Biological and pathological features according to anti-MAG antibody titre
| Findings, n (%) | Anti-MAG titre ≥10 000 BTU (n=180) | Anti-MAG titre <10 000 BTU (n=22) |
| Mean low anti-MAG titre (BTU) | – | 4544(1000-9600, SD 2966) |
| Mean median (≥10 000 to <70 000 BTU) anti-MAG titre (BTU) (n=104) | 34 752(10 000–69 107, SD 17 244) | – |
| Anti-MAG titre≥70 000 BTU | n=76 | – |
| Anti-SGPG antibodies>1 UA/mL (ELISA Bühlmann) | 37/37 | 5/7 |
| Anti-ganglioside antibodies | 23/115 (20) | 6/18 (33.3) |
| IgM anti-GM1-GM2-GD1b-GQ1b-GM4-GM3 | 6-3-2-0-2-1 | 4-1-0-1-0-0 |
| IgM directed against two or more gangliosides | 9 | 0 |
| Albuminocytologic dissociation on CSF analysis | 68/86 (79.1) | 7/11 (63.6) |
| Mean CSF protein (mg/dL) | 85 (25–270) | 75 (41–200) |
| MGUS during disease course | 120 (66.7) | 17 (77.3) |
| Waldenström’s macroglobulinemia during disease course | 54 (30) | 5 (22.7) |
| Monoclonal gammopathy associated to other malignant haematological diseases during disease course* | 6 (3) | 0 |
| Monoclonal light chain kappa | 154 (85.6) | 18 (81.8) |
| Reasons for nerve biopsy | 13 (7.2) | 6 (27.2) |
| Unusual clinical presentation or course | 7/13 (53.8) | 1/6 (16.7) |
| Low anti-MAG titre | 0 | 6/6 (100) |
| EDX suggestive of axonal neuropathy | 4/13 (30.8) | 1/6 (16.7) |
| Neuropathological findings | ||
| Suggestive of demyelinating neuropathy | 12/13 (92.3) | 5/6 (83.3) |
| Suggestive of IgM anti-MAG demyelinating neuropathy | 6/13 (46.2) | 3/6 (50) |
| Endoneurial IgM deposits | 4/6 | 3/4 |
| Widening of the myelin lamellae (electron microscopy) | 3/6 | 1/3 |
*Chronic lymphocytic leukaemia (two), B-cell lymphoma (three), myelodysplastic syndrome.
BTU, Bühlmann Titre Units; CSF, cerebrospinal fluid; EDX, electrodiagnostic; MAG, myelin-associated glycoprotein; MGUS, monoclonal gammopathy of undetermined significance; SGPG, Sulfated Glucuronyl Paragloboside.