OBJECTIVE:Autoantibodies to lens epithelium-derived growth factor (LEDGF) depict a distinctive nuclear dense fine speckled (DFS) pattern in the indirect immunofluorescence antinuclear antibody assay (IIF-ANA). Definition of the clinical spectrum associated with anti-LEDGF antibodies has been evolving over the last decade. We investigated the frequency, clinical spectrum, and immunologic specificity of the DFS pattern in a general clinical laboratory routine. METHODS. All serum samples entered for IIF-ANA determination within a 2 year period were examined for the DFS pattern. Positive samples with consistent clinical information were studied further by IIF with isotype-specific conjugate and immunoblot analysis.RESULTS:Among 13,641 ANA-positive samples, 5081 (37%) presented the DFS pattern. Within a 6 month nested period, there were 650 samples with DFS pattern, and consistent clinical data were available for 81 of these. DFS reactivity was mainly due to IgG. Most samples (86%) presented titer > or = 1/640. Eighty of the 81 DFS samples reacted with a 75 kDa band that comigrated with the band elicited by the standard anti-LEDGF serum. Antibodies that were affinity-purified from the 75 kDa band reproduced the DFS pattern on IIF-ANA. The clinical spectrum associated with DFS reactivity included autoimmune diseases (39%) and an array of nonautoimmune conditions (61%). Among the autoimmune patients, over half presented evidence of autoimmune thyroiditis.CONCLUSION:Anti-LEDGF/p75 antibodies are a common finding among ANA-positive individuals with no evidence of rheumatic autoimmune disease, and should be regarded as a low specificity finding even when in moderate or high titer.

The objective of the present study was to investigate the prevalence, clinical characteristics, and HLA associations of C2 deficiency in the Brazilian population. The frequency of C2 deficiency profile (C2Q° profile) was 2.2% among 1503 blood donors and 6.6% among 166 patients with systemic lupus erythematosus (SLE). A higher incidence of clinical manifestations possibly related to immune complex disease was observed among blood donors with C2Q° profile and their relatives with C2Q° profile when compared to the normal C2 relatives. The comparison of clinical and laboratory features between SLE patients with C2Q° profile and those with normal C2 revealed earlier disease onset, higher frequency of oral ulcerations and lower frequency of anti-native DNA antibodies in the first group. The HLA study conducted on 18 individuals with C2Q° profile (11 blood donors and 7 SLE patients) confirmed the previously reported association with the antigens HLA-A25, B18 and DR2, supporting the concept that probably most C2 deficiency cases, throughout the world, are due to a single mutation in the C2 gene in linkage disequilibrium with the A25B 18DR2 haplotype.

In order to evaluate the pattern of ANA testing solicitation, 506 patients with ANA testing requested from July 1st. 1988 to December 31st, 1988, had their charts reviewed. These patients, randomly selected, were regularly attending the outpatient clinic at the "Escola Paulista de Medicina" (EPM). 289 patients were followed up at the Rheumatology Division (group A) and 217 patients at other clinical divisions at EPM (group B). The diseases that most frequently motivated the request for ANA test were: group A--SLE (22.5%), RA (18.0%), undefined arthropathies (6.2%), PSS and CREST (5.9%) and Raynaud phenomena (5.5%); and group B--rheumatic diseases (24.4%), nephropathies (17.1%), neuropathies (16.6%), dermopathies (7.8%), hemopathies (4.6%), pneumopathies (4.2%) and ophthalmopathies (3.7%). The positivity of ANA test in groups A and B was 32.9% and 17.5% respectively. 94 SLE patients were clinically diagnosed. The positivity of ANA and anti-dsDNA tests in this group was respectively 85.1% and 26.6%. The sensitivity and specificity of 1982 ARA revised criteria were 94.7% and 99% respectively. The likelihood ratio (LR) of a positive or a negative test was established for this population. LR of a positive test was 6.5 while for a negative test it was 0.17. The ANA test, although lacking specificity, has been commonly requested by different specialties in order to practically rule-out the diagnosis of some connective rheumatic diseases. Immunofluorescence technique (IF) using antibodies conjugated with fluorochromes. was first described by Coons et al. in 1941. This method has been used as an important diagnostic tool in routine laboratory tests ever since.(ABSTRACT TRUNCATED AT 250 WORDS)

1. This study describes a simple radial immunohemolysis method for determining the hemolytic activity of the second component of complement (C2) in human serum. The assay is based on the recovery of hemolytic activity of normal serum which has been pretreated to inactivate endogenous C2 and then mixed with test serum containing an unknown amount of C2. 2. The pretreated serum, designated R2 reagent, is obtained by heating normal human sera under carefully standardized conditions of temperature, time, volume and type of test tube. 3. R2 reagent is incorporated into agarose together with hemolysin-sensitized erythrocytes, and spread on a plate. The test serum is placed in wells cut in the agarose and, after appropriate incubation, the diameters of the hemolytic areas are measured. The area of hemolysis is directly proportional to the logarithm of the serum concentration. As a standard for C2 functional activity, dilutions of a pool of normal sera are tested on the same plate. 4. The method is specific for C2 and can detect as little as 20% of the C2 in normal serum (about 6 micrograms C2 protein/ml). The error in reproducibility is about 3% of the mean. In normal serum, the lower confidence limit of the distribution of the C2 values (based on a sample of 80 individuals) corresponded to 70% of undiluted serum. 5. This method is suitable for use in clinical laboratories since it is simple, rapid, quantitative and inexpensive, and does not require special equipment.

Cultures of human peripheral blood lymphocytes were maintained for 21 days in the presence of subthreshold concentration of PHA. The identification of T and B human lymphocytes by membrane markers showed that at day 21 of culture, the cell population surviving is constituted predominantly of T lymphocytes.