Amyloidosis and rheumatoid arthritis

In spite of an apparent decrease in its occurrence during the last 2-3 decades, amyloidosis associated with rheumatoid arthritis is a significant cause of increased morbidity and early death in both juvenile- and adult-onset rheumatoid arthritis (RA). Like other forms of reactive amyloidosis, the amyloid fibrils associated with rheumatoid disorders are of the protein AA type, and the acute phase reactant SAA, which is complexed to high density lipoprotein in serum, is its putative precursor. Raised SAA appears to be one of the prerequisites for the development of reactive, AA amyloid. Effective treatment of the underlying disorder i.e. rheumatoid arthritis, which lowers the levels of SAA is, therefore, recommended both as a prophylactic and therapeutic measure against reactive amyloidosis. As renal disease is the most severe and life-threatening consequence of reactive amyloidosis, both hemodialysis and renal transplantation are also to be considered in such patients.

The amyloid in familial amyloid cardiomyopathy of Danish origin is related to pre-albumin

Amyloid obtained from the myocardium of a patient (Han) with familial amyloid cardiomyopathy of Danish origin was studied. Gel filtration and electrophoresis of purified and denatured amyloid fibrils Han revealed various fractions ranging in mol. wt from 40,000 to 8,000 daltons. Amyloid Han and fractions reacted with an antiserum against amyloid Han showing a reaction of identity with each other; partial identity between Han and human pre-albumin was observed, while no reaction was seen with AA or AL proteins. Cardiac tissue sections from Han showed reactivity with antisera to amyloid Han, pre-albumin and protein AP, but not with anti-AA or anti-AL in indirect immunofluorescence. Amino acid composition and sequence studies of a protein fraction of amyloid Han with mol. wt 15,000 daltons confirmed the structural relationship with pre-albumin.

Amyloid 'degrading factor activity': a non-specific calcium-mediated effect

The clarification of turbid AA-amyloid-fibril-containing agarose gels by serum has been ascribed to degradation of the fibrils and designated as 'amyloid degrading factor'. In the present study, sera of 32 healthy blood donors and 32 patients with rheumatoid arthritis all showed 'degrading factor activity' against both AA amyloid fibrils and a non-fibrillar reticulin preparation of normal liver in an agarose plate assay. AL amyloid fibrils were not affected. The 'degrading activity' of serum was correlated with the serum albumin concentration, and the effect was also given by purified human and bovine serum albumin, although it was not seen with other serum proteins. The 'degrading activity' of serum against AA amyloid and reticulin was significantly correlated: both substrates showed low levels in a chronic disease such as rheumatoid arthritis, and reticulin inhibited 'degrading activity' against AA amyloid and vice versa. These results suggest the same process involves both substrates. 'Degrading activity' was also given by EDTA and a specific calcium chelator, and was inhibited by calcium and magnesium. An enzyme inhibitor showed only partial inhibition of the 'degrading activity' of serum, purified albumin, and EDTA. These results suggest that serum 'degrading factor activity' is a non-specific calcium-mediated effect against AA amyloid and reticulin preparations dispersed in agarose. It may represent a change in the degree of aggregation of these proteins rather than being an effect of proteolytic degradation. This confirms the conclusions of other workers that amyloid 'degrading factor activity' is an phenomenon in vitro of doubtful pathophysiological significance.

Transformation of amyloid precursor SAA to protein AA and incorporation in amyloid fibrils in vivo

Experimental amyloidosis was induced in mice by intraperitoneal injections of endotoxin (lipopolysaccharide (LPS)). In addition to LPS, a group of mice received high-density lipoprotein (HDL)-SAA complexes isolated from human acute-phase serum, whereas a group of control mice received saline in addition to LPS. Isolated amyloid fibrils from the mice given HDL-SAA contained human AA protein, as shown by immunodiffusion, immunoblot, and enzyme-linked immunosorbent assay techniques, in addition to mouse AA. In contrast, amyloid from the control mice contained exclusively AA of mouse origin. Thus, the experiments provided solid evidence that SAA is the precursor for amyloid fibril protein AA.

IgG heavy chain (Gm) allotypes in ankylosing spondylitis

A comparison between 70 patients with ankylosing spondylitis and 97 controls revealed no significant differences in Gm allotypes. In the patients, no association was found between Gm types and various clinical features.

Amyloid-related serum protein (SAA) during and after pregnancy in healthy women and women with rheumatic disease

The usefulness of amyloid-related serum protein (SAA) as an indicator of disease activity has been evaluated in 11 patients with rheumatoid arthritis (RA), 2 patients with psoriatic arthritis (PA) and 13 patients with ankylosing spondylitis (AS) prospectively studied during and after pregnancy. For comparison, SAA levels were recorded serially during and after pregnancy in 28 healthy pregnant women. SAA levels were unaltered by gestation and thus within the normal range during normal pregnancy, but were raised in healthy pregnant women with episodes of intercurrent infections. In RA and AS patients, SAA concentrations correlated to disease activity during and after pregnancy. Serial levels of SAA and C-reactive protein in healthy women and patients paralleled each other with the most pronounced inflammatory response displayed by SAA. We conclude that SAA is a sensitive and reliable indicator of inflammatory events both in the pregnant and non-pregnant state.

Immunohistochemical studies of interleukin-2 and gamma-interferon in rheumatoid arthritis

Synovial tissues were studied, using immunofluorescence techniques, for localization of lymphocytic infiltrates and immune reactants, including C3, C5b-9, C9, and Ia antigen. Tissue distribution of interleukin-2 (IL-2) and gamma-interferon was also determined, using mouse monoclonal antibodies. IL-2 was found in association with OKT8 and OKT4 T cells, and gamma-interferon was noted in association with T cells, B cells, and macrophages. Staining both for IL-2 and for gamma-interferon was surprisingly faint in view of the intensity of lymphocytic infiltration.

A clinical comparison between males and females with ankylosing spondylitis

Forty-four females and 82 male patients with ankylosing spondylitis (AS) were compared in a retrospective study. No differences were found with respect to age at onset of disease, initial symptoms, work performance or peripheral joint involvement. Furthermore, males and females did not differ in restriction of spinal mobility, chest expansion, frequency of acute anterior uveitis or mean concentration of IgA. Males had significantly higher frequency of elevated C-reactive protein whereas mean erythrocyte sedimentation rate showed no such difference.

IgG heavy chain (Gm) allotypes in rheumatoid arthritis and in healthy individuals seropositive for IgM-rheumatoid factor

The frequencies of Gm allotypes a, x, f, b, g and n have been investigated in classical seropositive rheumatoid arthritis (RA), erosive definite seronegative RA, non-erosive definite RA and in healthy individuals with serum IgM-RF. No differences in the frequencies of these Gm allotypes were found between patients and healthy controls. It is concluded that any possible putative genes outside the HLA region involved in RA are most likely unrelated to the genes coding for the constant regions of IgG heavy (gamma) chains.

The prevalence of HLA-DR4 and HLA-DR3 in healthy persons with rheumatoid factor

The frequency of the HLA antigen DR4 has been determined in healthy individuals with serum IgM RF. HLA DR4 was found in 11.6% of these persons as compared with 27% in healthy controls. Thus, no association between IgM RF and HLA-DR4 could be found in this material of healthy individuals. HLA-DR3 was found in 35% of healthy RF-positive persons, which was no different from the 30% prevalence among healthy controls. HLA-DR3 did not seem to be associated with high immune responsiveness of RF in RF-positive individuals.

Roentgenological features of ankylosing spondylitis. A comparison between patients attending hospital and cases selected through an epidemiological survey

A roentgenological comparison between 105 hospital cases (HOSP AS) of ankylosing spondylitis and 27 cases selected through an epidemiological survey (EPI AS) was performed. The male HOSP AS patients exhibited more severe X-ray changes in the sacroiliac joints as compared to male EPI AS patients. The female HOSP AS patients more frequently exhibited lumbar X-ray changes typical of AS when compared to the female EPI AS patients. The main impression from the findings were that more severe and extensive radiological features were present in the AS cases selected through the Department of Rheumatology than in the cases present in the general population.

Coexistence of temporal arteritis/polymyalgia rheumatica and rheumatoid arthritis

A patient with biopsy proven temporal arteritis/polymyalgia rheumatica and erosive rheumatoid arthritis is presented. Only 15 such patients have previously been documented in the literature. The coexistence has been thought to be extremely infrequent, but could merely by chance appear in far more patients than previously reported.

Ankylosing spondylitis: a comparative study of patients in an epidemiological survey, and those admitted to a department of rheumatology

Seventy-four hospitalized patients with ankylosing spondylitis (HOSP AS) were compared clinically with 27 AS patients found in an epidemiological study (EPI AS). The distribution of radiographic changes, initial symptoms and age at onset of AS, frequency of HLA-B27 and acute anterior uveitis were similar in the 2 groups. The EPI AS patients had less restricted spinal and chest mobility than the hospitalized patients. Restriction of mobility thus appears to be an important factor for referral of patients with AS to hospital. A higher frequency of employment among EPI AS patients was found.

Pregnancy and rheumatic disease. A review of recent studies in rheumatoid arthritis and ankylosing spondylitis

The present paper reviews the results of recent investigations into the influence of pregnancy and sex hormones on rheumatoid arthritis (RA) and ankylosing spondylitis (AS). Prospective patient studies have shown that pregnancy exerts a beneficial effect on the majority of RA patients, while AS patients generally have unchanged disease activity during gestation. In AS, gestational remission was confined to patients with accompanying diseases. A postpartum disease flare-up occurred commonly in both RA and AS. Blood parameters reflected mainly the biochemical changes of normal pregnancy. A decrease of circulating immune complexes has been found in RA patients remitting during pregnancy. No single serum factor or combination of serum factors responsible for gestational remission could be detected. The possible influence of alpha 2-pregnancy-associated globulin on disease activity in pregnant patients remains contradictory. Hormonal contraceptives have been found to be protective against the manifestation of RA in four of five studies. However, no beneficial effect of sex hormones on the symptoms of established RA and AS could be demonstrated.

Radiological changes in men and women with ankylosing spondylitis

The radiographic changes of ankylosing spondylitis were studied in 50 females and 82 males. There was a tendency for the males to have more severe arthritic changes in the sacroiliac joints than the females, but the difference did not reach statistical significance. Males significantly more often had radiological involvement of the lumbar spine. More restricted lumbar mobility, total spinal flexion, and chest expansion were found in males with x-ray changes in the lumbar spine than in males without such features. No such significant difference could be found in females. These findings may indicate a less severe disease as judged roentgenologically in females than in males. The correlations between restriction of chest and spinal mobility and x-ray changes were stronger in males.

HLA haplotypes in multiple case families with rheumatoid arthritis

In 9 families of which at least two members were affected by rheumatoid arthritis (RA), no specific combination of HLA genes, i.e., HLA haplotype was found to be associated with transmission of disease susceptibility. The results suggested an important role of HLA-DR4 in the etiology of RA, irrespective of other HLA markers. In addition, it may be concluded that genetic markers other than DR4 may act together with this HLA antigen in determining which individuals are at risk of developing this rheumatic disorder.

HLA-B27 and allotypes of complement components in ankylosing spondylitis

Thirteen families were studied for the frequency of HLA-B27 and allotypes of the components of complement, C2, C4 and Bf. The 13 probands all suffered from definite ankylosing spondylitis (AS) as defined by the New York criteria. The results showed that HLA-B27 positive haplotypes in AS patients possessed different complement allotypes. Thus, it is postulated that the gene conferring predisposition to the development of AS is either HLA-B27 itself or another gene in very close proximity to the HLA-B locus.

A study of IgM rheumatoid factors in a middle-aged population of Northern Norway

A random selection of 8807 blood samples was analysed for the presence of IgM rheumatoid factor (RF). The sera were obtained from an epidemiological survey of rheumatoid arthritis in a middle-aged population of Northern-Norway. The prevalence of IgM-RF was 1.36% for the total population, but a prevalence of IgM RF in healthy individuals between 0.48-0.49% was found with no significant difference between males and females. The majority of RF positive sera were low titred. Only 11.4% of the persons possessing serum IgM RF suffered from classical or definite rheumatoid arthritis. Eighty-one per cent of the IgM RF positive individuals converted to seronegativity in the course of 3.5 years.

HLA antigens in palindromic rheumatism, nonerosive rheumatoid arthritis and classical rheumatoid arthritis

The frequency of HLA antigens has been investigated in patients with definite rheumatoid arthritis (RA) who lacked characteristic erosive radiographic changes that we called nonerosive rheumatoid arthritis ( NERA ). The frequency of HLA-DR4 in patients with NERA was significantly lower than that in classical, erosive RA. A normal frequency of HLA antigens was also found in patients with palindromic rheumatism (PR). Those of the PR patients who however, developed RA during followup, carried HLA-DR4. The patients with PR, NERA and RA who had familial RA demonstrated increased frequency of HLA-DR4.

The prevalence of HLA-B27 in Northern Norway

The incidence of the tissue antigen HLA-B27 has been studied in 176 consecutive blood donors in Tromsø, Northern Norway. The prevalence of HLA-B27 was 15.9%, which was significantly higher than that found in Southern Norway (10%). The frequency of 15.9% is comparable to the prevalence of this antigen found in Northern Sweden (16.6%) and Finland (14-16%).

A comparative study of serum amyloid a protein (SAA) from mink and man

Serum amyloid A protein (SAA) was isolated from mink and human serum by ultra-centrifugation and gel filtration and characterized by two-dimensional gel electrophoresis and Western blotting followed by autoradiography. SAA was found in similar quantities in the high density lipoprotein (HDL) fraction of serum from a patient suffering from systemic juvenile rheumatoid arthritis (JRA) and mink stimulated with lipopolysaccharide (LPS). Only very small quantities were present in normal human controls and not detectable in normal mink. Striking similarities were found in molecular weight, isoelectric point and degree of heterogeneity for human and mink SAA, while immunologic cross-reactivity between the two species was not found. In contrast to human HDL, mink HDL was found not to contain apoA-II and only minute amounts of apoC proteins.