Abstract: The Prevalence Of Anti-Neutrophil Cytoplasmic Antibodies In
A Variety Of Connective Tissue Diseases.
Authors: Merkel,Niles,Siates,Convey,Polisson
Mass.General Hospital,Boston,MA.
Source: American College Of Rheumatology
Sept.1995-Vol38, #9
Purpose: To determine the prevalence of anti-neutrophil cytoplasmic
antibodies (ANCA) in patients with connective tissue diseases CTD).
Methods: ANCA were measured by indirect immunofluorescence(IF) for
perinuclear(P-ANCA) and cyctoplasmic(C-ANCA) patterns and antigen-
specific ELISA for myeloperoxidase(MPO) and proteinase 3(PR3) in the
baseline serum samples of patients in a cSSRD 5-yr.inception-cohort,
prospective study of early rheumatic diseases: RA(N=70), SLE(70),
scleroderma(PSS,45), myositis(PM/DM ,36) and early undifferentiated
connective tissue disease (EUCTD,165). Diagnosis was based on
standardized criteria and determined at the last study visit. A nested
group of patients with Sjogren's syndrome(SJ,44) was also
defined.Serum from 200 blood donors(BB)served as controls.Laboratory
personnel were blinded to sample diagnostic group.
Results: If and ELISA results are shown in the table. Of the 28
patients with P-ANCA,24(86%) were ANA+. None of the ELISA+ patients
had renal vasculitis in follow-up. If the study patients are performed
to not have vasculitis,the combined specificity in these CTD patients
is 92.7% for P-ANCA, 100% for C-ANCA, 99.5% for anti-MPO ELISA, and
98.2% for anti-PR3 ELISA.
Conclusions: In patients with CTD,who are known to develop multiple
autoantibodies, antigen-specific ANCA positivity is very rare. C-ANCA
IF is highly specific. However, P-ANCA IF, where ANAs may result in a
positive text, is much less specific .For patients with CTD, ANCA IF
should always be accompanied by antigen-specific ELISA testing.
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