Abstract: Background: B-cell differentiation and B-cell tolerance checkpoints may be different
in antiphospholipid syndrome (APS) from systemic lupus erythematosus (SLE) and can help to
understand differences between them. Our aim was to define alterations of B-cell subsets in patients
with primary APS (pAPS) and to compare them with SLE patients and healthy controls (HC).
Methods: Cross-sectional study including three study groups: 37 patients with pAPS, 11 SLE
patients, and 21 age- and gender-matched HC. We determined the frequencies of different B-cell
subsets in peripheral blood naïve and memory compartments. In addition, we measured serum
B cell-activating factor (BAFF) levels and circulating pro-inflammatory cytokines, such as IL-6,
by commercial ELISA and CBA, respectively. Results: Patients with pAPS showed a lower percentage
of immature and naïve B cells than patients with SLE (p = 0.013 and p = 0.010, respectively) and a
higher percentage of non-switched memory B cells than patients with SLE (p = 0.001). No differences
either in the percentage of switched memory cells or plasma cells were found among the different
groups. Serum BAFF levels were higher in SLE patients than in healthy controls and pAPS patients
(p = 0.001 and p = 0.017, respectively). A significant increase in the serum BAFF levels was also
observed in pAPS patients compared to HC (p = 0.047). Circulating IL-6 levels were higher in
SLE and pAPS patients than HC (p = 0.036 and p = 0.048, respectively). A positive correlation
was found between serum BAFF and IL-6 levels in patients with SLE but not in pAPS (p = 0.011).
Conclusions: Our characterization of peripheral blood B-cell phenotypes in pAPS demonstrates
different frequencies of circulating B cells at different stages of differentiation. These differences in
the naïve B-cell repertoire could explain the higher number and variety of autoantibodies in SLE
patients in comparison to pAPS patients, especially in those with obstetric complications.
Fuente: International Journal of Molecular Sciences Volume 19, Issue 2, 16 February 2018, Article number 589
Publisher: MDPI
Publication date: 01/02/2018
No. of pages: 11
Publication type: Article
DOI: 10.3390/ijms19020589
ISSN: 1661-6596,1422-0067
Publication Url: https://doi.org/10.3390/ijms19020589