Human rheumatoid factor crossidiotypes. I. WA and BLA are heat-labile conformational antigens requiring both heavy and light chains.

Evidence was obtained that both the WA and BLA crossidiotype (XId) groups are conformational antigens requiring both L and H chains and that with heat denaturation the antigens that define the XIds and antigen-binding activity are lost in parallel. In contrast, the primary structure-dependent crossreactive idiotype (CRI), PSL2, which is only weakly detected on native Wa and Bla monoclonal rheumatoid factors (mRFs), became prominently detected on the heated Wa and Bla mRFs. Heat denaturation may provide a simple method for distinguishing Ids determined by conformational antigen from primary structure-dependent Ids. In addition to heat denaturation, some acid conditions commonly used for preparation of RFs were also found to cause marked loss of Id antigen. The finding of PSL2-CRI on Bla mRF indicates that this Id is not unique to the WA XId.

OCCURRENCE OF gamma-GLOBULIN COMPLEXES IN SERUM AND JOINT FLUID OF RHEUMATOID ARTHRITIS PATIENTS: USE OF MONOCLONAL RHEUMATOID FACTORS AS REAGENTS FOR THEIR DEMONSTRATION.

gammaG globulin complexed in an unusual form has been demonstrated in the serum of many patients with rheumatoid arthritis. Such complexes have been detected and isolated principally through precipitation reactions with monoclonal gammaM rheumatoid factors. These monoclonal rheumatoid factors exhibited a greater sensitivity to react with small complexes or aggregates of gamma-globulin than polyclonal rheumatoid factor from rheumatoid arthritis sera or isolated C1q. The serum complexes consisted in large part of high molecular weight but acid-dissociable 7S gammaG globulin molecules They however differed from the complexes in the joint fluid by not yielding precipitates with C1q and were not found in association with evidence of marked serum complement fixation or activation. A small number of systemic lupus erythematosus sera, primarily those forming cryoprecipitates, also gave reactions with monoclonal rheumatoid factor. Sera from patients with a variety of nonrheumatic diseases gave a low incidence of reactions. The exact nature of the complexes in the rheumatoid arthritis sera remains somewhat in doubt although gammaG rheumatoid factors appear partly involved.

Antibodies to polynucleotides in human sera: antigenic specificity and relation to disease.

The specificities of anti-polynucleotide antibodies found in human sera were studied using several immunological procedures. Anti-native DNA (NDNA) antibodies and certain anti-double-stranded RNA (DSRNA) antibodies were found to react with single-stranded DNA (SDNA), and anti-NDNA antibodies were observed to react more avidly with SDNA than with NDNA in most sera tested. Antibodies to NDNA showed no preferential reactivity with NDNA or SDNA derived from mammalian tissue, bacterial, or viral sources. Precipitating antibodies reactive with individual bases, with common determinants of bases, and with common determinants of SDNA and NDNA were detected utilizing synthetic polydeoxyribonucleotides. Antibodies to DSRNA were also heterogeneous and reactive with both Poly A . Poly U and Poly I . Poly C in addition to reactivity with Poly A and SDNA. In contrast, antibodies to a ribonucleo-protein determined by hemagglutination and by precipitation showed no reaction with NDNA, SDNA, or DSRNA. Serial studies of serum specimens from patients with systemic lupus erythematosus (SLE) indicated that anti-NDNA antibodies were closely associated with disease activity. Titers of antibodies to SDNA or DSRNA were also frequently increased during these periods but in addition showed peaks during quiescent periods. Anti-NDNA antibodies were detected in most patients' sera at sometime during the course of the disease. Three patients were observed with active SLE, who did not develop anti-NDNA antibodies, even in the presence of severe renal disease. Evidence that other antigen-antibody systems may also play a role in the pathogenesis of the renal disease was particularly apparent in these patients. Anti-ribonucleoprotein antibodies were not well correlated with the peaks of antibody activity of other polynucleotide antibodies, suggesting that an independent immunogen was responsible for induction of these antibodies. The close association of certain populations of anti-polynucleotide antibodies during the course of active SLE, the presence of cross-reacting antigenic determinants of SDNA, NDNA, and DSRNA, the preferential avidity of anti-NDNA antibodies for SDNA, and the frequent increase of anti-SDNA antibodies in SLE and other diseases associated with active tissue destruction suggest that SDNA is a ubiquitous antigen that may stimulate the formation of antibodies reactive with a variety of polynucleotides.

Systemic lupus erythematosus: prototype of immune complex nephritis in man.

Serological studies, immunofluorescence studies, and immunochemical assays of glomerular eluates indicate that several antigen-antibody systems may be involved in the pathogenesis of the tissue lesions of SLE. The NDNA-anti-NDNA system appears to be operative in most patients with active SLE. In addition, antibodies to SDNA are found with considerable frequency in SLE sera and glomerular eluates. It is not known if these antibodies fix to NDNA which has been denatured after deposition in glomeruli or if SDNA-anti-DNA complexes are deposited initially. NDNA antigen has been demonstrated in both serum and glomerular deposits, and SDNA determinants have also been found in glomerular deposits. In addition, there is evidence that rheumatoid factor contributes to the immune complex deposition in certain patients either by fixing to preformed immune complexes or as part of an independent gamma-globulin-anti-gamma-globulin system. It is anticipated that the definition of these immune systems, and the assessment of their relative toxicity will provide insight into underlying etiologic factors as well as provide a sound basis for therapy in this form of glomerulonephritis.

Evidence for a subset of rheumatoid factors that cross-react with DNA-histone and have a distinct cross-idiotype.

Cross-reactivity of a monoclonal rheumatoid factor with an antigen present on IgG and DNA-nucleoprotein was demonstrated, and evidence presented that the combining site of the antibody was involved in the reaction. The antigen on the DNA-nucleoprotein was shown to involve both DNA and histone fraction H2A + H2B and was trypsin sensitive. The relative binding affinity of the antibody appeared to be greater for IgG than the DNA-histone antigen. Similar polyclonal cross-reactive rheumatoid factors were found in a variety of diseases. A high incidence was found among patients with rheumatoid arthritis and mixed connective tissue disease. None were detected in patients with systemic lupus erythematosus and idiopathic cryoglobulinemia. Studies on one representative isolated polyclonal rheumatoid factor demonstrated the same reactivity with DNA-histone H2A + H2B as the monoclonal antibody. Cross-idiotype studies using antigen-binding inhibition methods demonstrated the same cross-idiotype on the polyclonal and the monoclonal rheumatoid factor which reacted with DNA-histone. This cross-idiotype was shown to be distinct from the cross-idiotypes previously demonstrated on monoclonal IgM proteins with anti-gamma-globulin activity.

Cross-idiotypic specificity among monoclonal IgM proteins with anti- -globulin activity.

Through the use of absorbed idiotypic antisera prepared against single isolated monoclonal IgM anti-gamma-globulins, partial cross-idiotypic specificity was demonstrated with other IgM anti-gamma-globulins. Such antisera classified these proteins into at least three groups. The major group which included 60% of the anti-gamma-globulins was particularly homogeneous. The anti-gamma-globulin specific antigens were detected best in hemagglutination and hemagglutination inhibition systems. They were not found in monoclonal IgM proteins that lacked anti-gamma-globulin activity although related antigens were detected at low concentrations in pooled immunoglobulin preparations as well as in heterogeneous anti-Rh antibodies. Several lines of evidence were obtained indicating that the antibody combining site was involved in the specific determinants. Attempts were made to analyze the fine specificity of each anti-gamma-globulin for the Fc fragment of different subclasses of human immunoglobulins as well as those of other species. Differences were observed but these were not readily related to the cross-specificity antigens. The anti-gamma-globulin specific antigens were very analogous to those previously described for monoclonal IgM cold agglutinins. Although each protein could be distinguished from all the others on the basis of individual idiotypic antigens, the antigens common to the specific groups of proteins with each of these activities were prominent and readily detected with multiple antisera. The results indicate basic similarities between proteins of a given activity even in unrelated individuals.

C1q PRECIPITINS IN THE SERA OF PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND OTHER HYPOCOMPLEMENTEMIC STATES: CHARACTERIZATION OF HIGH AND LOW MOLECULAR WEIGHT TYPES.

Precipitin reactions of C1q in gel diffusion proved useful in detecting unknown complexes containing gamma-globulin in the sera of patients with SLE. Using this method low molecular weight C1q reactants also have been detected in a number of sera from patients with SLE as well as other diseases. Both the circulating complexes and the unidentified low molecular weight reactants are associated with disease activity and in vivo complement depression. In some sera from patients with SLE, circulating complexes as detectable by C1q precipitation were closely associated with cryoprecipitins and an active nephritic process. Evidence is presented that both rheumatoid factors and C1q interact with circulating complexes in these patients and that the interaction is related to cryoprecipitation. The demonstration of the same rheumatoid factors in the cryoprecipitates and in the renal glomerular deposits suggests that rheumatoid factors have a special significance in the presence of circulating complexes.

Human rheumatoid factor crossidiotypes. II. Primary structure-dependent crossreactive idiotype, PSL2-CRI, present on Wa monoclonal rheumatoid factors is present on Bla and other IgM kappa monoclonal autoantibodies.

The amino acid sequence of the L-CDR2 (complementarity-determining region) of Bla mRF (monoclonal rheumatoid factor) is identical to that of the Wa mRFs. The PSL2-CRI (crossreactive idiotype), as determined by anti-PSL2, which has been shown to be present on all Wa mRFs, is also present on the Bla mRF and other monoclonal autoantibodies. PSL2-CRI is, therefore, not unique to Wa mRFs and may be present on most IgM kappa monoclonal autoantibodies. Whether PSL2-CRI is a crossidiotype (XId) that is selectively present on autoantibodies or represents an allotypic marker for a V kappa III gene is undetermined.

Human rheumatoid factor cross-idiotypes. IV. Studies on WA XId-positive IgM without rheumatoid factor activity provide evidence that the WA XId is not unique to rheumatoid factors and is distinct from the 17.109 and G6 XIds.

The WA cross-idiotype (XId) is the major XId among human monoclonal rheumatoid factors (mRF) and is almost always associated with the light (L) chain XId, 17.109, and the heavy (H) chain XId, G6. A cell line, 35G6, was cloned that bears the WA XId, but shows no reactivity with immunoglobulin G (IgG) and is negative for the 17.109 and G6 XIds. The 35G6 L chain appears to be derived from the same VKIII-JKI genes as most WA mRFs L chains. In contrast to the WA mRFs H chains in which VH1 genes are used, the 35G6 IgM expresses a VH3 gene. Sequence comparisons with other WA XId-positive mRF suggested several common structural features that may be related to the WA XId and differences that may relate to lack of IgG reactivity. Cells similar to 35G6 have previously been described in pokeweed mitogen-stimulated cell lines of peripheral blood lymphocytes from normal individuals and patients with rheumatoid arthritis and type II mixed cryoglobulinemia. These observations were confirmed, and in addition, it was shown that the majority of WA XId-positive cells in these cultures were negative for the 17.109 and G6 XIds. The presence of the WA XId in the absence of IgG reactivity suggests that the WA XId is more directly associated with an antigen specificity other than IgG, and its association with RF activity may be incidental. It is postulated that these WA XId-positive RF-negative antibodies may serve a physiologic role as natural antibodies to a pervasive pathogen, and that IgG reactivity is a consequence of somatic diversification accompanying proliferation of the WA XId-positive RF-negative cell.

Antibodies to polynucleotides: distribution in human serums.

Hemagglutination procedures were used to determine the distribution of antibodies to native DNA, single-stranded DNA, and double-stranded RNA. Antibodies to all three polynucleotides were found in a high percentage of the serums of patients with systemic lupus erythematosus. Antibodies to native DNA occurred almost exclusively in serums of patients in the active stages of systemic lupus erythematosus, whereas antibodies to single-stranded DNA were observed in the serums of patients with several diseases and of some normal individuals.

Detection of immune complexes. The use of radioimmunoassays with Clq and monoclonal rheumatoid factor.

This study describes two sensitive, rapid, relatively simple, competitive inhibition radioimmunoassays for detecting immune complex. The tests are based on the inhibition of I125-Clq or I125-monoclonal rheumatoid factor (mRF) binding to an insoluble substrate, IgG-Sepharose. The assays can be performed in 5 h utilizing 10 micronl of serum. Heating of serum is not required and polyclonal rheumatoid factors do not interefere. With the two assays, a wide range of complexes of various size and complement fixing activity can be detected. The Clq test can detect complement fixing Ig complexes larger than 19S, while the mRF tests detect complexes of IgG as small as 8S irrespective of their complement fixing activity. Mouse, rabbit, and human aggregated IgG (agg IgG) can be detected in the Clq test, and human and rabbit agg IgG in the mRF test. As low as 4 microng/ml of isolated human agg IgG can be detected in the Clq test and 0.5 microng/ml in the rheumatoid factor test. Sensitivity is greater for mouse agg IgG. For pathologic sera which must be diluted to eliminate interfering factors, the sensitivity of the assay is approximately 10 times less. The Clq test showed marked inhibition by systemic lupus erythematosus sera with close correlation with CH50 levels and disease activity. The mRF test showed better correlation with rheumatoid arthritis sera. In addition, anionic macromolecules known to react with Clq and other Clq reactants that occur in pathologic sera such as the "low molecular weight" substances in systemic lupus erythematosus are also detected. These reactants are not detectable in the mRF test and can be eliminated in the Clq test by performing the test at higher ionic strength. The tests can be applied to the study of a variety of pathologic states where immune complexes appear to play a role.

The occurrence of single-stranded DNA in the serum of patients with systemic lupus erythematosus and other diseases.

Single-stranded DNA (SDNA) occurs in high incidence and in greatest concentration in the sera of patients with systemic lupus erythematosus (SLE), where levels as high as 250 mug/ml were observed. SDNA appears to be an imunogen for anti-SDNA antibodies and forms complexes in vivo of both anti-SDNA-SDNA and anti-NDNA-SDNA types, which apparently play a role in the pathogenesis of the glomerulonephritis found in patients with SLE, SDNA is also found in high incidence but at lower levels in the sera of patients with rheumatoid arthritis. Lesser amounts of SDNA are found in several other diseases in which a low incidence of anti-SDNA antibodies is observed.

Two distinct abnormalities in patients with C8 alpha-gamma deficiency. Low level of C8 beta chain and presence of dysfunctional C8 alpha-gamma subunit.

The sera from three C8 alpha-gamma deficient patients previously reported to have a selective C8 alpha-gamma defect were analyzed by SDS-PAGE and Western blot using two polyclonal antisera to C8 alpha-gamma and a monoclonal antibody to C8 alpha. All three sera exhibited C8 alpha-gamma bands that dissociated into alpha and gamma chains under reducing conditions. Quantitation of the alpha-gamma subunit in these sera by a sensitive ELISA revealed an amount approximately 1% of that found in normal human serum. A similar assay performed with a specific antiserum to C8 beta showed unexpectedly low levels of C8 beta in these sera, which were confirmed by hemolytic titration of C8 beta. The remarkable differences between C8 alpha-gamma and C8 beta in the C8 alpha-gamma deficient sera was that in spite of their comparable immunochemical levels, C8 beta still exhibited functional activity whereas C8 alpha-gamma was totally inactive. That the residual C8 alpha-gamma was inactive was also proved by its inability to show lytic bands in an overlay system after SDS-PAGE and subsequent removal of SDS. The implications of these findings for a novel concept of C8 deficiency are discussed.

Complement-human histocompatibility antigen haplotypes in C2 deficiency.

C4 allotyping 13 homozygous C2-deficient individuals demonstrated 23 of 25 haplotypes to be of the relatively rare type C4A4 B2. This is of the same magnitude as the association of C2Q0 with HLA-DW2/DR2.

Prevalence and functional role of anti-IgE autoantibodies in urticarial syndromes.

The prevalence of autoantibodies of immunoglobulin G (IgG) and immunoglobulin M (IgM) classes directed against myeloma immunoglobulin E (IgE) were determined in distinct subsets of urticaria, using an enzyme immunoassay. IgG anti-IgE antibodies were found in five of nine patients (55%) with cold urticaria, four of eight patients (50%) with urticarial vasculitis, and three of six patients (50%) with chronic urticaria. IgM anti-IgE antibodies were found exclusively in cold urticaria (two of nine patients, 22%). Heating of these sera increased the binding to IgE, suggesting immune complex formation. Several positive sera were capable of inducing histamine release from normal peripheral basophils and caused a wheal-flare response upon intradermal injection. Sera containing such autoantibodies from three cold urticaria patients were studied for passive transfer of cold sensitivity. One serum containing IgG anti-IgE gave a strongly positive transfer test at 5 h but not 48 h, suggesting a pathogenic role for the IgG.

Lymphocytic hypophysitis in a man.

Fewer than 20 patients with lymphocytic adenohypophysitis have been reported, all of them women, and it usually occurs during pregnancy or the postpartum period. We report the recognition of lymphocytic adenohypophysitis in a man. The patient presented with anterior hypopituitarism and an intrasellar mass on computed tomography. Antipituitary antibodies, found in only one of the previous patients, were not present in this man, although low titer antinuclear antibodies were found. The implications of this latter finding are unclear. The patient's histocompatibility antigen (HLA) types were A2, B8, Bw58, DR1, and DR5. The degree of pituitary failure seemed out of proportion to the size of the mass seen on computed tomographic scan.

Immune complex assays in rheumatic diseases.

A wide variety of antigen-nonspecific immune complex assays have been developed in recent years for the detection and quantitation of immune complexes in pathologic fluids. These assays detect complexed antibody regardless of the antigen involved. Almost all of these assays use biologic reagents that may react with substances other than complexed antibody. In addition, the assays do not differentiate nonspecifically aggregated antibody from antigen-complexed antibody. Hence, these assays are not absolute tests for immune complexes. On the basis of studies using these assays, "immune complexes" have been detected in a large number of rheumatic diseases. While these findings have been of considerable investigative interest, thus far they have been of little practical clinical utility. The detection of immune complexes has not been shown to be essential in any clinical conditions but may be helpful in monitoring disease activity in systemic lupus erythematosus (SLE) and may provide useful diagnostic information in two rare syndromes, Lyme arthritis and SLE-related syndrome.