Table 2. Autoantibody Characteristics of Patients With SPS, Epilepsy, and T1DM.
| Patient No. | Diagnosis | GAD Autoantibody Titer, U/mL | IHC | GAD Autoantibody KD, nmol | WB rhGAD65, IOD % | IgG Binding, Scorea | ||
|---|---|---|---|---|---|---|---|---|
| EGFP-Expressing Neurons | GABA-Expressing Neurons | EGFP/GABA-Negative Neurons | ||||||
| 1 | C-SPS | 700 000 | Positive | 0.13 | 95.3 | 3 | 4 | 1 |
| 2 | C-SPS | 180 000 | Positive | 0.54 | ND | 2 | 4 | 0 |
| 3 | C-SPS | 75 000 | Positive | 0.13 | ND | 1 | 3 | 0 |
| 4 | C-SPS | 50 000 | Positive | 0.33 | 80.2 | 2 | 2 | 0 |
| 5 | C-SPS | 34 000 | Positive | 0.43 | 56.7 | 1 | 0 | 0 |
| 6 | C-SPS | 21 324 | Positive | 0.13 | 80.5 | 2 | 2 | 0 |
| 7 | C-SPS | 12 500 | Positive | 0.28 | 51.6 | 2 | 1 | 0 |
| 8 | C-SPS | 7500 | Positive | 0.33 | 38.1 | ND | ND | ND |
| 9 | C-SPS | 4800 | Positive | 0.78 | 40.4 | ND | ND | ND |
| 10 | C-SPS | 3600 | Negative | 0.33 | 13.6 | 0 | 0 | 0 |
| 11 | C-SPS | 889 | Negative | 0.06 | 3.8 | 0 | 0 | 0 |
| 12 | C-SPS | 836 | Negative | 0.14 | ND | 0 | 0 | 0 |
| 13 | SLS | 5682 | Positive | 0.17 | 59.6 | 2 | 2 | 0 |
| 14 | SLS | 676 | Negative | 0.14 | 13.4 | ND | ND | ND |
| 15 | SLS | 405 | Negative | 0.65 | 19.2 | 1 | 2 | 1 |
| 16 | SLS | <1 | Negative | ND | 0 | 0 | 0 | |
| 17 | SLS | <1 | Negative | ND | 0 | 1 | 0 | |
| 18 | J-SPS | 4200 | Negative | 0.28 | 26.8 | 0 | 0 | 0 |
| 19 | J-SPS | 1 | Negative | ND | 0 | 0 | 0 | |
| 20 | J-SPS | 4 | Negative | ND | 0 | 0 | 0 | |
| 21 | A-SPS | 80 000 | Positive | 0.74 | 88.4 | ND | ND | ND |
| 22 | A-SPS | 17 000 | Positive | 0.17 | 14.2 | ND | ND | ND |
| 23 | A-SPS | <1 | Negative | ND | 0 | 0 | 0 | |
| 24 | A-SPS | <1 | Negative | ND | 0 | 0 | 0 | |
| 25 | PERM | 5451 | Positive | 0.17 | ND | 0 | 1 | 0 |
| 30 | LADA | 285 | Negative | 0.68 | 10.3 | ND | ND | ND |
| 31 | T1DM | 72 | Negative | 0.34 | 7.3 | ND | ND | ND |
| 32 | T1DM | 72 | Negative | 0.13 | ND | ND | ND | ND |
| 33 | T1DM | 60 | Negative | 0.31 | 5.9 | ND | ND | ND |
| 34 | T1DM | 12 | Negative | 0.15 | 6.8 | ND | ND | ND |
Abbreviations: EGFP, enhanced green fluorescent protein; GABA, γ-aminobutyric acid; GAD, glutamic acid decarboxylase; IHC, immunohisto-chemistry; IOD, integrated optical densities of immunoreactive bands on Western blotting of recombinant human GAD65 (rhGAD65) expressed as a percentage of the IOD of GAD monoclonal antibody; KD, antibody dissociation constant; ND, not determined; WB, Western blot. Other abbreviations: See Table 1.
Serum antibodies binding to surface determinants of unpermeabilized primary neurons in culture were scored as 0 (none), 1 (1%-20% of total GABAergic neurons), 2 (21%-40%), 3 (41%-60%), or 4 (>60%).