CD5L is a canonical component of circulatory IgM

Immunoglobulin M (IgM) is an evolutionary conserved key component of humoral immunity, and the first antibody isotype to emerge during an immune response. IgM is a large (1 MDa), multimeric protein, for which both hexameric and pentameric structures have been described, the latter additionally containing a joining (J) chain. Using a combination of single-particle mass spectrometry and mass photometry, proteomics, and immunochemical assays, we here demonstrate that circulatory (serum) IgM exclusively exists as a complex of J-chain-containing pentamers covalently bound to the small (36 kDa) protein CD5 antigen-like (CD5L, also called apoptosis inhibitor of macrophage). In sharp contrast, secretory IgM in saliva and milk is principally devoid of CD5L. Unlike IgM itself, CD5L is not produced by B cells, implying that it associates with IgM in the extracellular space. We demonstrate that CD5L integration has functional implications, i.e., it diminishes IgM binding to two of its receptors, the FcαµR and the polymeric Immunoglobulin receptor. On the other hand, binding to FcµR as well as complement activation via C1q seem unaffected by CD5L integration. Taken together, we redefine the composition of circulatory IgM as a J-chain containing pentamer, always in complex with CD5L.

Profiling cognitive-motor interference in a large sample of persons with progressive multiple sclerosis and impaired processing speed: results from the CogEx study

BACKGROUND

Performing cognitive-motor dual tasks (DTs) may result in reduced walking speed and cognitive performance. The effect in persons with progressive multiple sclerosis (pwPMS) having cognitive dysfunction is unknown.

OBJECTIVE

To profile DT-performance during walking in cognitively impaired pwPMS and examine DT-performance by disability level.

METHODS

Secondary analyses were conducted on baseline data from the CogEx-study. Participants, enrolled with Symbol Digit Modalities Test 1.282 standard deviations below normative value, performed a cognitive single task ([ST], alternating alphabet), motor ST (walking) and DT (both). Outcomes were number of correct answers on the alternating alphabet task, walking speed, and DT-cost (DTC: decline in performance relative to the ST). Outcomes were compared between EDSS subgroups (≤ 4, 4.5-5.5, ≥ 6). Spearman correlations were conducted between the DTCmotor with clinical measures. Adjusted significance level was 0.01.

RESULTS

Overall, participants (n = 307) walked slower and had fewer correct answers on the DT versus ST (both p < 0.001), with a DTCmotor of 15.8% and DTCcognitive of 2.7%. All three subgroups walked slower during the DT versus ST, with DTCmotor different from zero (p's < 0.001). Only the EDSS ≥ 6 group had fewer correct answers on the DT versus ST (p < 0.001), but the DTCcognitive did not differ from zero for any of the groups (p ≥ 0.039).

CONCLUSION

Dual tasking substantially affects walking performance in cognitively impaired pwPMS, to a similar degree for EDSS subgroups.

Rheumatoid factor autoantibody repertoire profiling reveals distinct binding epitopes in health and autoimmunity

BACKGROUND

Rheumatoid factors (RF) are one of the hallmark autoantibodies characteristic of rheumatoid arthritis (RA), and are frequently observed in other diseases and in healthy individuals. RFs comprise multiple subtypes with different specificities towards the constant region of human IgG. Studies indicate that these patterns differ between naturally occurring RFs and RFs associated with disease. However, individual specificities characteristic of either have not been clearly defined.

METHODS

In this study, we developed an extended set of engineered IgG-fragment crystallisable (Fc) targets with preferential RF binding to specific (conformational) epitopes, which was subsequently used for profiling of RF binding patterns in a compiled exploration cohort, consisting of sera from healthy donors with measurable RF and patients with RA, primary Sjögren's syndrome (pSS) and seropositive arthralgia.

RESULTS

We identified an epitope that is strongly associated with RA, which was targeted by both IgM-RF and IgA-RF. We also identified an epitope that is preferentially targeted by healthy donor (IgM) RFs. IgM-RFs derived from healthy donors and patients with RA and pSS all target distinct regions on the IgG-Fc, whereas overall, the IgA-RF repertoire is largely restricted to pathology-associated specificities. Using monoclonal RFs with different specificities, we furthermore demonstrate that the capacity to activate complement or even inhibit IgG-mediated complement activation varies according to the epitopes to which RFs bind.

CONCLUSIONS

Our results demonstrate both the need and feasibility to redefine 'RF' into pathological and physiological autoantibody subtypes.

Investigation of Te measurements discrepancies between ECE and Thomson diagnostics in high-performance plasmas in JET

For high-temperature JET and TFTR discharges, electron cyclotron emission (ECE) measurements of central electron temperature were systematically found to be up to 20% higher than those taken with Thomson scattering. In recent high-performance JET discharges, central Te measurements, performed with LIDAR Thomson scattering and the X-mode ECE interferometer, have been studied in a large database, including deuterium (DD), and deuterium-tritium plasmas (DT). Discrepancies between Te measurements have been observed outside of the experimental uncertainties. ECE measurements, at high Te, have been found to be higher or lower than those of LIDAR, depending on the specific plasma scenario. In addition, discrepancies between the peaks of the second and third harmonic ranges of the ECE spectrum have been interpreted as evidence for the presence of non-Maxwellian features in the electron distribution function. These comparisons seem to suggest that such features can be found in most of the high-performance scenarios selected in this JET database.

Polarimetric Thomson scattering measurements in Joint European Torus high temperature plasmas

Thomson scattered light is polarized in the same orientation as the incident laser beam at low electron temperatures (T_e). At high T_e, part of the spectrum begins to become randomly polarized due to relativistic reasons. First measurements of the depolarized Thomson scattering spectrum were obtained from Joint European Torus (JET) pulses in 2016. This paper builds upon these initial measurements with the data obtained during 2021. These new measurements improve upon first results, in particular, by obtaining spectral measurements of the depolarized spectrum. The recent JET campaign was well suited to these measurements with long and hot plasmas. The resulting data are averaged over many plasmas and laser pulses to obtain a measurement of the amount of "p" and "s" scattered light as a function of T_e. This experimentally obtained d(p/s)/dT_e is then fitted and found to show reasonable agreement with the theoretically predicted depolarized fraction. Error estimates on the measured "p/s" have been obtained and show that the measurements are meaningful. This is good news for ITER for which the intention is to use this measurement as a check on T_e determined by the core plasma Thomson scattering diagnostic by using conventional spectral measurement techniques.

Biased anti-idiotype response in rabbits leads to high-affinity monoclonal antibodies to biologics

Antibody formation to human(ized) therapeutic antibodies in humans is highly skewed toward anti-idiotype responses, probably because the idiotype is the only 'foreign' part of the antibody molecule. Here, we analyzed antibody responses to F(ab')2 fragments of a panel of 17 human(ized) therapeutic antibodies in rabbits. Homology between the rabbit germline and the human(ized) antibodies is moderate not only for the variable domains (both the complementarity-determining regions and the framework regions), but also for the constant domains (66% or less). Nevertheless, we observed a highly skewed anti-idiotype response in all cases, with up to >90% of the antibodies directed toward the idiotype. These results indicate that the idiotype may be inherently immunodominant. We used these biased responses to raise monoclonal rabbit anti-idiotype antibodies against secukinumab, ustekinumab, reslizumab, mepolizumab, palivizumab, and dupilumab and demonstrate the potential to develop sensitive pharmacokinetic assays with these antibodies.

The effect of methotrexate on tumour necrosis factor concentrations in etanercept-treated rheumatoid arthritis patients

OBJECTIVES

Recently, we demonstrated that early low concentrations of circulating, adalimumab-bound TNF in RA patients treated with adalimumab was associated with future anti-drug antibody formation. Furthermore, low TNF was associated with less frequent baseline MTX use. This is remarkable, because of the anti-inflammatory effects of MTX and a potential inhibiting effect on cytokine production. We hypothesized an indirect effect of non-MTX use on low TNF concentrations via immunogenicity. To investigate the effect of MTX on TNF concentrations independent of anti-drug antibody formation, we measured TNF in RA patients treated with etanercept, a drug with low immunogenicity.

METHODS

TNF was quantified in 186 consecutive etanercept-treated RA patients at baseline and at weeks 4, 16 and 28. The dynamics of TNF during etanercept treatment were compared with dynamics recently published for adalimumab.

RESULTS

We demonstrated that TNF concentrations at week 4 did not associate with baseline MTX or remission after 28 weeks. Furthermore, median (interquartile range) TNF increased from <112 (<112-<112) pg/ml at baseline to 548 (344-688) pg/ml at week 4 and remained stable at week 16 and 28 [598 (442-756) and 568 (444-755) pg/ml, respectively].

CONCLUSION

Circulating TNF did not associate with MTX usage in etanercept-treated patients. This implies that MTX does not have a direct effect on TNF concentrations in circulation and that the association between early low TNF and non-use of MTX for adalimumab is thus most likely due to anti-drug antibody formation.

Electronic visual analogue scales for pain, fatigue, anxiety and quality of life in people with multiple sclerosis using smartphone and tablet: a reliability and feasibility study

Objective:

To explore the reliability and feasibility of electronic visual analogue scales in people with multiple sclerosis (MS) and healthy individuals.

Design:

Cross-sectional observational study

Setting:

Clinical setting

Subjects:

Convenience sample of 52 people with MS and 52 matched healthy controls

Interventions:

NA

Main measures:

Participants scored 15 statements assessing fatigue, pain, anxiety and quality of life on an electronic visual analogue scale (eVAS), either using a smartphone or a tablet (randomly allocated). To check for test-retest reliability, statements were administered in two separate randomly ordered groups. Subjects completed a feasibility questionnaire.

Results:

Mean (SD) eVAS scores ranged from 35 (28.1) to 80 (22.1) in MS group, and from 57 (28.0) to 86 (13.2) in controls. Intra Class Correlations ranged from 0.73 to 0.95 in MS sample; 0.61 to 0.92 in controls. For most statements, Bland-Altman plots indicated no systematic error, but relatively large random error of the eVAS scores (exceeding 20mm). Considerable ceiling effects (i.e. better health) were found in healthy controls. Similar reliability was found among smartphone or tablet, different demographic groups and the experience-groups.

Conclusion:

Electronic visual analogue scales are reliable and useful for people with MS to register fatigue, pain, anxiety and quality of life.

Regulation of myoglobin in hypertrophied rat cardiomyocytes in experimental pulmonary hypertension

A major problem in chronic heart failure is the inability of hypertrophied cardiomyocytes to maintain the required power output. A Hill-type oxygen diffusion model predicts that oxygen supply is limiting in hypertrophied cardiomyocytes at maximal rates of oxygen consumption and that this limitation can be reduced by increasing the myoglobin (Mb) concentration. We explored how cardiac hypertrophy, oxidative capacity, and Mb expression in right ventricular cardiomyocytes are regulated at the transcriptional and translational levels in an early stage of experimental pulmonary hypertension, in order to identify targets to improve the oxygen supply/demand ratio. Male Wistar rats were injected with monocrotaline to induce pulmonary hypertension (PH) and right ventricular heart failure. The messenger RNA (mRNA) expression levels per nucleus of growth factors insulin-like growth factor-1Ea (IGF-1Ea) and mechano growth factor (MGF) were higher in PH than in healthy controls, consistent with a doubling in cardiomyocyte cross-sectional area (CSA). Succinate dehydrogenase (SDH) activity was unaltered, indicating that oxidative capacity per cell increased. Although the Mb protein concentration was unchanged, Mb mRNA concentration was reduced. However, total RNA per nucleus was about threefold higher in PH rats versus controls, and Mb mRNA content expressed per nucleus was similar in the two groups. The increase in oxidative capacity without an increase in oxygen supply via Mb-facilitated diffusion caused a doubling of the critical extracellular oxygen tension required to prevent hypoxia (PO_2crit). We conclude that Mb mRNA expression is not increased during pressure overload-induced right ventricular hypertrophy and that the increase in myoglobin content per myocyte is likely due to increased translation. We conclude that increasing Mb mRNA expression may be beneficial in the treatment of experimental PH.

Evaluation of the Modified Fatigue Impact Scale in four different European countries

Objective: To evaluate the psychometric properties of the Modified Fatigue Impact Scale (MFIS) in four different European countries. Methods: Individuals with definite multiple sclerosis (MS) were selected from centres in Italy (n=50), Spain (n=30), Slovenia (n=50) and Belgium (n=51) and completed the MFIS and the Fatigue Severity Scale (FSS) twice (interval ≤ 3 days). Results: In all four samples, the MFIS demonstrated a good reproducibility (intraclass correlation coefficient ≥ 0.84), with no significant differences between countries (P=0.77). Moderate correlations were found between the MFIS and FSS. No significant correlations were found between the MFIS and age, gender, type of MS, duration of the disease or EDSS score. Factor analysis of all samples (n=181) could not completely confirm the original assumptions concerning the physical, cognitive and psychosocial component. The total score, the physical and the cognitive subscale of the scale were homogeneous (Cronbach’s alpha 0.92, 0.88 and 0.92, respectively), but the psychosocial subscale had a Cronbach’s alpha of 0.65. Conclusions: No cultural or linguistic differences were found in the psychometric properties of the Belgian, Italian, Slovenian or Spanish version of the MFIS. We recommend this scale for research purposes and in clinical practice. Due to the limited value of the psychosocial subscale, we recommend interpreting this subscale with caution.

Within-session practice effect on paced auditory serial addition test in multiple sclerosis

The paced auditory serial addition test (PASAT) is increasingly used in multiple sclerosis (MS) studies. Since these studies rely on repeated assessments with relatively short inter-test intervals, practice effects can be a confounding factor. We examined intra-session PASAT practice effects in 70 relapsing remitting (RR) and 40 secondary progressive (SP) patients. The average number of correct answers increased from 39.6 ± 11.7 in the first PASAT run to 43.8 ± 11.4 in the second run for the RR group, and from 39.1 ± 11.6 to 41.8 ± 13.3 in the SP group. PASAT scores showed a consistent decrease when comparing the second half of each test to the first half for both patient groups, and for both runs. Items for which the answer was a number greater than 9 had the same discrimination ability as other test items, but were significantly more difficult. A simulation of `single-button' responses supported the use of the simplified scoring method which is currently used in fMRI studies. Our results demonstrate a within-session PASAT practice effect in MS, as well as a fatigability effect for both patient groups.

Multidisciplinary fatigue management programme in multiple sclerosis: a randomized clinical trial

Objective To establish the efficacy of a multidisciplinary fatigue management programme (MFMP) in MS.

Method Fifty-one subjects with MS were randomly allocated to group A, who only received the four weeks MFMP, or group B receiving a placebo intervention programme first and the MFMP after 6 months. In both groups, assessment was performed at baseline, 3 weeks and 6 months after the programmes and included Modified Fatigue Impact Scale (MFIS), Fatigue Severity Scale (FSS), MS Self-Efficacy scale (MSSE), Mental Health Inventory (MHI) and Impact on Participation and Autonomy (IPA).

Results The MFIS showed a significant change over time ( F(4,152) = 3.346, P = 0.012), which was similar in both groups (time*group interaction: F(4,152) = 1.094, P = 0.361). A clinically relevant reduction of MFIS score of 10 points or more was found in 17% of individuals following the MFMP, compared to 44% after the placebo intervention programme ( P = 0.06). Compared to no intervention, a significant effect of the MFMP after 6 months ( P = 0.003) was found in five participants (31%). No significant changes in FSS, MSSE, MHI and IPA, in both groups, were found.

Conclusion Although an additional effect was found, the multidisciplinary fatigue management programme showed no efficacy in reducing the impact of fatigue compared to a placebo intervention programme. Multiple Sclerosis 2007; 13: 996—1003. http://msj.sagepub.com

Origin of fatigue in multiple sclerosis: review of the literature

Fatigue is one of the most common and most disabling symptoms of multiple sclerosis (MS). Although numerous studies have tried to reveal it, no definite pathogenesis factor behind this fatigue has been identified. Fatigue may be directly related to the disease mechanisms (primary fatigue) or may be secondary to non-disease-specific factors. Primary fatigue may be the result of inflammation, demyelination, or axonal loss. A suggested functional cortical reorganization may result in a higher energy demand in certain brain areas, culminating in an increase of fatigue perception. Higher levels of some immune markers were found in patients with MS-related fatigue, whereas other studies rejected this hypothesis. There may be a disturbance in the neuroendocrine system related to fatigue, but it is not clear whether this is either the result of the interaction with immune activation or the trigger of this process. Fatigue may be secondary to sleep problems, which are frequently present in MS and in their turn result from urinary problems, spasms, pain, or anxiety. Pharmacologic treatment of MS (symptoms) may also provoke fatigue. The evidence for reduced activity as a cause of secondary fatigue in MS is inconsistent. Psychological functioning may at least play a role in the persistence of fatigue. Research did not reach consensus about the association of fatigue with clinical or demographic variables, such as age, gender, disability, type of MS, education level, and disease duration. In conclusion, it is more likely to explain fatigue from a multifactor perspective than to ascribe it to one mechanism. The current evidence on the pathogenesis of primary and secondary fatigue in MS is limited by inconsistency in defining specific aspects of the concept fatigue, by the lack of appropriate assessment tools, and by the use of heterogeneous samples. Future research should overcome these limitations and also include longitudinal designs.

P300 and treatment effect of modafinil on fatigue in multiple sclerosis

To evaluate the value of visual and auditory P300 for predicting the response of multiple sclerosis-related fatigue to modafinil treatment, 33 patients were treated with 100 mg modafinil once daily for 4 weeks, following a 4-week baseline phase and an optional 8-week extension phase. The main clinical outcome parameter was a decrease in the fatigue visual analogue score (VAS) before and after 4 weeks of treatment. Patients with shorter auditory P300 latency at baseline were more likely to benefit from modafinil treatment. Auditory P300 latency predicted treatment response with a specificity of 76% and a sensitivity of 75% at a cut-off latency of 350 ms. Visual P300 latency could not be used to predict treatment response. Baseline auditory P300 latency predicted treatment response, whereas visual P300 latency did not. Clinical improvement did not correlate with changes in either visual or auditory P300.

Validity of the TEMPA for the measurement of upper limb function in multiple sclerosis

OBJECTIVE

To investigate concurrent and construct validity of the TEMPA (Test d'Evaluation de la performance des Membres Supérieurs des Personnes Agées) in patients with upper limb dysfunction due to multiple sclerosis.

SUBJECTS

Forty-three patients with upper limb dysfunction due to multiple sclerosis.

DESIGN

Patients performed upper limb tests and were assessed on measures of functional independence.

SETTING

National Multiple Sclerosis Centre, Melsbroek, Belgium.

MAIN OUTCOME MEASURES

TEMPA, Jebsen Handfunction Test, Nine Hole Peg Test, Functional Independence Measure (FIM) and activities of daily living (ADL) self-questionnaire.

RESULTS

The correlation between TEMPA and Jebsen Handfunction and the Nine Hole Peg test respectively is good (0.56-0.87) and high (0.79-0.9). The correlation between TEMPA and the FIM and ADL self-questionnaire was moderate (0.44-0.61) although mostly higher than the correlation between the Jebsen Handfunction and the Nine Hole Peg test respectively and the measures of functionality (0.22-0.55/0.1-0.47).

CONCLUSIONS

This study provides data supporting the concurrent validity of the TEMPA with the Jebsen Handfunction and the Nine Hole Peg Test in patients with multiple sclerosis. The results suggest construct validity of the TEMPA for the measurement of functionality during activities of daily life in patients with upper limb dysfunction due to multiple sclerosis.

Safe and effective fluid management by automated gravitation during hysteroscopy

OBJECTIVE

The automated gravitational Vario Flow system with weighing-based electronic fluid deficit indicator was used in order to reduce the risk of fluid intravasation during continuous flow hysteroscopic procedures. Early experiences are reported.

METHODS

Between August 1996 and July 1997, the Vario Flow with fluid deficit indicator and alarm system was used in 203 hysteroscopic operations. Between January 1994 and August 1996 the Vario Flow without fluid deficit indicator was used in 240 hysteroscopic operations. In all, there were 443 hysteroscopic operations: 301 metroplasties, 20 endometrial ablations, 10 cases of lysis of synechiae, 58 myomectomies and 54 polypectomies. The data on fluid deficit before and after the introduction of the electronic fluid deficit indicator were similar.

RESULTS

Fluid deficit indicator was proved highly efficient in 203 operations. It provided the information on fluid deficit at any moment during hysteroscopic operations. Besides intrauterine pressure, the actual fluid deficit has become one of the leading parameters during our continuous flow hysteroscopic procedures.

CONCLUSIONS

We therefore conclude that by using an automated gravitational system with fluid deficit indicator and alarm system, the safety for patients during hysteroscopic procedures has been increased.