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Biomedical subjects

C M Lockwood

Publications and source records attributed to C M Lockwood.

At least 109 records · Page 6Linked to original sources
PubMed1991

IgG subclass distribution of autoantibodies to neutrophil cytoplasmic antigens in systemic vasculitis.

The IgG subclass distribution for both ANCA-specific, and total IgG subclasses, of sera from 48 patients with active systemic vasculitis was determined by solid-phase assay using monoclonal anti-human subclass reagents. To control for varying performance of the subclass reagents, the assays were calibrated with sera affinity-depleted into subclass specific fractions, whose ANCA IgG subclass distribution was determined by a common reagent. In 10 patients whose ANCA persisted during clinical remission, the ANCA IgG subclass distributions between active and remission phases of disease were compared. The total IgG subclass distribution of sera from patients with active vasculitis was similar to that found in a normal population. The ANCA IgG subclass distribution of the same sera showed relative enrichment for IgG3 and depletion of IgG2 (P less than 0.05). When the active and clinical remission ANCA IgG subclass distributions were compared, ANCA IgG3 levels had fallen and ANCA IgG2 levels were increased during remission (P less than 0.01).

Antibodies, Antinuclear↗
PubMed1990

Autoantibodies to GBM and neutrophil cytoplasm in rapidly progressive glomerulonephritis.

The incidence of autoantibodies to glomerular basement membrane (AGBMA) and neutrophil cytoplasmic antigens (ANCA) in the initial sera of 889 consecutive patients with a suspected diagnosis of rapidly progressive glomerulonephritis, was determined by prospective study. Forty-seven (5%) were positive for AGBMA alone, 246 (28%) were positive for ANCA alone, 576 (65%) had neither autoantibodies while 20 (2%) had both. Clinical and pathological data collected from patients with both autoantibodies suggested the coexistence of anti-glomerular basement membrane disease and systemic vasculitis. Together, assays for AGBMA and ANCA are important in the diagnosis and management of rapidly progressive glomerulonephritis and may help its further classification.

Antibodies↗
PubMed1990

Kinetics and pathogenicity of autoantibodies induced by mercuric chloride in the brown Norway rat.

Repeated low-dose injections of mercuric chloride (HgCl2) in the brown Norway (BN) rat result in polyclonal activation which includes the induction of anti-glomerular basement membrane (GBM) autoantibodies. We examined the kinetics of various autoantibodies produced in vivo, general features of polyclonal activation such as total IgG levels and immune complex formation, and the relationship between organ specific autoimmunity and tissue injury in the kidney and thyroid. The production of immune complexes and autoantibodies to GBM and thyroglobulin was short lived, and the increase in levels of total IgG and antibodies to ssDNA and dsDNA was prolonged; the antibody response to collagen types I and II was intermediate in duration. Autoantibodies induced by HgCl2 caused only mild and variable tissue injury in the kidneys and did not induce abnormalities in the thyroid. These studies demonstrate that immunostimulation by mercury may result in the formation of a range of autoantibodies, with variable kinetics and pathogenicity.

Animals↗
PubMed1990

Autoantibodies to endothelial cells and neutrophil cytoplasmic antigens in systemic vasculitis.

The interaction of circulating autoantibodies with the endothelium may be an important mechanism in the pathogenesis of systemic vasculitis. In a prospective study, we looked for circulating antiendothelial cell autoantibodies (AECA) and anti-neutrophil cytoplasm autoantibodies (ANCA) in 80 patients with suspected systemic vasculitis. AECA were measured using an isotype-specific cellular ELISA incorporating human umbilical vein endothelial cells. ANCA activity was determined by indirect immunofluorescence and radioimmunoassay. Sequential studies were performed on sera from four cases with dual positivity, where autoantibody binding was compared with von Willebrand factor (vWF) concentration and disease activity. IgG AECA were significantly higher in the 27 ANCA-positive sera as compared with normal controls (P = 0.027) with IgG (P = 0.009) and IgA (P = 0.046) AECA isotypes correlating with ANCA positivity; in contrast, no differences were found between AECA levels in the ANCA-negative sera and the normal controls. Cross-inhibition studies pointed to the co-existence of two autoantibody populations. An association between autoantibody binding, disease activity and vWF concentration was found for both ANCA and AECA. Some patients with systemic vasculitis have detectable AECA that recognize different epitopes to ANCA and like ANCA, their titre correlates with disease activity and thus they may have a pathogenetic role in these conditions.

Antibody Specificity↗
PubMed1990

The specificity of anti-neutrophil cytoplasm autoantibodies in systemic vasculitides.

Autoantibodies to neutrophil cytoplasmic antigens are found in patients with small or medium-size vessel systemic vasculitis such as Wegener's granulomatosis and microscopic polyarteritis. We studied the specificity of anti-neutrophil cytoplasm autoantibodies (ANCA) by examining the binding of sera from patients with different forms of systemic vasculitis, to neutrophil extract size-fractionated by gel filtration for high performance liquid chromatography. Sequential fractions were collected for solid-phase radioimmunoassay. Patients with Wegener's granulomatosis showed two peaks of activity over fractions of 12 and 2 kD. Patients with microscopic polyarteritis had two different peaks of activity over fractions of 100 and 25 kD. Patients with Takayasu's arteritis and dermal lymphocytic vasculitis were studied as controls (all were ANCA negative by indirect immunofluorescence studies and solid-phase radioimmunoassay). However, the patient with lymphocytic vasculitis showed a distinct peak of activity over 22 kD and patients with Takayasu's arteritis had a single peak of activity over 200 kD. These results suggest the binding pattern of sera to fractionated neutrophil extract could be useful in differentiating between different diseases within the spectrum of systemic vasculitis. Cryptic antigen recognition in certain vasculitides may only be revealed by this procedure. We conclude that the association of ANCA and systemic vasculitis may not be limited to diseases of small or medium-size vessels, but could also include large vessel disease such as Takayasu's arteritis.

Antibody Specificity↗
PubMed1990

Anti-neutrophil cytoplasm antibodies in patients with monoclonal gammopathies.

Anti-neutrophil cytoplasm antibodies (ANCA) are specific markers for systemic vasculitis. In view of the autoreactivity to other autoantigens reported in patients with monoclonal immunoglobulins (MIg), the reactivity of 150 sera from 125 patients with MIg was tested for ANCA by radioimmunoassay (RIA) with inhibition stage and indirect immunofluorescence (IIF). Seven were positive for IgG ANCA, all with IgG MIg and 5 were positive for IgM ANCA, 4 with IgM MIg and 1 with IgG MIg. No IgA ANCA were found. The patterns seen on IIF were identical to those seen with sera from patients with systemic vasculitis and were cytoplasmic in 6 and peri-nuclear in 6. The restriction of the ANCA activity to the MIg was studied in six sera by light chain specific RIA, and anion exchange fractionation of the sera. The ANCA activity appeared to be polyclonal in at least three sera and could be found in the monoclonal fraction in only three patients. Associated autoimmune diseases were found in some of these ANCA positive patients including Sjögren's syndrome, MacDuffie hypocomplementemic vasculitis and rheumatoid polyarthritis but the classical vasculitic features normally associated with ANCA were not observed. We conclude that ANCA is a further autoreactivity present in some sera with MIg and discuss the relation between monoclonal gammopathies and autoimmunity.

Aged↗
PubMed1990

Autoantibodies in primary systemic vasculitis.

Strong evidence for the presence of autoantibodies in the primary systemic vasculitides now exists, and there is a particularly marked association between ANCA and Wegener's granulomatosis and microscopic polyarteritis. The presence of ANCA serves to place these disorders in a firm autoimmune setting. Although ANCAs are of undoubted diagnostic significance, their role in etiology and pathogenesis has still to be fully explored, so further developments in this area are awaited with interest.

Autoantibodies↗
PubMed1990

Antineutrophil antibodies in vasculitis.

Antineutrophil cytoplasm antibodies appear highly specific to the primary systemic vasculitides, in particular to Wegener's granulomatosis and microscopic polyarteritis. Their occurrence in idiopathic crescentic rapidly progressive glomerulonephritis supports the view that this disorder may be regarded as a renal limited form of microscopic polyarteritis. The high sensitivity and specificity of ANCA detected using indirect immunofluorescence or solid phase techniques aids the primary diagnosis of these disorders; the measurement of ANCA may also be of value in long-term monitoring since disease relapse appears to occur only when ANCA are present, and it may therefore be inadvisable to withdraw immunosuppressive treatment until ANCA have been undetectable for extended periods of observation. However, the continued presence or reappearance of ANCA following initial induction of disease remission is not necessarily in concord with overt disease activity, although ANCA has been present in all patients in whom disease relapse has occurred. To understand further the role and relationship of ANCA to the vasculitic diseases requires elucidation of the autoantigen, and in this regard various neutrophil enzymes would appear to be likely candidates. Meanwhile, direct evidence of in vivo pathogenicity and studies of possible mechanisms of tissue injury, such as antiendothelial cell reactivity, are being sought.

Adult↗
PubMed1989

Antineutrophil cytoplasm antibodies in Kawasaki disease.

Autoantibodies against components of neutrophil cytoplasm develop during adult vasculitic diseases such as Wegener's granulomatosis and microscopic polyarteritis, and they are predominantly of the IgG class. Similar but distinct antibodies have been described in children with Kawasaki disease and both IgM and IgG class antibodies are represented. This adds another clinically distinct childhood form of vasculitis to the adult forms in which autoantibodies to neutrophil cytoplasmic antigens have been detected.

Autoantibodies↗