[Low prevalence of anti-centromere antibodies in scleroderma in Morocco (about 272 cases)]

assessment of autoantibodies prevalence during scleroderma within a Moroccan population by a retrospective survey.

272 patient (220 cases of systemic sclerosis, 45 cases localised scleroderma and 7 cases of mixed connective tissue disease (MCTD)) underwent a screening for antinuclear antibodies (ANA) by indirect immunofluorescence (IFI) on Hep-2 cells, followed, in 127 cases, by anti-extractable nuclear antigen (ENA) antibodies identification using a double immunodiffusion (IDD) method.

sixty eight for percent of patients presenting with a systemic sclerosis had positive ANA whose identification revealed: 23 cases (15.3%) of anti-topoisomerase I, 8 cases (5.3%) of anti-centromere (ACA) and 5 cases (3.3%) of anti-U1-RNP antibodies. Out of the 8 cases of ACA, 3 corresponded to a CREST syndrome. Anti-topoisomerase I antibodies were observed in 2 of the 4 patients having an interstitial pulmonary syndrome. Anti-U1-RNP antibodies were present in 3/38 patients (7.8%) having a systemic sclerosis associated to arthritis. 4/45 patients (9%), presenting with a localised scleroderma, had positive ANA, of which 2 were ACA. All patients admitted for MCTD had anti-U1-RNP antibodies, coexisting with anti-Sm antibody in 2 cases.

the low prevalence of ACA observed in this survey, when compared to American, European and Japanese studies, is probably due to ethnic variation in frequency of ANA. Indeed, low rates or absence of ACA have been reported in south-African, Afro-American, Indian, and Thai studies. The IDD, method of reference for detecting of anti-ENA antibodies, identify a small fraction of anti-nucleolar aspects of scleroderma. Thus, other methods such as ELISA and/or immunoblotting are required to complete their identification.