RT Book, Section
A1 Ali, Asra
A1 Bangert, Carolyn A.
A2 Ali, Asra
SR Print(0)
ID 1176116927
T1 Rheumatologic Diseases
T2 McGraw-Hill Education Specialty Board Review Dermatology: A Pictorial Review, 3e
YR 2015
FD 2015
PB McGraw-Hill Education
PP New York, NY
SN 9780071793230
LK dermatology.mhmedical.com/content.aspx?aid=1176116927
RD 2024/04/24
AB Group  of  systemic  autoimmune  diseasesScreeningAntinuclear  antibody  (ANA):  performed  using  indirect  immunofluorescence  (IF)Varying  concentrations  of  patient  serum  are  incubated  with  a  tissue  substrate  (usually  human  epithelial  tumor  line  HEp-2),  and  any  autoantibodies  to  nuclear  antigens  present  in  the  serum  bind  to  the  substrateA  fluoresceinated  antibody  is  added,  and  the  tissue  is  observed  under  fluorescent  microscopy  to  check  for  a  specific  staining  patternResults  reported  asTiter:  level  of  antinuclear  antibodies  significant  enough  to  be  defined  as  a  positive  ANA.  The  standard  definition  is  the  titer  exceeding  that  found  in  95%  of  normal  individuals  (5%  of  normal  individuals  can  be  ANA-positive,  with  titers  usually  ≥1:320  and  a  speckled  or  homogeneous  pattern)Pattern:  corresponds  to  the  presence  of  a  specific  antibody.  A  certain  pattern  may  indicate  the  presence  of  various  rheumatologic  diseasesA  positive  ANA  is  seen  inSystemic  lupus  erythematosus  (SLE):  99%Systemic  sclerosis  (SSc)  patients:  97%Dermatomyositis  (DM)  patients:  40  to  80%ANA  patterns  and  their  corresponding  antibodiesHomogeneous  pattern  (Fig.  22-1):  complete  nuclear  fluorescence;  specific  for  SLE–  Double-stranded  DNA  (dsDNA)  or  native  DNA:  70%  SLE,  associated  with  lupus  nephritis–  Histone:  50  to  70%  SLE;  also  the  antibody  found  in  drug-induced  SLE  (but  not  in  drug-induced  subacute  cutaneous  lupus  erythematosus)Rim  pattern:  fluorescence  at  edges  of  nucleus,  anti-DNA,  antihistone  and  antilaminin  antibodies:  SLE  (most  specific)  but  also  may  be  seen  in  chronic  active  hepatitisSpeckled  pattern  (Fig.  22-2):–  SS-A/Ro:  30  to  40%  SLE;  often  with  subacute  cutaneous  lupus  erythematosus  (SCLE),  drug-induced  SCLE,  and  neonatal  LE;  also  seen  in  Sjögren  syndrome  (SS),  DM–  SS-B/La:  15%  SLE  often  with  SCLE,  drug-induced  SCLE,  neonatal  LE–  Antiribonucleoprotein  (RNP):  30%  SLE;  associated  with  mixed  connective  tissue  disease  (MCTD)–  Anti-Smith  (Sm):  20  to  30%  SLE;  very  specificExtractable  nuclear  antigens  (ENAs)Soluble  cytoplasmic  and  nuclear  components  that  are  bound  by  autoantibodiesAntibodies  include  Ro,  La,  Sm,  RNP,  Scl-70,  and  Jo-1ENA-4  test–  Identifies  Ro,  La,  RNP,  and  Sm–  Used  to  diagnose  SLE,  MCTD,  and  SSNucleolar  pattern  (homogeneous,  speckled,  or  clumpy  staining  of  nucleolus)–  RNA  polymerase  I  (RNA  pol  1):  4  to  23%  SSc–  U3-RNP/fibrillarin:  SSc–  Topoisomerase  I  (Scl-70):  22  to  40%  of  SSc,  associated  with  diffuse  SSc–  PM-Scl:  SSc-polymyositis  overlapCentromere  pattern  (antibodies  to  kinetochore  proteins)–  Approximately  22  to  36%  of  SSc  patients–  Approximately  60  to  90%  of  limited  SSc  patients  (e.g.,  CREST  syndrome  [calcinosis,  Raynaud  phenomenon,  esophageal  dysmotility,  sclerodactyly,  telangiectasia])