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Biomedical subjects

A McWhirter

Publications and source records attributed to A McWhirter.

5 recordsLinked to original sources

Expression and function of surface antigens on scleroderma fibroblasts.

Dermal fibroblasts from patients with systemic sclerosis (SSc) bound a much greater number of T lymphocytes than did normal dermal fibroblasts. Monoclonal antibodies (MAb) against classes I and II antigens of the major histocompatibility complex (MHC) and their receptors, CD8 and CD4, had no effect on T cell interaction with SSc and normal cells, while MAb against lymphocyte function-associated antigen type 3 (LFA-3) and CD2 both strongly inhibited lymphocyte attachment. MAb against intercellular adhesion molecule type 1 (ICAM-1) and LFA-1 also prevented binding of T lymphocytes, but had a more marked effect on adhesion to SSc fibroblasts than to normal fibroblasts; they also completely abolished the increased binding to fibroblasts treated with interleukin-1 alpha, tumor necrosis factor alpha, and interferon-gamma. No difference was found in the proportion of normal and SSc fibroblasts that expressed MHC classes I and II and LFA-3, but more SSc cells expressed ICAM-1, and at a higher level, than did normal fibroblasts. These results show that cultured SSc cells have elevated binding to T lymphocytes, which possibly results from expansion of a subset of fibroblasts that produces high levels of ICAM-1.

Adult

Antireticulin antibody in systemic sclerosis.

The prevalence, immunoglobulin class, and IgG subclass of antireticulin antibody in the serum samples of 32 patients with systemic sclerosis were investigated by indirect immunofluorescence on unfixed rodent tissue. Antireticulin antibody was present in 22/32 (69%) of patients and belonged to the IgG class in 19/22 (86%), the IgA class in 13/22 (59%), and the IgM class in 6/22 (27%) of positive sera. IgG1 was the predominant subclass of IgG antireticulin antibody, occurring either alone or in association with IgG3 in 12/19 cases (63%). Thus antireticulin antibody of the IgG and IgA classes is found in most patients with systemic sclerosis. The finding of an autoantibody with reactivity for collagen-like fibres in systemic sclerosis indicates that the antibody has a potential role in the pathogenesis of the disease, and as it belongs to the IgA class this suggests that it arises in response to antigens presented to the immune system at the mucosal level.

Adolescent

Serum type III procollagen peptide concentrations in systemic sclerosis and Raynaud's phenomenon: relationship to disease activity and duration.

Serum levels of the amino-terminal type III procollagen peptide (P-3-NP) have been used as an index of collagen synthesis. Systemic sclerosis (SS) is characterized by uncontrolled production of collagen of several types. This study aimed to explore the profile of P-3-NP in patients with SS and Raynaud's phenomenon, a common forerunner of the disease. Using a radioimmunoassay, the mean level for P-3-NP was found to be raised in SS compared with both the control (p less than 0.001) and Raynaud's groups (p less than 0.001). Analysis of serial samples from the patients with SS suggested that the P-3-NP level reflected changing clinical activity. Three groups emerged: a group with stable disease which showed a less than 20% change in P-3-NP level (mean 5.7%); a group with increasing activity which showed an increase of greater than 20% (mean 35.8%) and a group of decreasing activity which showed a decrease of greater than 20% (mean 33.6%). These data suggest that there is an increase in collagen metabolism in SS and that changes in P-3-NP levels may reflect the clinical course of the disease.

Adult

Genetic susceptibility to scleroderma-like syndrome in symptomatic and asymptomatic workers exposed to vinyl chloride.

We have previously reported a genetic susceptibility to a scleroderma-like disorder in a group of workers exposed to polyvinyl chloride and this susceptibility could be mapped to the major histocompatibility complex area of the 6th chromosome. To date no genetic studies have been reported comparing affected with unaffected workers. We report such data and discuss it in the light of our previous findings in vinyl chloride exposed patients and in patients with classical scleroderma. Our results suggest that susceptibility to this disorder is increased in the presence of HLA-DR5 or of a gene in linkage disequilibrium with it and an antigen associated with the haplotype A1 B8, while DR3 favours progression of the disease.

Chemical Industry