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Biomedical subjects

S Whittingham

Publications and source records attributed to S Whittingham.

At least 19 recordsLinked to original sources
PubMed2000

The peculiar autoimmunity of primary biliary cirrhosis.

Autoantibodies to mitochondria (AMA, anti-M2) are a serologic hallmark of primary biliary cirrhosis (PBC). These react with three structurally and functionally related multienzymic complexes, the 2-oxoacid dehydrogenase complexes, but chiefly with the E2 subunit of pyruvate dehydrogenase complex (PDC-E2). Their very dose (95%) and specific association with PBC underpins the autoimmune concept of pathogenesis of that disease, notwithstanding several non-congruent features. Detailed studies, including structural analysis of epitopes, do not disclose how these autoantibodies originate. Their ubiquity in PBC has overshadowed the existence of a second set of relatively PBC-specific autoantibodies to nuclear antigens for which reactants have been cloned and characterized. These include centromeric proteins; proteins of the nuclear pore complex; nuclear dot proteins, which include Sp-100 and the promyelocytic leukemia antigen; and a recently identified autoantigen, SOX13. Certain of these reactants are DNA-binding proteins with transcriptional regulatory activity. Thus serum from individuals with the same clinical syndrome can have autoimmune reactivity to disparate mitochondrial and nuclear constituents in different cellular compartments. Antibody probing of phage displayed random peptide libraries, together with epitope scanning using overlapping sequential octameric peptides from the PDC-E2 sequence, showed that the discontinuous motifs MH, FV(E) and SYP contributed to a predicted conformational antibody epitope in the inner lipoyl domain of PDC-E2.

Acyltransferases↗
PubMed1999

Autoimmune cholangitis and primary biliary cirrhosis--an autoimmune enigma.

AIMS/BACKGROUND: Autoimmune cholangitis/cholangiopathy (AIC) is an enigmatic disease marked by chronic cholangitis, antinuclear antibodies (ANA) and sero-negativity for conventionally detected antimitochondrial antibodies (AMA). We examined whether AIC is a distinct entity, an AMA-negative variant of primary biliary cirrhosis (PBC), or a cholangiopathic variant of autoimmune hepatitis (AIH) by comparing the clinical, laboratory and autoantibody profiles of 21 cases of AIC, 37 cases PBC and 16 cases of AIH from selected Japanese patients. METHODS: The specificities of AMA and ANA were determined by immunofluorescence, immunoblotting and enzyme inhibition assays using various mitochondrial and nuclear autoantigens, and the frequencies for these groups were compared. RESULTS: By clinical, biochemical and histological data, AIC and PBC were similar and both were clearly distinct from AIH. Serologically, by immunofluorescence of AMA and ANA, there was polarisation. By immunoblotting, and notwithstanding the negative test for AMA, a proportion of the AIC sera reacted with the E2 subunits of the 2-oxo-acid dehydrogenase enzyme complexes, but more particularly with the lower molecular weight E2 subunits. The antinuclear reactivity in AIC was with centromere, Sp100 and nuclear pore complex proteins as in PBC, but preferentially with the nuclear pore complex. CONCLUSION: Our results demonstrate that AIC and PBC are similar diseases. However this duo is of interest because, usually, among sets of autoimmune syndromes, differences in serological targetting are matched by differences in clinical presentation: AIC and PBC are an exception to this.

Adult↗
PubMed1997

Autoantibodies associated with presymptomatic insulin-dependent diabetes mellitus in women.

Presymptomatic autoantibody markers of insulin-dependent (Type 1) diabetes mellitus (IDDM) are less well characterized in adults than in children. We quantitated anti-GAD, anti-ICA512 and ICA by titration to endpoint and compared frequencies and levels in 139 Finnish women from whom 390 serum samples had been archived during antecedent pregnancies for 10 years before and up to 1 year after diagnosis of diabetes. Also, we compared the autoantibody status in adults with IDDM with that of children with newly diagnosed IDDM. Of the 35 women seropositive for 1 or more autoantibodies, 77% developed IDDM, 11% non-insulin-dependent (Type 2) diabetes mellitus (NIDDM), 9% gestational diabetes mellitus requiring insulin (GDM-ins) and 3% GDM controlled by diet. The frequency of antibodies during the 10-year presymptomatic period was 83% for anti-glutamic acid decarboxylase (GAD), 52% for anti-ICA512 and 41% for islet cell antibodies (ICA) for those who developed IDDM, 25%, 17%, and 0% for NIDDM, 12%, 4%, and 8% for GDM-ins and 1%, 0%, and 1% for GDM-diet. Anti-GAD was found most consistently in early samples; 13 of 15 with a single autoantibody at their first test had anti-GAD. Among those who developed IDDM, the frequency of anti-GAD was constant, anti-ICA512 increased threefold, and ICA increased slightly before diagnosis. Levels of the autoantibodies varied between subjects, but were relatively stable in individual subjects. Comparison of tests on the women, and children after diagnosis of IDDM, showed the frequencies and levels to be the same for anti-GAD but lower for anti-ICA512 and ICA in adults. Our observations show in women the long latency of seropositivity before overt IDDM, the predominance of anti-GAD among these three serological markers, and the presence of these markers in NIDDM presumably representing a NIDDM phase of autoimmune insulitis.

Adolescent↗
PubMed1996

Autoimmune cholangitis syndrome with a bias towards primary biliary cirrhosis.

The apparent coexistence of primary biliary cirrhosis (PBC) and autoimmune hepatitis in the same patient raises unresolved problems for nosology and therapy. These are exemplified by a 45-year-old Japanese woman with overlapping clinical, serological and histological features of autoimmune cholangitis and autoimmune hepatitis. The classical serological test for PBC, antimitochondrial antibody (AMA) by immunofluorescence, was atypical. By immunoblotting there was reactivity with one of the enzymes of the 2-oxo-acid dehydrogenase complex (2-OADC) family, now recognized as autoantigens responsible for AMA reactivity. Also there was reactivity by immunofluorescence for antinuclear antibodies (ANA), one showing the typical speckled pattern of anti-Sp-100 and the other the peripheral pattern of antinuclear membrane antibody, both with titres > 10(6). There was also a positive result to the lupus erythematosus (LE) cell test. Treatment with ursodeoxycholic acid was beneficial. Thus while the clinical presentation suggested the overlapping syndrome of autoimmune hepatitis and PBC, PBC eventually proved to be the likely diagnosis. We suggest that apparent cases of overlapping PBC-autoimmune cholangitis-hepatitis syndromes, after detailed testing, will mostly align with PBC.

Antibodies, Antinuclear↗
PubMed1996

Autoantibodies to M2 mitochondrial autoantigens in normal human sera by immunofluorescence and novel assays.

Primary biliary cirrhosis (PBC) is characterized by the presence of antimitochondrial antibodies (anti-M2), directed against the E2 subunits of the 2-oxo-acid dehydrogenase complexes (2-OADC), chiefly pyruvate dehydrogenase complex (PDC-E2). We present here a detailed study, based on a large panel of normal sera, of the specificity of tests for anti-M2 by immunofluorescence and for anti-PDC by other assays for the diagnosis of PBC. The assays for anti-PDC included immunoblotting with bovine heart mitochondria, ELISA using recombinant PDC-E2 and an enzyme inhibition assay using purified porcine PDC. The positivity rates for normal sera were 0 (0/170), 2 (4/201), 1.5 (3/198) and 0% (0/186) for immunofluorescence, immunoblotting, ELISA and the enzyme inhibition assay, respectively. The seven positive reactions detected either by immunoblotting (n = 4) or ELISA (n = 3) were negative by the other three assays and in no instance did biochemical indices give any indication of chronic liver disease. Thus, as judged by reactivity with normal sera, the specificity of a positive test for the antibody to the major M2 autoantigen (PDC-E2) is 100% for immunofluorescence and the enzyme inhibition assay, 98% for immunoblotting and 98.5% for ELISA.

Autoantibodies↗
PubMed1994

Fibromyalgia syndrome and disease activity in systemic lupus erythematosus.

To study the effect of fibromyalgia syndrome (FS) on the expression of systemic lupus erythematosus (SLE) and on the measurement of disease activity, we performed a cross-sectional study of subjects with SLE. Eighty-seven subjects were studied and 22 (25.3%), all female, had FS (Yunus' criteria). Disease activity and organ system involvement were assessed using the systemic lupus activity measure (SLAM) and using 10 cm visual analogue scales (VAS) completed by both physician and patient. No significant difference between FS and non-FS groups in the objective measurement of disease activity was present, median (range) SLAM scores being 5 (0-18) and 6 (0-24), respectively (NS). Similarly, expression of SLE, as measured by the prevalence of specific organ system involvement, was similar in the two groups. In contrast the prevalence of glucocorticoid use, antibodies to DSDNA and fulfilling four ACR criteria was higher in the non-FS group. The rating of SLE disease activity was affected by concomitant FS. Physician and patient disease activity VAS correlated significantly with SLAM scores in non-FS subjects (P < 0.001, Spearman analysis), whereas in FS subjects, neither physician nor patient VAS correlated with SLAM scores. We conclude that FS is prevalent in individuals with SLE and does not affect disease expression but may interfere with the rating of disease activity.

Adult↗
PubMed1993

Cytokine production in response to Epstein-Barr virus infection of peripheral blood mononuclear cells in vitro.

To obtain a better understanding of the immune response to Epstein-Barr virus (EBV), we measured the cytokines tumour necrosis factor (TNF)-alpha/beta, interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) in the conditioned medium of peripheral blood mononuclear cells from 10 healthy adults before and at 48 h and at 1, 2, 3 and 4 weeks following infection in vitro with EBV. Cultures were examined for regression of outgrowths of nascent virus-transformed B cells, and populations of cells in the cultures were analysed by flow cytometry. TNF-alpha/beta was not detected in infected or non-infected cultures. In infected cultures assayed at the nominated times, the highest levels of IL-2 were detected at 48 hours, IFN-gamma at 1 week, IL-6 at 2 weeks and GM-CSF between 2 and 4 weeks. IL-6 and GM-CSF, but not IL-2 or IFN-gamma, were detected in non-infected cultures but at lower levels than in infected cultures. Nine of the 10 healthy adults showed regression of outgrowths of virus-transformed B cells and, of these, seven had antibodies to the EBV capsid antigen (VCA). Strong regression was associated with sequential increases in IL-2, IFN-gamma, and low levels of IL-6 and GM-CSF. Absent or weak regression was associated with an undetectable level of IL-2, a low level of IFN-gamma, high levels of IL-6 and GM-CSF and an increased frequency of cells bearing the phenotype CD20 and HLA-DR in the final weeks of culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Definition of a discontinuous immunodominant epitope at the NH2 terminus of the La/SS-B ribonucleoprotein autoantigen.

High-titer IgG autoantibodies to the La/SS-B ribonucleoprotein (RNP) are a hallmark of patients with primary Sjogren's syndrome. Anti-La/SS-B-positive human sera bind to multiple epitopes on recombinant La/SS-B, although the initial response is against an immunodominant epitope within the first 107 NH2-terminal amino acids (aa). Sequence analysis has identified a striking homology between aa 88-101 in this NH2-terminal region of La/SS-B and a feline retroviral gag polypeptide suggesting the anti-La/SS-B response may be initiated by cross-reactivity with an exogenous agent. In the present study, detailed mapping of this NH2-terminal epitope, using recombinant La/SS-B purified from the expression of overlapping DNA fragments spanning aa 1-107, has shown that this immunodominant epitope is a complex conformational or discontinuous epitope dependent upon both aa 12-28 and 82-99 for expression, even though these regions share no homology with each other. This requirement questions the significance of the homology between La/SS-B and a retroviral gag polypeptide in the generation of the B cell response to La/SS-B and is in accord with the general concept that B cells recognize conformational epitopes on antigens rather than small linear peptide sequences. The finding also reinforces the notion that native autoantigen could be the initiator of the autoimmune response.

Autoantibodies↗
PubMed1991

Enforced BCL2 expression in B-lymphoid cells prolongs antibody responses and elicits autoimmune disease.

The biological functions of the BCL2 gene were investigated in transgenic mice harboring human BCL2 cDNA under the control of an immunoglobulin heavy chain enhancer (E mu). Mice of a representative transgenic strain, E mu-bcl-2-22, had a great excess of B lymphocytes, immunoglobulin-secreting cells, and serum immunoglobulins, attributable to increased longevity of B-lineage cells. Pre-B and plasma cells as well as B cells exhibited prolonged survival in culture. Immunized animals produced an amplified and protracted antibody response. Within the first year of life, most mice spontaneously produced antibodies to nuclear antigens, and 60% developed kidney disease, diagnosed as immune complex glomerulonephritis. Thus E mu-bcl-2-22 mice constitute a transgenic model for a systemic autoimmune disease resembling the human disorder systemic lupus erythematosus.

Animals↗
PubMed1990

Mapping of multiple B cell epitopes on the 70-kilodalton autoantigen of the U1 ribonucleoprotein complex.

High titer IgG autoantibodies to the 70-kDa polypeptide component (p70) of the U1 ribonucleoprotein (RNP) complex occur in the sera of patients with mixed connective tissue disease, SLE, and related rheumatic diseases. To gain insight into the pathogenesis and diversity of this antibody response we have used recombinant DNA technology to map the linear B cell epitopes on p70. A full length 1.7-kb cDNA clone encoding p70 was isolated from a human placental library and restriction fragments or polymerase chain reaction-generated fragments of the gene subcloned into the bacterial expression vector pGEX. Purified fusion proteins representing specific regions of p70 were immunoblotted with a panel of 70 anti-(U1)RNP+ sera containing anti-p70 antibodies. Six epitopes, four major (A, B, C, and F) and two minor (D and E) were mapped and were located throughout the molecule. The anti-(U1)RNP sera displayed heterogeneity in their pattern of reactivity to the six epitopes although reactivity to epitope C was more frequently associated with SLE rather than mixed connective tissue disease. The identification of multiple B cell epitopes on p70 is consistent with the concept that this self Ag drives the autoantibody response.

Autoantigens↗
PubMed1989

The nucleotide sequence of a human cDNA encoding the highly conserved nucleolar phosphoprotein B23.

A cDNA clone containing the complete coding sequence for the human nucleolar phosphoprotein B23 was isolated from a Burkitt's lymphoma cDNA library by immunoscreening with human autoantibodies. The B23 clone contained a 1.3 kb cDNA insert encoding a polypeptide of 294 amino acids with a predicted molecular mass of 32,539 daltons. The deduced B23 amino acid sequence contained 2 acidic domains rich in aspartic and glutamic acid, a feature shared by a number of nuclear and nucleolar proteins. The human B23 amino acid sequence showed 98% homology with rat B23 and 68% homology with the Xenopus laevis nucleolar phosphoprotein, NO38 showing that the primary structure of B23 is highly conserved among these species.

Amino Acid Sequence↗
PubMed1989

Racial differences in antinuclear antibody patterns and clinical manifestations of scleroderma.

The profile of antinuclear antibodies (ANA) in 49 Thais with scleroderma (systemic sclerosis) was compared with that in 68 white Australians with scleroderma. Forty-eight (98%) of the Thais and all (100%) of the white Australians were positive for ANA, with the majority (100% and 97%, respectively) showing a diffuse speckled pattern of nuclear fluorescence. The distribution of the patterns was different in the 2 races; 35 (71%) of the Thais and 17 (25%) of the Australians showed staining of the nucleolus, and 1 (2%) of the Thais and 35 (51%) of the Australians showed staining of the centromeres. The frequency of precipitating antibodies to extractable nuclear antigens was also strikingly different: 86% in Thais and 26% in Australians (P less than 0.001). Precipitating antibodies to Scl-70 (topoisomerase I), the predominant extractable nuclear antigen in patients with scleroderma, were detected in 37 (76%) of the Thais and 18 (26%) of the Australians, and these were shown by Western blotting to react with the Scl-70 (topoisomerase I)-associated polypeptides. Differences in the frequencies of the ANA specificities in the 2 races were consistent with differences in the clinical manifestations of scleroderma; all of the Thai patients, in contrast to 15% of the Australian patients, had diffuse scleroderma with widespread skin involvement. This suggest that environmental or genetic factors may influence the expression of scleroderma.

Adolescent↗
PubMed1989

Autoantibodies to the major nucleolar phosphoprotein B23 define a novel subset of patients with anticardiolipin antibodies.

Of 164 sera with antinucleolar antibodies, 7 (4.3%) were shown by Western blotting to react with a 37-kd polypeptide in a nuclear extract of HeLa cells and with the recombinant protein expressed by a complementary DNA clone encoding the major nucleolar protein B23. Six of the 7 sera (86%) had antibodies to cardiolipin (aCL), and the sample that was negative for aCL had had lupus anticoagulant on previous testing. All 7 patients had either systemic lupus erythematosus (SLE) or a variant of SLE, suggesting that anti-B23 identifies a subset of patients with SLE associated with a high frequency of aCL.

Adult↗
PubMed1989

Anticardiolipin antibodies in homosexual men: prevalence and lack of association with human immunodeficiency virus (HIV) infection.

Tests for anticardiolipin antibodies (ACL) on sera from 100 male homosexuals and 60 male heterosexuals showed that 57% of the homosexuals, in contrast to none of the heterosexuals, were ACL positive. The ACL were predominantly of the immunoglobulin G isotype and, in a high proportion of cases tested (82%), were reactive with other phospholipids, especially those with a negative charge. ACL were not related to the clinical status of the homosexuals, being evenly distributed among 40 with acquired immunodeficiency syndrome (AIDS), 20 with AIDS-related complex (ARC), 20 with asymptomatic infection with human immunodeficiency virus (HIV) and/or lymphadenopathy syndrome, and 20 who were HIV-antibody negative. Nor were they associated with thrombocytopenia, thrombosis, neurologic disease, a biological false-positive test for syphilis (BFP), or antibodies to DNA. It is concluded that factors other than infection with HIV are responsible for ACL positivity in homosexual males and that the epitopes recognized by ACL in this group are distinct from those associated with thromboembolism or the BFP reaction or cross-reactive with DNA.

AIDS-Related Complex↗