Incidence, Risk Factors, and Outcome of Immune-Mediated Neuropathies (IMNs) following Haploidentical Hematopoietic Stem Cell Transplantation.

Immune-mediated neuropathies (IMNs) following hematopoietic stem cell transplantation have been described recently, which, excluding Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy, may present with atypical patterns. This retrospective, nested, case-control study reviewed data from 3858 patients who received haploidentical hematopoietic stem cell transplantation (haplo-HSCT) during the past 10 years at a single center, and 40 patients (1.04%) with IMN following haplo-HSCT were identified. Chronic graft-versus-host disease (cGVHD) (P = .043) and cytomegalovirus (CMV) viremia (P = .035) were recognized as independent risk factors for the development of IMN after haplo-HSCT. There were no significant differences in overall survival (P = .619), disease-free survival (P = .609), nonrelapse mortality (P = .87), or the incidence of relapse (P = .583) between patients with and without IMN after haplo-HSCT. However, patients with post-transplant IMN were at higher risk of developing cGVHD (P = .012) than patients who did not develop IMN. Twenty-four of the 40 patients with IMN (60%) attained neurologic improvement after treatments including vitamins B1 and B12 and/or immunomodulatory agents. However, 19 (47.5%) patients still had persistent motor/sensory deficits despite receiving timely treatment. More studies are needed to help develop standardized diagnostic and therapeutic strategies for patients with post-transplant IMN.

IgPro20, the Polyneuropathy and Treatment with Hizentra® study (PATH), and the treatment of chronic inflammatory demyelinating polyradiculoneuropathy with subcutaneous IgG.

Subcutaneous IgG (SCIG) administration may be preferred over the intravenous route (IVIG) in chronic inflammatory demyelinating polyneuropathy (CIDP) because it minimizes 'end of cycle' treatment-related fluctuations, reduces systemic adverse effects, improves convenience/quality of life and potentially lowers overall costs. Early reports of the use of highly concentrated SCIG preparations suggested they were effective and well-tolerated in chronic inflammatory demyelinating polyneuropathy. This was confirmed in the Polyneuropathy and Treatment with Hizentra® study of 172 subjects randomized to receive maintenance therapy with placebo or one of two doses of IgPro20 (20% IgG stabilized with L-Proline) for 6 months. Risk of relapse was reduced by SCIG in a dose-related manner as compared with placebo. A total of 88% of polyneuropathy and treatment with hizentra subjects felt the subcutaneous method was 'easy to learn'. Local adverse events were mostly mild or moderate, and systemic adverse events were infrequent. Some patients may prefer maintenance therapy with SCIG over IVIG.

[Immunopathology and treatments of Guillain-Barré syndrome and of chronic inflammatory demyelinating polyneuropathy]. / Mécanismes immunitaires et traitements du syndrome de Guillain-Barré et des polyradiculonévrites inflammatoires chroniques.

The concepts of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) have changed over the last decade. The spectrum of GBS ranges from acute inflammatory demyelinating polyneuropathy to pure motor, sensory-motor or bulbar variants and the Miller Fisher syndrome. Also CIDP includes different variants in addition to the typical clinical picture with symmetrical proximal and distal weakness, such as a form with predominant distal weakness, a pure sensory form, an asymmetric form and a form with predominant cranial nerve involvement. Detailed immunopathologic features have been described in GBS and CIDP: most current investigations are centered on the hypothesis of molecular mimicry in GBS and together with the pathogenic role of cell-mediated immunity different antibodies have been discovered in GBS which interfere with nerve impulse conduction on neuromuscular transmission. The immunopathogenesis of CIDP remains fragmentary and insufficient for a unified hypothesis. Activated macrophages and T-cells with the participation of T-1 helper cell related cytokines seem to play a fundamental role in demyelination. The nature of antigen presenting cells, T-cell receptors, adhesion molecules and the proinflammatory cytokines need to be explored to design more specific immunotherapies. Established treatments in GBS include intravenous immunoglobulin and plasma exchange. Randomized trials have shown the efficacy of prednisone, intravenous immunoglobulin and plasma exchange in CIDP. New insight in the pathogenetic role of the cytokine-network in CIDP opens new therapeutical possibilities with the modification of the T-1 helper cell reaction with interferon.