ObjectiveSensory neuropathies (SNs) are often classified as idiopathic even if immunological mechanisms can be suspected. Antibodies against the intracellular domain of the fibroblast growth factor receptor 3 (FGFR3) possibly identify a subgroup of SN affecting mostly the dorsal root ganglion (DRG). The aim of this study was to identify the frequency of anti-FGFR3 antibodies and the associated clinical pattern in a large cohort of patients with SN.MethodsA prospective, multicentric, European and Brazilian study included adults with pure SN. Serum anti-FGRF3 antibodies were analysed by ELISA. Detailed clinical and paraclinical data were collected for each anti-FGFR3-positive patient and as control for anti-FGFR3-negative patients from the same centres (‘center-matched’).ResultsSixty-five patients out of 426 (15%) had anti-FGFR3 antibodies, which were the only identified autoimmune markers in 43 patients (66%). The neuropathy was non-length dependent in 89% and classified as sensory neuronopathy in 64%, non-length-dependent small fibre neuropathy in 17% and other neuropathy in 19%. Specific clinical features occurred after 5–6 years of evolution including frequent paresthesia, predominant clinical and electrophysiological involvement of the lower limbs, and a less frequent mixed large and small fibre involvement. Brazilians had a higher frequency of anti-FGFR3 antibodies than Europeans (36% vs 13%, p<0.001), and a more frequent asymmetrical distribution of symptoms (OR 169, 95% CI 3.4 to 8424).ConclusionsAnti-FGFR3 antibodies occur in a subgroup of SN probably predominantly affecting the DRG. Differences between Europeans and Brazilians could suggest involvement of genetic or environmental factors.
Background and purpose
Chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN) are rare autoimmune diseases. Guidelines were published in 2010 for their diagnosis and treatment. In France, intravenous immunoglobulins (IVIGs) are mainly used for the first‐line treatment. The burden of healthcare costs is often underlined but rarely studied. The aim of this survey was to compare to guidelines, the daily practice of French neurologists with IVIGs for CIDP and MMN treatment.
Methods
This was a retrospective observational study consisting of an online questionnaire performed between March and May 2014. A total of 49 questionnaires were included, a quarter of which were from neurologists working in neuromuscular reference centers (NRCs).
Results
A total of 182 patient case reports were studied. Patients were referred to an NRC for initial diagnosis in approximately 30% of cases in CIDP and 50% of cases in MMN. The initial management of IVIG (frequency, dose and duration) was not different between NRCs and non‐NRCs. Guidelines were followed and neurologists were relatively at ease in diagnosing and treating patients.
Conclusions
This was the first national study to describe the implementation of the European Federation of Neurological Sciences/Peripheral Nerve Society guidelines in the daily management of IVIGs in patients with MMN and CIDP in France. Efforts are needed to improve long‐term tailored treatment and home treatment to reduce economic costs.
Purpose: Identifying autoantigens of serological autoantibodies requires expensive methods, such as protein microarrays or IP+MS. Thus, sera are commonly pre-screened for interesting immunopatterns via immunocytochemistry/immunohistochemistry. However, distinguishing immunopatterns can be difficult and intracellular antigens are less accessible. Therefore, a simple and cheap immunoblot screening able to distinguish immunopatterns and to detect refractory proteins is presented. Experimental Design: Five steps of immunoblotting-based autoantigen screening are revised: (1) choice of protein source, (2) protein extraction, (3) protein separation, (4) protein transfer, (5) antigen detection. Thereafter, 52 patients' sera with chronic inflammatory demyelinating polyneuropathy (CIDP) and 45 controls were screened. Results: The protein source impacts the detected antigen set. Steps 2-4 can be adapted for refractory proteins. Furthermore, longitudinal cutting of protein lanes saves ࣙ75% of time and material and allows for exact comparison of band patterns. As the latter are individually specific and temporarily constant, we call them "immunological fingerprints". In a proof-of-principle, a 155 kDa immunoband was detected with two anti-neurofascin-155-positive CIDP sera and two further immunobands (120/220 kDa) specific to a subgroup of 3-6 of 52 CIDP patients. Conclusions and Clinical Relevance: Adapted immunoblotting is a cheap and simple method for accurate serum screening including refractory and intracellular antigens.
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