| 5’-NT | 5′-nucleotidases |
| ADA | Adenosine deaminase |
| ADEM | Acute disseminated encephalomyelitis |
| AHSCT | Autologous haematopoietic stem cell transplantation |
| AML | Acute myelogenous leukaemia; acute myeloid leukaemia |
| AOSD | Adult-onset Still’s disease |
| ASCT | Allogeneic stem cell transplantation |
| BMT | Bone marrow transplantation |
| CIS | Clinically isolated syndrome |
| CMV | Cytomegalovirus |
| CNS | Central nervous system |
| CSF | Cerebrospinal fluid |
| CTL | Cytotoxic T lymphocytes |
| DCK | Deoxycytidine kinase |
| DHODH | Dihydroorotate dehydrogenase |
| DMF | Dimethyl fumarate |
| DMT | Disease-modifying therapy |
| DRESS | Drug reaction with eosinophilia and systemic symptoms |
| EBV | Epstein-Barr virus |
| ECG | Electrocardiogram |
| EDSS | Expanded Disability Status Scale |
| EID | Extended interval dosing |
| EMA | European Medicines Agency |
| EP | Evoked potential |
| FBC | Full blood count |
| FDA | Federal Drug Administration |
| GCN | Granule cell neuronopathy |
| Gd-enhancing | Gadolinium-enhancing |
| GnRH | Gonadotropin-releasing hormone |
| HCP | Healthcare professional |
| HIV | Human immunodeficiency virus |
| HLA | Human leukocyte antigen |
| HLH | Haemophagocytic lymphohistiocytosis |
| HPV | Human papillomavirus |
| HSCT | Haematopoietic stem cell transplantation |
| Ig | Immunoglobulin |
| IgA | Immunoglobulin A |
| IgG | Immunoglobulin G |
| IgM | Immunoglobulin M |
| IM | Intramuscular |
| IRIS | Immune reconstitution inflammatory syndrome |
| IRT | Immune reconstitution therapy |
| ITP | Immune thrombocytopenic purpura |
| IVF | In vitro fertilisation |
| ivi | Intravenous infusion |
| JCV | JC virus |
| LFT | Liver function test |
| LVEF | Left ventricular ejection fraction |
| MCS | Microscopy, culture and sensitivity (urine test) |
| MEDA | Minimal evidence of disease activity |
| MET | Maintenance/escalation therapy |
| MMF | Monomethyl fumarate |
| MMR | Measles/mumps/rubella |
| MRI | Magnetic resonance imaging |
| MUGA | Multigated acquisition (scan) |
| NAbs | Neutralising antibodies |
| NEDA | No evident disease activity |
| NEIDA | No evident inflammatory disease activity |
| NFL | Neurofilament light |
| NHS | National Health Service |
| NK | Natural killer |
| NMO | Neuromyelitis optica |
| OCB | Oligoclonal bands |
| OCT | Optic coherence tomography |
| PALS | Patient Advice and Liaison Service |
| PCP | Pneumocystis pneumonia |
| PCR | Polymerase chain reaction |
| PIRA | Progression independent of relapses |
| PML | Progressive multifocal leukoencephalopathy |
| PPMS | Primary progressive MS |
| PRES | Posterior reversible encephalopathy syndrome |
| PRMS | Progressive relapsing MS |
| PROMS | Patient-related outcome measures |
| RES | Rapidly evolving severe MS |
| RIS | Radiologically isolated syndrome |
| RRMS | Relapsing–remitting MS |
| RSPMS | Relapsing secondary progressive MS |
| S1P | Sphingosine 1-phosphate |
| SAP | Single-attack progressive MS |
| SC | Subcutaneous |
| SIR | Standardised incidence rate |
| SLE | Systemic lupus erythematosus |
| SmPC | Summary of product characteristics |
| SPMS | Secondary progressive MS |
| TB | Tuberculosis |
| TB ELISpot | Tuberculosis enzyme-linked immune absorbent spot |
| TBI | Total body irradiation |
| TFT | Thyroid function test |
| TLI | Total lymphoid irradiation |
| TTP | Thrombotic thrombocytopenic purpura |
| U&E | Urea and electrolytes |
| VZV | Varicella zoster virus |
| WHO | World Health Organization |
