Table 2.
Assays used in the AINI EQA program.
| Test | Assay | N of labs/total* | Main features |
|---|---|---|---|
| Oligoclonal IgG bands | Semi-automated systems | 15/23 | Precast agarose gels (small-medium size); manufacturer's recommended run conditions; direct immunofixation |
| In-house assembled systems | 8/23 | In-house or commercial precast agarose gels (large size); run conditions optimized in each laboratory; capillary blotting and immunofixation | |
| Intracellular neuronal antibodies | Immunohistochemistry on fixed primate brain + blot A | 6/16 | Commercial (Euroimmun) chip + line-blot (Ravo), antigens: HuD, Yo, Ri, CV2 (CRMP5), Amphiphysin, Ma1, Ma2 |
| Immunohistochemistry on fixed primate brain + blot B | 6/16 | Commercial (Euroimmun) chip + line-blot (Euroimmun), antigens: HuD, Yo, Ri, CV2 (CRMP5), Amphiphysin, Ma, PCA-2, Tr, SOX1, titin, recoverin | |
| blot A only | 4/16 | Line-blot (Ravo or Euroimmun), antigens: see above | |
| Neuronal Cell Surface antibodies | Immunohistochemistry on rat brain + in-house CBA | 2/16 | In-house obtained slices from lightly fixed rat brain + in-house fixed (Euroimmun), or live CBA designed according to the staining pattern on tissue (10, 36)# |
| In-house CBA | 1/16 | Live CBAs for specific antigens (38, 39)# | |
| Commercial CBA | 13/16 | Fixed CBA mosaic chip (Euroimmun); antigens: NMDAR, LGI1, CASPR2, AMPAR 1/2, GABABR | |
| AQP4 antibodies | In-house CBA | 2/20 | Live CBA, transfection with M23 AQP4 isoform |
| Commercial CBA | 17/20 | Fixed CBA (Euroimmun), transfection with M23 AQP4 isoform | |
| Commercial ELISA | 1/20 | RSR Limited, no information on AQP4 isoform used | |
| MOG antibodies | In-house CBA A | 3/13 | Live CBA, transfection with full-length MOG, total IgG secondary antibody, titration cut-off (1:160) (8, 9)# |
| In-house CBA B | 1/13 | Live CBA, transfection with full-length MOG, IgG1 secondary antibody (7)# | |
| In-house CBA C | 1/13 | Live CBA, transfection with full-length MOG, total IgG secondary antibody, titration cut-off 1:160 + IgG1 secondary antibody (7, 9)# | |
| In-house live CBA D | 2/13 | Like CBA A, cytofluorimetric analysis (40)# | |
| Commercial CBA | 6/13 | Live CBA, transfection with full-length MOG, total IgG secondary antibody, titration cut-off (1:10) | |
| MAG antibodies | Commercial ELISA | 10/14 | Bühlmann |
| Immunohistochemistry | 1/14 | Commercial, Immco Diagnostics | |
| Immunohistochemistry+blot | 1/14 | Commercial, not specified | |
| Commercial blot | 1/14 | Ravo | |
| Commercial blot | 1/14 | Euroimmun | |
| Antibodies to Gangliosides | In-house ELISA | 5/15 | In accordance with INCAT (41) |
| Commercial blot | 3/15 | Line blot (Euroimmun) | |
| Commercial ELISA | 4/15 | Bühlmann | |
| Commercial blot | 3/15 | Dot blot (Generic Assay) | |
| AChR antibodies | Commercial RIA | 5/8 | IBL International; RSR Limited |
| Commercial ELISA | 3/8 | RSR Limited | |
| MuSK antibodies | Commercial RIA | 4/5 | RSR Limited |
| Commercial ELISA | 1/5 | RSR Limited |
NMDAR, N-methyl-D-aspartate receptor; LGI1, leucine rich glioma inactivated 1; CASPR2, contactin-associated protein-like 2; GABABR, γ-aminobutyric acid B receptor; AMPAR, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor; AQP4, aquaporin 4; ELISA, enzyme-linked immunosorbent assay; MOG, myelin oligodendrocyte glycoprotein; MAG, myelin associated glycoprotein; INCAT, Inflammatory Neuropathy Cause and Treatment; RIA, radioimmunosorbent assay; AChR, acetylcholine receptor; MuSK, muscle specific kinase.
*
Single laboratories can use more than one test; CBA, cell-based assay; #In-house assays were performed according to published protocols, but adapted to each laboratory routine.