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L B Keil

Publications and source records attributed to L B Keil.

23 records · Page 2Linked to original sources
PubMed1987

Characteristics of antibodies adsorbed on the DNA immunoadsorbent, agarose poly-L-lysine-DNA.

Agarose-poly-L-lysine (Ag-(lys)n-DNA) has been used to bind DNA for assay of anti-DNA antibodies (ab). In this work, an algorithmic approach has been used to classify antinuclear ab (ANA) as being directed against native DNA (dsDNA), denatured DNA (ssDNA), DNA-protein complexes (deoxyribonucleoprotein; DNP), and against antigens which are independent of DNA (iDNA). These ab were subjected to Ag-(lys)n-DNA, and the selectivity of this adsorbent for the various specificities of ab was determined. The DNA on the columns was left untreated or treated with S1 nuclease, this being effected either by treating the DNA prior to introducing it onto the columns or by adding S1 nuclease to the columns after the DNA was bound. Ag-(lys)n-DNA adsorbs ab directed against ssDNA and DNP as well as ab to dsDNA; iDNA ab are not adsorbed. S1 nuclease treatment does not effectively remove ssDNA regions from the Ag-(lys)n-DNA, but it does result in the abolition of the adsorption of a population of ab which are in the anti-DNP sera and contribute to the total ANA load. While anti-iDNA ab are not adsorbed onto the columns, they do contribute to the ANA titer, unlike anti-ssDNA ab which are adsorbed onto the Ag-(lys)n-DNA but do not contribute to the ANA titer. We conclude that Ag-(lys)n-DNA bears antigenic sites for dsDNA, ssDNA, and DNP ab and suggest that our understanding of the characteristic ab-binding profile of this versatile immunoadsorbent may have applications in the study of autoimmune diseases.

Antibodies, Antinuclear↗
PubMed1984

KB cells for antinuclear antibody determination: comparison with HEp-2 cells and the Crithidia luciliae assay.

Fifty-seven sera from 53 patients were assayed simultaneously on KB and HEp-2 cells and compared with regard to pattern and titer. Additionally, KB cell fluorescent antinuclear antibody (FANA) titer and pattern in 310 sera from 194 patients were compared with regard to the presence of antinative DNA antibodies (anti-nDNA ab) as determined by the Crithidia luciliae assay. Sixty-five percent (37/57) of the sera had the same titer on both KB and HEp-2 cells; the remainder had higher titers using KB cells. Regression analysis yielded a highly significant, unbiased correlation between the substrates. Forty-four percent (25/57) of these sera gave identical patterns on both substrates, another 25 of the 57 sera (44%) gave different patterns on the two substrates and 12% (7/57) could not be compared because they were negative on HEp-2 cells. KB cells detected positive FANA in 30 of 30 (100%) diagnosed cases of systemic lupus erythematosus; HEp-2 cells detected 29/30 (97%). From the standpoint of sensitivity, these data indicate a slight advantage to the use of KB over HEp-2 cells. Seventeen percent (53/310) of the sera were positive for anti-nDNA ab. The highest percentage of these positive sera occurs at reciprocal FANA titers between 320 and 1280. No association was found between KB FANA patterns and a positive Crithidia luciliae assay.

Antibodies, Antinuclear↗
PubMedDate not supplied

The association of antibodies to beta 2 glycoprotein I with the antiphospholipid syndrome: a meta-analysis.

The precise target of marker autoantibodies in the antiphospholipid syndrome (APS) has been controversial. Recently, the theory that surface-bound beta 2 glycoprotein I (beta 2 GPI) presents a normally encrypted autoepitope and that antibodies to beta 2 GPI (anti-beta 2 GPI) are associated with APS, has been prominent. The literature has been searched from 1990 to 1995 (inclusive) to find studies in which: (1) anti-beta 2 GPI antibodies were measured and, (2) adequate clinical data describing the patients were included. These conditions were met in four studies, from August 1992 to December 1995, in which patient samples ranged from 15 to 39 cases, the total of the four studies being 90 cases. Applying the diagnostic criteria of > or = 2 clinical manifestations of APS, 65 cases had APS while 25 did not. For the group with APS, 58/65 (89 percent) were anti-beta 2 GPI (+); among those who did not meet the criteria, 11/25 (44 percent) were anti-beta 2 GPI (+) (p < 0.0001). The presence of either the primary (1 degree) or secondary (2 degrees) form of APS made no difference in association with anti-beta 2 GPI; 13/16 (81 percent) patients with 1 degree APS and 45/49 (92 percent) with 2 degrees APS had anti-beta 2 GPI. The presence of lupus anticoagulant (LAC) did not predict APS: 25/58 (38 percent) APS (+) cases were LAC (+); 11 APS (-) were all LC (+) (p < 0.0001). IgG anticardiolipin also showed a closer association with APS absence (25/25 cases; 100 percent) than with APS presence (40/65; 62 percent, p < 0.0001). These data support the contention that anti-beta 2 GPI antibodies are closely associated with APS and that their measurement may facilitate the diagnosis.

Antibodies↗
PubMedDate not supplied

Phospholipid-independent binding of beta 2glycoprotein I by IgA from patients with antiphospholipid syndrome.

beta 2glycoprotein I (beta 2GPI) is a phospholipid-binding protein of the coagulation system. In patients with the antiphospholipid syndrome (APS), antibodies to beta 2GPI contribute to the population of "antiphospholipid antibodies" measured in the anticardiolipin antibody (aCL) assay. In fact, both IgG and IgM antibodies from patients with APS bind beta 2GPI in the absence of anionic phospholipids if the antigen is bound to a suitable surface, i.e., one which exposes the epitope. The binding of IgA was studied from patients with APS, using an enzyme-linked immunosorbent assay (ELISA), and significantly higher binding of IgA was observed from 39 patients compared to a control group of 50 healthy individuals (p < 0.0001). Moreover, 15 out of 39 APS subjects (38 percent) exhibited binding greater than 5 standard deviations (SD) above the mean of the control group. All 39 APS patients had elevated IgG anti-beta 2GPI; however, depletion of IgG from two APS sera diminished, rather than enhanced, binding of IgA. Pre-incubation with purified IgG from a subject with APS led to inhibition of IgA binding at inhibitor levels > 125 micrograms IgG/well. These data demonstrate that patients with APS have IgA anti-beta 2GPI autoantibodies and that the epitope(s) which are recognized by these antibodies can be presented in the absence of cardiolipin or other anionic phospholipids.

Antiphospholipid Syndrome↗