CD27+IgD+B cells are less
competent in producing IgM in SLE
To examine CD27+IgD+B cells’
functional changes, their ability to produce IgM was assessed in SLE
patients. CD27+IgD+B cells isolated
from active SLE cases
(SLEDAI>5) and HCs
underwent ELISPOT and qRT-PCR. As depicted in Figure 3A, ELISPOT
revealed significantly reduced IgM-producing ability for
CD27+IgD+B cells in SLE, which was
confirmed by decreased IgM mRNA levels as examined by qRT-PCR (Figure
3B). Jointly, the above data indicated that
CD27+IgD+B cells had impaired
function regarding IgM production in SLE.
CD27+IgD+B cells are recovered in SLE cases with treatment-related disease
remission
To ascertain CD27+IgD+ B cells’
usefulness as a biomarker of disease activity, whether they are restored
following effective treatment was assessed. Totally 12 patients
previously diagnosed with SLE were assessed during relapse and 4 weeks
post-treatment initiation. As
expected, treatment markedly decreased disease activity based on the
SLEDAI (Table 2). In addition, anti-dsDNA and 24h urinary protein
amounts were reduced, with serum C3 and C4 level normalization to a
certain degree. Total leukocyte and platelet levels were heightened
post-treatment.
Next,
CD27+IgD+B cell amounts were
assessed pre-treatment and at 4 weeks post-treatment initiation (Figure
4A). As measured by the SLEDAI, all cases had a significant reduction in
disease activity after treatment (Figure 4B); meanwhile,
CD27+IgD+B cell amounts were
remarkably elevated (Figure 4C). Jointly, the above findings suggested
that CD27+IgD+ B cell amount
impairment in SLE patients could be alleviated by effective treatment.