Routine blood monitoring in maintenance immunoglobulin treatment of inflammatory neuropathy: Is it clinically relevant?

BACKGROUND: Pre-treatment screening for IgA deficiency and close monitoring of full blood count(FBC) and renal function is recommended with intravenous immunoglobulin(IVIg) therapy in neurological diseases. AIMS: To examine the frequency of biochemically defined and clinically significant episodes of treatment associated haemolysis, neutropenia, thrombocytopenia and acute kidney injury(AKI) in a cohort of patients on maintenance Immunoglobulin(Ig) therapy for inflammatory neuropathy. METHODS: A retrospective review of routine blood monitoring in patients from two UK specialist peripheral nerve centres. Accepted definitions for clinically and biochemically significant haemolysis, neutropenia, thrombocytopenia and AKI were used. RESULTS: 1919 infusion episodes in 90 patients were analysed. Age(mean(S.D)) = 58.09(14.4)years, 63% male, 72% CIDP(28% MMN), 97% IVIg(3% SCIg). Dose = 1.57(0.79)g/kg/month or 97.1(37.3)g/infusion, frequency:3.9(1.4) weeks. Relative IgA deficiency was noted in 2 individuals (prevalence:2.2%, 95%C.I.:0-5.2) who received a combined total of 38 infusions(3800 g IVIg) without adverse event. No clinically significant episodes of haemolysis, neutropenia, thrombocytopenia or AKI occurred in relation to treatment. An asymptomatic drop>10 g/L haemoglobin(Hb) occurred in 3.5%(95%CI:2.7-4.3) of treatment episodes in 38 individuals, mean reduction:17.7(7.4)g/L; lowest Hb:86 g/L. Lower pre-treatment haemoglobin correlated with risk of recurrent Ig-related drop(p:0.007). Two patients with chronic renal failure(stage 1 and 3) received 28(IV) and 104(SC) infusions respectively(6416 g) without impact on estimated glomerular filtration rate(eGFR). CONCLUSIONS: No clinically significant Ig-related episodes of haemolysis or AKI were identified in this representative cohort. This suggests that routine monitoring is not essential in long-term Ig use but should be considered when clinically indicated.

Immunohistochemistry and electrophysiological findings in swine abattoir workers with immune-mediated polyradiculoneuropathy.

IMPORTANCE: Workers exposed to aerosolized brain in a swine-processing plant developed immune-mediated polyradiculoneuropathy (IP) possibly triggered by an immune response. OBJECTIVE: Immunohistochemistry results were correlated with electrophysiological variables to examine the immunopathogenesis of this disorder. DESIGN/SETTING: Laboratory studies used normal nerve tissue that was exposed to sera from 12 IP patients; 10 exposed controls; and 10 unexposed controls. Clinical and electrophysiological data from IP patients were obtained from medical record reviews. MAIN OUTCOME MEASURES: Analysis included electromyography results of IP patients and nerve conduction studies examining CMAP amplitude, distal motor latency, motor conduction velocity, F-wave latency, sensory nerve action potential amplitude, and sensory nerve conduction velocity. Case and control results were compared relative to distance from exposure. RESULTS: Electrodiagnostic findings revealed prolongation of the distal and f-wave latencies suggestive of demyelination at the level of the nerve root and distal nerve terminals. Immunohistochemical results identified an antibody to the peripheral nerve, with staining at the level of the axolemma. Thus, IP may be a primary axonopathy with secondary paranodal demyelination causing the conduction changes. Staining of the distal and proximal portions of the nerve appears consistent with easier access through the blood-nerve barrier. CONCLUSIONS AND RELEVANCE: IP is an immune-mediated neuropathy related to antibodies to an axon-based antigen on peripheral nerves. Secondary paranodal demyelination is likely. Further studies to identify the primary axonal antigenic target would be useful.

25-Hydroxy vitamin D3 serum concentration in dogs with acute polyradiculoneuritis compared to matched controls.

OBJECTIVES: To determine if dogs with acute polyradiculoneuritis have lower serum 25-hydroxy vitamin D3 concentration compared to a control group of dogs with idiopathic epilepsy. MATERIALS AND METHODS: Retrospective case-control study of 21 dogs with acute canine polyradiculoneuritis and 21 control dogs with idiopathic epilepsy matched for year and season of presentation from a referral hospital population in the UK. Serum concentration of 25-hydroxy vitamin D3 was compared between groups using Student's t-test. RESULTS: Dogs with acute canine polyradiculoneuritis had significantly lower (P=0·033) serum 25-hydroxy vitamin D3 concentration (87·1 nmol/L ±55·4 nmol/L) compared to a control group with idiopathic epilepsy (113 nmol/L ±66·3 nmol/L). CLINICAL SIGNIFICANCE: The cause and clinical significance of the altered vitamin D status in dogs with acute polyradiculoneuritis are not clear and require further investigation. Our findings pave the way for improved understanding of acute canine polyradiculoneuritis and, potentially, improved clinical management, if a causal role for 25-hydroxy vitamin D3 is defined.

Varied immuno-related adverse events induced by immune-check point inhibitors - Nivolumab-associated psoriasiform dermatitis related with increased serum level of interleukin-6.

Nivolumab is a standard recombinant antibody treatment for patients with malignant melanoma (MM), which functions as an immune checkpoint inhibitor by blocking the programmed cell death-1 (PD-1) pathway in T cells. However, it leads to various immune-related adverse events (irAEs), and also exacerbates underlying autoimmune diseases. Herein we report cases of MM with irAE. Case 1: A 69-year-old woman with MM developed destructive thyroiditis resulting in hypothyroidism after 3 doses of nivolumab, and had been treated with thyroid gland auxiliary therapy. Case 2: A 80-year-old man with MM developed an acute onset of hyperthyroidism after 4 doses of nivolumab. Case 3: A 85-year-old woman with MM developed polyradiculoneuropathy resulting in somatosensory disorder and muscle weakness after 2 doses of nivolumab, and had been treated with intravenous immunoglobulin and oral predonisolone (40 mg/day). Case 4: A 77-year-old man with MM developed psoriasiform dermatitis after local injections of IFN-ß and 11 doses of nivolumab. Case 5: Case 2 also developed psoriasiform dermatitis. We analyzed serum levels of inflammatory cytokines in MM patients before/after treatments with nivolumab. All six patients who developed psoriasiform dermatitis with/without anamnesis of psoriasis after treatment with nivolumab, and all seven patients with other irAE exhibited increased serum IL-6 levels after nivolumab treatment, while decreased serum levels of IL-6 were observed in 5 of 7 non-afflicted MM patients. In addition, MM patients who achieved good responses to nivolumab significantly exhibited decreased serum TNF-α levels after nivolumab treatment compared to progressive MM patients.

Anti-GM2 ganglioside antibodies are a biomarker for acute canine polyradiculoneuritis.

Acute canine polyradiculoneuritis (ACP) is considered to be the canine equivalent of the human peripheral nerve disorder Guillain-Barré syndrome (GBS); an aetiological relationship, however, remains to be demonstrated. In GBS, anti-glycolipid antibodies (Abs) are considered as important disease mediators. To address the possibility of common Ab biomarkers, the sera of 25 ACP dogs, 19 non-neurological, and 15 epileptic control dogs were screened for IgG Abs to 10 glycolipids and their 1 : 1 heteromeric complexes using combinatorial glycoarrays. Anti-GM2 ganglioside Abs were detected in 14/25 ACP dogs, and anti-GA1 Abs in one further dog. All controls except for one were negative for anti-glycolipid Abs. In this cohort of cases and controls, the glycoarray screen reached a diagnostic sensitivity of 60% and a specificity of 97%; a lower sensitivity (32%) was reported using a conventional glycolipid ELISA. To address the possible pathogenic role for anti-GM2 Abs in ACP, we identified GM2 in canine sciatic nerve by both mass spectrometry and thin layer chromatography overlay. In immunohistological studies, GM2 was localized predominantly to the abaxonal Schwann cell membrane. The presence of anti-GM2 Abs in ACP suggests that it may share a similar pathophysiology with GBS, for which it could thus be considered a naturally occurring animal model.

Long-term response to rituximab and fludarabine combination in IgM anti-myelin-associated glycoprotein neuropathy.

We report the clinical response and biological effects of treatment with rituximab and fludarabine (RF) in five patients with IgM anti-myelin-associated glycoprotein (MAG) demyelinating neuropathy. Between November 2006 and October 2009, four men and one woman aged 52-85 years received intravenous rituximab at 375 mg/m(2) on day 1 and oral fludarabine at 40 mg/m(2) /day from days 1 to 5, in a treatment cycle that was repeated every month for up to 6 months. Two patients had IgM monoclonal gammopathy of undetermined significance and three low tumor mass Waldenstrom's macroglobulinemia. Four patients showed a major hematological response with a decrease in anti-MAG titer in three and clearing in one. One patient did not respond. For the responding patients, symptoms and electrophysiological parameters improved significantly. No patient relapsed at post-RF treatment follow-up (12-45 months), and no toxicity was reported. The combination of RF induced significant responses in IgM anti-MAG demyelinating neuropathies, without toxicity. Clinical improvements were correlated to hematological and immunological results.

Detection of anti-MAG antibodies in polyneuropathy associated with IgM monoclonal gammopathy.

BACKGROUND: Detection of serum antibodies to myelin-associated glycoprotein (MAG) by Western blot (WB) is a valuable assay to diagnose a distinct type of demyelinating polyneuropathy with immunoglobulin M (IgM) monoclonal gammopathy. In this study, the diagnostic accuracy of a new and more practical ELISA to detect these antibodies was validated. METHODS: Routine WBs from 2 independent laboratories and ELISA were used to detect anti-MAG IgM in serum from 207 patients with neuropathy and controls. The sensitivity and specificity of these assays were compared and related to the patient clinical and electrophysiologic characteristics. RESULTS: In ELISA, anti-MAG antibodies were found in serum from 49 (72%) of 68 patients with demyelinating polyneuropathy and IgM monoclonal gammopathy. However, in this subgroup of patients, only 30 (44%) and 37 (54%) were positive in the 2 WBs. All of the patients positive in the 2 WBs were also positive in ELISA. A high correlation was found for IgM activity in ELISA to MAG and sulfate-3-glucuronyl paragloboside (SGPG) (Spearman rho = 0.72, p < 0.0001), supporting the notion that the shared sulfated glucuronic acid moiety of MAG and SGPG is preserved. Most patients positive in anti-MAG ELISA had a slowly progressive sensory-motor demyelinating polyneuropathy, even if the WB was negative. In control groups, however, 4 WB-negative patients with a nondemyelinating monoclonal gammopathy-related polyneuropathy were positive in anti-MAG ELISA. The remaining samples were negative in ELISA. CONCLUSION: ELISA is more sensitive than Western blot to diagnose anti-myelin-associated glycoprotein related polyneuropathy, although a positive serology may be found in other forms of polyneuropathy as well.

Efficacy of immunotherapy in seropositive and seronegative putative autoimmune autonomic ganglionopathy.

OBJECTIVE: To evaluate the efficacy of immunotherapy in the treatment of patients with seropositive and seronegative putative autoimmune autonomic ganglionopathy (AAG) using validated autonomic function tests and instruments. BACKGROUND: AAG is an immune-mediated disorder characterized by prominent and selective involvement of autonomic nerve fibers or ganglia. Treatment with i.v. immunoglobulin (IVIg) or plasma exchange (PE) has been reported to be effective in single case reports. METHODS: We studied six patients, four with seropositive and two with seronegative putative AAG, who underwent autonomic function tests and completed two validated questionnaires, to assess autonomic symptoms before and after immunomodulatory treatment. Patients were treated with standard doses of IVIg, PE, or immunosuppressants in a specific sequential therapy protocol depending on clinical response. RESULTS: Of the six patients (all women, mean ages 49.3 +/- 10.6 years), four patients were ganglionic (alpha3) AChR autoantibody positive and two were autoantibody negative. All patients showed clinical improvement after treatment. Sudomotor function assessed by quantitative sudomotor axon reflex test and thermoregulatory sweat test improved in four patients after treatment. CONCLUSIONS: Immunomodulatory treatment can be effective in both seropositive and seronegative putative autoimmune autonomic ganglionopathy. Plasma exchange or combined therapy with immunosuppressive agents should be considered in patients who do not benefit from i.v. immunoglobulin alone.

Glial fibrillary acidic protein as a marker of axonal damage in chronic neuropathies.

We evaluated serum glial fibrillary acidic protein (GFAP) levels by enzyme-linked immunosorbent assay (ELISA) in controls (n = 30) and in patients with chronic sensory-motor axonal neuropathy (CSMAN) (n = 30), chronic inflammatory demyelinating polyneuropathy (CIDP) (n = 30), multifocal motor neuropathy (MMN) (n = 30), and primary muscular spinal atrophy (PMSA) (n = 15). GFAP levels, expressed as optical density, were increased in CSMAN (median = 1.05) compared to controls (median = 0.41; P < 0.05) and CIDP (median = 0.53, P < 0.05). They were also increased in PMSA (median = 0.99) compared to controls (P < 0.05) and MMN (median = 0.66; P < 0.05). To differentiate CSMAN from CIDP and PMSA from MMN, we applied a cutoff of GFAP levels at 0.66, and we obtained good sensitivity and specificity. In neuropathies, serum GFAP correlated with summated sensory nerve action potential amplitudes (r = -0.57; P = 0.0006) and disease severity (r = 0.37; P = 0.0011). Thus, we propose serum GFAP as a marker of axonal damage and severity in chronic neuropathies.

Characterization of neuropathies associated with elevated IgM serum levels.

BACKGROUND: In contrast to the IgM monoclonal gammopathies the neuropathy associated with polyclonal IgM gammopathy has not been well characterized. OBJECTIVE: To characterize the neuropathy in patients with elevated serum IgM. DESIGN: Retrospective review. SETTING: Academically based neuropathy center. PATIENTS: 45 patients with elevated quantitative immunoglobulin M were identified. MAIN OUTCOME MEASURES: Patients are described with regard to clinical phenotype, electrodiagnostic features of demyelination or focality, presence of IgM monoclonal gammopathy, and presence of autoantibody activity. RESULTS: Elevated IgM levels occurred in 45 (11.5%) of 391 patients. Of these, 24 (53%) had polyclonal gammopathy and 21 (47%) had an IgM monoclonal gammopathy. Anti-nerve antibodies occurred in 14/21 (67%) of patients with monoclonal gammopathy, as compared to 1/24 (4%) with polyclonal gammopathy. Clinically, most patients in all groups had a predominantly large fiber sensory neuropathy. Thirty patients underwent electrodiagnostic testing. Of these, 22/30 (73%) fulfilled at least one published criteria for CIDP, including 92% of the monoclonal gammopathy patients and 59% of the polyclonal gammopathy patients. Fifteen of the 30 patients had evidence of focality or multifocality, with 14 of these 15 showing evidence of demyelination. CONCLUSIONS: Monoclonal and polyclonal IgM patients have similar distributions of neuropathy phenotypes. Neuropathy in association with elevated serum IgM, with or without monoclonal gammopathy or autoantibody activity, is more likely to be demyelinating or multifocal. Serum quantitative IgM level and immunofixation in neuropathy patients may aid in identification of an immune mediated or a demyelinating component.

Autonomic function and autoantibodies to autonomic nervous tissues at follow-up in a cohort of young patients with type 1 diabetes. Effects of serum from diabetic patients on human adrenergic cells.

Recent studies have linked autoimmunity to nervous tissue structures and diabetic autonomic neuropathy. To evaluate prospectively the early stage of type 1 diabetes and the natural history of this association, we monitored the autonomic function and the presence of autoantibodies (Ab) to sympathetic and parasympathetic nervous structures in a cohort of 92 diabetic adolescent patients, recruited and followed-up after 40+/-3 months. The presence of circulating Ab and their ability to activate complement was also assessed using a human adrenergic neuroblastoma cell line, and the effect of patients' sera on these cells was evaluated by different methods assessing cytotoxic effects and apoptosis. Thirty-nine percent of the Ab-positive patients had one abnormal test (p=0.07 vs. Ab-negative patients). Serum from four patients positive for anti-cervical ganglia Ab showed positive staining of neuroblastoma cells and displayed ability to activate complement. Serum from two adolescent patients with anti-cervical ganglia and anti-neuroblastoma cells Ab, induced cytotoxic effects and damaged the plasma membrane of the neuroblastoma cells. Moreover, sera from two adult patients with overt autonomic neuropathy, used as positive controls, induced apoptosis of these cells, assessed by TUNEL. Our data indicate that symptomatic autonomic neuropathy is not characteristic of young diabetic patients, but that autoantibodies to autonomic structures are present and persist in the first 20 years of disease, possibly associated with subtle autonomic dysfunction and cytotoxic effect on sympathetic cells.

Intravenous immunoglobulin therapy in multifocal motor neuropathy: a double-blind, placebo-controlled study.

We conducted a double-blind, placebo-controlled, study of 19 patients fulfilling eligibility criteria for multifocal motor neuropathy with persistent conduction block. They were enrolled and divided into two groups: those who had never been treated previously with intravenous immunoglobulins (IVIg) (Group 1: 10 patients) and those who presented recurrent symptoms after previously successful treatment with IVIg (Group 2: nine patients). They were randomized prospectively to receive either IVIg or placebo at a dose of 500 mg/kg/day for 5 consecutive days, once a month for 3 months. At month 4, patients found to be responders remained on the same treatment for the 3 following months, while non-responders were switched to the alternative study drug for the 3 following months. Clinical assessment was conducted with the MRC score in 28 muscles and a self-evaluation scale (five daily motor activities scored from 0 to 5). In Group 1, nine patients completed the study, of whom initially four received IVIg and five placebo; four patients responded to IVIg (two at months 4 and 7, and a further two at month 7 after switching treatment at month 4), two patients responded to placebo at months 4 and 7, and three patients did not respond to either treatment. In Group 2, nine patients completed the study. Five patients first received IVIg and all responded at months 4 and 7. Four patients first received placebo and none responded at month 4; all were then switched to IVIg and three responded at month 7. When the 18 patients were considered together, seven out of the nine patients who received IVIg first were responders at month 4, compared with two of the nine patients who received placebo first, a difference that was statistically significant (P = 0.03). On the other hand, there was no significant difference in MRC score but a significant difference in the self-evaluation score, at month 4, between IVIg patients and placebo patients. Electrophysiological studies did not show significant differences at month 4 in motor parameters between IVIg patients and placebo patients. IgM anti-GM1 titres did not change significantly in patients treated with IVIg compared with those who received placebo, between baseline, month 4 and month 7. However, of five patients who had significantly high anti-GM1 titres (>3200) at baseline, four responded to IVIg. This trial confirms that IVIg is a promising therapeutic option for multifocal motor neuropathy.

Short-term variability of blood pressure and heart rate in Guillain-Barré syndrome without respiratory failure.

The effect of Guillain-Barré syndrome (GBS) on the short-term variability of blood pressure and heart rate was evaluated in six patients presenting with a moderate form of the syndrome, i.e. unable to stand up unaided and without respiratory failure, at the height of the disease and during recovery. The patients were compared with six age-matched healthy volunteers. During the acute phase of the syndrome, GBS patients exhibited a significant heart rate elevation (+26 beats/min compared with healthy subjects), but the acceleratory response to atropine, or to 60 degrees head-up tilt, was maintained. Resting plasma noradrenaline levels were high in acute GBS, but the secretory response to tilt was preserved. Desensitization to noradrenaline was observed in acute GBS with a reduced pressor action of this alpha-adrenoceptor agonist. Blood pressure levels were normal and head-up tilt did not induce orthostatic hypotension in this moderate form of GBS. Power spectral analysis demonstrated marked alterations in cardiovascular variability. The overall heart period variability was markedly reduced with the reduction predominantly in the high-frequency (respiratory) range (-73%). The low-frequency component of heart period variability was also reduced (-54%). This cardiovascular profile of moderate GBS at the height of the disease could result from a demyelination of the reflex loop controlling respiratory oscillations in heart rate and from a desensitization of the arterial tree to an elevated plasma noradrenaline. Sympathetic nervous activation may contribute to the high resting heart rate in acute GBS.

The soluble 60-kDa tumour necrosis factor receptor: no difference found between patients with relapsing-remitting multiple sclerosis and controls: increasing levels are associated with the recovery from Guillain-Barré syndrome.

We determined serum and cerebrospinal fluid (CSF) levels of the soluble 60-kDa tumour necrosis factor (TNF) receptor (sTNF-R p60) in 50 patients with relapsing-remitting multiple sclerosis (MS) and in 18 patients with Guillain-Barré syndrome (GBS). Neither in serum nor in CSF samples was there a statistically significant difference between mean receptor concentrations of patients with MS (serum: 1064, SD 262 pg/ml; CSF: 555, SD 130 pg/ml), with other noninflammatory neurological diseases (serum: 1008, SD 248 pg/ml; CSF: 530, SD 112 pg/ml) and with healthy control subjects (serum: 918, SD 180 pg/ml). In order to determine disease activity, magnetic resonance imaging (MRI) of the brain was performed in all MS patients. The mean sTNF-R p60 levels of patients who showed gadolinium DTPA enhancement on MRI were not different from those without enhancement (1034, SD 274 pg/ml vs 1099, SD 248 pg/ml in serum samples and 546, SD 109 pg/ml vs 565, SD 152 pg/ml in CSF samples). In GBS, the sTNF-R p60 levels of serum and CSF samples were significantly higher than in MS and all control groups except for the group with viral meningitis (VM) (GBS: 1544, SD 834 pg/ml in serum, 882, SD 147 pg/ml in CSF; VM: 1518, SD 375 pg/ml in serum, 1131, SD 611 pg/ml in CSF; P < 0.001 for serum samples and P < 0.005 for CSF samples). Serial serum sTNF-R p60 measurements in 13 patients with GBS showed an increase in receptor levels parallel with the recovery from the disease (1276, SD 374 pg/ml at the time of disease onset, 1554, SD 482 pg/ml 14-24 days later and 1787, SD 525 pg/ml after 28-32 days). From our results and the conflicting data of previous studies, we could not agree with the suggestion that the assessment of sTNF-R p60 in MS patients is a useful marker for disease activity. In GBS, subsequently increasing sTNF-R p60 levels are associated with recovery from the disease. It remains to be shown whether they might represent a relevant pathogenetic factor during this stage of GBS.

Neuromuscular blockade by IgG antibodies from patients with Guillain-Barré syndrome: a macro-patch-clamp study.

Guillain-Barré syndrome (GBS) is often associated with serum antibodies to glycoconjugates such as GM1 and GQ1b. The pathogenic role of these antibodies and other serum factors has not yet been clarified. We have investigated the effect of serum, plasma filtrate, and highly purified IgG and IgM from 10 patients with typical GBS on motor nerve terminals in the mouse hemidiaphragm. Quantal endplate currents were recorded by means of a perfused macro-patch-clamp electrode. The plasma filtrate of all GBS patients led to a 5- to 20-fold reduction of evoked quantal release within 7 to 15 minutes of continuous superfusion. In 4 patients, the amplitudes of single quanta were clearly reduced (by 10-66% of control values), indicating an additional postsynaptic action. Blocking effects could be reversed to a variable degree within 15 to 18 minutes after washout. Purified IgG was as effective as native serum, whereas a purified GBS IgM fraction did not block transmission. Sera from convalescent patients and IgG from healthy subjects were without blocking effect. The effects were complement independent and there was no link to the presence (in 6 patients) or absence (in 4 patients) of detectable antibodies to GM1 or GQ1b. In GBS, antibodies to an undetermined antigen depress the presynaptic transmitter release and, in some cases, the activation of postsynaptic channels. We suggest that weakness in the acute stage of GBS may be caused in part by circulating antibodies.

Acute renal failure due to severe Landry-Guillain-Barré syndrome.

BACKGROUND: Blood urea nitrogen (BUN) >60 mg/dl has been reported to occur commonly in patient's with severe Landry-Guillain-Barré syndrome. AIMS: To find out the cause for this high BUN we compared the renal function tests of 30 consecutive cases with severe Landry-Guillain-Barré syndrome to those of 30 controls. RESULTS: Acute renal failure occurred in seven patients with Landry-Guillain-Barré syndrome and none of the control group. Acute renal failure was found more in cases with Landry-Guillain-Barré syndrome compared to controls (P=0.0049). Six out of seven cases with Landry-Guillain-Barré syndrome and acute renal failure had dysautonomia and became oliguric while being in a hypotensive state. Of 30 patients with Landry-Guillain-Barré syndrome seven cases died. From eight patients with dysautonomia six cases who had acute renal failure died. The mortality rate was higher in cases with dysautonomia and acute renal failure (P = 0.0001 and 0.00001, respectively). Interestingly no glomerular disease was found. CONCLUSION: In conclusion acute renal failure can occur commonly in cases with severe Landry-Guillain-Barré syndrome particularly in those with dysautonomia, causing high mortality.

Recovery from Guillain-Barré syndrome is associated with increased levels of neutralizing autoantibodies to interferon-gamma.

Guillain-Barré syndrome (GBS) is an immune-mediated demyelinating disease of peripheral nerves that is often preceded by an infection and is usually self-restricted. The Th1 cytokine interferon-gamma (IFN-gamma) is thought to be disease-promoting in organ-specific autoimmune diseases. We report the spontaneous induction of IFN-gamma and a mechanism involving the generation of neutralizing autoantibodies (Aabs) to IFN-gamma that may regulate the disease. Numbers of cells spontaneously secreting IFN-gamma in peripheral blood were augmented in GBS, in particular at the peak of clinical disease, and decreased during recovery. This decrease was associated with elevated serum concentrations of IgG Aabs to IFN-gamma. These Aabs specifically bound to IFN-gamma and neutralized its effects in a biological assay. Aabs to IFN-gamma are proposed to be another important regulatory mechanism in IFN-gamma-driven GBS.