Costs of illness in chronic inflammatory demyelinating polyneuropathy in Germany.

INTRODUCTION: Cost of illness studies are essential to estimate societal costs of chronic inflammatory demyelinating polyneuropathy (CIDP) and identify cost-driving factors. METHODS: In total, 108 patients were recruited from 3 specialized neuroimmunological clinics. Costs were calculated for a 3-month period, including direct and indirect costs. The following outcomes were assessed: inflammatory neuropathy cause and treatment disability scale, Mini-Mental State Examination, Beck Depression Inventory, Charlson comorbidity index, EuroQol-5D, World Health Organization quality of life instrument, and socioeconomic status. Univariate and multivariate analyses were applied to identify cost-driving factors. RESULTS: Total quarterly costs were €11,333. Direct costs contributed to 83% of total costs (€9,423), whereas indirect costs accounted for 17% (€1,910) of total costs. The cost of intravenous immunoglobulin (IVIg) was the main determinant of total costs (67%). Reduced health-related quality of life and depressive symptoms were identified as independent predictors of higher total costs. DISCUSSION: CIDP is associated with high societal costs, mainly resulting from the cost of IVIg treatment. Muscle Nerve 58: 681-687, 2018.

Intravenous immunoglobulin maintenance treatment in myasthenia gravis: a randomized, controlled trial sample size simulation.

INTRODUCTION: In cases of exacerbation or crisis, myasthenia gravis (MG) patients can be treated with intravenous immunoglobulin (IVIg), plasmapheresis, or immunoadsorption. However, IVIg efficacy data in maintenance treatment are sparse. METHODS: We prospectively observed 16 index patients with chronic and insufficiently controlled MG under standard immunosuppressant therapy and symptomatic treatment. The IVIg treatment response was measured using changes in quantitative myasthenia gravis (QMG) score and surrogates. Based on these results, a sample size calculation for a future randomized, controlled trial (RCT) was simulated. RESULTS: There was an enduring decline in QMG score and other parameters of about 50% under IVIg maintenance treatment. RCT sample size calculation results in 73 or 33 patients per arm to detect at least a 20% vs. 30% clinical difference in QMG score. CONCLUSION: We recommend using the QMG score as a primary endpoint for an RCT of IVIg maintenance for chronic MG.

Coping as a resource to allow for psychosocial adjustment in fatal disease: results from patients with amyotrophic lateral sclerosis.

Background: Amyotrophic lateral sclerosis (ALS) is a fatal disorder, which imposes a severe emotional burden on patients. Appropriate coping mechanisms may alleviate this burden and facilitate wellbeing, with social support known to be a successful coping strategy. This observational study aimed to determine the interplay of general coping traits of hope for success and fear of failure, coping behavior of social activity, and patients' wellbeing. Methods: In this cross-sectional study, patients with ALS from a clinical-epidemiological registry in Southwestern Germany were interviewed regarding coping traits (achievement-motivated behavior: hope for success and fear of failure), coping behavior of social activity, and psychosocial adjustment, determined using measures of depressiveness, anxiety [both measured by Hospital Anxiety and Depression Scale (HADS)], and quality of life [Anamnestic Comparative Self-Assessment (ACSA)]. Demographics, clinical [ALS Functional Rating Scale revised version (ALSFRS-R)], and survival data were recorded. Results: A total of 868 patients [60.70% male patients, mean age: 64.70 (±10.83) years, mean ALSFRS-R: 37.36 ± 7.07] were interviewed. Anxiety in patients was found to be associated with a high fear of failure. In contrast, a generally positive attitude in patients exemplified in high hopes for success was associated with better wellbeing. Finally, coping behavior of social activity explained up to 65% of the variance of depressiveness among the patients with ALS. Conclusion: In this study, we present evidence that the wellbeing of patients with ALS is not an immediate fatalistic consequence of physical degradation but rather determined by coping traits and behavior, which may be trained to substantially increase the wellbeing of patients with ALS.

Cystatin C based estimation of chronic kidney disease and amyotrophic lateral sclerosis in the ALS registry Swabia: associated risk and prognostic value.

Kidney function as part of metabolic changes could be associated with amyotrophic lateral-sclerosis (ALS). We investigated the associations between estimated chronic kidney disease (CKD), based on the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin C equation, and the risk at onset and prognostic value of CKD for ALS. Between October 2010 and June 2014, 362 ALS cases (59.4% men, mean age 65.7 years) and 681 controls (59.5% men, means age 66.3 years) were included in a population-based case-control study based on the ALS registry Swabia in Southern Germany. All ALS cases were followed-up (median 89.7 months), 317 died. Serum samples were measured for cystatin C to estimate the glomerular filtration rate (eGFR) according to the CKD-EPI equation. Information on covariates were assessed by an interview-based standardized questionnaire. Conditional logistic regression models were applied to calculate odds ratios (OR) for risk of ALS associated with eGFR/CKD stages. Time-to-death associated with renal parameters at baseline was assessed in ALS cases only. ALS cases were characterized by lower body mass index, slightly lower smoking prevalence, more intense occupational work and lower education than controls. Median serum cystatin-C based eGFR concentrations were lower in ALS cases than in controls (54.0 vs. 59.5 mL/min pro 1.73 m2). The prevalence of CKD stage ≥ 3 was slightly higher in ALS cases than in controls (14.1 vs. 11.0%). In the adjusted models, CKD stage 2 (OR 1.82, 95% CI 1.32, 2.52) and stage 3 (OR 2.34, 95% CI 1.38, 3.96) were associated with increased ALS risk. In this cohort of ALS cases, eGFR and CKD stage ≥ 3 (HR 0.94; 95% CI 0.64, 1.38) were not associated with prognosis. In this case-control study, higher CKD stages were associated with increased ALS risk, while in the prospective cohort of ALS cases, no indication of an association of CysC-based CKD on mortality was seen. In addition, our work strengthens the importance to evaluate renal function using a marker independent of muscle mass in ALS patients.

Impaired inhibitory Fcgamma receptor IIB expression on B cells in chronic inflammatory demyelinating polyneuropathy.

The inhibitory Fc-gamma receptor FcgammaRIIB, expressed on myeloid and B cells, has a critical role in the balance of tolerance and autoimmunity, and is required for the antiinflammatory activity of intravenous Ig (IVIG) in various murine disease models. However, the function of FcgammaRIIB and its regulation by IVIG in human autoimmune diseases are less well understood. Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common treatable acquired chronic polyneuropathy, and IVIG is widely used as a first-line initial and maintenance treatment. We found that untreated patients with CIDP, compared with demographically matched healthy controls, showed consistently lower FcgammaRIIB expression levels on naive B cells, and failed to up-regulate or to maintain up-regulation of FcgammaRIIB as B cells progressed from the naive to the memory compartment. Concomitantly, the rare -386C/-120A FcgammaRIIB promoter polymorphism resulting in reduced promoter activity previously associated with autoimmune phenotypes was overrepresented in CIDP. Also, FcgammaRIIB protein expression was up-regulated on monocytes and B cells after clinically effective IVIG therapy. Thus, our results suggest that the inhibitory FcgammaRIIB is impaired at a critical B cell differentiation checkpoint in CIDP, and that modulating FcgammaRIIB expression might be a promising approach to efficiently limit antibody-mediated immunopathology in CIDP.

Sibling disability risk at onset and during disease progression in familial multiple sclerosis.

BACKGROUND: The objective of this study was to address the differences in onset and disease progression between familial and sporadic multiple sclerosis (MS) and the association within sibling pairs. METHODS: Ninety-eight siblings and their controls were included from a database of 763 sporadic MS-patients, randomly pair-matched for age, gender, clinical course, disease duration and treatment. Sixty-eight available siblings completed a prospective six-year follow-up. Outcome parameters included baseline Expanded Disability Status Scale (EDSS), age at onset, mono- or multifocal onset, disease progression and conversion to secondary progression of initially relapsing-remitting MS. For statistical analyses Wilcoxon's signed-rank statistics for categorical differences, t-statistics for continuous variables, McNemar's test for relative frequencies of categories, intra-class correlations for within sibling-pair associations, or Kaplan-Meier analysis for survival analyses were used; all two-sided at the 5% level. RESULTS: Disease onset was slightly earlier (29.01 vs. 29.44 years, p = 0.0492) and multifocal onset significantly more often (p = 0.0052) in familial than in sporadic MS. Notably, a substantial within sibling-pair correlation for disease progression (rho = 0.40; p = 0.0062) as well as a higher risk for siblings than for controls to convert into secondary progression (0.545 vs. 0.227; p = 0.018) could be observed. CONCLUSIONS: Familial MS differs from sporadic cases with respect to age at onset, multifocal involvement as first clinical event, and conversion into secondary progression. The progression rate of one out of two affected siblings may act as a predictor for the other sib.

Economic burden in a German cohort of patients with multiple sclerosis.

AIMS: To estimate costs of multiple sclerosis (MS) in a German cohort according to severity of the disease and clinical symptoms. METHODS: 144 patients were recruited from an MS outpatient clinic. Costs were calculated according to current German health-economic guidelines from the perspective of the social health insurance system. Patients were either interviewed or completed a questionnaire. Cost assessment covered a 3-month period. Health outcomes were: Expanded Disability Status Scale, MS Functional Composite, Functional Assessment of MS, fatigue, depression (Beck Depression Inventory II) and patients' socioeconomic status. Multivariate linear regression identified independent cost predictors. RESULTS: Total quarterly costs per patient were EUR 10,329 (95% CI 9,357-11,390). Direct costs were EUR 5,344 for the social health insurance system and EUR 140 for the patient. Drugs represented the major share of direct costs (and 35% of total costs); indirect costs accounted for 47% of total costs. Univariate and multivariate analyses identified age, disability, fatigue and depression as independent predictors for total, indirect or drug costs. CONCLUSION: MS represents a high economic burden, with direct costs exceeding indirect costs. To reduce costs, research should focus on prevention that slows down progression of MS. Rehabilitation and symptomatic treatment may have merits in decreasing indirect costs.

Identification of Epstein-Barr virus proteins as putative targets of the immune response in multiple sclerosis.

MS is a chronic inflammatory and demyelinating disease of the CNS with as yet unknown etiology. A hallmark of this disease is the occurrence of oligoclonal IgG antibodies in the cerebrospinal fluid (CSF). To assess the specificity of these antibodies, we screened protein expression arrays containing 37,000 tagged proteins. The 2 most frequent MS-specific reactivities were further mapped to identify the underlying high-affinity epitopes. In both cases, we identified peptide sequences derived from EBV proteins expressed in latently infected cells. Immunoreactivities to these EBV proteins, BRRF2 and EBNA-1, were significantly higher in the serum and CSF of MS patients than in those of control donors. Oligoclonal CSF IgG from MS patients specifically bound both EBV proteins. Also, CD8(+) T cell responses to latent EBV proteins were higher in MS patients than in controls. In summary, these findings demonstrate an increased immune response to EBV in MS patients, which suggests that the virus plays an important role in the pathogenesis of disease.

Early MRI changes in a mouse model of multiple sclerosis are predictive of severe inflammatory tissue damage.

MRI is routinely used for in vivo detection of multiple sclerosis (MS) lesions. Histopathological correlates of MRI signal alterations are still poorly defined. In the present study, we describe a mouse model of MS presenting with inflammatory brain lesions. During the acute disease phase, two independent lesion patterns were identified by T1- and T2-weighted high-resolution 3D MRI: lesions with reduced signal intensity on both T1- and T2-weighted images (type A) and lesions with slightly reduced signal intensity on T1-weighted images and increased signal intensity on T2-weighted images (type B). Type A lesions were characterized by significantly denser inflammatory cell infiltrates and more myelin loss than type B lesions. Lesion cellularity, myelin loss and immunoglobulin deposition correlated with MRI signal intensities in both lesion types. Gd-DTPA enhancement correlated with Ig deposition and spacially matched to areas with abundant activated microglia cells at the lesion border. Using serial MRI, type A lesions revealed a persistent hypointense pattern reflecting axon and myelin loss. Signal intensity increases on T2-weighted images of type B lesions decreased during lesion evolution, and no significant T1 signal alterations developed. Taken together, MRI of mouse EAE models with brain lesions provide new insights into lesion pathology and evolution and may prove useful for the in vivo assessment of new therapeutic strategies in MS.

Acetylcholine Receptor Antibody Titers and Clinical Course after Influenza Vaccination in Patients with Myasthenia Gravis: A Double-Blind Randomized Controlled Trial (ProPATIent-Trial).

BACKGROUND: It is a continuous matter of discussion whether immune activation by vaccination in general and Influenza vaccination in particular increases the risk for clinical deterioration of autoimmune diseases. This prospective study investigated the serological and clinical course of autoimmune Myasthenia gravis (MG) after a seasonal influenza vaccination. METHODS: This randomized, placebo-controlled, double-blind study enrolled MG patients with antibodies against acetylcholine-receptors (AChR-ab). They were allocated to receive seasonal influenza vaccine or placebo. The primary endpoint was the relative change of AChR-ab-titer over 12weeks. A relative increase of 20% was set as non-inferiority margin. Secondary endpoints were clinical changes in the modified Quantitative Myasthenia Gravis Score (QMG), increase of anti-influenza-ELISA-antibodies, and changes of treatment. The study is registered with Clinicaltrialsregister.eu, EudraCT number 2006-004374-27. FINDINGS: 62 patients were included. Mean±standard deviation (median) in the vaccine and placebo group were AChR-ab-titer changes of -6.0%±23.3% (-4.0%) and -2.8%±22.0% (-0.5%) and QMG score changes of -0.08±0.27 (0.17) and 0.11±0.31 (0.00), respectively. The difference between groups (Hodges-Lehmann estimate with 95% CI) was - for the AChR-ab-titer change 4·0% [-13.3%, 4.5%] (p=0.28 for testing a difference, p<0.0001 for testing non-inferiority) and for the QMG change 0·00 [-0.17, 0.00] (p=0.79 for testing a difference). The occurrence of 74 adverse events (AE) was comparable between groups. The most common AE was flu-like symptoms. One serious AE (hospitalisation following gastrointestinal haemorrhage) in the verum group was not related to the vaccine. INTERPRETATION: Influenza vaccination in MG is safe. Uprating the potential risk of a severe course of MG exacerbation during influenza infection compared to the 95% CI differences for the endpoints, vaccination is principally indicated in this patient population.

Procalcitonin is elevated in the cerebrospinal fluid of patients with dementia and acute neuroinflammation.

Procalcitonin (PCT) is an established marker for severe systemic bacterial infection and sepsis in blood. Here we measured PCT by immunoassay in CSF and matched serum/plasma samples of controls and patients with different primary dementia disorders and acute neuroinflammation. PCT in CSF was significantly increased in patients with probable Alzheimer's disease, vascular dementia, dementia with Lewy bodies, frontotemporal dementia and acute neuroinflammation (encephalitis, meningitis) compared to non-demented controls. In contrast, PCT levels in matched plasma samples were normal in dementia groups, but elevated in meningitis/encephalitis. Our results indicate a central production of PCT and suggest PCT as a valuable marker candidate for the monitoring of dementia and acute neuroinflammation.

Suppression of autoimmune encephalomyelitis by a neurokinin-1 receptor antagonist--a putative role for substance P in CNS inflammation.

Substance P (SP) is an excitatory neurotransmitter in the central and peripheral nervous system. Most of its physiological functions are mediated through binding to the neurokinin-1 receptor (NK-1R). Recently, proinflammatory properties of SP have been described. In this study we utilized T cell transfer experimental autoimmune encephalomyelitis (EAE) to investigate the role of SP in CNS autoimmune disease. Treatment with the NK-1R antagonist CP-96,345 dramatically reduced clinical and histological signs of EAE if administered before disease onset. The protective effect of CP96,345 treatment was related to a reduced expression of the adhesion molecules ICAM-1 and VCAM-1 on CNS endothelia. The cellular composition or activation status of splenocytes was not affected by CP-96,345 administration, while the secretion of proinflammatory Th1 cytokines was reduced in treated animals. Th2 cytokines remained largely unaffected by NK-1 receptor antagonist treatment. In summary, our findings suggest that the protective effect of CP96,345 treatment is mediated by stabilization of the blood-brain barrier and suppression of Th1 immunity.

Short-lived plasma blasts are the main B cell effector subset during the course of multiple sclerosis.

Multiple sclerosis is a chronic inflammatory and demyelinating disorder of the CNS with an unknown aetiology. Although intrathecal immunoglobulin G (IgG) synthesis is a key feature of the disease, little is still known about the B cell response in the CNS of multiple sclerosis patients. We analysed the phenotype and kinetics of different B cell subsets in patients with multiple sclerosis, infectious disease (IND) and non-inflammatory neurological disease (NIND). B cells were detected in the CSF of multiple sclerosis and IND patients, but were largely absent in NIND patients. In the CSF, the majority of B cells had a phenotype of memory B cells and short-lived plasma blasts (PB); plasma cells were absent from the compartment. The proportion of PB was highest in multiple sclerosis patients and patients with acute CNS infection. While PB disappeared rapidly from the CSF after resolution of infection in IND patients, these cells were present at high numbers throughout the disease course in multiple sclerosis patients. CSF PB numbers in multiple sclerosis patients strongly correlated with intrathecal IgG synthesis and inflammatory parenchymal disease activity as disclosed by MRI. This study identifies short-lived plasma blasts as the main effector B cell population involved in ongoing active inflammation in multiple sclerosis patients.

The immune response at onset and during recovery from Borrelia burgdorferi meningoradiculitis.

BACKGROUND: Borrelia burgdorferi causes a wide range of neurologic syndromes. In Europe, acute meningoradiculitis is the most common manifestation. OBJECTIVE: To address the nature of the immune response during the course of B burgdorferi meningoradiculitis, with special respect to the early and late changes in cerebrospinal fluid (CSF). METHODS: Serial immunophenotyping was performed and cytokine measurements were obtained in the peripheral blood and CSF of 12 European patients with definite B burgdorferi meningoradiculitis. RESULTS: Early during infection and before initiation of treatment, we observed high levels of interleukin (IL) 10, IL-6, and IL-8, and large numbers of B cells and plasma cells in the CSF of most patients. At the same time, we found a mainly unspecific intrathecal antibody synthesis. During resolution of the infection, cytokine levels normalized rapidly and plasma cells disappeared from the CSF. In parallel, the percentage of B cells in the CSF increased over several months, accompanied by rising levels of intrathecally produced B burgdorferi-specific antibodies. CONCLUSIONS: Our findings demonstrate that the early phase of B burgdorferi meningoradiculitis is characterized by a well-coordinated immune response involving specific cytokine release and plasma cell recruitment, followed by a long-lasting, antigen-specific B-cell response in the central nervous system.

The role of the polio virus receptor and the herpesvirus entry mediator B genes for the development of MS.

Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the central nervous system (CNS). Although the cause of MS is still uncertain, it is well accepted that both genetic and environmental factors are important for the development of disease. In this study, we focused on the Polio Virus Receptor (PVR) and Herpesvirus entry mediator B (HVEB) receptor genes, which are located on chromosome 19q13, a region previously linked to MS. Both receptors are expressed in the brain and immune system and play an important role for inter-cellular adhesion and entry of neurotropic viruses to the brain. We identified four new polymorphisms in the PVR gene, which were located in the promoter region and three different exons. All exonic polymorphisms altered the amino acid sequence of the receptor. No new polymorphisms were found in the HVEB gene, but we confirmed a previously identified intronic polymorphism. We analyzed the frequency of the polymorphisms by RFLP analysis in sporadic MS patients, MS families, and healthy controls and determined the surface expression of HVEB and PVR on peripheral blood monocytes. We did not find differences in the frequency of the polymorphisms or surface expression between MS patients and controls. Overall, our findings do not support a role of HVEB and PVR genes in the development of MS.

Multiple sclerosis -- a coordinated immune attack across the blood brain barrier.

Multiple sclerosis (MS) is a chronic disease of the central nervous system (CNS). The acquired immune system plays a central role in the pathogenesis of MS although target antigens and effector mechanisms are still poorly defined. Studies in animal models of infectious or autoimmune encephalomyelitis suggest that the acquired immune response targeting the CNS in MS originates from the periphery. Both T and B cells undergo activation and maturation in the lymphoid system allowing them to cross the blood brain barrier and infiltrate CNS tissue. Within the CNS, they require a local proinflammatory milieu contributed by macrophages and microglia to mediate their effector function which ultimately leads to damage of myelin sheath, oligodendrocytes, and neurons. In the current review, we elucidate the role of the immune system in MS with particular emphasis on activation and migration of immune cells to the CNS, the role of CNS cells in the inflammatory process and the contribution of the immune system to damage and repair. Based on these considerations we discuss new strategies to investigate pathogenetic pathways in multiple sclerosis.

Autosomal dominant congenital nystagmus is not linked to 6p12, 7p11, and 15q11 in a German family.

PURPOSE: Congenital nystagmus (CN) is an eye-movement disorder that usually starts within the first months of life. Autosomal dominant, autosomal recessive, and X-chromosomal pedigree patterns are observed. Causative genes are yet unknown. Several loci were implicated to contain disease-relevant genes for autosomal dominant CN (AD CN). AD CN cosegregated with a balanced translocation of 7;15 in a family. In a large black pedigree linkage was demonstrated to 6p12. DESIGN: In this study, we describe a large German family with AD congenital nystagmus. Linkage of AD in this family was tested with previously implicated loci. METHODS: Affected family members and unaffected members underwent genetic analysis. Key family members underwent ophthalmologic testing and oculography. RESULTS: No linkage of AD CN to the implicated loci on 6p12, and 7p11, and 15q11 was found in this study. CONCLUSION: In the presented pedigree genes on 15q11, and on the assumption of full penetrance, 6p12 and 7p11 are not involved in the development of AD congenital nystagmus.

Stress, depression and antidepressant treatment options in patients suffering from multiple sclerosis.

Stress constitutes a risk factor for diseases where the immune system plays a significant role. Stress is recognized as a possible trigger for flare ups during the course of multiple sclerosis (MS). The disclosure to the patient of the diagnosis of MS, the commencement of immunomodulatory therapy, and the unpredictability and vagaries of disease progression are all sources of stress. Biological stress systems such as the hypothalamic-pituitary-adrenal system and the sympathetic nervous system may influence the pathogenesis and the disease course of MS. The ability to cope with stress may also be impaired, mediated for example by cognitive deficits or loss of abilities and resources as disease progresses or by the high prevalence of concurrent mood disturbances such as depression and chronic fatigue. Psychiatric comorbidities of MS disease or therapy as well as impairments of coping strategies are underrecognized in clinical practice. Treatment plans for depression among MS patients, as the most common psychiatric comorbidity, should be individualized with integrated approaches. Antidepressants are effective for the treatment of depression in MS patients although further clinical research into the neurobiological and psychological bases of depressive disorders in MS patients is clearly needed. In therapy, coping strategies can be enhanced through multidisciplinary assessment of the various challenges and restrictions imposed by the disease and assisting and supporting the patient in addressing these. Exercise, as a form of positive stress (eustress), also has a role in therapy.

Midregional Proenkephalin A and N-terminal Protachykinin A are decreased in the cerebrospinal fluid of patients with dementia disorders and acute neuroinflammation.

Midregional Proenkephalin A (MR-PENK A) and N-terminal Protachykinin A (NT-PTA) are stable fragments of the precursor peptides for enkephalins and substance P, respectively. We measured MR-PENK A and NT-PTA concentrations by sensitive chemiluminescence immunoassays in cerebrospinal fluid (CSF) of 19 neurologically healthy controls (NHC), 28 patients with other neurologic disorders (OND), 70 patients with dementia disorders (38 Alzheimer's disease [AD], 8 dementia with Lewy bodies [DLB], 12 frontotemporal dementia [FTD], and 12 patients with vascular dementia [VD]), and 16 patients with acute neuroinflammation (AN). Median concentrations of NT-PTA were decreased in all patient groups compared to NHC showing significant differences between patients with NHC and AN (p<0.001), OND and AN (p<0.001), FTD and AN (p<0.01) and pAD and AN (p<0.05). Median MR-PENK A levels were lower in patients with OND, dementia disorders (including AD, FTD, DLB and VD) and AN compared to NHC subjects, although this differences did not reach statistical significance (p>0.05). A maximum difference of both proneuropeptide fragments was found between NHC subjects and patients with AN, with a more than 2fold decrease in median NT-PTA and a 1.5fold decrease in median MR-PENK A levels. Concentrations of both proneuropeptide fragments were positively correlated in all patients (r=0.77, p<0.001). Our results indicate alterations of the cerebral PENK A- and PTA-system in both, dementia and acute neuroinflammatory disorders. These neuropeptide systems seem to be highly correlated in healthy and pathological status.