Serum B cell activating factor (BAFF) as a biomarker for induction of remission with rituximab in ANCA-associated vasculitis

Figures & data

Table 1. Baseline characteristics.

	Remission-achieved group (n = 20)	Non-achieved group (n = 7)	p-value
Age (years)	71.9 ± 9.1	64.7 ± 16.9	.17
Male/female (n)	3/17	2/5	.58
MPA/GPA (n)	6/14	3/4	.65
Disease duration (months)	35.7 ± 44.8	54.1 ± 64.6	.50
Induction after relapse (n)	10/20	3/7	1.00
Relapse times (times)	1.7 ± 1.1	3.3 ± 3.2	.17
RTX induction
Four/two once-weekly (n)	13/7	3/4	.39
PSL (mg/day)
Before RTX induction	29.3 ± 9.4	31.1 ± 19.1	.73
6 months after RTX	9.4 ± 3.1	13.1 ± 4.1	.06
CRP (mg/dl)
Before RTX induction	1.5 ± 3.1	1.7 ± 2.1	.90
6 months after RTX	0.3 ± 0.5	0.7 ± 1.3	.28
ANCA (U/mL)
Before RTX induction	43.5 ± 67.2	81.2 ± 105.1	.40
6 months after RTX	1.0 ± 1.5	6.0 ± 2.5	.09
Blood CD19-positive B cell count (/μl)
Before RTX induction	162.7 ± 253.3 (n = 17)	140.1 ± 127.2 (n = 4)	.80
6 months after RTX	0.8 ± 1.0 (n = 13)	0.6 ± 1.1 (n = 5)	.76

MPA, microscopic polyangiitis; GPA, granulomatosis with polyangiitis; PSL, prednisolone; RTX, rituximab; CRP, C-reactive protein; ANCA, antineutrophil cytoplasmic antibody.

Table 2. Frequency of affected organs in each group.

	Remission-achieved group (n = 20)	Non-achieved group (n = 7)	p-value
Skin involvement, n (%)	0 (0%)	0 (0%)	1.00
Ear, nose, and throat involvement	12 (60%)	4 (57%)	1.00
Interstitial lung disease	5 (25%)	3 (43%)	.63
Renal involvement	6 (30%)	5 (71%)	.08
Nervous system involvement	6 (30%)	4 (57%)	.36
Peripheral neuropathy	4 (20%)	2 (29%)	.63

Table 3. Frequency of previous treatments in each group.

	Remission-achieved group (n = 20)	Non-achieved group (n = 7)
Corticosteroid
Prednisolone (n)	19	7
Methylprednisolone
Per os	1	0
Intravenous	14	6
Cyclophosphamide
Per os	3	2
Intravenous	8	2
Immunosuppressive drug
Azathioprine	9	2
Tacrolimus	1	0
Cyclosporin A	2	2
Methotrexate	1	1
Mizoribine	1	1
Biological therapy
Infliximab	2	1

Figure 1. Change in BAFF levels over the 6-month study period. Remission-achieved group (●), non-achieved group (■). The mean values of BAFF in the remission-achieved group increased uniformly over the period before, 1 month after, and 6 months after RTX induction; however, the mean values of BAFF in the non-achieved group were all within the normal range. BAFF, B cell activating factor; RTX, rituximab.

Figure 2. Change in APRIL levels over the 6-month study period. Remission-achieved group (●), non-achieved group (■). There was no statistically significant difference in serum APRIL levels between the two groups before, 1 month after, or 6 months after RTX induction. APRIL, A proliferation-inducing ligand; RTX, rituximab.