June 2017

 

EMTICS cohort studies and database management

EMTICS is now entering its final phase, i.e. data analysis. The past 6 months have been dedicated to a very intensive and laborious data cleaning process which is now at its final act, thanks to the constant dedication of Andrea Dietrich and Pieter Hoekstra in UMCG, Groningen, Zachos Anastasiou, statistician working at the UCL site, and the Database team of the Istituto Superiore di Sanita’ (ISS) in Rome.
Over the past weeks this task force has been very active in obtaining an error-free statistical database, containing all clinical and laboratory data. They have been in contact with all clinical sites with regard to visit date/type inconsistencies.
Many thanks to all sites for their very helpful responses!
As a result of this effort:
•    314 visits that had not yet been closed have now been entered/closed;
•    167 visits with an incorrect visit date have been identified;
•    160 visits with incorrect type or visit numbering have been identified;
•    137 visits that needed to be deleted have been identified (as were erroneously entered fake visits).
It is really crucial that we now have correct visit dates as we aim to find longitudinal associations between infections and stressful events to the clinical course of symptoms over time (and then even one wrong visit date could ruin the analyses of a participant).
We are now also in the final stages of having a fully workable numerical output plus codebook. Furthermore we have coupled the lab data (all serum results, hair cortisol, DNA, RNA and throat swab results) to the correct visits, which will become part of the overall statistical database.
As next steps, we will again contact all clinical sites, this time to clarify improbable or missing clinical data entries (of which we have already identified quite a few). This is a very important part of the cleaning as we obviously need to have correct and complete values for the clinical ratings (including the core ratings of tic, ADHD and OCD severity) as we aim to relate these to the various lab results.
As a final update we are pleased to mention that Andrea has been co-ordinating the entries of the weekly diaries of all participants. This is allows us to obtain many more time-points of tic severity fluctuations than we have been able to identify through the visits.
At the current stage of follow-up (mean duration 1.35 years), 260 participants have been recruited in ONSET, and 55 of these 260 (21%) manifested a new onset of tics. In the COURSE study, 716 patients were enrolled and have been followed up to date for a mean duration of 1.07 years; 181 (25%) underwent at least one clinically relevant exacerbation, for a total number of 213 exacerbations of tics from the whole cohort.

Immunological studies in EMTICS
The analysis of immune markers from serum and whole blood of cohort participants is a key component of the EMTICS study, managed by our LMU partners. The analyses focusing on the adaptive cellular immune response have been finalized. Serum sample testing has been completed with respect to streptococcal serology, cytokines and soluble immune factors, as well as monomeric and pentameric C-reactive protein. Analyses of anti-neuronal antibodies are ongoing. Serological assays for different non-streptococcal pathogens and tryptophan pathway intermediates have been established and will be conducted in the last trimester of 2017.

Exploring psychosocial stress
Workpackage 8 of EMTICS investigates the influence of stress on the tic fluctuations. At the present stage the TU Dresden group continues its analyses of cortisol in hair samples of all patients. The analyses will be completed at the end of July 2017. In addition to questionnaires, reports and observations, this biomarker is important for estimating the influence of psychosocial stress on tic severity. Therefore the results will be included in the database at the end of July. Furthermore, some analyses of hair samples from mice investigated at the Istituto Superiore di Sanita’ (ISS) in Rome have been conducted (see next paragraph).

Animal model studies
These studies have been conducted at the Istituto Superiore di Sanita’ (ISS) in Rome. The studies conducted in previous years showed that repeated exposure to GAS injections resulted in behavioural and neurochemical alterations isomorphic to TS/PANDAS symptoms. In previous studies our partners also demonstrated that neonatal exposure to corticosterone (an experimental paradigm to mimic neonatal stress) compensated for most of the identified abnormalities.
An independent study was performed to investigate whether exposure to social stress during development (i.e. at the same time in which mice were exposed to GAS administration) modulated the TS-like phenotype in a different way compared to neonatal exposure to stress. Social stress was operationalised through the presence of an aggressive mouse in the same cage in which the focal mouse was housed: although mice were constantly in visual contact, physical interaction was limited to a maximum of 10 minutes per day. In this study our partners replicated the finding that GAS exposure induces alterations in phenotypes isomorphic to TS symptoms. Exposure to social stress altered the individual phenotype independently of GAS administration. However, exposure to social stress neither normalised nor deteriorated the GAS-dependent phenotype.
Blood and brain samples from these mice will be investigated through immunological and neurochemical analyses.


We are all looking forward to the crucial work that will be undertaken in the next months and to the final general assembly that will take place in Mallorca (May 2018)!