Autoantibodies in scleroderma

Autoantibody profile in the experimental model of scleroderma induced by type V human collagen

The aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti-topoisomerase I (Anti-Scl70) by enzyme-linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti-Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi-like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175,000 and 220,000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera.

CONCLUSION

The production of autoantibodies, including anti-Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced-experimental model and brings out its potential for understanding the pathophysiology of SSc.

Studies of scleroderma at The Alfred Hospital, Melbourne

Scleroderma had been virtually unrecognized in this country before this study. Our interest in this condition was raised by the discovery that certain patients being investigated for ischaemic disease of the hand had scleroderma. Although uncommon, it is not excessively rare and we have been able to study an increasingly large number of patients, eventually resulting in 177 patients over a period of 35 years. The clinical features in these patients have been delineated. At first, the patients were subdivided into types: type 1, skin changes obvious only in the hands; type 2, skin changes extending beyond the hands but excluding the trunk; type 3, skin changes diffuse and involving the trunk. All types have similar visceral changes, but these are more severe and there is a worse prognosis in type 3 patients. Types 1 and 2 can conveniently be combined as acrosclerosis. Types 1 and 2 have a similar and good prognosis with survival at 30 years of 40%. Type 3 patients have a much worse prognosis, with no type 3 patients living more than 20 years. All types have a high incidence of autoantibodies, but these are generally not related to the severity of the disease and do not occur in relatives or spouses, this being the evidence of the absence of hereditary and environmental factors in their presence. Although patients may receive much relief from symptomatic measures, no treatment had lessened the skin stiffness and there is no specific treatment for the visceral lesions. The cause of the condition remains unknown.

Clinical correlations and prognosis based on serum autoantibodies in patients with systemic sclerosis

Of 397 systemic sclerosis (scleroderma) patients from the University of Pittsburgh, who had serum determinations of both anti-Scl-70 and anticentromere antibody (ACA), 26% had anti-Scl-70 and 22% had ACA. No patient had both autoantibodies. Weak associations with HLA-DR5 and HLA-DR1 were detected with anti-Scl-70 and ACA, respectively. ACA was found almost exclusively (96%) in patients with limited cutaneous scleroderma (the CREST syndrome variant), but the majority (57%) of patients with limited scleroderma did not have this antibody. Among patients with limited scleroderma, those with ACA more often had calcinosis and telangiectasias and less often had pulmonary interstitial fibrosis and restrictive lung disease. However, the frequency of pulmonary hypertension and the survival rates were similar in the ACA+ and ACA- limited scleroderma patients. Two-thirds of patients with anti-Scl-70 had diffuse scleroderma, but only 33% of all diffuse scleroderma patients had this antibody. Within the subset of diffuse scleroderma, anti-Scl-70 was associated with peripheral vascular disease (digital pitting scars) and pulmonary interstitial fibrosis, but was not predictive of cardiac or renal involvement or survival. ACA and anti-Scl-70 are useful in diagnosing and classifying systemic sclerosis variants and in predicting the natural course of the disease. Their mutually exclusive occurrence suggests either 2 separate clinical entities or important host factors determining their production.

Antinuclear antibodies in the relatives of patients with systemic sclerosis

Antinuclear antibodies were studied by indirect immunofluorescence and double immunodiffusion in 21 patients with systemic sclerosis and 35 of their relatives. When HEp-2 cells were used as the substrate, the frequency of antinuclear antibodies in the patients' sera was 100% and that in the relatives was 26%. When rat liver sections were used, the values were 86% and 17%, respectively. Anticentromere antibody was detected in the serum from the mother of one patient whose serum had anti-Scl-70 antibody. Antibody to n-RNP was positive in the sera from the brother and daughter of another patient whose serum was positive for anti-n-RNP and anti-Scl-70 antibodies. The high frequency of antinuclear antibodies in the sera from the relatives of systemic sclerosis patients suggests that immunological abnormalities play a part in the pathogenesis of this condition.

Management of sclerodermal finger ulcers

Ninety-three percent of 59 patients with scleroderma reviewed in this study presented with Raynaud's phenomenon at a mean age of 43 years; 65% of these developed fingertip ulcers within 4 years. Other common findings were sclerodactyly, distal phalangeal resorption, calcinosis cutis, and digital contractures. Medical management of the digital ulcers with systemic and regional vasodilating drugs was unsatisfactory. Sympathectomy, when performed early, temporarily relieved vasospastic pain but did not affect the course of the ulcers. Severe digital pain was the most incapacitating symptom resulting from vasospasm early in the course of the disease and irreversible arterial luminal narrowing later in the course. Conservative fingertip amputations for nonhealing ulcers constituted the management of choice to eradicate the ulcer, to reduce or eliminate the pain, and to return the hand to early useful function. A decision tree for the management of these ulcers is proposed.

The immunopathology of progressive systemic sclerosis (PSS)

Progressive systemic (sclerosis) is one of the most enigmatic of the rheumatic diseases. It is a connective tissue disorder of unknown etiology characterized by fibrosis in skin and internal organs. Although similar lesions are found with increased prevalence in workers exposed to coal, gold, silica, and polyvinyl chloride, most patients have had no known predisposing factors. Select reports of a familial occurrence of PSS have been observed but a definitive genetic basis is lacking and no clear associations with the major histocompatability complex have been demonstrated. Moreover, although a variety of immunologic abnormalities in patients with PSS have been reported, they are generally diffuse and non-diagnostic. Such abnormalities include defects in cell mediated immunity, increases in sera immunoglobulins, antinuclear antibodies, and cryoglobulins. In contrast to these non-specific findings, there appears to be significant evidence of a relationship between cell mediated immunity to collagen and appearance of scleroderma. For example, peripheral blood lymphocytes in patients with scleroderma undergo lymphocyte transformation when cultured with specific collagen preparations. The pathology of skin and internal organs in PSS generally reflects both collagen deposition and small vessel occlusion. All organ systems may be involved but mortality significantly increases with involvement of heart, kidney, or lung. Unfortunately, at present a reliable experimental model of PSS has not been found although similar immunopathology can be induced in homologous disease of rats and in chronic graft vs host disease of humans.

Diversity of antinuclear antibodies in progressive systemic sclerosis. Anti-centromere antibody and its relationship to CREST syndrome

Antinuclear antibodies were demonstrated in the sera of 43 of 45 (96%) patients with progressive systemic sclerosis (22 of 24 with diffuse scleroderma and 21 of 21 with the CREST syndrome variant). This high percentage of positive reactions resulted from the use of a tissue culture substrate (HEp-2) to detect antinuclear antibodies by the indirect immunofluorescent method. Patterns of nuclear staining included diffuse fine speckles, large coarse speckles, nucleolar and centromere staining. When organ sections such as mouse kidney were used as substrate for the detection of antinuclear antibodies, nucleolar staining and centromere staining were the two patterns most frequently overlooked. Three types of antibodies appeared to be highly specific for scleroderma: antibody to Scl-70 antigen, antibody to centromere, and antinucleolar antibody. The anti-centromere antibody appeared to be highly selective for the CREST variant of progressive systemic sclerosis.

The systemic involvement in scleroderma

A survey was made of the systemic involvement in 38 patients with scleroderma: 33 with the acrosclerotic form (Type 1, 18, Type 2, 15) and five with the diffuse form. The study comprised inquiry about symptoms, physical examination, and the laboratory tests, such as radiological examination of chest and hands, barium swallow and meal X-ray examination, electrocardiography, pulmonary function tests, haematology tests, examination for autoantibodies, and a battery of biochemical tests. Evidence of some systemic involvement (that is, in addition to skin) was almost universal. Similar disturbances occurred both in the acrosclerotic and in diffuse forms. The most common clinical involvement was that of the joints and gastrointestinal tract. The most common confirmatory signs were a positive "neck test" (tethering of the skin of the root of the neck and upper part of the chest on extending the head) and telangiectasia. The most common abnormalities in test results were those found in X-ray films of the hands (about 80%), and in pulmonary function, and barium swallow and meal X-ray studies (each about 70%). The most frequent abnormalities in the biochemical scan were increased levels of immunoglobulin M (IgM), and decreased creatine clearance.

Lymphokine stimulation of collagen accumulation

Lymphokine-rich supernates from normal human peripheral blood mononuclear cells, stimulated by the mitogen phytohemagglutinin, have been shown to cause enhanced collagen accumulation by human embryonic lung fibroblasts (WI-38), as measured by hydroxyproline content of fibroblast monolayers, [14C] proline incorporation into soluble collagen and collagenase release of radioactivity in supernates and monolayers of cultures incubated with [14C] proline. This fibroblast-stimulating activity, demonstrable by suitable dilutions of the supernates, coexisted with a number of other lymphokine activities such as lymphotoxin, proliferation inhibitory factor, and cloning inhibitory factor, which tend to reduce the numbers of function of fibroblasts. The increased content of collagen appeared to be the product of selected surviving and responding fibroblasts. The factor causing this increased collagen accumulation was nondialyzable and stable at -70 degrees C. It represents the first described lymphoid cell-derived activity capable of enhancing collagen accumulation. Fibroblast-stimulating activity may be implicated in the abnormal fibrosis seen in association with chronic inflammation in a variety of disease states. It may have special relevance to progressive systemic sclerosis.

Scleroderma and primary biliary cirrhosis

Two cases of scleroderma and primary biliary cirrhosis are described. One had systemic sclerosis with primary biliary cirrhosis of six years' duration at the stage of ductular proliferation. The other had the C.R.S.T. syndrome (calcinosis, Raynaud's phenomenon, sclerodactyly, and telangiectases) with primary biliary cirrhosis at the florid stage. Several similar cases were found in a review of other reports, and it is suggested that the association may be due to a common "autoimmune" process.