Page 162 - Livre électronique du congrès national de pneumologie 2017

XXII è me Congrès National de Pneumologie. Tunis 14-16 Décembre 2017

P48

PREVALENCE AND PATTERNS OF ANCA IN PATIENTS WITH
RESPIRATORY DISEASES

N. GHRAIRI , N. AJMI, S. YALAOUI

LABORATOIRE DE BIOLOGIE MEDICALE, ABDERRAHMANE MAMI HOSPITAL,ARIANA,TUNISIA (TUNISIA)

Background : Anti- neutrophil cytoplasmic antibodies (ANCA) are important tools in
the diagnosis of systemic vasculitis, usually more requested in multidisciplinary
medical centers with departments of internal medicine, kidney diseases,
gastrointestinal diseases and rheumatology. So we aimed to determine their
prevalence and specificity in samples sent to the laboratory of immunology of a
respiratory diseases hospital.

Methods : Over of 4 years period(2013-2016) , we analyzed the blood samples of 570
Tunisian patients [sex ratio: 0.76 mean age 48.3 years (3-85 yrs)] for ANCA detection
by indirect immunofluorescence (IIF) on ethanol fixed neutrophils. Positive samples
were further tested for 7 antigenic specificities (PR3, MPO, LF, BPI, elastase, lysozyme
and cathepsine G) by Enzyme linked immunosorbent assay (ELISA).

Results : Only Nineteen (19) patients were ANCA positive (3.3%). Mean age of these
ANCA positive patients was 53.2 years (19-84 yrs) comparatively to 47.9 years of
negative patients. Requests for ANCA detection were justified by different clinical
situations e.g: persistent severe asthma, interstitial lung disease, bronchiectasis ,
diffuse alveolar haemorrhage. ANCA positivity was equally distributed between males
and females (sex ratio :0.9). ANCA patterns were equally perinuclear (P-ANCA) and
cytoplasmic (c-ANCA). MPO (31 .5 %) and PR3 ( 26 %) were the main antigenic targets
and were essentially found among patients suffering a granulomatosis with polyangiitis.
BPI, another antigenic specificity was found in 21 % of the cases and was associated
with chronic lung infections with bronchiectasis.

Conclusion : We showed a prevalence of 3.3% of ANCA positivity which is in line with
the fact that ANCA associated systemic vasculitis is a rare condition. We found that
ANCA directed against BPI are mostly detected in patients with chronic pulmonary
infections whilst ANCA targeting MPO and PR3 are associated with small vessel
vasculitides .

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