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Biomedical subjects

W J Yount

Publications and source records attributed to W J Yount.

At least 19 recordsLinked to original sources
PubMed1990

Immediate "steroid flare" from intraarticular triamcinolone hexacetonide injection: case report and review of the literature.

We describe a patient who had an immediate, intense, localized synovitis due to intraarticular triamcinolone hexacetonide injection. The reaction was secondary to rapid intracellular ingestion of the steroid microcrystals as demonstrated by compensated polarized microscopy. We report the unique nature of this patient's response, and we review previous literature regarding "steroid flare" after intraarticular injection.

Adult↗
PubMed1988

Antigenic specificities of human monoclonal and polyclonal IgM rheumatoid factors. The C gamma 2-C gamma 3 interface region contains the major determinants.

The binding site specificity of 12 monoclonal and 11 polyclonal IgM rheumatoid factors (RF) isolated from human plasma or serum has been studied. All IgM RF bound best to sites on IgG and intact Fc. The monoclonal IgM RF did not bind at all to fragments lacking the C gamma 2 or C gamma 3 domains. In contrast, low level binding to the pFc' fragment, composed of the C gamma 3 domain, was seen with seven IgM RF, mainly from patients with rheumatoid arthritis (RA). IgG1 binding appeared to be a requisite specificity of all human IgM RF. IgM RF binding to IgG3 subclass was common among the monoclonal IgM RF. Most RA polyclonal IgM RF but only 2 of the monoclonal IgM RF possessed the IgG1, 2 and 4 binding pattern. Monoclonal IgM RF which bound best to histidine-modified IgG also bound well to IgG3. The 7-kDa fragment D of staphylococcal protein A inhibited the IgG binding of most monoclonal and to a lesser degree polyclonal IgM RF. Thus, the results indicate that the C gamma 2-C gamma 3 interface region of IgG contains the predominant determinants for monoclonal and polyclonal IgM RF. For some monoclonal IgM RF the binding site, even though at the interface of the C gamma 2 and C gamma 3 domains, is not the staphylococcal protein A site. Furthermore, polyclonal IgM RF possess specificities not encountered among the monoclonal IgM RF. These specificities may have special

Animals↗
PubMed1988

Distribution of IgG subclasses among human autoantibodies to Sm, RNP, dsDNA, SS-B and IgG rheumatoid factor.

The IgG subclass distribution of human autoantibodies to Sm, double-stranded DNA (ds-DNA), ribonucleoprotein (RNP), SS-B (La), and IgG rheumatoid factor (RF) have been determined using sensitive ELISA or by indirect immunofluorescence on Crithidia lucilia in sera from patients with systemic lupus erythematosus (SLE), Sjögren's syndrome, and rheumatoid arthritis. For anti-Sm and anti-RNP, IgG1 was the predominant isotype. For anti-ds-DNA and anti-SS-B, IgG1 and a lesser contribution of IgG3 was found. In contrast, IgG1 and IgG4 were the predominant isotypes of human IgG RF. The preponderance of isotypes noted for these autoantibodies did not extend to the IgG subclass distribution for antibodies to trinitrophenol-bovine serum albumin (TNP), tetanus toxoid (Tet. tox.), pneumococcal polysaccharides (Pneumo), and group A streptococcal cell walls (Strep.). The restriction of human humoral responses as well as autoantibodies has both pathogenetic and immunoregulatory implications, and suggests that for these autoantibodies, T-cell-dependent responses, probably driven by antigen, are of importance.

Arthritis, Rheumatoid↗
PubMed1987

The subclass distribution of human IgG rheumatoid factor.

The subclass distribution of IgG rheumatoid factor (RF) was determined by a sensitive ELISA assay in sera from patients with rheumatoid arthritis and from normal controls. In both instances, the most important subclasses were IgG1 and IgG4. The IgG4 RF was directed against the Fc region of IgG, and recognized human as well as rabbit IgG. Although human IgG4 myeloma proteins bound to rabbit IgG better than did myelomas of other IgG subclasses, the IgG4 RF activity in rheumatoid sera showed an additional specificity, because the fraction of IgG4 RF/total IgG4 for rheumatoid arthritis sera was far greater than for myelomas. This inference was supported by the observation that there was persistent, albeit diminished, IgG RF activity in pepsin-digested, RF-containing sera (but not myeloma proteins), indicating that a critical component of IgG4 RF activity was contained within the Fab region of the IgG4 molecule. The finding of large quantities of IgG4 RF was not due to a bias of the assay, because the preponderance of IgG4 did not extend to the subclass distribution of antibodies directed against other antigens. The demonstration of an important role for IgG4 as a RF is of special interest because of the relative inability of this subclass to fix complement or to bind to Fc receptors, and because of its potential role as a mediator of increased vascular permeability.

Antibody Specificity↗
PubMed1986

Subclass restriction of anti-SS-B (La) autoantibodies.

Antibodies to the SS-B (La) nuclear ribonucleoprotein particle are relatively specific for the diagnoses of Sjögren's syndrome or systemic lupus erythematosus. The formation of such autoantibodies is likely, then, to reflect the basic immunopathogenesis of these disorders. We have studied the isotype distribution of anti-SS-B antibodies as a clue to their immunoregulation. Using specific ELISA assays, we found that nearly all anti-SS-B antibodies in 39 patients were IgG, and, of these, only the IgG1 and, to a much lesser extent, IgG3 subclasses were represented. Both kappa and lambda light chain antibodies were found in most sera, and the overall kappa/lambda ratio approximated that of normal serum immunoglobulin. These results suggest that the formation of anti-SS-B antibodies is T-cell dependent and that the response is polyclonal in most patients.

Antigens↗
PubMed1985

Subclass restriction and polyclonality of the systemic lupus erythematosus marker antibody anti-Sm.

Anti-Sm antibodies are highly specific markers for the diagnosis of systemic lupus erythematosus (SLE). This specificity suggests that the immunoregulation of these autoantibodies would reflect fundamental immune abnormalities in this disorder. As a clue to this immunoregulation, we have investigated the isotype distribution of anti-Sm antibodies by enzyme-linked immunosorbent assays. We have found that the anti-Sm response is markedly restricted to the IgG1 heavy chain isotype. On the other hand, the light chain distribution reflects that in normal serum, while isoelectric focusing analysis fails to show an oligoclonal pattern. The related specificity, anti-ribonucleoprotein, is also restricted to IgG1, while the SLE-specific antibody anti-double-stranded DNA is mostly IgG1 with a lesser contribution by IgG3. These results suggest that antinuclear antibodies that are strongly associated with SLE are produced by a T cell-dependent response, probably driven by antigen. The immunoregulation of the response to several autoantigens may be quite similar.

Antibodies, Antinuclear↗
PubMed1985

Disease-associated loss of erythrocyte complement receptors (CR1, C3b receptors) in patients with systemic lupus erythematosus and other diseases involving autoantibodies and/or complement activation.

Although surface membrane density of complement receptor type one (CR1) on erythrocytes (E) is probably an inherited trait among normal individuals, recent evidence from our laboratories suggests that the reduced number of CR1 per E observed in patients with systemic lupus erythematosus (SLE) results from acquired as well as genetic factors. In the present investigation, the number of CR1 per E was quantitated with 125I-monoclonal anti-CR1 and was found to vary inversely with disease activity in patients with SLE who were followed serially for as long as 14 mo. Although evidence for E surface-bound immune complexes or fixed C3b/iC3b was not obtained, periods of disease activity and low amounts of CR1 per E correlated with the presence of 100 to 800 molecules per E of fixed C3dg fragments (less than 100 C3dg per E in normal subjects). Reduced CR1 and excess fixed C3dg on E also were observed in patients with other disorders associated with complement activation, including chronic cold agglutinin disease, autoimmune hemolytic anemia, paroxysmal nocturnal hemoglobinuria (PNH), Sjögren's syndrome, and mycoplasma pneumonia. A significant negative correlation (r = -0.498) between CR1/E and fixed C3dg/E was demonstrable in 255 individual assays evaluated by regression analysis. CR1 decreased and fixed C3dg increased during active disease; the converse was obtained during remission. In patients with active SLE, both serum complement activity and E CR1 decreased, whereas fixed C3dg fragments increased. By piecewise linear regression analysis, the appearance of 100 to 400 C3dg molecules on patients' E corresponded to a 27 to 60%, reduction in the number of CR1 per E (p less than 0.0002), confirming that fixation of C3 to E was correlated with a loss of CR1. In patients with PNH, low values for CR1 were observed on moderately complement-sensitive PNH type II E in association with increased fixed C3 fragments; however, the markedly complement-sensitive PNH type III E had essentially normal amounts of CR1 and bore little fixed C3. The addition of soluble DNA/anti-DNA immune complexes to normal blood generated levels of fixed C3dg fragments on E comparable to those observed on E from patients with SLE. Kinetic experiments indicated that C3b was fixed to E during the process of immune complex binding and release from E CR1, and that this fixed C3b was subsequently degraded rapidly to fixed iC3b and more slowly to fixed C3dg without the loss of CR1 that occurs in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)

Anemia, Hemolytic↗
PubMed1981

Recurrent bacterial meningitis associated with C8 and IgA deficiency.

A patient with recurrent bacterial meningitis who lacked circulating C8, serum IgA, and secretory IgA is reported. The combined absence of C8 and IgA deficiency has not been previously noted. Although the association of disseminated neisserial infection and absence of the terminal complement components is now well established, the deficiency of bactericidal capability as well as mucosal humoral defense may have been additive in predisposing the patient to recurrent meningitis. The pedigree was uninformative regarding possible linkage of these two uncommon genetic errors.

Adolescent↗
PubMed1981

Distribution of surface, cytoplasmic and secreted IgG subclasses in human lymphoblastoid cell lines and normal peripheral blood lymphocytes.

Twenty-two IgG-positive human lymphoblastoid cell lines and normal peripheral blood lymphocytes were studied for surface and cytoplasmic IgG, IgG subclasses, IgD and IgM, using monospecific fluorescein- and rhodamine-conjugated F(ab')2 antibody fragments, and for secretion by double antibody radioimmunoassay. Several parallel observations and several differences in IgG subclass expression were noted between cell lines and normal lymphocytes. Surface IgG2 was frequently expressed in normal IgG-positive lymphocytes but was seldom expressed in cell lines. Cell lines resembled normal IgG-positive lymphocytes in the frequent expression of cytoplasmic IgG3 and IgG4, often without secretion. Cell lines and normal lymphocytes both showed more frequent distribution of IgG and IgG subclasses in cytoplasm than in surface immunoglobulin, and often a discrepancy of surface versus cytoplasmic IgG subclass. A good correlation was noted between surface, cytoplasmic and secreted IgG1. Despite a predominance of IgG2 and IgG4 surface IgG subclasses, and IgG3 and IgG1 in cytoplasm, secreted immunoglobulins from normal lymphocytes in short-term culture showed a similar distribution of IgG subclasses to that seen in normal sera. Multiple expression of IgG subclasses was much more frequent in IgG-positive cell lines than in normal peripheral blood lymphocytes, both in surface and cytoplasmic IgG.

Animals↗
PubMed1981

Hormonal effects on the immunocytochemical location of 3',5'-cyclic adenosine monophosphate-dependent protein kinase in rat tissues.

Homogeneous preparations of type I and type II regulatory subunits (RI and RII, respectively) of cAMP-dependent protein kinase (cAMP kinase) were utilized as antigens to obtain isozyme specific antisera. Injections of pure catalytic subunit (C) from the type I isozyme resulted in antisera that reacted with C subunit obtained from either isozyme type. Cross-reactivity of the antisera raised against isolated subunits of the kinase was assessed by immunodiffusion analysis and by measuring the cAMP binding and phosphotransferase activities of the subunits after immunoprecipitation. These antisera were used to localize subunits of type I and type II cAMP kinases in rat skeletal muscle, liver, and adrenal by using indirect immunofluorescence and immunoperoxidase techniques. Specificity of the immunofluorescence was shown by absorption of the antisera with pure homologous antigens. In skeletal muscle, both R and C subunits of the type I and type II cAMP kinases were localized in the area of the sarcoplasmic reticulum and in periodic crossbands. Specific fluorescence for these components was observed in both isotropic and anisotropic band regions of the sarcomere. Densitometric determinations of immunoperoxidase staining revealed a larger amount of RI, RII, and C subunits in the isotropic band than in the anisotropic band regions. In liver, C, RI, and RII subunits were distributed both in cytoplasmic and nuclear areas and along plasma membranes of hepatocytes; however, there were qualitative differences observed among these various subcellular sites. With each antiserum, fluorescence was blocked by prior absorption with homologous antigen. After treatment of rats with glucagon, dramatic changes in the relative distribution patterns of C and RII were noted in the nucleus. In the adrenal gland, RI, RII, and C subunits were localized in both cytoplasmic and nuclear areas, and an apparent redistribution of these subunits occurred after treatment of (dexamethasone-suppressed) rats with ACTH. The application of this immunocytochemical approach provides a tool for examining and monitoring the subcellular distribution of these components of cAMP kinase in biological systems.

Adrenal Glands↗
PubMed1980

Skin immunopathology in system lupus erythematosus.

The role of skin immunopathology in the evaluation and management of patients with systemic lupus erythematosus (SLE) remains controversial. Four simultaneous biopsy specimens from nine patients with SLE (two from buttock and two from forearm skin) were evaluated. Specimens from eight of nine patients showed symmetrical deposits. A poor correlation of skin biopsy score and clinical activity score was noted. A positive correlation was noted between serum C3 levels and skin biopsy score, but a poor correlation was noted with criteria for active nephritis with the exception of microscopic hematuria. In most instances, findings from a single skin biopsy specimen are sufficient and of diagnostic value but correlate poorly with other measurements of disease activity. Serial studies suggested that persistence of cutaneous deposits for many months after flares of SLE may in part explain poor correlation with active disease.

Antigen-Antibody Complex↗
PubMed1980

I and i antigens of human peripheral blood lymphocytes cocap with receptors for concanavalin A.

Surface immunofluorescence experiments using a human anti-i and two anti-I antisera have been performed on human peripheral blood lymphocytes. These are known to contain cold-reactive monoclonal IgM antibodies against the carbohydrate sequence: (formula: see text). A high proportion of B- and T-type lymphocytes express these I and i determinants. In the presence of anti-human immunoglobulin, the cold-reactive membrane-associated complexes of I-anti-I and i-anti-i become stabilized, and redistribution (with patching and capping) can be elicited at 37 degrees C. Dual fluorescence experiments have shown striking concordant staining of I or i (fluorescein) caps and patches with concanavalin A (rhodamine) reactive sites on normal and leukemic cells, suggesting that a proportion of I and i active structures of lymphocyte membranes are structurally associated or physiologically coupled with glycoproteins carrying oligosaccharides with branched mannosyl cores.

Antigens, Surface↗
PubMed1980

Subclasses of IgG antibodies in immune thrombocytopenic purpura (ITPO).

The subclasses of platelet-associated IgG were measured on the platelets of patients with immune thrombocytopenic purpura (ITP) by modification of the antiglobulin consumption test. All subclasses were found. In most patients, one subclass was predominant; this was usually IgG1. The platelet-associated IgG in normal donors is predominantly IgG1 and IgG2.

Adult↗
PubMed1980

Distribution of IgG subclasses in human B lymphocytes: evidence for dual expression of subclasses in surface and cytoplasmic IgG in minor B lymphocyte subpopulations.

The distribution of B lymphocytes expressing surface IgG subclasses has been defined by using immunochemically purified, subclass-specific, F(ab')2 fragments. Studies in normal adults showed 1.16% of peripheral lymphocytes to be positive for IgG. Percentages of IgG subclasses were IgG2, 0.50%; IgG4, 0.40%; IgG1, 0.33%; and IgG3, 0.14%. Dual label experiments indicated that minor subpopulations of normal lymphocytes may express more than one IgG subclass, both on surface IgG as well as in the cytoplasm. Cord blood showed significantly less IgG4-positive cells than were present in adults. Preliminary studies of patients with common variable immunodeficiency showed shifts in cell populations paralleling those previously noted in serum. Some patients with multiple myeloma were noted to exhibit striking shifts in the distribution of B lymphocytes toward a population of cells showing a similar IgG subclass to that of the M-component.

Antibody Specificity↗
PubMed1979

Deposition of beta 1H globulin in kidneys of patients with immune renal disease.

Renal biopsies from patients with a variety of immune type renal diseases were examined by immunofluorescence for the presence of C3 and its control protein, beta 1H globulin. Deposits of beta 1H were found in every instance (21 of 21 biopsies) in which C3 deposits were observed, irrespective of the underlying disease resulting in the C3 deposits, including lupus nephritis, acute poststreptococcal glomerulonephritis, idiopathic membranous glomerulonephritis, and Goodpasture's syndrome. In no instance was beta 1H found independently of C3. As previously shown in in vitro systems, beta 1H also binds to C3, presumably C3b, during activation of the complement system in immunologically induced renal disease.

Anti-Glomerular Basement Membrane Disease↗