Clinical significance of C4d deposition in renal tissues from patients with primary Sjögren’s syndrome—a preliminary study

Table 3 Comparison between the C4d-positive and C4d-negative groups

Items	TI-C4d⁺ (n = 16)	TI-C4d⁻ (n = 23)	P
Age (years, M ± SD)	41 ± 12.6	42 ± 15.4	NS
SS duration (years, M ± SD)	9.9 ± 9.17	8.4 ± 9.91	NS
Renal duration (years, IQR)	4.0 [2.0, 9.3]	0.9 [0.1, 2.0]	0.001
ANA positive	16/16	21/23	NS
ANA 1:1280	5/16	3/23	NS
Anti-SSA (+)	13/16	21/23	NS
Anti-SSB (+)	6/16	7/23	NS
Serum IgG elevation	11/15	14/23	NS
Serum IgA elevation	8/15	6/23	NS
Serum IgM elevation	3/15	1/23	NS
Hypocomplementemia Low CH50	2/16	1/22	NS
Low C3	4/16	2/22	NS
Low C4	3/15	3/20	NS
CRP elevation	3/13	0/19	0.058
Scr (μmol/L, IQR)	132.5 [89.7, 165.5]	83.0 [70.7, 102.0]	0.008
eGFR (mL/min.1.73 m2, M ± SD)	58.7 ± 27.31	78.3 ± 24.65	0.025
24-h urine collection (g/day, M ± SD)	1.9 ± 2.09	2.5 ± 4.48	NS
Glomerular sclerosis (%, IQR)	19.1 [0, 49.6]	4.2 [1.9, 6.3]	0.051
Interstitial fibrosis (M ± SD)	2.3 ± 1.29	1.4 ± 1.04	0.035

Tubular atrophy and interstitial fibrosis were scored according to the percentage of interstitial area involved: 0 (absent), 1 (≤25%), 2 (25–50%), 3 (50–75%), and 4 (> 75%)
NS not significant, TI-C4d tubulointerstitial C4d, SS Sjögren’s syndrome, ANA anti-nuclear antibodies, CRP C reactive protein, Scr serum creatinine, eGFR estimated glomerular filtration rate (calculated with CKD-EPI creatinine equation), M ± SD mean ± standard deviation, IQR interquartile range

ISSN: 1471-2369