New insights into the pharmacokinetics and pharmacodynamics of natalizumab treatment for patients with multiple sclerosis, obtained from clinical and in vitro studies

BACKGROUND

The monoclonal antibody natalizumab (NAT) inhibits the migration of lymphocytes throughout the blood-brain barrier by blocking very late antigen (VLA)-4 interactions, thereby reducing inflammatory central nervous system (CNS) activity in patients with multiple sclerosis (MS). We evaluated the effects of different NAT treatment regimens.

METHODS

We developed and optimised a NAT assay to measure free NAT, cell-bound NAT and VLA-4 expression levels in blood and cerebrospinal fluid (CSF) of patients using standard and prolonged treatment intervals and after the cessation of therapy.

RESULTS

In paired CSF and blood samples of NAT-treated MS patients, NAT concentrations in CSF were approximately 100-fold lower than those in serum. Cell-bound NAT and mean VLA-4 expression levels in CSF were comparable with those in blood. After the cessation of therapy, the kinetics of free NAT, cell-bound NAT and VLA-4 expression levels differed. Prolonged intervals greater than 4 weeks between infusions caused a gradual reduction of free and cell-bound NAT concentrations. Sera from patients with and without NAT-neutralising antibodies could be identified in a blinded assessment. The NAT-neutralising antibodies removed NAT from the cell surface in vivo and in vitro. Intercellular NAT exchange was detected in vitro.

CONCLUSIONS

Incorporating assays to measure free and cell-bound NAT into clinical practice can help to determine the optimal individual NAT dosing regimen for patients with MS.

Determination of seven selected neuro- and immunomodulatory steroids in human cerebrospinal fluid and plasma using LC-MS/MS

Dehydroepiandrosterone (DHEA) and its 7-oxo- and 7-hydroxy-metabolites occurring in the brain are considered neurosteroids. Metabolism of the latter is catalysed by 11β-hydroxysteroid dehydrogenase (11β-HSD) which also interconverts cortisol and cortisone. The concurrent metabolic reaction to DHEA 7-hydroxylation is the formation of 16α-hydroxy-DHEA. The LC-MS/MS method using triple stage quadrupole-mass spectrometer was developed for simultaneous quantification of free DHEA, 7α-hydroxy-DHEA, 7β-hydroxy-DHEA, 7-oxo-DHEA, 16α-hydroxy-DHEA, cortisol and cortisone in human plasma and cerebrospinal fluid (CSF). The method employs 500 μL of human plasma and 3000 μL of CSF extracted with diethyl ether and derivatized with 2-hydrazinopyridine. It has been validated in terms of sensitivity, precision and recovery. In plasma, the following values were obtained: limit of detection: 2-50p g/mL; limit of quantification: 5-140 pg/mL; within-day precision 0.58-14.58%; between-day precision: 1.24-13.89% and recovery: 85-113.2%). For CSF, the values of limit of detection: 2-28 pg/mL; limit of quantification: 6-94 pg/mL; within-day precision; 0.63-5.48%; between-day precision: 0.88-14.59% and recovery: 85.1-109.4% were acquired. Medians and concentration ranges of detected steroids in plasma and CSF are given in subjects with excluded normal pressure hydrocephalus (n=37; 65-80 years). The method enables simultaneous quantification of steroids important for the estimation of 11β-HSD activity in human plasma and CSF. It will be helpful in better understanding various degenerative diseases development and progression.

Interleukin-10 and tumor necrosis factor-alpha: model of immunomodulation in multiple sclerosis

OBJECTIVES

The mechanisms involved in the pathogenesis of relapsing-remitting multiple sclerosis are still unclear. The aim of the present study was to evaluate both cerebrospinal fluid (CSF) CD4+ CD7+ T cells and peripheral blood (PB) interleukin-10 (IL-10) as well as tumor necrosis-alpha (TNF-alpha) levels in patients with definite multiple sclerosis of the relapsing-remitting type.

METHODS

To assess the above-mentioned cytokine levels we performed our test by the means of ELI-spot assay; the T-helper cell subset was assayed using flow cytometry.

RESULTS

PB IL-10 levels of multiple sclerosis (MS) patients in remission were significantly (p<0.001) higher than in MS patients in the active phase. There was significant and increased evidence of TNF-alpha levels only in the MS patients in the active phase. CD4+ CD7+ T cells, characterized by a preferential Th1-like cytokine profile, were detectable only in seven patients in the active phase without evidence of a statistical significance with respect to cytokine levels.

CONCLUSION

The data indicate that the production of different cytokines characterized the expression of relapsing-remitting MS. The data also suggest that is it possible to control MS using the regulatory cytokine balance.

[The immunologic factors in cerebrospinal liquor under bacterial, fungous or parasitic neuro-infections: a literature review]

The prognosis of course and outcome of inflectional inflammatory diseases of central nervous system, indicators of inflammatory reaction and immune response in cerebrospinal liquor in patients has been investigated.

[The utility of QuantiFERON TB Gold for diagnosing tuberculous meningitis in children]

MATERIAL AND METHODS

We performed QuantiFERON-TB Gold in Tube (QFT-G) in blood and CSF at 40 children diagnosed with TB meningitis and at 39 children with non TB meningitis, admitted between October 2006 and December 2009.

RESULTS

The CSF analyses were suggestive for TB at 27 patients and only 14 had positive culture. The sensitivity of QFT-G in CSF was 72.72% and 69.44% in blood; specificity 96.96% in CSF and 89.18% in blood; the positive predictive value was 96% in CSF and 86.2% in blood; negative predictive value was 78.04% in CSF and 75% in blood. The sensitivity of TST was 61.76% and specificity 82.05%. The sensitivity of the culture from CSF was only 35%. The sensitivity and specificity of QFT-G was higher than TST and culture and better in CSF than in blood.

CONCLUSIONS

The determination of alpha-interferon in serum and CSF is useful diagnostic marker of tuberculosis who could improve the management of TB meningitis.

Correlation of CSF proinflammatory cytokines with MRI in tuberculous meningitis

RATIONALE AND OBJECTIVES

To demonstrate the correlation of proinflammatory cytokines (PCs), intercellular adhesion molecule (sICAM-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) in CSF of tuberculous meningitis (TBM) patients with magnetic resonance imaging (MRI) including diffusion tensor imaging (DTI) and also to look for the changes in imaging parameters after antitubercular treatment (ATT) in these patients.

MATERIALS AND METHODS

Forty patients with TBM (median age, 27.7 years) and 30 age-/sex-matched controls were included in this study. PCs were quantified from the CSF of TBM patients at the time of hospital admission (baseline). MRI including DTI was performed at the time of baseline study and 6 months after ATT.

RESULTS

Significant positive correlation of PCs with fractional anisotropy (FA) values and post-contrast signal intensity (PCSI) collected from cerebral cortical regions was observed in TBM patients. A significant positive correlation of FA values with PCSI was also observed at both time points in patient groups. At baseline study significantly high FA values were observed in patients compared to controls. Significantly decreased FA values and PCSI were observed in the patients after 6 months of ATT compared to the baseline study.

CONCLUSIONS

Results of this study suggest that the DTI-derived anisotropy have the potential to delineate meningeal inflammation and it may be used in assessment of therapeutic response in TBM patients as an additional method to conventional imaging.