8/13/2019 TR06-Sep-2001

1/7

COLLECTED REPORTS ON THE

Rheumatic Diseases2005SERIES 4 (REVISED)

Published by theArthritis Research Campaign (arc)

Editors:Ade O Adebajo FRCP(Glasgow)

D John Dickson MBChB FRCP(Glasgow) FRCP(London) MRCGP

These reports are produced under the direction of thearc

Education Sub-Committee.They were first published individually between 2000 and 2003and were subsequently reviewed for this volume.

8/13/2019 TR06-Sep-2001

2/7

34

RHEUMATIC DISEASES

ASSOCIATED WITH

ANTINUCLEAR ANTIBODIES

First published September 2001; reviewed April 2005

A fully revised version of this paper is scheduled for publi-cation as Topical Reviews (Series 5) No 8, February 2006.

Peter J Maddison

Consultant Rheumatologist, North West Wales NHSTrust/Professor of Joint and Muscle Disorders, Schoolof Sport, Health and Exercise Sciences, University of

Wales, Bangor

Antinuclear antibodies (ANA) are aprominent feature of autoimmune

rheumatic diseases

Detection of ANA plays an important

part in diagnosis and, to some extent,

predicting prognosis (best use of

serology described below)

Immunouorescence using HEp-2

cells is a sensitive screening test for

ANA but has low positive predictive

value for diagnosing systemic lupus

erythematosus (SLE)

When considering the diagnosis of

lupus, it is not cost-effective to proceed

to specic assays if the ANA test is

negative unless the clinical picture

dictates

If the ANA test is positive it is importantto dene the ANA prole using specic

assays

ANA relevant to autoimmune rheumatic

diseases are usually present at the time

of clinical onset, tend to persist, and

may be helpful in predicting the pattern

of disease expression

INTRODUCTION

The presence of antinuclear antibodies (ANA) is a hall-

mark of autoimmune rheumatic diseases. Since first be-

ing detected by indirect immunofluorescence (IMF),1

ANA have been the subject of intensive study to under-

stand their origin and role in pathogenesis. Laboratory

methods to detect certain of these antibodies have pro-vided the clinician with valuable tools to assist in diag-

nosis and, to some extent, prognosis in patients with

autoimmune rheumatic diseases. Serology is of particu-

lar value in situations where clinical expression of a dis-

ease such as systemic lupus erythematosus (SLE) is in-

complete when the presence of a particular ANA profile

can be diagnostic. However, ANA can be found in a var-

iety of clinical settings and their occurrence does not

necessarily indicate the presence of disease at all. There-

fore it is imperative that ANA tests are planned and the

results are interpreted in the light of the clinical findings.

Conversely, to be of most use to the clinician the serology

laboratory should have the facility to detect a wide range

of relevant antibody specificities.

ANA are a diverse group of antibodies, often directed

to large cellular complexes containing protein and nu-

cleic acid components. The most frequently occurring

ANA react with components of deoxyribonucleic acid

(DNA)-protein or ribonucleic acid (RNA)-protein com-

plexes.2,3A large number of studies indicate that the pro-

duction of these autoantibodies, which are generally high-

titre, high-affinity immunoglobulin G (IgG) antibodies,

is T-cell dependent and driven by the host autoantigen.4

Screening tests for ANA generally employ techniques

such as IMF using cultured cell lines expressing a wide

range of autoantigen targets. As illustrated in Table 1,

in addition to autoimmune rheumatic diseases ANA are

found in organ-specific autoimmune diseases and in

other clinical settings such as infection and lymphopro-

liferative disorders. About 15% of healthy adults and 8%

of children have detectable ANA, usually in low titre.5

Thefrequency of ANA in normal people is higher in women

and increases with age so that at least 25% of women

over the age of 60 years are positive. The frequency is

8/13/2019 TR06-Sep-2001

3/7

35

also higher in healthy first-degree relatives of patients

with autoimmune rheumatic diseases.6,7

An important observation is that ANA are directed to

very characteristic autoantigen targets in patients with

autoimmune rheumatic diseases. Furthermore, in the in-

dividual patient the ANA profile is often quite restricted.

It is now appreciated that certain autoantibody profiles

are associated with diagnostic categories of autoimmune

rheumatic diseases and sometimes with particular pat-

terns of clinical manifestations.8Therefore once ANA

have been detected with a screening test it is important

to determine their specificity. This is now part of the

standard operating procedures of serology laboratories

but the process is greatly facilitated by the clinician pro-

viding adequate clinical information when ANA testingis requested.

DETECTION OF ANTINUCLEAR

ANTIBODIES

IMF using whole cell preparations detects a wide range

of ANA specificities and is the technique used by most

serology laboratories as a primary screening test for ANA.

Human cell lines particularly HEp-2 epithelial cells, de-

rived from a human laryngeal carcinoma are now used

in preference to cryostat sections of mammalian tissuessuch as mouse or rat liver or kidney. HEp-2 cells have the

advantage that, in addition to the easy visualisation of

individual cells and their organelles, as rapidly dividing

cells they present antigens only expressed during certain

stages of the cell cycle, which are either absent or occur

only in small quantities in the resting nuclei of tissue

sections. Also, ANA in autoimmune rheumatic diseases,

such as anti-Ro antibodies, are directed primarily to the

human antigen.9Interpretation of this assay still depends

on the skill of the technician, but with the advent of com-

mercially available cell-culture substrates, easily availablepositive standards,10and the requirement for labora-

tories to participate in quality assurance schemes, the

IMF technique is generally reliable and reproducible.

Both the ANA pattern and the titre will generally be re-

ported. The pattern of immunofluorescence will give

some hints to the principal ANA specificity in the serum

and may influence the subsequent approach to deter-

mine the antibody specificity.11Although a low-titre ANA

is not necessarily clinically insignificant, higher titres

(>1:160) are more likely to indicate the presence of anautoimmune rheumatic disease.12In some instances, the

IMF ANA test gives a false negative result. This may occur

if the antigen is located outside the nucleus (e.g. anti-

Jo-1 and anti-ribosomal P, both frequently categorised

under the umbrella term ANA) or if it is present in a

form not recognised by a particular autoantibody (e.g.

when anti-Ro is directed exclusively to determinants on

the native Ro molecule not expressed in cultured HEp-2

cells). In these situations the clinical picture will dictate

that specific assays need to be undertaken.

In order to reduce technician time and expertise by in-

troducing automation, a number of commercial enzyme-

linked assays for ANA screening are now available. These

employ various principles for preparing the substrate,

including whole cell extracts and specific mixtures of

purified or recombinant autoantigens. These assays vary

considerably in their sensitivity and specificity13and they

have not yet taken over from IMF, which is still the gold

standard.

Autoantibodies binding native, double-stranded DNA

(nDNA) and/or denatured, single-stranded DNA (ssDNA)

have a central place in the immunology of lupus. It is

techniques to detect anti-nDNA antibodies, which are

most specific for SLE,14that are routinely used in the di-

agnostic laboratory. Indirect immunofluorescence using

the haemoflagellate Crithidia luciliae15is a frequently

used technique for detecting anti-nDNA, combining

high sensitivity with high disease specificity,16but is only

semi-quantitative. This microorganism contains a giant

mitochondrion which consists of pure nDNA, and it is

the fluorescence of this which constitutes a positivetest. The Farr assay is a fluid phase radioimmunoassay

in which antibodies combined to 125I-labelled DNA are

precipitated by 50% saturated ammonium sulphate.17

TABLE 1.Antinuclear antibodies (ANA) in variousdiseases detected by indirect immunofluorescence.

1. Autoimmune rheumatic disease

Drug-induced lupus 100%

Systemic lupus erythematosus 98%

Systemic sclerosis 98%

Sjgrens syndrome 80%

Pauciarticular juvenile idiopathic arthritis 70%

Polymyositis/dermatomyositis 60%

Rheumatoid arthritis 50%

2. Organ-specific autoimmunity

Primary autoimmune cholangitis 100%

Autoimmune hepatititis 70%

Myaesthenia gravis 50%

Autoimmune thyroid disease 45%

3. Other conditions

Waldenstroms macroglobulinaemia 20%

Subacute bacterial endocarditis 20%

Infectious mononucleosis 15%

Leprosy 15%

4. Normal population

Children 8%

Adults 15%

Frequency of ANACondition

8/13/2019 TR06-Sep-2001

4/7

36

Modifications of this include the use of filters or an anti-

human immunoglobulin serum. It is important that the

substrate is impeccably pure, double-stranded DNA. The

Farr assay detects high-affinity antibody and is at least as

specific as IMF using Crithidia, and titres correlate best

with disease activity. Increasingly, however, laboratories

are turning for convenience to enzyme-linked immuno-

assays (ELISA). The ELISA is more sensitive but generallyless specific than the Farr and IMF assays because it de-

tects low- as well as high-affinity antibody. Different com-

mercial ELISA assay systems are not always comparable18

and are influenced by important factors such as character-

istics of the DNA antigen, how the DNA is presented to

antibody in the serum, and the reaction conditions.

The presence of antibodies reacting with certain highly

conserved, nucleic acid-binding proteins (extractable nu-

clear antigens ENA) is a very characteristic feature of

autoimmune rheumatic diseases. The first observations

were made over 40 years ago when antibodies to what

are now called Ro and La were detected by immunodif-

fusion in the sera of patients with Sjgrens syndrome.19,20

Subsequent clinical interest in these systems results from

observations that certain profiles of these antibodies are

associated with particular patterns of disease.

Traditionally these antibodies have been detected by im-

munodiffusion using buffered saline extracts of mam-

malian tissue, such as rabbit or calf thymus extract and

human spleen extract. A range of prototype sera, avail-

able from the Centers for Disease Control and Prevention

(CDC), Atlanta, are used to detect a precipitin system.

Increasingly, more sensitive methods of antibody detec-

tion are being used, such as immunoblotting, protein

or RNA immunoprecipitation, and ELISA. The techniques

of immunoblotting and immunoprecipitation are de-

scribed elsewhere.21They tend to be too labour inten-

sive for the routine laboratory but are the principal ways

of identifying many of the myositis- and scleroderma-

associated antibodies. ELISAs using purified antigens have

been developed and provide a sensitive, quantitative wayof detecting these antibodies. Initially, immunoaffinity-

purified antigens were used, but recombinant antigens

are increasingly used as the substrate. Commercial ELISAs

vary in their performance22but generally show high sen-

sitivity but a corresponding lack of disease specificity

compared to immunodiffusion.

CLINICAL ASSOCIATIONS WITH

ANTINUCLEAR ANTIBODY PROFILES

Systemic lupus erythematosusThe use of HEp-2 cells enhances the sensitivity of the

ANA test in SLE so that ANA can be detected in 95%

of active, untreated patients. The main difference from

using rodent substrates is the increased detection of

patients with an immune response predominantly to

Ro. The identification of this patient subset can be fur-

ther enhanced by using HEp-2 cells transfected with

human 60 kD Ro antigen gene.23Thus in the situation

where the clinician wishes to exclude the possibility of

SLE, IMF is sufficient as a screening test for ANA, and it

is not cost-effective automatically to test for anti-DNAor other antibody specificities.24However, a very small

number of SLE patients are ANA-negative even using

HEp-2 cells, and proceeding with other techniques to

look for SLE-associated antibodies is indicated if the

clinical picture dictates. Conversely, since the positive

predictive value in an ANA test for SLE is low as low

as 11% in some studies25 once the ANA test is positive

it is then important to look for antibodies reacting with

DNA or nucleic acid-binding proteins.

Approximately 70% of untreated patients with active SLE

have anti-nDNA detected by IMF or the Farr technique.

In some patients, but not in all, a steady increase in anti-

DNA levels followed by a sharp drop in titre precedes a

clinical exacerbation.26Consequently there is value in

monitoring serial serum anti-DNA levels. In studies where

the relative proportion of high- and low-avidity anti-DNA

antibodies was measured, clinical exacerbation was often

heralded by an increase in high-avidity antibodies.26

In SLE, antibodies react most frequently with four groups

of RNA-binding proteins, namely Sm, U1RNP, Ro, and La.27

The antigens have been well characterised at a molecular

level.28,29High titres of these antibodies, for example as

detected by immunodiffusion, are found frequently and

almost exclusively in the context of autoimmune rheu-

matic diseases. Anti-Sm has the greatest specificity for SLE

but there is a marked ethnic variation in the presence of

these antibodies, being more commonly found in Afro-

Caribbeans than in northern European Caucasians.30These

antibodies identify distinctive serological subsets within

the spectrum of SLE. Antibodies to Sm frequently occur

in association with anti-U1RNP and antibodies to La are

virtually always accompanied by anti-Ro. It is apparent

that these serological subsets are associated with certain

patterns of disease expression (Table 2) in which they may

have a pathogenetic role. These antibodies are usually

present from the beginning of the clinical presentation and

are detectable throughout the course of the disease. Using

an ELISA, fluctuations in antibody titre can be detected,

but there is an inconsistent relationship between titres

measured in longitudinal studies and disease activity.31A

variety of other antibody specificities, for example anti-

PCNA (cyclin),32

SL (Ki),33

and ribosomal P protein,34

canbe detected in SLE. They occur in a small proportion of

sera and although clinical associations have been reported,

such as anti-ribosomal P proteins and CNS lupus, these

8/13/2019 TR06-Sep-2001

5/7

37

associations require confirmation in larger, prospectivestudies and the role of these antibodies in routine SLE

serology is not yet defined.

Sjgrens syndrome

With sensitive techniques, antibodies to Ro and La can be

detected in virtually all patients.35They are a marker for

Sjgrens syndrome developing in SLE, systemic sclerosis

and primary biliary cirrhosis. Several studies, including

that of Pease et al,36have shown that antibodies to Ro

and La identify patients at greatest risk of developing

extraglandular complications such as vasculitis.

Systemic sclerosis

Antinuclear and/or antinucleolar antibodies are an

almost universal feature of patients with systemic scler-

osis (SSc). Several of these antibodies are highly specific

for the disease, are rarely found in other clinical settings,

and occur as an early feature so that their identification

has an important role in early diagnosis.37Certain of these

antibodies can be detected in the routine serology lab-

oratory by observing a typical pattern of IMF (in the caseof anticentromere antibodies) or using immunodiffusion

or a specific ELISA (in the case of anti-topoisomerase-1).

However, many of these systems require techniques such

as immunoprecipitation for their detection and it is rec-ommended to have sera from SSc patients analysed by

a specialised reference laboratory when possible. An im-

portant observation is that there is virtually no overlap

between subsets of patients identified by a particular anti-

body profile and these subsets tend to be associated with

certain patterns of clinical expression. Thus anticentro-

mere antibodies38and antibodies to the nucleolar con-

stituent ThRNP are almost exclusively found in patients

with limited cutaneous systemic sclerosis39and identify

patients at risk of micro- and macrovascular disease. By

contrast, antibodies to topoisomerase-1, RNA polym-

erases I, II and III and to U3RNP identify clinical subsets

of SSc with severe disease involving extensive sclero-

derma and visceral organ involvement.40

Dermatomyositis and polymyositis

Multiple antibody systems are also found in polymyositis

or dermatomyositis. These include a number of myositis-

specific antibodies.41Each specificity occurs in a small

proportion of patients and is associated with a charac-

teristic pattern of clinical expression (Table 2). Antibodiesto Jo-1 (histidyl-tRNA synthetase) is the most common

specificity, occurring in approximately 20% of adult

patients with polymyositis. These patients frequently

TABLE 2.Antinuclear antibody (ANA) specificities in diagnosis and disease expression.

Disease

Systemic lupuserythematosus

Sjgrenssyndrome

Systemicsclerosis

Dermato/polymyositis

Antibody

Anti-nDNA

Anti-Sm

Anti-U1RNP

Anti-Ro

Anti-La

Anti-rRNP

Anti-Ro

Anti-La

Anticentromere

Anti-ThRNP

Anti-topoisomerase-1

Anti-RNA-polymerases

Anti-U3RNP

Anti-PM-Scl

Anti-Ku

Anti-Jo-1

(antibodies to othertRNA synthetases)

Anti-SRP

Anti-Mi2

Frequency

70%

1025%*

30%

40%

15%

15%

6090%**

3585%**

30%

4%

25%

20%

5%

5%

2%

30%

(3%)

4%

10%

Clinical association

Lupus nephritis

Vasculitis; CNS lupus

Raynauds phenomenon, swollen fingers, arthritis,myositis, MCTD

Photosensitive rash, SCLE, neonatal lupus, CHB,Sjgrenssyndrome

As for anti-Ro

CNS lupus

Extraglandular disease, vasculitis, lymphoma

As for anti-Ro

Limited cutaneous disease, micro/macrovascular disease,telangiectasia

Limited cutaneous disease

Diffuse cutaneous disease, interstitial lung disease

Diffuse cutaneous disease, renal disease

Diffuse cutaneous disease, pulmonary hypertension

Scleroderma/polymyositis overlap

Scleroderma/polymyositis overlap

Antisynthetase syndrome

(Antisynthetase syndrome)

Severe myositis

Dermatomyositis

* higher frequency in blacks and Asians ** using sensitive ELISA assays

CHB congenital heart block; CNS central nervous system; MCTD mixed connective tissue disease; SCLE subacute cutaneous lupuserythematosus

8/13/2019 TR06-Sep-2001

6/7

38

develop additional clinical features such as interstitial

lung disease, polyarthritis, Raynauds phenomenon and

mechanics fingers (the antisynthetase syndrome). Anti-

Jo-1 antibodies can be detected in the routine serology

laboratory by ELISA but other myositis-specific antibodies

require the input of a specialised reference laboratory.

ROLE OF ANTINUCLEAR ANTIBODIESIN DISEASE

The current view is that while most ANA are the result

rather than the cause of disease, certain ANA speci-

ficities may be directly involved in pathogenesis of tis-

sue injury. For example, there is evidence that subsets

of anti-DNA antibodies cause lupus nephritis. This in-

cludes observations that high titres of anti-DNA predict

exacerbations of nephritis,26the elution of anti-DNA

antibodies from affected kidneys,42and, more recently,

the demonstration that some, but not all, monoclonalanti-DNA antibodies, of both mouse and human ori-

gin, can cause renal pathology when infused into non-

autoimmune mice.43There is similar evidence44,45suggest-

ing that antibodies to Ro can also be pathogenic. The

striking association between anti-Ro and anti-La and neo-

natal lupus and congenital heartblock is particularly per-

suasive for a role of these antibodies in pathogenesis.46

To what extent tissue injury results from direct binding of

antibodies to autoantigens expressed in the target organ

or from the presence of immune complexes is still not

known. Additional mechanisms for antibody-mediated

injury may also be operating. There is some evidence,

for example, that certain autoantibodies such as anti-

DNA, anti-ribosomal P and anti-U1RNP can penetrate

living cells and influence the process of apoptosis,47,48

thereby inducing tissue damage or dysregulation of im-

mune functions.

REFERENCES1. Holborow EJ, Weir DM, Johnson GD. A serum factor in lupus ery-

thematosus with affinity for tissue nuclei. Br Med J 1957;13(5047):732-4.

2. van Venrooij WJ, Maini RN (ed). Manual of biological markers ofdisease. Section B: Autoantigens. Dordrecht: Kluwer Academic Pub-lishers; 1994.

3. von Muhlen CA, Tan EM. Autoantibodies in the diagnosis of sys-temic rheumatic diseases. Semin Arthritis Rheum 1995;24(5):323-58.

4. Reichlin M, Harley JB. Antinuclear antibodies: an overview. In:Wallace DJ, Hahn BH (ed). Dubois Lupus erythematosus. 5th edn.Baltimore: Williams & Wilkins; 1997. p.397-405.

5. Forslid J, Heigl Z, Jonsson J, Scheynius A. The prevalence of anti-nuclear antibodies in healthy young persons and adults, comparingrat liver tissue sections with HEp-2 cells as antigen substrate. Clin ExpRheumatol 1994;12(2):137-41.

6. Fielder AH, Walport MJ, Batchelor JR et al. Family study of themajor histocompatibility complex in patients with systemic lupus ery-thematosus: importance of null alleles of C4A and C4B in determiningdisease susceptibility. Br Med J (Clin Res Ed) 1983;286(6363):425-8.

7. Maddison PJ, Stephens C, Briggs D et al. Connective tissue dis-ease and autoantibodies in the kindreds of 63 patients with systemicsclerosis. Medicine (Baltimore) 1993;72(2):103-12.

8. Harley JB, Gaither KK. Autoantibodies. Rheum Dis Clin North Am1988;14(1):43-56.

9. Reichlin M, Rader M, Harley JB. Autoimmune response to theRo/SSA particle is directed to the human antigen. Clin Exp Immunol1989;76(3):373-7.

10. Feltkamp TE. Standards for ANA and anti-DNA. Clin Rheumatol1990;9(1 Suppl 1);74-8.

11. Homburger HA. Cascade testing for autoantibodies in connectivetissue diseases. Mayo Clin Proc 1995;70(2):183-4.

12. Tan EM, Feltkamp TE, Smolen JS et al. Range of antinuclear anti-bodies in healthy individuals. Arthritis Rheum 1997;40(9):1601-11.

13. Emlen W, ONeill L. Clinical significance of antinuclear antibodies:comparison of detection with immunofluorescence and enzyme-linkedimmunosorbent assays. Arthritis Rheum 1997;40(9):1612-8.

14. Aarden LA, Lakmaker F, Feltkamp TE. Immunology of DNA. I.The influence of reaction conditions on the Farr assay as used forthe detection of anti-ds DNA. J Immunol Methods 1976;10(1):27-37.

15. Aarden LA, Smeenk R. Measurements of antibodies specific forDNA. In: Lefkovits I, Pernis B (ed). Immunological methods. Vol 2.New York: Academic Press; 1981. p.75-82.

16. Smeenk R, van der Lelij G, Aarden L. Measurement of low avidityanti-dsDNA by the Crithidia luciliae test and the PEG assay. Clin ExpImmunol 1982;49(3):603-10.

17. Smeenk R, Brinkman K, van den Brink H, Swaak T. A comparisonof assays used for the detection of antibodies to DNA. Clin Rheumatol1990;9(1 Suppl 1):63-72.

18. Avina-Zubieta JA, Galindo-Rodriguez G, Kwan-Yeung L, Davis P,Russell AS. Clinical evaluation of various selected ELISA kits for thedetection of anti-DNA antibodies. Lupus 1995;4(5):370-4.

19. Jones BR. Lacrimal and salivary precipitating antibodies in Sjgrenssyndrome. Lancet 1958;2(7050):773-6.

20. Anderson JR, Gray KG, Beck JS, Kinnear WF. Precipitating autoanti-bodies in Sjgrens disease. Lancet 1961;2(7200):456-60.

21. Verheijen R, Salden M, van Venrooij WJ. Protein blotting. In: van

Venrooij WJ, Maini RN (ed). Manual of biological markers of disease.Section A: Methods of autoantibody detection. Dordrecht: KluwerAcademic Publishers; 1993. p.4.1-25.

22. Tan EM, Smolen JS, McDougal JS et al. A critical evaluation of en-zyme immunoassays for detection of antinuclear autoantibodies ofdefined specificities. I. Precision, sensitivity and specificity. ArthritisRheum 1999;42(3):455-64.

23. Fritzler MJ, Miller BJ. Detection of autoantibodies to SS-A/Ro byindirect immunofluorescence using a transfected and overexpressedhuman 60 kD Ro autoantigen in HEp-2 cells. J Clin Lab Anal 1995;9(3):218-24.

24. Clough JD, Calabrese LH, Valenzuela R. The ANA profile; qualityand cost-effective laboratory utilization [erratum in Cleve Clin J Med1989;56(5):548]. Cleve Clin J Med 1989;56(3):245-8.

25. Slater CA, Davis RB, Shmerling RH. Antinuclear antibody testing: a

study of clinical utility. Arch Intern Med 1996;156(13):1421-5.

26. ter Borg EJ, Horst G, Hummel EJ, Limburg PC, Kallenberg CG.Measurement of increases in anti-double-stranded DNA antibody levelsas a predictor of disease exacerbation in systemic lupus erythematosus:a long-term, prospective study. Arthritis Rheum 1990;33(5):634-43.

27. Reichlin M, Harley JB. Immune response to the RNA protein par-ticles in systemic lupus erythematosus: a distinctive dichotomy. Am JMed 1988;85 Suppl 6A:35-7.

28. van Venrooij WJ, Sillekens PT. Small nuclear RNA associated pro-teins: autoantigens in connective tissue diseases. Clin Exp Rheumatol1989;7(6):635-45.

29. Scofield RH, Farris AD, Horsfall AC, Harley JB. Fine specificity of theautoimmune response to the Ro/SSA and La/SSB ribonucleoproteins.

Arthritis Rheum 1999;42(2):199-209.

30. Arnett FC, Hamilton RG, Roebber MG, Harley JB, Reichlin M.Increased frequencies of Sm and nRNP autoantibodies in Americanblacks compared to whites with systemic lupus erythematosus. J Rheu-matol 1988;15(12):1773-6.

8/13/2019 TR06-Sep-2001

7/7

39

31. de Rooij DJ, Habets WJ, van de Putte LB, Hoet MH, Verbeek AL,van Venrooij WJ. Use of recombinant RNP peptides 70K and A inan ELISA for measurement of antibodies in mixed connective tissuedisease: a longitudinal follow up of 18 patients. Ann Rheum Dis 1990;49(6):391-5.

32. Asero R, Origgi L, Crespi S, Bertetti E, DAgostino P, Riboldi P.Autoantibody to proliferating cell nuclear antigen (PCNA) in SLE: aclinical and serological study. Clin Exp Rheumatol 1987;5(3):241-6.

33. Sakamoto M, Takasaki Y, Yamanaka K, Kodama K, Hashimoto H,Hirose S. Purification and characterization of Ki antigen and detec-tion of anti-Ki antibody by enzyme-linked immunosorbent assay inpatients with systemic lupus erythematosus. Arthritis Rheum 1989;32(12):1554-62.

34. Elkon KB, Bonfa E, Weissbach H, Brot N. Antiribosomal antibodiesin SLE, infection, and following deliberate immunization. Adv ExpMed Biol 1994;347:81-92.

35. Harley JB, Alexander EL, Bias WB et al. Anti-Ro (SS-A) and anti-La(SS-B) in patients with Sjgrens syndrome. Arthritis Rheum 1986;29(2):196-206.

36. Pease CT, Charles PJ, Shattles W, Markwick J, Maini RN. Serologicaland immunogenetic markers of extraglandular primary Sjgrens syn-drome. Br J Rheumatol 1993;32(7):574-7.

37. Weiner ES, Hildebrandt S, Senecal JL et al. Prognostic significanceof anticentromere antibodies and anti-topoisomerase I antibodies inRaynauds disease: a prospective study. Arthritis Rheum 1991;34(1):

68-77.38. Steen VD, Powell DL, Medsger TA Jr. Clinical correlations andprognosis based on serum autoantibodies in patients with systemicsclerosis. Arthritis Rheum 1988;31(2):196-203.

39. Falkner D, Wilson J, Medsger TA Jr, Morel PA. HLA and clinicalassociations in systemic sclerosis patients with anti-Th/To antibodies.

Arthritis Rheum 1998;41(1):74-80.

40. Bunn CC, Denton CP, Shi-Wen X, Knight C, Black CM. Anti-RNApolymerases and other autoantibody specificities in systemic scler-osis. Br J Rheumatol 1998;37(1):15-20.

41. Targoff IN. Polymyositis and dermatomyositis in adults. In: MaddisonPJ, Isenberg DA, Woo P, Glass DN (ed). Oxford Textbook of Rheuma-tology. 2nd edn. Oxford: Oxford University Press; 1998. p.1249-87.

42. Winfield JB, Faiferman I, Koffler D. Avidity of anti-DNA antibodiesin serum and IgG glomerular eluates from patients with systemiclupus erythematosus: association of high avidity antinative DNA anti-body with glomerulonephritis. J Clin Invest 1977;59(1):90-6.

43. Ehrenstein MR, Katz DR, Griffiths MH et al. Human IgG anti-DNAantibodies deposit in kidneys and induce proteinuria in SCID mice.Kidney Int 1995;48(3):705-11.

44. Maddison PJ, Reichlin M. Deposition of antibodies to a solublecytoplasmic antigen in the kidneys of patients with systemic lupuserythematosus. Arthritis Rheum 1979;22(8):858-63.

45. Lee LA, Gaither KK, Coulter SN, Norris DA, Harley JB. Patternof cutaneous immunoglobulin G deposition in subacute cutaneouslupus erythematosus is reproduced by infusing purified anti-Ro (SSA)autoantibodies into human skin-grafted mice. J Clin Invest 1989;83(5):1556-62.

46. Kitridou RC. The neonatal lupus syndrome. In: Wallace DJ, HahnBH (ed). Dubois Lupus erythematosus. 5th edn. Baltimore: Williams& Wilkins; 1997. p.1023-35.

47. Reichlin M. Presence of ribosomal P protein on the surface of humanumbilical vein endothelial cells. J Rheumatol 1996;23(7):1123-5.

48. Alarcon-Segovia D, Llorente L, Ruiz-Arguelles A. The penetration ofautoantibodies into cells may induce tolerance to self by apoptosis ofautoreactive lymphocytes and cause autoimmune disease by dysregu-lation and/or cell damage. J Autoimmun 1996;9(2):295-300.