Significance of nuclear immunofluorescent patterns

Prevalence of antinuclear antibodies among healthy blood donors: An experience of a regional blood transfusion center

Objectives:

Antinuclear antibodies (ANAs) are antibodies directed against one or more molecules within the nucleus. Although ANA is present in patients suffering from connective tissue diseases, few reports reveal the presence of ANA in a healthy population. The present study aimed to identify the prevalence of ANA in healthy blood donors.

Materials and Method:

Blood samples from 370 healthy blood donors were included in the present study. To detect serum ANA, an indirect immunofluorescence technique was used using HEp-2000 slides. A titer of 1:80 was used and the type of pattern (if positive) cases were also noticed.

Results:

Out of 370 healthy donors, there were 187 males and 183 females (M: F = 1.02:1). ANA was detected in four out of 370 samples (1.081%). All the positive donors were female (100%). Among all the positive cases, three cases showed a speckled pattern and one showed a homogenous pattern at 1:80 dilution.

Conclusion:

In conclusion, there is a low prevalence of ANA positivity among healthy individuals. Although, along with clinical signs and symptoms, ANA is diagnostic of autoimmune disease, the mere presence of ANA is not synonymous with the presence of clinically significant autoimmune disease.

Recent Approaches To Optimize Laboratory Assessment of Antinuclear Antibodies

The presence of antinuclear antibodies (ANAs) is a hallmark of a number of systemic autoimmune rheumatic diseases, and testing is usually performed as part of the initial diagnostic workup when suspicion of an underlying autoimmune disorder is high. The indirect immunofluorescence antibody (IFA) technique is the preferred method for detecting ANAs, as it demonstrates binding to specific intracellular structures within the cells, resulting in a number of staining patterns that are usually categorized based on the cellular components recognized and the degree of binding, as reflected by the fluorescence intensity or titer. As a screening tool, the ANA patterns can guide confirmatory testing useful in elucidating a specific clinical diagnosis or prognosis. However, routine use of ANA IFA testing as a global screening test is hampered by its labor-intensiveness, subjectivity, and limited diagnostic specificity, among other factors. This review focuses on current efforts to standardize the nomenclature of ANA patterns and on alternative methods for ANA determination, as well as on recent advances in image-based computer algorithms to automate IFA testing in clinical laboratories.

The rarity of Felty's syndrome in blacks

Evidence is presented that Felty's syndrome (FS) is rare among black patients with rheumatoid arthritis (RA). All of 12 patients with FS seen at Parkland Memorial Hospital, Dallas, Texas betwen 1964 and 1978 were white. During this period 52% of patients admitted to the Parkland medical service were black and 31% of patients dischargd with a diagnosis of RA were black. The number of expected black cases of FS on the basis of the racial distribution of hospitalized patients with RA was 3.7 (P is less than 0.02 when the zero incidence in blacks was compared with the expected incidence). All 7 cases of FS observed at Charity Hospital, New Orleans, Louisiana between 1968 and 1978 were also white. During this period, 65% of patients discharged with a diagnosis of RA were black, and the number of expected black cases of FS was 4.5 (P is less than 0.001). These findings suggest a genetic basis for the development of leukopenia and splenomegaly in RA patients.

Relation of titred peripheral pattern ANA to anti-DNA and disease activity in systemic lupus erythematosus

This study compared the clinical usefulness of the peripheral pattern detected in immunofluorescent antinuclear antibody (ANA) testing with anti-DNA measured by the modified Farr technique. 48 patients with active or inactive systemic lupus erythematosus (SLE) were studied at one point in the course of their disease. There was no association between titres of serum giving a peripheral ANA pattern (tp-ANA) and anti-DNA values. Tp-ANA did not correlate with activity of SLE. In contrast with this finding, anti-DNA correlated with severity of renal disease, decreased serum complement, and number of SLE criteria. In a separate group of 9 patients with flare-ups of SLE, tp-ANA and anti-DNA fell as disease activity was controlled. Nevertheless, these two parameters were independent of one another. It was concluded that tp-ANA did not accurately reflect anti-DNA or activity of SLE.

Antinuclear antibodies (ANA): immunologic and clinical significance

The methods currently used for the detection of ANA have been analyzed, with emphasis on their practical application to the diagnosis of the CTD. The use of the indirect IF-ANA test was recommended as a screening procedure to detect ANA. The need to standardize the technique using a single substrate and fluorescent conjugates with uniform F/P ratios was stressed. Most importantly, the value of titrating ANA for the diagnosis of the CTD was discussed. ANA titers higher than 1/500 are usually very significant clinically, often found in spontaneous or drug-induced SLE and few other CTD. The immunologic aspects of ANA and their potential value as aids in the diagnosis and management of the CTD were discussed. Anti-nDNA antibodies have been found to have a high degree of specificity for SLE and high titers of these antibodies correlate well with low levels of serum complement and severity of kidney involvement. The spectrum of ANA in the sera from patients with SLE has been expanded with the finding of anti-Sm antibodies which, when detected by gel precipitation with prototype serum, have been found so far only in SLE. Some of these antibodies have been found to have prognostic significance. Patients with MCTD and a group of patients with SLE have high titers of serum ANA with specificity for an RNase-sensitive component of ENA. The group of SLE patients defined by the presence of these antibodies (anti-Mo) have a better prognosis and in general develop only mild nephritis or have no kidney involvement at all. High titers of pure antinucleolar antibodies probably are found almost exclusively in the sera of patients with scleroderma. Some ANA have organ specificity, and GS-ANA have been found in all patients with Felty's syndrome and in a large proportion of patients with RA. One of the great advances in the field has been the recognition that ANA can be induced in the human and in experimental animals by the use of a number of therapeutic agents. Some of these agents can also induce a clinical picture resembling spontaneous SLE, though kidney involvement does not occur or is extremely mild. It is interesting that the whole spectrum of ANA can be found in drug-induced LE except anti-nDNA antibodies which have been associated to the pathogenesis of immune complex nephritis in spontaneous SLE. There is no doubt that research on ANA has contributed a great deal to the understanding of the CTD and will continue to be a valuable tool for the clinician and the investigator.

Combined titre and fluorescent pattern of IgG antinuclear antibodies using cultured cell monolayers in evaluating connective tissue diseases

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Complement-fixing ability of antinuclear factors. Studies in adult and juvenile rheumatoid arthritis and systemic lupus erythematosus

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