3.3 Associations of serum concentration of CXCL13 in different
disease activities in SLE patients, LN/non-LN patients, active/inactive
LN patients, and high-avidity/low-avidity IgG ANAs
In our cohort of 97 SLE patients, a total of 20 patients (20.6%, 20/97)
were diagnosed with no/mild disease activity SLE (0≤SLEDAI≤9), 44
patients (45.4%, 44/97) were diagnosed with moderate disease activity
SLE (10≤SLEDAI≤14), and 33 patients (34.0%, 33/97) were diagnosed with
severe disease activity SLE (SLEDAI≥15). A total of 54 patients (55.7%,
54/97) were diagnosed with LN, and 73 (75.3%, 73/97) patents were
diagnosed with high-avidity IgG ANAs of SLE. Significantly higher serum
CXCL13 levels were observed in SLE patients with severe disease activity
[1023.077 (648.565-1768.138) pg/ml] among the no/mild disease
activity [212.523 (30.229-297.550) pg/ml] and moderate disease
activity SLE [341.845 (222.341-514.179) pg/ml] groups
(p <0.001). (Figure 2a). We also found that the serum
CXCL13 levels were significantly higher in the LN group [609.746
(338.472-1101.573) pg/ml] and active LN group [683.145
(399.065-1205.628) pg/ml] than in the non-LN group [279.310
(115.381-482.276) pg/ml] and inactive LN group [251.475
(125.930-315.340) pg/ml] (p <0.001) (Figure 2b, c). As
in our previous study, we divided the SLE patients into a high-avidity
IgG ANA group (RAI%≥40%) and a low-avidity IgG ANA group
(RAI%<40%) according our detection assay. We found that the
serum CXCL13 level was significantly higher in the high-avidity IgG ANA
group [590.915 (280.092-1045.527) pg/ml] than in the low-avidity IgG
ANA group [266.978 (117.615-408.526) pg/ml]
(p <0.001) (Figure 2d).
3.4 Correlation analysis of the serum levels of CXCL13
with the SLEDAI, the RAI (relative avidity index) of HA IgG ANAs, the
serum levels of anti-dsDNA, the ESR, and the C3 and C4 complements in
SLE patients
In SLE patients, there was a correlation among the level of CXCL13,
disease activities and laboratory results. The results showed that the
concentration of CXCL13 was positively correlated with the SLEDAI score
and RAI of HA IgG ANAs (r=0.7547, p <0.0001; r=0.5590,p <0.0001) (Figure 3a, b). The concentration of CXCL13
was positively related to the serum level of anti-dsDNA and ESR
(r=0.4860, p <0.0001; r=0.3082, p =0.0021) (Figure
3c, d). Furthermore, the concentration of CXCL13 was negatively related
and significantly decreased with serum C3 and C4 levels (r=-0.4605,p <0.0001; r=-0.5165, p <0.0001) (Figure
3e, f).