Significance of antinuclear factors in older persons

High prevalence of autoantibodies among Danish centenarians

The aim of this study was to investigate the prevalence of organ and nonorgan specific autoantibodies in relation to disability and comorbidity in an unselected population of centenarians. A population-based survey of all persons living in Denmark who celebrated their 100th birthday during the period 1 April 1995 to 31 May 1996, a total of 276 persons, was undertaken. Participants underwent an interview, a physical examination and blood sampling. Organ specific autoantibodies (Tg-ab, TPO-ab, PCA-ab) and nonorgan specific autoantibodies (ANA, IgM RF, IgA RF, MPO-ab, c-ANCA, p-ANCA, oxLDL-ab, IgM ACA, IgG ACA, PR3-ANCA, histone-ab, SSA-ab, SSB-ab, Mit-ab) were measured, and comorbidity and disability (Katz Index of ADL) were registered. In all, 207 (75.0%) of 276 eligible subjects participated, and 148 agreed to blood tests. A large majority (79.3%) had at least one autoantibody detected. Organ specific autoantibodies were present in 32.1% of the centenarians. The high level of autoantibodies did not reflect an equally high level of overt autoimmune disease. While nonorgan specific autoantibodies were equally represented in less-disabled/disabled subjects as well as in subjects with low/high comorbidity, significantly fewer subjects with organ specific autoantibodies were found among less-disabled subjects or subjects with low comorbidity. Autoantibodies (both nonorgan and organ specific) are common in an unselected population of centenarians of today, but do not reflect an equally high level of overt autoimmune disease. Non-organ specific autoantibodies are evenly distributed irrespective of the level of disability or comorbidity, suggesting underlying, undiagnosed pathological processes which may be part of the processes involved in frailty.

Detection of Antinuclear Antibodies by Solid-Phase Immunoassays and Immunofluorescence Analysis

Background: Antinuclear antibodies (ANAs) are associated with several inflammatory rheumatic diseases. The aim of the present work was to evaluate enzyme immunoassays (EIAs) and compare them with classic immunofluorescent analysis (IFA) for the detection of ANA.

Methods: Seven enzyme immunoassays were used in this study. All assays were applied as described by the manufacturers. Three populations were included in the study: (a) a population of patients with well-established autoimmune inflammatory disease (n = 102); (b) a population in which a rheumatic disease was diagnosed up to 5 years after an IFA was performed (n = 164); and (c) a population of consecutive outpatients suspected to have a rheumatic disease (n = 101). The current clinical diagnoses of the patients served as the standard against which performance of the assays was evaluated.

Results: In patients with well-established rheumatic disorders, the newly developed EIA in which HEp-2 extracts were included had sensitivities and specificities comparable to or in some instances better than the IFA. The assays without HEp-2 extracts included had significantly lower sensitivities and specificities. In the outpatient population, up to 51% of patients had positive ANA tests that did not correspond to classic ANA-associated disease. However, in the assays in which the HEp-2 extracts were not included, the false-positive rate was <10%. The false-negative rate judged against IFA differed from assay to assay and disease to disease and was mostly <10%.

Conclusions: In this study, the sensitivities of EIAs and IFA were largely comparable. However, EIAs without HEp-2 extracts included had a low sensitivity but a high specificity, particularly in nonselected populations. The choice of test is highly dependent on the clinical setting in which the ANA test is to be used and on laboratory policy.

Autoimmunity and geriatrics: clinical significance of autoimmune manifestations in the elderly

The immune system undergoes continuous morphologic and functional changes throughout the years, and it is now believed that the immune response has its peak function in puberty and gradually decreases with age (immunosenescence). Recent studies in healthy octogenarian patients suggest that the immune system, instead of suffering a generalized deterioration, undergoes a remodelling/readjustment of its major functions. Increase in two contrasting phenomena coexist in immunosenescence: on the one hand, a decrease in the capacity of the immune response and, on the other hand autoantibody production. The possible consequences of this progressive 'ageing' of the immune system are the increase in autoimmune phenomena, incidence of neoplasia and predisposition to infections. The study of autoimmune manifestations in elderly populations should be considered a priority for future medical research because of increasing life expectancy, especially in developed countries. This review analyses the main immune disorders associated with immunosenescence, the prevalence and clinical significance of autoantibodies in the elderly and the clinical expression of the main autoimmune diseases in older patients.

Frequency and levels of autoantibodies in healthy adult Omanis

BACKGROUND

A previous pilot study showed a high frequency of anti-smooth muscle autoantibody in Omani blood donors and pregnant women. We conducted this larger-scale study to investigate the frequency and significance of several autoantibodies in healthy individuals from different regions of Oman.

METHODS

Sera obtained from 1537 healthy Omanis (1153 males and 384 females), ranging in age from 18 to 57 years, were tested for the presence of ten different autoantibodies using indirect immunofluorescence, haemagglutination and latex agglutination techniques.

RESULTS

Low levels of autoantibodies were detected in 33.5%, whereas a few individuals (1.8%) showed high autoantibody titres. Anti-smooth muscle autoantibodies (ASMA) were the most prevalent (11%). Anti-nuclear autoantibodies (ANA) were the second most prevalent (7.6%). Anti-thyroid microsomal autoantibodies (ATMA) and anti-thyroglobulin autoantibodies (ATA) were present in 6.5% and 4.4% of individuals, respectively. The other autoantibodies were detected much less frequently: anti-parietal cells autoantibodies (APCA) were found in 1.6%, anti-brush border antibodies (ABBA) in 1.3%, anti-reticulin autoantibodies (ARA) in 1%, antimitochondrial antibodies (AMA) in 0.8%, antiglomerular basement membrane antibodies (AGBMA) in 0.7% and rheumatoid factor (RF) in 0.4%.

CONCLUSION

The data indicate that autoantibodies are present in healthy Omani individuals, and therefore caution should be taken when interpreting laboratory results of patients suspected of having autoimmune disease.

Occurence of autoantibodies in healthy Omani individuals

OBJECTIVES

To investigate the occurence of various autoantibodies in the Omani population.

METHOD

Sera from 392 healthy Omani individuals comprising 183 pregnant women and 209 blood donors (183 men and 26 women) were investigated. Autoantibodies were detected using immunofluorescence, haemagglutination and latex agglutination techniques.

RESULT

Low levels of autoantibodies were detected in approximately 50% of the subjects; very few subjects showed high autoantibody titres. Anti smooth muscle autoantibodies (ASMA) were the most prevalent, and were detected in 31.6% of the individuals. Anti thyroid microsomal autoantibodies (ATMA) and anti thyroglobulin autoantibodies (ATA) were present in 5.9% and 4.9% of individuals respectively. The other autoantibodies were detected much less frequently, viz. anti nuclear autoantibodies (ANA) in 1.5%, anti parietal cells autoantibodies (APCA) in 1.8%, anti reticulin autoantibodies patterns (ARAP) in 3.0% and rheumatoid factor (RF) in 1.0% of the subjects.

CONCLUSION

The data indicate that autoantibodies do exist in healthy Omani individuals and the results of clinical tests for these autoantibodies must be interpreted with caution.

Antinuclear antibodies in healthy aging people: a prospective study

In order to evaluate the expression of antinuclear antibodies (ANA) in normal elderly individuals over time and clinical significance, a cross-sectional ANA testing in healthy Japanese was performed, followed by annual evaluations of ANA positive aged (> or = 65 years) and a control group. ANA was more prevalent in the aged (11.4% vs. 3.8%) and most were persistent after 4 years. Anti-ssDNA and anti-histone antibodies were increased in aged ANA positive as compared to ANA negative controls. Except for a history of spontaneous abortion, there was no differences in clinical findings. HLA DRB1*0901 and the DQB1*0602 + 0302 + 0303 set of alleles were increased in ANA positive. Therefore, ANA in the aged were persistent, apparently directed toward chromatin elements, and shared MHC associations with autoimmune diseases. Longer follow-up may be necessary to improve the evaluation of clinical significance of ANA in the aged.

Tropical rheumatology. Immunological aspects

The presence of auto-antibodies in infectious diseases continues to puzzle and provoke. It is hoped that sequencing studies in particular will yield further clues as to the role and mechanism of production of autoantibodies in infectious diseases. This, in turn, may also provide further insights into the role of auto-antibodies in auto-immune diseases. From a practical clinical viewpoint, the search for improved auto-antibody tests and new diagnostic markers with improved sensitivity and specificity must continue in the tropics. Until this is achieved, the results of auto-antibody tests in persons living in the tropics, persons from the tropics or patients with tropical infections, must be interpreted with caution.

The significance of natural autoantibodies

Since Burnet first introduced his "forbidden clones" theory, the discrimination between self and non-self and the physiologic mechanisms of avoiding autoimmunity remained an enigma. The realization in the past two decades that autoantibodies reacting with various self antigens are common in normals has led to intensive research on the origin and physiologic role of these "natural autoantibodies". After reviewing the extensive literature on the appearance of natural autoantibodies in normal animals and humans, and the studies proving unequivocally that natural autoantibodies are coded by germ line genes, we will discuss the current hypotheses explaining their appearance and physiologic role. Despite the fact that numerous hypotheses explaining the origin of natural autoantibodies have been postulated only the two important ones will be discussed. The first, proposed by Cunningham, holds that clonal deletion as viewed by Burnet operates in early life; however, later in life all autoreactive B cells not eliminated during ontogeny are prevented from expanding and secreting anti-self antibodies by a compensatory suppressor mechanism. Therefore, natural autoantibodies are postulated to be autoantibodies which are produced only in minute quantities allowed by the suppressor mechanism. The second hypothesis views autoantibody formation as a result of cross reaction between foreign and self determinants. It is suggested that the part of the B cell population which gives rise to autoantibodies carries a polyspecific receptor; fixation of a foreign antigen to this receptor induces the B cell to undergo a series of divisions and mutations, which under the selective pressure of the antigen leads to production of a highly specific antibody. Thus natural autoantibodies may constitute the antibodies secreted by these B cells prior to encountering foreign antigens. The biologic role of natural autoantibodies is also elusive. The common denominator to all the theories dealing with that puzzling question is the view that natural autoantibodies have a positive role in normal immune reactions, perhaps even an essential role without which normal immune function would be disrupted. Grabar suggested that natural autoantibodies are part of a physiologic mechanism for cleansing the organism of self and non-self products in which classical antibodies serve to clear the body of foreign invading agents, while natural autoantibodies rid the organism of its own catabolic products.(ABSTRACT TRUNCATED AT 400 WORDS)

Ageing and autoantibodies

Immune responsiveness decreases with age, while the production of autoantibodies increases, indicating that these are end results of perturbations in the regulatory mechanisms of the immune system. The effects of ageing on the immune system are reviewed.

Reduced B-cell galactosyltransferase activity in rheumatoid arthritis

Autosensitisation to IgG may be important in the pathogenesis of rheumatoid arthritis and could be related to reduced glycosylation of the oligosaccharides in the C gamma 2 region of serum IgG. The activity of galactosyltransferase, the enzyme that catalyses the addition of galactose to the oligosaccharide chains, was measured in the circulating B cells of seventeen patients with classic rheumatoid arthritis. It was significantly lower than that of a group of eleven controls (p less than 0.001) or of nine age-matched controls (p less than 0.001). In contrast, the enzyme activity of the T cells was within the range of that in nine age-matched controls, and enzyme activity in monocyte-rich mononuclear-cell populations was higher than in controls, possibly reflecting stimulation of the monocytes in rheumatoid arthritis. These findings suggest that galactosyltransferase may regulate the degree of glycosylation during IgG synthesis and could therefore be implicated in the rheumatoid inflammatory process.

Antinuclear antibodies during psoralens plus ultraviolet A (PUVA) therapy--are they worthwhile?

From 1979 to 1985, 497 patients with psoriasis were started on psoralens plus ultraviolet A (PUVA) therapy at Northwestern University. Two hundred sixty-nine of these received therapy for greater than 3 months and had at least two antinuclear antibody (ANA) determinations. We have found that the difference between the number of significantly positive ANAs pre-PUVA therapy (4 of 269) compared to post-PUVA therapy (16 of 269) was not statistically significant. Furthermore, of the patients who did develop a significantly positive ANA, not one was found to have any symptoms, signs, or laboratory evidence of systemic lupus erythematosus. We therefore suggest obtaining ANAs prior to initiating PUVA therapy and obtaining follow-up ANAs only if the initial ANA is significantly positive. Patients with pre-PUVA--positive ANAs can be started on PUVA therapy if there is no evidence of lupus erythematosus.

Serum immunoglobulins and autoantibodies in patients with oral lichen planus

A qualitative and quantitative determination of serum immunoglobulins was made in 34 patients (27 female, 7 male) with histologically verified oral lichen planus (OLP). The subjects ranged in age from 33 to 80 years and 28 of the cases had OLP changes of atrophic-erosive type. The possible presence of rheumatoid factors (RF), antinuclear antibodies (ANA) or antibodies to mitochondrias, renal glomeruli and smooth muscles was studied in 30 of the patients. The investigation also comprised a control group of 23 patients (17 female, 6 male) without mucosal changes. Immunoelectrophoresis showed an abnormal pattern in 10 OLP cases (29%), the most common change being a polyclonal increase of IgG in 8 persons. Elevated levels of serum IgG (greater than 15 g/l) were seen in a total of 9 OLP patients (26%), but only in 1 of the control cases (4%). The mean IgG value was significantly higher in the OLP than in the control group, 13.4 and 10.3 g/l, respectively. Regarding levels of IgA and IgM, no difference was noted between the groups. Autoantibodies were registered in 27% of the OLP patients and in 9% of the controls. The immune changes could be correlated in some respect to positive fungal cultures, allergies and decreased unstimulated saliva, but not to age, endocrine disorders or joint diseases.

Autoantibodies in healthy subjects of different age groups

Autoantibody determinations in 1284 healthy Caucasian subjects of various age groups were made by indirect immunofluorescence for anti-nuclear, anti-gastric, and anti-thyroglobulin antibodies. A sex-dependent relationship between age and prevalence of anti-gastric and anti-thyroglobulin antibodies was found. No association was found between age and anti-nuclear antibodies.

Cell-mediated immunity in an ageing population

Eight hundred and eighty patients hospitalized in a geriatric hospital were routinely tested with 2, 10, 30 and 100 i.u. tuberculin. Among these, fifty-four patients were selected on the basis of negative skin tests and absence of evident diseases interfering with the function of the immune apparatus. A battery of tests analysing cell-mediated immunity was applied to those fifty-four patients. It appears that elderly patients having a negative test to 100 i.u. tuberculin show very infrequent sensitization to three other thymus-dependent antigens. The capacity of this selected population to become sensitized to DNCB is poor (20%). Furthermore they exhibit a low per cent of peripheral blood T cells (36%) and a poor capacity to respond in vitro to mitogens such as PHA. Testing the in vitro response to a battery of antigens demonstrates a good correlation with the results of the skin tests. Finally the leucocytes of 25% of this selected population failed to produce LIF in vitro in the presence of PHA. These results suggest not only an absolute decrease in the population of circulating T lymphocytes in those elderly humans; but very likely, at least in some cases, a functional impairment of T cells.

Histocompatibility antigens in childhood-onset arthritis

One hundred and twelve well-studied patients with a prior diagnosis of juvenile rheumatoid arthritis were differentiated into seven clinically distinct subgroups, including a group in whom recognizable ankylosing spondylitis had developed by time of follow-up. An apparent increased prevalence of HLA-B27 in the entire series (26%) was clearly related to its increased prevalence in only two subgroups: patients whose disease had progressed to overt ankylosing spondylitis (five of five patients) and boys with pauciarticular arthritis whose disease would be consistent with early ankylosing spondylitis (11 of 18 patients). There were no significant associations of B27 with systemic onset JRA, polyarticular JRA, pauciarticular JRA in girls, or JRA with chronic iridocyclitis. The only other significant alterations found were increased prevalences of HLA-A2 and HLA-BW15 in patients with polyarticular disease without identifiable rheumatoid factor. This study emphasizes that the clinical disorders included under the category of juvenile rheumatoid arthritis represent more than a single disease and that this heterogeneity must be considered in interpreting studies such as those of histocompatibility typing.

Antinuclear factors in sera from healthy blood donors

Sera obtained from 466 healthy blood donors were investigated for presence of granulocyte-specific and organ-nonspecific antinuclear factors of the IgM, IgA and IgG classes, 110 sera also for complement-fixing and IgD class antinuclear factors. When undiluted sera were studied, most sera were found to contain antinuclear factors of one or more immunoglobulin classes (77 per cent). IgM, IgA and IgG antinuclear factors were found in 53, 44 and 14 per cent, respectively. At dilution 1:16, antinuclear factors of the IgM class were still detected in 16 per cent of the sera, while IgA and IgC antinuclear factors wre demonstrated in 6 and 2 per cent, respectively. Organ-nonspecific antinuclear factors were clearly more common than granulocyte-specific antinuclear factors. No serum contained complement-fixing or IgD class antinuclear factors. This study indicates the importance of using qualitative as well as quantitative techniques to distinguish between antinuclear factors in health and disease.