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Biomedical subjects

L A Rubin

Publications and source records attributed to L A Rubin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Investigating the genetic basis for ankylosing spondylitis. Linkage studies with the major histocompatibility complex region.

OBJECTIVE: To assess the hypothesis that B27 or a gene(s) in close proximity (e.g., within or near the major histocompatibility complex [MHC]) represents a disease-causing ankylosing spondylitis (AS) gene, and therefore contributes directly to the pathogenesis of this disorder. METHODS: MHC haplotypes were determined by both serologic and molecular analyses in 15 multiple-case AS families from Toronto and Newfoundland. Segregation of MHC haplotypes with AS within these families was examined by linkage and identity-by-descent analyses. Attributable risk estimates for various genetic markers and for sex were calculated. RESULTS: Linkage analyses established significant linkage between AS and the MHC, the maximal logarithm of odds (LOD) score being 3.48 at a recombination frequency (O) of 0.05. In a second analysis in which the population association of the MHC gene HLA-B27 with AS was taken into account, the maximal LOD score was 7.5 at O = 0.05. Identity-by-descent analyses showed a significant departure from random segregation among affected avuncular (P < 0.05) and cousin (P < 0.01) pairs. The presence of HLA-B40 in HLA-B27 positive individuals increased the risk for disease more than 3-fold, confirming previous reports. Disease susceptibility modeling suggested an autosomal dominant pattern of inheritance, with penetrance of approximately 20%. CONCLUSION: These data provide the first conclusive demonstration of linkage between the MHC region and AS, and confirm that genes within this region contribute directly to the genetic susceptibility for AS.

Adolescent↗
PubMed1993

Selective impairment of CD43-mediated T cell activation in the Wiskott-Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is associated with defective glycosylation and altered membrane expression of the leukocyte sialoglycoprotein CD43. To investigate whether such modifications of CD43 are relevant to T cell dysfunction in WAS, we have analyzed peripheral blood mononuclear cells from WAS patients for proliferative responses to both CD43-interacting and other T cell mitogenic stimuli. While patient lymphocytes proliferated in response to phytohaemagglutinin, concanavalin A, interleukin-2 and neuraminidase/galactose oxidase, no responses were elicited upon attempted triggering of the CD43 signalling pathway using periodate or anti-CD43 antibody. Cells from four of five patients with clinical profiles resembling, but not identical, to that of classic WAS also failed to respond to periodate or anti-CD43 antibody stimulation. These results indicate that the aberrant expression of CD43 on WAS lymphocytes is associated with selective impairment of CD43-induced T cell proliferation and that detection of this defect may be useful in the diagnosis of WAS and its variant forms.

Adolescent↗
PubMed1991

Soluble interleukin-2 receptor in juvenile rheumatoid arthritis.

Juvenile rheumatoid arthritis (JRA) is a chronic, relapsing, inflammatory childhood disease characterized by arthritis and systemic inflammation. At present there is no rapid, efficient laboratory method of assessing disease activity and degree of immune activation. We measured serum soluble interleukin 2 receptor (sIL-2R) levels in 85 samples from 72 patients (22 samples from patients with systemic JRA, 34 from polyarticular patients, 29 from pauciarticular patients, of which 10 were HLA-B27 positive). The mean sIL-2R level from patients was 1565 U/ml, which is significantly elevated compared to control values of 594 U/ml (p less than or equal to 0.005). The highest levels were seen in patients with systemic JRA (mean value 2121 U/ml) while the lowest values were seen in HLA-B27 positive (+) patients (mean value 899 U/ml). Patients with clinically active disease had significantly elevated levels (mean value 1745 U/ml) compared to patients with inactive disease (mean value 846 U/ml, p less than or equal to 0.01). Highest levels were seen in patients with active systemic JRA (mean value 2419 U/ml) while patients with pauciarticular JRA and B27 + JRA had the lowest sIL-2R levels (1167 and 1045 U/ml, respectively). sIL-2R levels were elevated in all subgroups of clinically active patients compared to controls (p less than or equal to 0.0005). Three of the 4 patients with serial sIL-2R measurements showed falling values during the period of clinical remission. Using regression analysis and likelihood ratio tests, we found a significant correlation between sIL-2R levels and both disease activity and joint count (p less than or equal to 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1991

Cellular localization of the target structures recognized by the anti-Jo-1 antibody: immunofluorescence studies on cultured human myoblasts.

Antibodies to Jo-1 (alpha Jo-1) are most characteristically detected in patients with the idiopathic inflammatory muscle disease polymyositis (PM). The Jo-1 antigen has previously been identified as histidyl-tRNA synthetase (HRS). In order to clarify the cellular localization of the antigenic targets recognized by the alpha Jo-1 antibody, immunofluorescence (IF) studies were performed with cultured human myoblasts. Incubation with alpha Jo-1 positive sera demonstrated granular cytoplasmic as well as nuclear staining, but only the cytoplasmic fluorescence was specifically inhibited by preabsorbing the sera with recombinant histidyl-tRNA synthetase (rHRS). A polyclonal rabbit anti-rHRS sera demonstrated granular cytoplasmic IF which was also specifically inhibited by preincubation with rHRS protein. Alpha Jo-1 negative healthy control or patient sera demonstrated nonspecific low intensity staining. 35S methionine biosynthetically labelled myoblast cell extracts immunoprecipitated with alpha Jo-1 positive sera and analyzed by SDS-PAGE revealed a specific band of the same molecular weight as the rHRS antigen. Our studies demonstrate that alpha Jo-1 specifically binds to antigen in the cytoplasm of cultured myoblasts. Alpha Jo-1 has been shown to inhibit HRS activity in vitro. Given the importance of aminoacyl tRNA synthetases such as HRS to intracellular protein assembly, intracytoplasmic binding and enzyme inhibition in vivo may potentially contribute to the pathogenesis of autoimmune muscle damage in PM.

Antibodies, Antinuclear↗
PubMed1990

The soluble interleukin-2 receptor: biology, function, and clinical application.

PURPOSE: To review the biologic origin, functional characteristics, and current and potential clinical applications of a novel marker of immune system activation, the soluble interleukin-2 receptor (sIL-2R). DATA IDENTIFICATION: Studies reported since 1985 were identified by a computer search using MEDLINE as well as from bibliographies of published work. STUDY SELECTION: Sixty-two reports on the clinical applications of the sIL-2R, largely from peer-reviewed journals, were identified. These reports address the utility and significance of sIL-2R measurements in various conditions. Basic scientific investigations delineating the biochemical and molecular features of the human interleukin-2 receptor complex and the sIL-2R protein were reviewed. DATA EXTRACTION: The validity of sIL-2R quantitation as an index of in-vivo immune system activation and its usefulness as a measure of disease activity and outcome were examined. RESULTS OF DATA ANALYSIS: The quantitation of sIL-2R, a novel laboratory measure of in-vivo immune system activation, correlates reliably with disease activity in autoimmune inflammatory disorders, transplantation rejection, and specific infectious disorders. Markedly elevated serum sIL-2R levels are a particularly prominent feature of certain hematologic malignancies, such as human T lymphotropic retrovirus type I-associated adult T-cell leukemia and hairy cell leukemia, reflecting tumor burden and response to therapy. The sIL-2R level at disease onset may also reliably predict long-term prognosis in non-Hodgkin lymphoma, and it appears to provide an additional serologic measure in the assessment of clinical progression in patients with human immunodeficiency virus infection and the acquired immunodeficiency syndrome. CONCLUSIONS: Studies have suggested that sIL-2R levels offer a rapid, reliable, and noninvasive measure of disease activity, response to therapy, and, in some cases, prognosis in a broad spectrum of conditions associated with T- or B-cell immune activation.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Linkage relationships of the Wiskott-Aldrich syndrome to 10 loci in the pericentromeric region of the human X chromosome.

Twelve families with Wiskott-Aldrich syndrome (WAS) were studied by linkage analysis using 10 polymorphic marker loci from the X-chromosome pericentromeric region. The results confirm close linkage of WAS to the DXS14, DXS7, TIMP, and DXZ1 loci and are consistent with previous data suggesting that WAS maps to the proximal Xp and is flanked by the DXS14 and DXS7 loci. The strongest linkage (Z = 10.19 at theta = 0.00) was found to be between WAS and the hypervariable DXS255 locus, a marker locus already mapped between DXS7 and DXS14 and which was informative for all meioses included in this analysis. Linkage of the WAS to two pericentromeric Xq loci, DXS1 and PGK1, was also established. On the basis of these results, accurate predictive testing should now be feasible in the majority of WAS families.

Chromosome Mapping↗
PubMed1990

The molecular basis for the generation of the human soluble interleukin 2 receptor.

Using an enzyme-linked immunosorbent assay (ELISA) employing two monoclonal antibodies recognizing distinct epitopes on the interleukin 2 receptor (IL2R) alpha chain (Tac molecule), we previously demonstrated that activated lymphocytes release a soluble interleukin 2 receptor molecule (sIL2R) in vitro and in vivo. The sIL2R is biochemically and structurally related to Tac, but its precise origin and functional role remain to be defined. We report here that a single IL2R cDNA is sufficient to direct the synthesis of both cell-associated and soluble released IL2R molecules. Northern analysis of IL2R cDNA transfected L-cell lines revealed the presence of mRNA species unaccounted for by known transcription termination or internal splice sites. Nevertheless, S1 nuclease digestion studies failed to detect alternately spliced mRNA transcripts that specifically lack transmembrane or cytoplasmic domains and which may encode a secreted IL2R molecule. Therefore sIL2R does not appear to be the product of a unique post-transcriptional splicing event. In the absence of any post-translational modifications, sIL2R is most likely generated by enzymatic cleavage and release of cell surface Tac. This proteolytic release of Tac may be but one example of a common cellular mechanism for regulating the membrane expression of cell surface molecules.

Animals↗
PubMed1990

A human anti-cardiolipin autoantibody is encoded by developementally restricted heavy and light chain variable region genes.

Based on recent structural analyses of monoclonal autoantibodies, it appears that a number of these antibodies express germ-line immunoglobulin variable region (V) genes with little or no somatic mutation. In addition, our group and others have noted the identity or near identity of some autoantibody-associated V genes to V genes apparently expressed preferentially in the fetal pre-B cell repertoire. To extend these data, we now report that the heavy and light chain V genes of an anti-cardiolipin antibody derived from a healthy individual display 99% nucleotide sequence homology with V genes expressed in early B cell ontogeny. Sequence comparisons indicate the likely use of fetal-restricted V genes by this autoantibody. Taken together with other data on autoantibody V gene usage, these findings provide further evidence for overlap between the autoantibody-associated and early ontogeny expressed V gene repertoires and suggest that natural autoreactivity may be instrumental in the development and maintenance of the normal immune repertoire.

Amino Acid Sequence↗
PubMed1990

Serial levels of soluble interleukin 2 receptor in the peripheral blood of patients with rheumatoid arthritis: correlations with disease activity.

We serially assayed soluble interleukin 2 receptor (sIL-2R) levels in the peripheral blood (PB) of 22 patients with rheumatoid arthritis (RA) followed for a period of 12 months, and correlated these levels with disease activity. We examined the relationship between the direction in which each of the disease measures changed between assessments and the direction of change in sequential sIL-2R levels. In 22 of the 25 (88%) instances where there was a 30% change in the active joint count between sequential assessments, the direction of change of the PB sIL-2R level was found to be in parallel (chi 2 = 11.7, p less than 0.008). Our results suggest that serial sIL-2R levels are a useful means of confirming clinically significant changes in disease activity in patients with RA, irrespective of therapy.

Anti-Inflammatory Agents↗