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Biomedical subjects

K Aho

Publications and source records attributed to K Aho.

At least 19 recordsLinked to original sources
PubMed1992

Immunopathology of rheumatoid arthritis. Antikeratin antibodies precede the clinical disease.

OBJECTIVE: We sought to determine whether circulating antikeratin antibodies (AKA) precede the onset of rheumatoid arthritis (RA). METHODS: By matching the registers of 2 previous population studies with the registry of patients receiving antirheumatic drugs several years later, pre-illness serum specimens could be obtained from 39 individuals who subsequently developed RA. AKA were assayed with the standard indirect immunofluorescence technique. RESULTS: Ten of 39 serum specimens from individuals who subsequently developed seropositive RA, and 1 of 15 sera from individuals who developed seronegative RA, were positive for IgG-class AKA by immunofluorescence assay. The AKA-positive sera were also positive for rheumatoid factors. CONCLUSION: The findings focus attention on the role of pre-illness immunologic events in the pathogenesis of RA.

Antibodies↗
PubMed1992

Systemic lupus erythematosus and related systemic diseases in a nationwide twin cohort: an increased prevalence of disease in MZ twins and concordance of disease features.

Concordance rates for systemic rheumatic diseases among monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs ascertained from the older (twins born before 1958) and younger (twins born during the period 1958-1986) parts of the Finnish Twin Cohort were studied. Nine MZ pairs and 10 DZ pairs with at least one member affected by systemic lupus erythematosus (SLE) were identified. Only one MZ pair was concordant for definite SLE by American Rheumatism Association (ARA) criteria. In addition, two more MZ pairs that fulfilled three ARA criteria may have been concordant. None of the DZ pairs were concordant for SLE. MZ twins also had a higher concordance rate for tests of autoantibodies, but the numbers were small. Other systemic rheumatic diseases were infrequent. The cumulative incidence of systemic rheumatic diseases among MZ twin individuals (1.7/1000) was significantly higher than that among DZ twin individuals (0.7/1000).

Adult↗
PubMed1992

Antinuclear antibodies heralding the onset of systemic lupus erythematosus.

On the basis of record linkage with the Social Security Institution's population register, 16 specimens from healthy subjects who subsequently developed systemic lupus erythematosus or mixed connective tissue disease could be traced from stored sera collected in connection with nationwide maternity welfare program in Finland. The sera were tested for antinuclear antibodies (ANA) using an immunofluorescence technique. Ten of the 16 specimens were positive. Eight of 11 cases were positive when the interval from taking the blood specimen to the onset of the first symptoms of disease was 2 years or less and 2 of 5 cases were positive when the interval was over 3 years. Eighteen of 21 sera with established disease and 5 of 85 control sera from the same serum collection were positive. Thus, ANA as detected by a sensitive technique frequently precede the onset of disease indicating that they are not a secondary manifestation of inflammation or tissue destruction.

Adult↗
PubMed1991

Risk factors for subarachnoid hemorrhage in a longitudinal population study.

The known risk factors of atherosclerotic diseases may be involved in the development of a subarachnoid hemorrhage. We studied the morbidity and mortality due to subarachnoid hemorrhage among 42,862 men and women aged 20-69 years who had participated in a large health survey in Finland. During a mean follow-up of 12 years, 102 non-fatal and 85 fatal cases of subarachnoid hemorrhage were observed. The total incidence was 37 per 100,000 person-years. Smoking and hypertension were positively associated and body mass index was inversely associated with the risk of subarachnoid hemorrhage. These associations were not confounded by age or each other. No statistically significant association with risk was detected for serum cholesterol level, hematocrit content, known heart disease, or diabetes. The risk was especially elevated among lean hypertensive subjects and lean smoking subjects. The age-adjusted relative risks of subarachnoid hemorrhage for lean, hypertensive smokers were 18.3 (95% confidence interval (CI), 7.8-42.7) among women and 6.7 (95% CI, 2.3-19.7) among men as compared to the risk among subjects without these risk factors. We conclude that modifiable risk factors are predictive of subarachnoid hemorrhage, for which reason subarachnoid hemorrhage may in part be preventable. Leanness combined with arterial hypertension and/or smoking, in particular, poses a substantially elevated risk.

Adult↗
PubMed1991

Rheumatoid arthritis in identical twins: a clinical and immunogenetic study of eight concordant pairs derived from a nationwide twin panel.

The nationwide Finnish Twin Cohort was linked with the national Sickness Insurance Register. Eight identical twin pairs concordant for rheumatoid arthritis (RA) fulfilling the American Rheumatism Association criteria were identified. All 16 cases were known to be seropositive. Four pairs had at least one additional first-degree relative with RA, and the prevalence of RA among all the first-class relatives was 9%. HLA-typing was performed for 15 patients representing the eight pairs; six pairs carried the DR4 allele, and three of these pairs were putative homozygotes. Nodules and Sjögren syndrome occurred fairly frequently (in 7 of 16 and 6 of 13 cases examined, respectively), but concordance within pairs was no higher than that expected by chance. The course of the disease was fulminant in one patient and in several others the disease had led to marked joint destructions. The findings pointed out to some intrapair similarity in the progression of the joint damage and in the type of complications caused by gold.

Adult↗
PubMed1991

Rheumatoid factors antedating clinical rheumatoid arthritis.

The relationship between rheumatoid factors (RF) and rheumatoid arthritis (RA) was studied in the Mini-Finland Health Survey. This covered a representative sample of the Finnish population over 30 years of age, initially comprising 8,000 persons, of whom 7,217 participated in the field survey carried out in 1978-80. The participants were followed using record linkage with the Social Insurance Institution's population register to identify patients entitled to free medication. Until the end of 1988, 21 persons had developed new seropositive RA. In 15 cases, preillness specimens contained elevated levels (greater than or equal to 20 IU/ml) of RF. In the remaining 6 cases with RF negative preillness specimens, the interval from taking the blood specimen to the onset of disease was 4 years or more. RF represent a key element in the rheumatoid inflammatory process. Their occurrence in preillness specimens suggests that they may have a primary role in the pathogenesis of the disease.

Adult↗
PubMed1991

Measuring rheumatoid factor in nonrheumatoid subjects: immunoturbidimetric assay, latex slide test, and enzyme-linked immunosorbent assay compared.

Previous studies of patients with rheumatoid arthritis (RA) have shown a good correlation between results from immunoturbidimetric assays of rheumatoid factor (RF) and latex fixation tests. To extend the research to non-RA subjects, we tested sera from 1000 pregnant women, half each in the first and third trimesters. By turbidimetry, 24 non-RA sera were regarded as positive for RF (greater than or equal to 20 int. units/mL) and 18 sera as borderline (15-19 int. units/mL). By the latex fixation test, 28 non-RA sera gave a clear reaction (positive) and 17 sera a weak reaction (borderline). The association between the tests was statistically highly significant (P less than 0.001). All sera with positive and borderline reactions were tested by enzyme-linked immunosorbent assay for RF isotypes, together with a random subsample of about one-sixth of the original serum samples. Positive RF results by immunoturbidimetry were predominantly due to the presence of IgM-RF. In contrast to some earlier findings, we saw no difference in the prevalence of positive RF reactions between sera from the first and third trimesters.

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

Occurrence of two germline-related rheumatoid factor idiotypes in rheumatoid arthritis and in non-rheumatoid seropositive individuals.

Human rheumatoid factor (RF) paraproteins express two distinct light chain cross-reactive idiotypes defined by the monoclonal antibodies 17.109 and 6B6.6. These germline gene-related cross-reactive idiotypes are both carried on VK3 light chains and are each present on about one-third of IgM RF paraproteins. We assessed the degree to which these idiotypes are represented in polyclonal RFs. We used rheumatoid arthritis (RA) and non-RA RF-positive sera selected from a large cross-sectional population study (the Mini-Finland Health Survey), and sera from a community-based follow-up study of recent-onset RA patients from Heinola, Finland. In the Mini-Finland Health Survey, elevated levels of the 17.109 RF idiotype were seen in sera of 13% of the RA and 19% of the non-RA group; 6B6.6 RF was seen in 26% of the RA and 28% of the non-RA group. In sera of the Heinola follow-up study, 17.109 RF was seen in 12% initially, but in only 3% at 8 years. Similarly, 6B6.6 RF was detected in 25% initially, but in only 7% at 8 years. Ten sera positive for RF prior to the onset of clinical RA were identified from individuals of a second large population study from Finland (North Karelia project); two of these sera exhibited the 6B6.6 idiotype; none exhibited the 17.109 idiotype. The data are consistent with the concept that these germline gene-related cross-reactive RF idiotypes occur frequently in the polyclonal RF of non-RA as well as RA sera, and that in RA the idiotypes may sometimes be reduced or lost as a consequence of somatic diversification of the RF through somatic mutation, usage of new germline genes, or both.

Arthritis, Rheumatoid↗
PubMed1990

Smoking, lung function, and rheumatoid factors.

Positive rheumatoid factor (RF) reactions commonly precede the onset of clinically manifest rheumatoid arthritis (RA). Thus if items associated with RF reactions were traced at the community level this might provide clues to the cause of RA. The relations between smoking and lung functions and the occurrence of RA and RFs in a population sample representative of the adult Finnish population were studied. Rheumatoid factor testing was performed for 7124 subjects (89% of the sample) by the sensitised sheep cell agglutination test. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were measured with spirometry. 'False positive' RF reactions occurred twice as often in current smokers and ex-smokers than in those who had never smoked. The prevalence of high titres was fourfold greater among current smokers than among those who had never smoked. These associations were statistically significant and independent of age, FVC, and FEV1 in both sexes. The women with airflow limitation (FEV1/FVC less than 70%) had a significantly increased occurrence of RFs which was independent of their smoking history, but no such relationship was found in men. The results suggest an impact of smoking on RF production; a follow up study may show whether the raised RF titers in smokers will be reflected as an increased incidence of RA.

Adult↗
PubMed1990

Antibodies to synthetic peptides from Epstein-Barr nuclear antigen-1 in sera of patients with early rheumatoid arthritis and in preillness sera.

We studied IgG antibody levels to synthetic peptides (p62, E11 and E3) from Epstein-Barr nuclear antigen-1 (EBNA-1) protein sequence in sera of patients with rheumatoid arthritis (RA), in pre-RA and in rheumatoid factor (RF) positive non-RA sera from Finland. Anti-E11 and anti-E3 antibody levels were significantly elevated in RA sera, compared with both RF negative and RF positive nonrheumatoid controls. The concentrations of anti-E11 and anti-E3 antibodies in the preillness sera were lower than those in RA sera. Eight-year followup samples of patients with RA had slightly decreased levels of anti-E3 and anti-E11 antibodies compared with samples taken within 6 months of the disease onset. Anti-p62 antibody levels did not differ significantly between any of the groups studied. Thus, elevated levels of antibodies to 2 of the glycine containing EBNA-1 peptides were associated with clinical RA.

Adult↗
PubMed1989

Clinical arthritis associated with positive radiological and serological findings in Finnish adults.

The Mini-Finland Health Survey was designed to analyse the epidemiology of major public health problems. The study covered a representative sample of the Finnish population aged 30 years or over, and initially comprised 8,000 people. Serum rheumatoid factor was determined in 7,124 cases (89%). There were 138 cases of clinical arthritis in the series, corresponding to a prevalence of 1.9% (1.0% in males and 2.7% in females). Fifty-nine of the cases (0.8% of the population) were seropositive, and 50 cases (0.7%) had in their hand radiographs changes characteristic of rheumatoid arthritis. Twelve of the X-ray positive cases were seronegative. One-half of these proved to be seroconversion cases or rheumatoid variants typically seronegative, such as early-onset juvenile rheumatoid arthritis.

Adult↗
PubMed1989

Serologic response against cardiolipin and enterobacterial common antigen in young patients with acute myocardial infarction.

Elevation of anticardiolipin antibodies has been observed in myocardial infarction and in many infections. To elucidate this topic, paired serum specimens from 40 patients with acute myocardial infarction were tested for anticardiolipin antibodies (solid-phase enzyme immunoassay) and enterobacterial common antigen antibodies (indirect hemagglutination test). Forty-one randomly selected individuals and 30 patients with chronic coronary heart disease served as controls. All individuals were males whose maximum age was 50 years. In patients with acute myocardial infarction the levels of anticardiolipin antibodies in paired sera rose significantly in all immunoglobulin classes (18% in the IgG class, 26% in the IgA class, and 43% in the IgM class), whereas no elevations occurred in the other groups. Fifteen of the acute myocardial infarction patients also showed at least a fourfold increase in enterobacterial common antigen antibodies, as compared with only one such increase in the two other groups combined. The increases were less marked than those seen in pronounced enterobacterial infections. These two reactions were closely associated.

Adult↗