Table 1 Correlation between infliximab (IFX), anti-IFX antibodies (antibodies towards IFX, ATI) determined by SPR and ELISA in the serum of patients treated with IFX (trough levels, just before the next infusion) and clinical characteristics of the patient population during the study period.

From: A Surface Plasmon Resonance-based assay to measure serum concentrations of therapeutic antibodies and anti-drug antibodies

PT ID

Centre

Diagnosis

Months of IFX therapy

Dose regimen at sampling

Disease activity

Concomitant thiopurines

IFX (μg/mL undiluted serum)

ATI (μg Eq/mL undiluted serum)§

SPR

ELISA

SPR

ELISA

#1

ICH

CD

29

2 = 5 mg/kg E4W

Remission

No

4.76 ± 0.03

3.89–4.55

<LLOQ

<LLOQ

#2

ICH

CD

21

5 mg/kg E8W

Moderate

No

7.70 ± 0.13

6.92–7.86

<LLOQ

<LLOQ

#3

ICH

CD

29

5 mg/kg E8W

Remission

No

3.03 ± 0.03

3.57–3.22

<LLOQ

<LLOQ

#4

ICH

UC

97

5 mg/kg E8W

Remission

No

2.31 ± 0.01

2.57–2.74

<LLOQ

<LLOQ

#5

ICH

CD

46

5 mg/kg E8W

Remission

No

2.63 ± 0.02

2.76-2.77

<LLOQ

<LLOQ

#6

ICH

CD

30

5 mg/kg E8W

Mild

No

<LLOQ

<LLOQ

37.57 ± 0.21

3.9-4.0*

#7

ICH

CD

22

5 mg/kg E8W

Remission

No

<LLOQ

<LLOQ

<LLOQ

0.04–0.07

#8

ICH

UC

7

5 mg/kg E8W

Remission

Yes

<LLOQ

<LLOQ

6.64 ± 0.14

over

#9

ICH

CD

30

5 mg/kg E8W

Remission

No

7.48 ± 0.02

6.61–7.90

<LLOQ

<LLOQ

#10

ICH

UC

3

5 mg/kg E8W

Remission

No

<LLOQ

<LLOQ

5.67 ± 0.10

0.57–0.63*

#11

ICH

CD

7

5 mg/kg E8W

Remission

No

1.39 ± 0.05

1.52–1.69

2.54 ± 0.04

<LLOQ

#12

FI

CD

4

5 mg/kg E8W

Mild

Yes

4.62 ± 0.10

4.84–5.32

<LLOQ

<LLOQ

#13

FI

CD

4

5 mg/kg E8W

Remission

No

4.09 ± 0.03

4.13–4.32

<LLOQ

<LLOQ

#14

FI

CD

5

5 mg/kg E8W

Remission

No

4.11 ± 0.04

3.98–4.35

<LLOQ

<LLOQ

#15

FI

UC

7

5 mg/kg E8W

Remission

No

<LLOQ

<LLOQ

3.60 ± 0.34

0.08-0.09

  1. For SPR data, each value is the mean ± SD of three independent replications; the single values of the two replications are shown for ELISA. §ATI are expressed as μg Equivalents/mL, to highlight that the ATI used for the calibration curves are different from those produced by the patients. ICH: Humanitas Research Hospital (Rozzano, Milan, Italy); FI: Careggi University Hospital (Florence, Italy) Lower limits of quantifications (LLOQ) for SPR analysis were 0.2 μg/mL for IFX and 2.5 μg Eq/mL for ATI. LLOQ for ELISA was set at the lowest point of the calibration curve: 0.5 μg/mL for IFX and 0.025 μg Eq/mL for ATI. *Extrapolated, since the highest point of the calibration curve was 0.2 μg Eq/mL for ATI. “Over” indicates a value not measurable in the spectrophotometer.
Back to article page