Development of Immunocapture-LC/MS Assay for Simultaneous ADA Isotyping and Semiquantitation

Table 3

LC/MS peak area ratio responses and calculated ADA isotope/subclass levels in PEA positive human plasma with drug as ADA capture reagent (numbers in bold italic are above respective cut-points).

Lot #	IgG1	IgG1 conc. (µg/mL)	IgG2	IgG3	IG4	IgE	IgM	IgA1 + IgA2
1	0.0874	—	0.0033	0.0476	0.0096	—	0.0499	0.0441
2	0.0838	—	0.0452	0.0762	0.0070	—	0.0421	0.0422
3	0.4200	0.660	0.0061	0.0263	0.0088	—	0.0111	0.0847
4	0.1970	—	0.0047	—	0.0020	0.0113	0.0068	0.0497
5	0.0239	—	0.0044	0.0119	0.0020	—	0.0007	0.0480
6	0.0827	—	0.0141	0.0205	0.0192	0.0054	0.0316	0.0771
7	0.0188	—	0.0041	—	—	—	0.0127	0.0239
8	0.0150	—	0.0109	0.0315	0.0017	0.0119	0.0027	0.0712
9	0.0788	—	0.0009	—	0.0009	0.0150	0.0099	0.0727
10	0.0641	—	0.0076	0.0192	—	0.0155	0.0314	0.0424
11	0.4330	0.680	0.0041	0.0303	0.0031	—	0.1010	0.0652
Cut point (95%)	0.0507	—	0.0224	0.0416	0.0265	0.0183	0.0854	0.0160

—: below the limit of quantitation for IgG1 concentration or no peak was detected for other isotypes/subclasses.