Supplementary Table 1. Results from high throughput sequencing analysis of the immunoglobulin heavy chain variable (IGHV) genes in TG2-specific or non-TG2 specific IgA plasma cells (PCs). The cells were sorted from cell preparations of individual small intestinal biopsies of two untreated celiac disease patients.

Patient, biopsy number and
specificity of sorted PCs / Number of PCs / Number of unique clones established by IGHV sequencing
CD1191
Non TG2-specific PCs
Biopsy 1 / 1200 / 419
Biopsy 2 / 2000 / 681
Biopsy 3 / 2000 / 720
Biopsy 4 / 2000 / 804
Biopsy 5 / 2000 / 582
TG2-specific PCs
Biopsy 1 / 127 / 26
Biopsy 2 / 187 / 67
Biopsy 3 / 360 / 33
Biopsy 4 / 260 / 91
Biopsy 5 / 240 / 69
CD1192
Non TG2-specific PCs
Biopsy 1 / 2000 / 914
Biopsy 2 / 2000 / 784
Biopsy 3 / 2000 / 784
Biopsy 4 / 2000 / 675
Biopsy 5 / 2000 / 910
TG2-specific PCs
Biopsy 1 / 264 / 45
Biopsy 2 / 330 / 80
Biopsy 3 / 273 / 95
Biopsy 4 / 209 / 40
Biopsy 5 / 200 / 73

Supplementary Table 2. Primer sequences. In bold, partial read R1 (for J_back) and R2 (for VH1-6) adapters. The remaining parts of Illumina MiSeq adapters on R1 and R2 are shown in Italic black. Six random nucleotides (i.e. NNNNNN) are shown underlined, followed by a specific index that is composed of 6 known nucleotides. Gene specific nucleotides are shown in regular black font.

PCR / Name / Sequence (5´-3´)
1st / VH1-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)CTGGGTGCGACAGGCCCCTGGACAA
1st / VH2-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)TGGATCCGTCAGCCCCCAGGGAAGG
1st / VH3-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)GGTCCGCCAGGCTCCAGGGAA
1st / VH4-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)TGGATCCGCCAGCCCCCAGGGAAGG
1st / VH5-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)GGGTGCGCCAGATGCCCGGGAAAGG
1st / VH6-FR2 / GGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNN(Index)TGGATCAGGCAGTCCCCATCGAGAG
1st / J_Back / ACACTCTTTCCCTACACGACGCTCTTCCGATCTNNNNNN(Index)CTTACCTGAGGAGACGGTGACC
2nd / R1 / AATGATACGGCGACCACCGAGATCTACACTCTTTCCCTACACGACGCTCTTCCGATC