removal of IgG but not IgM greatly reduced inhibition. Inhibitory factors were present in 7S and heavier fractions containing IgG. Five systemic lupus erythematosus patients were studied serially to determine if improvement in clinical status could be correlated with a decrease in serum inhibitory factors as studied by inhibition of normal antibody-dependent cell-mediated cytotoxicity. Indeed, a greater serum inhibitory capacity was found in each patient during periods of greater disease activity.     

Light-chain ratios of immunoglobulins G, A, and M determined by enzyme immunoassay

We describe an enzyme-linked immunosorbent assay for determination of light-chain ratios for IgG, IgA, and IgM in serum. A commercial serum with known overall kappa and lambda concentrations was used as standard. To capture the respective immunoglobulins, we used antibodies to gamma, lambda and mu chains coated onto microtiter plates. Peroxidase-conjugated anti-kappa and anti-lambda chain antisera were reacted with light chains on the captured immunoglobulins, and the amount of enzyme bound was monitored with o-phenylenediamine and urea-hydrogen peroxide as substrates. Calculation of absorbance ratios allowed determination of kappa and lambda chain concentrations of individual immunoglobulins in the standard and samples. Within-run and between-run CVs (n = 25) ranged from 5.9% to 13.0% for "high," "normal," and "low" kappa/lambda ratios for IgG, IgA, and IgM. The thoroughness of light-chain detection, expressed as, e.g., (IgA kappa + IgA lambda)/(total IgA), for 150 sera was 91-110%. The detection limit was 1 microgram/L. Reference intervals (mean +/- SD) for kappa/lambda ratios in sera from 100 apparently healthy adults were 2.34 +/- 0.80 for IgG, 1.59 +/- 0.40 for IgA, and 1.86 +/- 0.76 for IgM.     

Pediatric and perinatal reference intervals for immunoglobulin light chains kappa and lambda.

In routine analysis for immunoglobulin light chains in pediatric diagnostics, the age-related reference intervals for serum kappa (kappa) and lambda (lambda) light chains were evaluated in 1543 healthy subjects (newborns to age 16 years, including 168 premature infants). Light-chain analysis was performed by rate nephelometry. IgG, IgA, and IgM were measured simultaneously, and heavy- and light-chain differences were calculated for control purposes. Results for IgG, IgA, and IgM generally agreed with reference intervals reported in the literature. kappa showed age-related changes comparable with changes in IgG concentrations, whereas lambda showed moderate fluctuations. The kappa/lambda ratio showed an almost linear increase with age, starting with 0.97 at four months and reaching the highest value of 2.21 at 15 years (mean values). Preterm infants presented with markedly low serum concentrations of IgG and corresponding light chains but with adult-type kappa/lambda ratios because of the maternal-origin IgG.     

Altered immunoglobulin metabolism in systemic lupus erythematosus and rheumatoid arthritis

IgG and IgM metabolism was evaluated in 10 patients with systemic lupus erythematosus (SLE), 10 patients with rheumatoid arthritis (RA), and in seven normal volunteers. The biological half-lives of purified IgG and IgM, labeled with (131)I and (125)I, respectively, were determined by serial measurements of radioactivity in the blood and urine with a gamma well counter, and by serial counts of total body radioactivity in a total body counting chamber.The mean survival half-life for IgG in patients with SLE was 8.2 days as compared to an average of 18 days in normal controls. An average of 10.1% of total body IgG was catabolized daily compared to a mean of 3.9% in normal controls. Turnover of IgM in patients with SLE was, with very few exceptions, normal. In contrast, patients with rheumatoid arthritis revealed a milder abnormality of IgG metabolism, but markedly abnormal IgM catabolism with a mean half-life averaging 5.9 days as compared to 9.3 days in control subjects. An average of 14.2% of total body IgM was catabolized daily in patients with RA as compared to 8.1% in normal controls.Our data suggest that there are basic differences between patients with RA and SLE in the synthesis and catabolism of IgG and IgM not readily apparent from serum IgG and IgM concentration. Abnormal IgG and IgM metabolism may be related to underlying immunological mechanisms in these diseases. Immunoglobulin turnover studies appear to be an additional means for the characterization of rheumatic diseases.     

Natural antibodies in sera of patients with systemic lupus erythematosus

Sera obtained from fifty-five patients with active systemic lupus erythematosus (SLE) and from four patients with mixed connective tissue disease (MCTD) previously shown by immunofluorescence and by double immunodiffusion to possess antinuclear antibodies, were tested for the presence of natural antibodies of IgG, IgA, and IgM isotypes. Antibody activity to actin, myosin, DNA, TNP, albumin, and tubulin was examined, using an enzyme-linked immunosorbent assay (ELISA). It was found that, in comparison with the antibody titers in normal sera, most of the SLE and MCTD sera possessed statistically greater amounts of IgG, IgA, and IgM antibodies directed against all the antigens tested. Furthermore, the IgG, IgA, and IgM antibody activity to DNA and TNP, compared to that found with all the other antigens, was significantly higher. Antibodies reacting with a saline extract of calf thymus (ECT) were studied by ELISA and by immunodiffusion. No correlation was observed between the natural antibody titers and the serum antibody levels to ECT detected either by ELISA or by immunodiffusion.     

抗核小体抗体在系统性红斑狼疮中的诊断意义

【目的】了解抗核小体抗体(ANuA)诊断系统性红斑狼疮(SLE)的特异性和敏感性。【方法】使用酶联免疫吸附试验(ELISA)检测88例SLE患者、51例其他疾病患者以及50例正常健康人血清中的ANuA。【结果】在70例SLE患者(79．5％)、1例类风湿关节炎和1例系统性硬化患者中检测出ANuA,它在SLE中的特异性为98．0％(99／101)。ANuA在6例男性狼疮患者中均为阳性。正常健康人中不能检测出此抗体。【结论】ANuA在SLE中特异性和敏感性较高,是诊断SLE的良好指标,在男性狼疮患者中更具意义。     

抗α-胞衬蛋白IgA和IgG抗体联合检测诊断干燥综合征的价值

目的探讨抗α-胞衬蛋白IgA和IgG抗体联合检测在干燥综合征（Sjgrens syndrome,SS）诊断中的价值。方法32例原发性干燥综合征（primary SS,pSS）患者（pSS组）,51例继发性干燥综合征（secondary SS,sSS）患者（sSS组）,39例系统性红斑狼疮（systemic lupus erythematosus,SLE）患者（SLE组）,51例类风湿关节炎（rheumatoid arthritis,RA）患者（RA组）和60例体检健康者（对照组）,各组采用ELISA法定量检测血清抗α-胞衬蛋白IgA、IgG抗体的表达情况。结果 pSS组、sSS组、SLE组、RA组和对照组血清抗α-胞衬蛋白IgA抗体阳性表达率分别是90.6%、72.5%、12.8%、19.6%、5.0%,血清抗α-胞衬蛋白IgG抗体阳性表达率分别是50.0%、76.4%、30.8%、38.5%、5.0%,除SLE组、RA组外,余各组血清抗α-胞衬蛋白IgA和IgG阳性表达率比较差异均有统计学意义（P〈0.05）;pSS组抗α-胞衬蛋白IgA抗体阳性表达率高于IgG抗体（P〈0.05）;SLE组、RA组抗α-胞衬蛋白IgA抗体阳性表达率低于IgG（P〈0.05）。结论抗α-胞衬蛋白IgA和IgG抗体有助于干燥综合征的诊断和鉴别诊断。     

Rheumatoid factors isolated from patients with autoimmune disorders are derived from germline genes distinct from those encoding the Wa, Po, and Bla cross-reactive idiotypes.

To better understand the structural basis for rheumatoid factor activity, the nucleotide sequence of the light chain variable regions of nine human monospecific IgM rheumatoid factors were analyzed. Rheumatoid factors were isolated from three patients with rheumatoid arthritis, a patient with systemic lupus erythematosus, and a normal individual. The VL gene segments used by these rheumatoid factors are not as restricted as previous work on mixed cryoglobulin rheumatoid factors had suggested. Each of the different VK families is represented and there are two examples where a V lambda gene segment is used. Molecules with structures similar to those of the Wa and Po CRI, characteristic of mixed cryoglobulin rheumatoid factors, are not common among these rheumatoid factors isolated from patients with rheumatoid arthritis. While there are clear examples of rheumatoid factors that are direct copies of germline genes, most of the sequence data suggest that the processes of antigenic selection and somatic mutation contribute significantly to the generation of monospecific rheumatoid factors in patients with autoimmune disease.     

Serum glycylproline p-nitroanilidase activity in rheumatoid arthritis and systemic lupus erythematosus

Glycylproline p-nitroanilidase activity in serum of patients with advanced rheumatoid arthritis or with systemic lupus erythematosus but with normal hepatic function was found to be significantly lower than that of normal adult controls. Decrease of this enzyme's serum activity was more pronounced in systemic lupus erythematosus. A significant inverse correlation was observed between the enzyme activity and the duration of rheumatoid arthritis.     

系统性红斑狼疮患者抗双链DNA抗体检测及其与免疫学指标的相关性

目的探讨系统性红斑狼疮患者抗双链DNA（dsDNA）抗体与免疫学指标的相关性。方法收集77例系统性红斑狼疮患者血清,采用短膜虫间接免疫荧光法（CLIFT）及酶联免疫吸附测定（ELISA）检测血清抗dsDNA抗体、总补体、补体C3、补体C4水平。结果 77例系统性红斑狼疮患者50例抗dsDNA抗体阳性,27例抗dsDNA抗体阴性。抗dsDNA抗体阳性组和阴性组患者血清IgG、IgM、IgA水平的差异没有统计学意义（P〉0.05）,抗dsDNA抗体阳性组患者血清总补体、补体C3、补体C4水平明显低于阴性患者（P〈0.05）。抗dsDNA抗体阳性患者血清抗dsDNA抗体水平与总补体、补体C3显著相关（P〈0.05）。结论抗dsDNA抗体可能通过补体旁路途径而非经典途径抑制补体生成。     

Selective deposition of immunoglobulin A1 in immunoglobulin A nephropathy, anaphylactoid purpura nephritis, and systemic lupus erythematosus.

To further characterize the IgA deposits found in glomeruli of patients with IgA nephropathy, anaphylactoid purpura nephritis, and systemic lupus erythematosus, renal biopsies from patients with these disorders were stained by immunofluorescence with monoclonal anti-IgA subclass reagents, anti-light chain reagents and anti-J chain. The mesangium and peripheral capillary were brightly stained for IgA1 and were negative for IgA2. IgA1 and, to a lesser extent, IgA2 were contained in tubular casts. Both kappa and lambda light chains were found in all deposits. The intensity of J chain staining correlated with the intensity of IgM and not IgA staining. Biopsies brightly stained for IgA but negative for IgM were negative for J chain. These results indicate that glomerular IgA deposits in these disorders consist predominantly of monomers of IgA1.     

Differential immunoadsorption coupled with rate nephelometry for estimation of DNA-binding immunoglobulins

We describe a technique for estimating the mass of anti-DNA antibodies by immunonephelometry of serum immunoglobulins (IgG, IgA, IgM) before and after adsorption onto DNA bound to agarose-polylysine columns. Sixteen patients with systemic lupus erythematosus and 16 age- and sex-matched controls were studied. Precision was determined for high-value (in 10 patients) and low-value (in nine controls) ranges for each of the immunoglobulins. Within-run CVs ranged from 3.0% (IgG, controls) to 11.8% (IgA, patients); between-run CVs ranged from 15.5% (IgG, patients) to 25.2% (IgM, patients). We found anti-DNA antibody concentrations (mean +/- SD) in systemic lupus erythematosus of 1.981 +/- 1.015 g/L for IgG (controls: 0.243 +/- 0.231, p less than 0.001), 0.257 +/- 0.215 g/L for IgA (controls: 0.038 +/- 0.035, p less than 0.001), and 0.282 +/- 0.234 g/L for IgM (controls: 0.191 +/- 0.165, p greater than 0.05). Sensitivity and linearity are such that fivefold dilutions of patients' serum with either a buffered albumin solution or control serum yielded values close to the expected values for IgG. Similarly diluted sera gave inordinately high values in the radiometric binding assay. Neither parametric (linear regression) nor nonparametric correlation methods (Spearman's rank and Kendall's tau) show a significant correlation between patients' data obtained by the present technique and that by a radiometric binding assay (p greater than 0.05), although combined data from patients and controls demonstrate a significant nonparametric correlation (p less than 0.005 for Spearman's and p less than 0.02 for Kendall's).     

抗CyP A自身抗体与SLE关系的探讨

以ｒｈＣｙＰＡ为包被抗原，用间接ＥＬＩＳＡ检测了４５例ＳＬＥ病人血浆抗ＣｙＰＡ自身抗体的ＩｇＧ、ＩｇＡ、ＩｇＭ三种类型，并探讨了此抗体与多项临床指标的相关性。结果显示，ＩｇＧ、ＩｇＡ、ＩｇＭ三类抗ＣｙＰＡ自身抗体的阳性率分别为３６％，２０％，１８％，总阳性率为４８％。存在皮肤粘膜损害、白细胞减少、发热、关节痛表现或活动期的ＳＬＥ病人抗ＣｙＰＡ自身抗体阳性率显著高于无相应症状或非活动期ＳＬＥ病人     

Desirable performance characteristics and clinical utility of immunoglobulin and light-chain assays derived from data on biological variation

Using automated assays of IgG, IgA, and IgM, and kappa (kappa) and lambda (lambda) light-chains, we assessed the analytical, intra-individual, and interindividual components of variation in a cohort of 12 apparently healthy subjects to examine the utility of the Kallestad Immunochemical Evaluation system. The immunoglobulins and light-chains had small intra-individual variation, and, in consequence, good analytical precisions (CV) of 2.3%, 2.5%, 3.0%, 2.4%, and 2.4% are required for IgG, IgA, IgM, kappa, and lambda assays, respectively. All of these analytes, and the derived kappa/lambda and heavy-/light-chain ratios, have marked individuality. Conventional population-based reference values are of limited utility; therefore, the assays are unlikely to have high diagnostic sensitivity but will be very useful for monitoring individuals. The kappa/lambda ratio may be of particular value in monitoring because a change exceeding 4% does imply a significant (P less than or equal to 0.05) difference in serial results.     

Abnormalities in the Distribution of Serum Immunoglobulin Concentrations in Juvenile Rheumatoid Arthritis

Concentrations of serum IgG. IgA, and IgM were determined in 200 patients with juvenile rheumatoid arthritis. The relative frequency distribution of IgG and IgM approached that of a log-normal curve; however, there was marked skewing of the distribution of the serum concentrations of IgA. The prevalence of selective IgA deficiency was 4%. In order to permit further intragroup comparisons, the serum immunoglobulin concentrations were standardized by comparison to a sex-age matched control group. By this process it was found that there was concordance of the serum levels of IgG with IgA, and IgG with IgM. The standardized concentrations of IgA and IgM were less in females than males. The aberration in distribution of serum IgA concentrations found in this study, and the relative inability of females to respond to their disease by increasing specific serum immunoglobulin levels, add further data supporting the concept of immunodeficiency in the pathogenesis of juvenile rheumatoid arthritis.     

4种结缔组织病患者血管内皮细胞生长因子检测的分析

目的检测4种结缔组织病患者血清中血管内皮细胞生长因子(VEGF)水平,并探讨其意义。方法115例患者中,类风湿关节炎(RA)40例,系统性红斑狼疮(SLE)30例,多发性肌炎/皮肌炎(PM/DM)25例,系统性硬化症(SSc)20例,正常对照30例,采用酶联免疫吸附试验(ELISA)方法检测了血清中的VEGF(ng/L)的含量。结果血清VEGF水平(单位ng/L)分别为RA558.58±348.45,SLE244.63±87.44,PM/DM355.12±258.56,SSc362.72±177.52,类风湿关节炎、系统性红斑狼疮、多发性肌炎/皮肌炎、系统性硬化症患者血清VEGF水平均明显高于正常对照(P<0.01,P<0.05)。结论血清VEGF水平的测定对结缔组织病病情监测可能具有非常重要意义。     

The predictive power of serum kappa/lambda ratios for discrimination between monoclonal gammopathy of undetermined significance and multiple myeloma.

The predictive power of serum kappa/lambda ratios on initial presentation of immunoglobulin G (IgG) or IgA monoclonal component was studied to differentiate between monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patients. The retrospective study involved 145 patients clinically diagnosed with monoclonal gammopathy of undetermined significance or multiple myeloma, who had serum M-protein IgG <35 g/L or IgA <20 g/L at M-protein detection. Serum light chains kappa and lambda were measured by fixed-time nephelometry. Test performance indices, predictive values and likelihood ratios were calculated according to the Weissler recommendation. MM patients were considered as diseased and MGUS patients as non-diseased in order to estimate the performance characteristics of serum kappa/lambda ratios. There was a statistically significant difference in kappa/lambda ratios distribution between both groups of patients, in both M-protein kappa-type (Mann-Whitney U=168, p<0.001) and in M-protein lambda-type (Mann-Whitney U=143, p<0.001). Negative likelihood ratios at threshold levels of 0.6 and 4.2 were 2.17- and 3.32-fold greater, respectively, than positive likelihood ratios, so that the predictive power of a serum kappa/lambda ratio within these limits is better in ruling out (negative predictive power) than ruling in disease (positive predictive power). The post-test characteristics of a serum kappa/lambda ratio interval between 0.6 and 4.2 in discriminating MGUS from MM in our geographic population were: sensitivity 0.96 (0.93-0.99 95% CI); specificity 0.70 (0.63-0.77); positive predictive value 0.68 (0.64-0.73); negative predictive value 0.96 (0.94-0.99); likelihood ratios (+)LR 3.23 (2.68-4.04); and (-)LR 17.16 (11.00-63.00). Thus, serum M-protein with a kappa/lambda ratio between 0.6 and 4.2 increases the posterior probability of MGUS from 0.60 to 0.96 in asymptomatic patients, for whom only monitoring may be suggested when the serum kappa/lambda ratio is within these limits.     

Immunoglobulins on the surface of lymphocytes. IV. Distribution in hypogammaglobulinemia, cellular immune deficiency, and chronic lymphatic leukemia

The distribution of peripheral blood lymphocytes that contain surface Ig has been studied by means of immunofluorescence in humans. Normal individuals, individuals with sex-linked and acquired agammaglobulinemia, selective IgA deficiency, cellular immune deficiencies, and individuals with chronic lymphatic leukemia (CLL) were studied. Approximately 28% of the peripheral blood lymphocytes from normal individuals contained surface Ig. On an average 15% contained IgG, 6%, IgA, and 8%, IgM; and the kappa: lambda ratio was 2:1. Lymphocytes from patients with CLL appeared to be "monoclonal" in that the cells from a given individual had a single Ig associated with them (e.g., kappa IgM). In three-quarters of the cases the H chain class was IgM; in the remaining one-quarter no H chain could be detected on the cell surface. The L chain class was kappa in 12 cases and lambda in 8. Four patients with sex-linked agammaglobulinemia and one with "acquired" agammaglobulinemia had markedly decreased numbers of cells with surface Ig (0-4%). In contrast, the three patients with selective IgA deficiency and no detectable serum IgA contained normal numbers of cells (6-8%) with surface IgA. Five patients with cellular deficiency states, including two with Wiskott-Aldrich syndrome, contained a normal or low percentage of cells with surface Ig.     

系统性红斑狼疮和类风湿性关节炎患者外周循环中APRIL表达水平的检测和意义

目的探讨增殖诱导配体（APRIL）在系统性红斑狼疮（SLE）和类风湿性关节炎（RA）中的表达情况及其与B细胞刺激因子（BLyS）、抗双链DNA抗体（抗dsDNA）及疾病预后的相关性。方法用逆转录-实时定量聚合酶链反应（PCR）检测19例SLE和39例RA患者及20名健康对照者的外周血单个核细胞（PBMC）中A-PRIL和BLyS mRNA的表达,用酶联免疫吸附试验（ELISA）检测血清中APRIL和BLyS蛋白水平。同时,检测血清IgG、IgA、IgM、类风湿因子（RF）和抗dsDNA水平。结果SLE和RA患者未缓解组较对照组、疾病初发组和治疗后缓解组APRIL mRNA水平显著升高,与BLyS mRNA表达水平呈中等程度的相关性。疾病组外周循环中BLyS蛋白显著升高,APRIL蛋白未见升高,APRIL与BLyS无相关性,APRIL蛋白与抗dsDNA和疾病活动度之间无相关性。结论检测APRIL mRNA含量在判断自身免疫病患者病情和疾病预后中有一定价值。