Oligoclonal bands (OCBs) represent the presence of intrathecal immunoglobulin G (IgG) as detected by isoelectric focusing and immunofixation. Cerebrospinal fluid (CSF) analysed alongside a paired serum sample gives five different immunofixation patterns. These are: type 1—the normal physiological state with no intrathecal IgG synthesis; type 2—evidence for intrathecal IgG synthesis, with CSF-restricted OCBs; type 3—evidence for intrathecal IgG synthesis, with CSF-restricted OCBs, but with additional, identical bands in the CSF and serum; type 4—absence of intrathecal IgG synthesis, but with identical OCBs in CSF and serum; and type 5—absence of intrathecal IgG synthesis, with a monoclonal band in CSF and serum. Analysis of these patterns can help to diagnose a range of neurological conditions, including multiple sclerosis. However, it is important to interpret OCB results alongside other CSF tests and their clinical context.

Background: Neurological immune related adverse events (N-irAEs) following immune checkpoint inhibitor (ICI) therapy are associated with significant morbidity and mortality. The early involvement of neurological services is therefore recommended to assist diagnosis and guide management. However, the practical experience of specialist neurology involvement is poorly understood. Methods: A multi-centre, retrospective case note review was performed in a unified healthcare setting in the United Kingdom via predetermined proforma to investigate the involvement and impact of neurology services in this setting. Results: One hundred and nine patients with N-irAE were identified with a median time from ICI treatment to symptom onset of 52 days. Neurology service models, reasons for referral and referral rates varied by centre. Overall, eighty-seven (79.8%) patients (range 52.9–100% by centre) had neurology involvement. Neurology input was associated with younger age (median 67.2 vs. 72.8 years), anatomical location (Central > Peripheral) and severity of neurotoxicity (p < 0.001, q < 0.004). Patients with neurology involvement were more likely to undergo specialist investigations: MR imaging (p = 0.041, q = 0.043), lumbar puncture (p < 0.001, q < 0.004), and neurophysiology (p = 0.005, q = 0.007) resulting in a broader range of specific N-irAE diagnoses. Steroids were appropriately prescribed, with second line treatment (Intravenous immunoglobulins/Plasma exchange) associated with neurology involvement. At lower grades (CTCAE ≤ 2), resolution rates were similar in those with or without neurology involvement. At grades 3–4, one-third of patients with neurology involvement had resolution. In a centre with a model of early neurology involvement for all possible N-irAEs the aetiology of the neurological presentation was changed in 63.7%. Conclusions: This study highlights the potential to improve diagnosis and treatment algorithms and therefore patient outcomes through development of uniform N-irAE models of care to support this area of growing clinical need.

Neurological involvement at onset in acute myeloid leucaemia (AML) is rare, with only a few isolated case reports. We present the case of a 46-year-old man with rapidly progressive polyradiculoneuropathy as the presenting feature of AML. The proposed mechanism for this is postulated to be direct intraneural infiltration, although a paraneoplastic, autoimmune-related phenomenon could be possible. Despite chemotherapeutic intervention, the patient died 1 month after initial presentation. Although rare, neurological manifestations of AML do occur and it is important to include haematological malignancies in the differential diagnosis in patients presenting with neurological symptoms.