Anti-phospholipid antibodies in systemic autoimmune diseases: a study among a sub-Saharan population

Résumé

Introduction: Anti phospholipids antibodies (aPL) can be
circulating during connectivitis without clinical
manifestations. Their prevalence in the general caucasian
population is low but can reach 55% in lupus and 57.5% in
systemic scleroderma. In sub-Saharan Africa, the
prevalence of these antibodies during systemic diseases is
unknown. Earlier studies conducted have mainly focused
on their clinical détails linked to a connectivitis.
Objective: To determine the frequency of aPL and their
morbidities when associated with systemic autoimmune
diseases among a Sub-Saharan population.
Patients and methods: We conducted a cross-sectional
multicenter study with prospective recruitment in Le
Dantec Hospital Internal Medicine and Dermatology
departments and also dermatology department of the Social
Hygiene Institute of Dakar. All patients with a systemic
autoimmune disease and who agreed to the informed
consent form were included. Test Samples for aPL
detection were conducted in the Hematology laboratory of
Le Dantec Hospital. A 12-week interval control sample was
performed for each patient who presented a positivity for
one or more antibodies. The diagnosis of antiphospholipid
syndrome (APS) was based on the Sydney classification
criteria. Socio-demographic, clinical and paraclinical data
were collected. Statistical analysis was performed using
Epi-info 7.2 software. A p-value (less than) ≤ 0.05 was
statistically significant.
Results: Sixty patients with systemic autoimmune diseases
were enrolled including 54 women (sex ratio=0.11). The
mean age was 41.15 years. The aPL frequency was 60%
(n=36) at the first blood test while the control test was
positive at 33.3% (n=10). Lupus anticoagulant (LA) was
positive in 35 patients corresponding to 58.3% and
anticardiolipin (ACL) antibodies in 2 patients representing
3.3%. No β2-glycoprotein antibodies (aβ2-GP1) were
detected. Five cases of APS were identified representing
8,4% of the sample. Five patients who didn’t meet the
diagnosis criteria of APS (Sydney) were persistently aPL
positive. Obstetric complications predominated with a
statistical significance p=0.04. Cutaneous and digital
ulcerations were not significantly correlated with APL
(p=0.34 p=0.17). Headaches were observed in 78% of Apl
positive cases without any statistical significance
(p=0.298). A similar result was observed for Raynaud’s
phenomenon (p=0.306).
Conclusion: aPL are frequently positive during
connectivitis but often transient. LA is the most common
antibody and SLE is the main cause.
Key words: connectivitis - antiphospholipid antibodies -
antiphospholipid syndrome - sub-saharan africa.