Evaluation of the Euroimmun immunoblot for detecting of antibodies recognizing extract nuclear antigens (ENA)

Evaluation of the Euroimmun immunoblot for detecting of antibodies recognizing extract nuclear antigens (ENA)

Vol. 16, No. 7/8,1996 116 CLINICAL IMMUNOLOGY Newsletter gorithm thesesampleswould be testedfurther only if specifically requested by a physician. Ba...

146KB Sizes 2 Downloads 63 Views

Vol. 16, No. 7/8,1996

116 CLINICAL IMMUNOLOGY Newsletter gorithm thesesampleswould be testedfurther only if specifically requested by a physician. Basedon our comparisonof ANA titers

with dsDNA reactivity we proposedthat specimenswith a homogeneouspattern and a titer of 1:160 or greaterbe testedfor antidsDNA antibodies. By comparing ANA and ENA results, we determinedthat ENA testing is appropriate for specimenswith a speckledtiter of 1:80 or greaterand sampleswhich showeda homogeneousor a nucleolar titer of 1:160 or greater.Our data also suggestedENA testing for all sampleswhich exhibited a mixed staining pattern. According to this strategy, the number of samples testedfor antibodies to dsDNA and ENA would be reducedby approximately 40% while eliminating fewer than 5% of dsDNA or ENA positive samplesfrom testing. Conclusion: Thesedata suggestthat utilizing a reflexive testing strategyfor autoantibody testing at UNC Hospitals would reduce significantly the volume of dsDNA and ENA testing, therebyproviding a more efficient and economical use of laboratory resources while maintaining the quality of patient care. EVALUATION OF THE EUROIMMUN IMMUNOBLOT FOR DETECTION OF ANTIBODIES RECOGNIZING EXTRACTABLE NUCLEAR ANTIGENS (ENA)

H. Prince, Y. Pamintuan, S. Vogeli, W. Hogrefe MRL Reference Laboratory, Cypress, CA Objective: To assessthe performanceof the Euroimmun ENA Profile Plus immunoblot for the simultaneousdetection of antibodies recognizing individual ENAs. Methods: 60 serapositive by ENAS ELISA (Inova) and 3 sera positive by Jo-l ELISA (Inova) were testedin the immunoblot assayand 5 individual ENA ELISAs (SSA, SSB,RNP/Sm, Sm, and Scl-70, all from Inova). 10 of the ENAS serawere also tested in the Jo-l ELISA. Serawith discrepantimmunoblot versus ELISA results were resolved by immunodiffusion (Inova). 15 ENAS serawere testedin the immunoblot assayonly. Results: All 15 ENA serashowed no immunoblot reactivity (100% specificity). Immunoblot results for the 63 reactive (ENAs and/or Jo-l(+)) seraare shown below.

RNP/Sm,and Jo-l. The sensitivity of the blot for detecting Scl-70 antibody also appearsacceptable.In contrast, the immunoblot in its current format shows low sensitivity for Sm antibody detection. UNRECOGNIZED ALPHA-l-ANTITRYPSIN m LIVER DONORS

CARRIAGE

W. Oliveira, E. Stacy, D. Normansell, S. Caldwell, M. Ishitoni, R. Dickson, W. Stevenson,M. Gaffey, J. Iezzoni, C. Mccullough, M. Sue,C. Driscoll, T. Pruett Pathology, Internal Medicine, Surgery, University of Virginia Medical Center, Charlottesville, VA Objective: Carriage of an abnormal alpha-1-antitrypsin (AlA) phenotypemay potentiate progression of chronic liver disease. Normal adults have the MM phenotype (PI). Carriage of an abnormal allele is often silent and hencemay go unrecognizedin donor organs.The prevalenceof carriage (2 or S alleles) is estimatedto be 10% in personsof Europeandescent(J Clin Invest 1986;78:1427).We have observeda prevalenceof 15% carriage [or abnormal alleles (Z, S, or F) in patients attending our liver clinICS(unpublished). We prospectively phenotyped AlA liver donor ;erum to determine the prevalenceof abnormal Al A types in dolor livers. Methods: 53 patients undergoing 57 liver transplantationswere studied.Serumwas stored at -70°C until assayed.PI type was determinedby isoelectric focusing performed on Ampholine plates :Pharmacia)at pH 4-5. 15~1of cystiene-reducedserum was applied to a prefocusedgel and focused for 3 hours at constant power(original settings 3OW, 14OOV.50mA). Results: 14 of 46 (30%) recipients had abnormal PI types: 8 were MS, 2 were MZ, 1 was MF, 1 was SS and 1 was ZZ. Among the lonor organs, 14 of 55 (26%) had abnormal PI types: 8 were MS, 3 were MZ and 1 was ZZ. The latter patient expressedabnormally low serum Al A post-operatively. He died six months post trans$ant from lymphoma. Conclusions: Abnormal AlA phenotype is fairly common in our liver recipients with various liver diseasesand in otherwise ieallhy appearingdonor livers. Long-term follow up of recipients If carrier organs will be necessaryto assessthe clinical signiti:ance of theseobservations. I-ECHNICAL ASPECTS RELATED TO IDENTIFYING LYME DISEASE SPECIFIC BANDS IN IMMUNOBLOT

M.F. Collins, W.Y. Craig, T.B. Ledue Foundation for Blood Research, Scarborough, ME

Further analysis of the 3 false negative serashowedthat the Scl70 false negative was nonreactive in another vendor’s Scl-70 ELISA (Elias USA); this finding suggeststhat the discrepancy may in fact reflect a false positive result using Inova Scl-70 antigen. Conclusion: The Euroimmun ENA immunoblot showsexcellent sensitivity and specificity for detecting antibodies to SSA, SSB, 0197-1859/96/50.00 + 15.00

Objective: Recent recommendationsby the CDClASTPHLD committee have specilied ten protein bandsas diagnostic for Lyme disease(LD). Whereaspositional identification of thesebandsis ideally accomplishedwith monoclonal antibodies (Mab), only four of the bandshave antibodies available. This situation leavesindividual laboratoriesto deal with lhe proper identification of the remaining six. Numerous technical parametersaffecting the separationand detection of theseproteins complicate their correct identification. The objective of the presentstudy was to optimize

0 1996 Elsevier Science Inc.