IL-11 in the Development of Multiple Sclerosis

Immunomodulatory therapies are most effective when administered early in the course of
relapsing remitting multiple sclerosis (RRMS). Therefore, investigators are seeking
biomarkers of the autoimmune response to accurately identify patients with clinically
isolated syndrome (CIS), the earliest phase of the disease. Investigators' preliminary
studies have identified IL--11 as the most significantly increased cytokine in the serum and
cerebrospinal fluid (CSF) of CIS patients. Serum IL--11 and IL--17A levels correlate with
brain MRI T2 and T1 lesion load and were significantly increased during clinical
exacerbations in comparison to disease remissions in untreated RRMS patients. Investigators
also found that IL--11 induces Th17 cell differentiation and expansion in CIS patients.
Investigators' human studies have identified that CD4+ cells represent the predominant source
of IL--11 within the peripheral circulation. In comparison to healthy controls (HCs),
IL--11+CD4+ cells from CIS patients were significantly increased in the peripheral
circulation and exhibited the highest CCR6 expression (86 %) among CD4+ T cell subsets. This
implied their potential for early migration to the CNS. Indeed, IL-11+CD4+ cells were
significantly enriched in the CSF of RRMS patients in comparison to their matched blood
samples (40.9 vs. 2.3%), with the most prominent increase in the number of
IL--17A+IL--11+CD4+ cells. Immunohistochemistry studies of active brain MS lesion biopsy
samples revealed an enrichment of IL--11+ cells within CD4+ infiltrating cells, suggesting
their important role in the development of inflammatory CNS lesions. Animal studies have
confirmed the causal role of IL--11 in the exacerbation of RR experimental autoimmune
encephalomyelitis (EAE), where IL--11 increased the number of central nervous system
(CNS)--infiltrating IL-17A+CD4+ cells in comparison to control mice with EAE, reflecting
IL--11 induction of CCR6 expression in CD4+ cells. IL--11Ra KO mice had an attenuated EAE
clinical course and lower serum IL--17A levels, as well as lower numbers of Il--17A+CD4+
cells in the brain and spinal cord inflammatory infiltrates, similar to the IL23p19 KO mice.
Administration of mouse anti IL--11R mAb in the preclinical phase of EAE induced a delayed
onset and decreased disease severity, with decreased IL--17A serum levels. The objectives of
this study are to (1) identify the molecular mechanisms involved in the IL--11--induced
migration of CD4+ cell subsets to the CNS, (2) Functionally characterize CSF--enriched
IL--11+CD4+ cells in CIS patients, (3) examine the potential of IL--11 to induce
encephalitogenic CD4+ cells, and determine the therapeutic effect of anti IL--11R mAb in
RREAE.

Specific Aims:

Aim 1. Characterize the IL--11--induced migration of CD4+ cell subsets in CIS patients.

1.A. Identify signaling pathways involved in the IL--11--induced migration of CD4+ cell
subsets to the CNS. Investigators will identify IL--11--stimulated signaling pathways
mediating expression of CCR6 and adhesion molecules on CD45RO+ cells.

1. B. Determine direct chemotactic effect of IL--11 in CD4+ cell subsets. In vitro
migration assays will determine a direct chemotactic effect of IL--11 on the migration
of CD4+ cell subsets through the endothelial cell (EC) barrier.

Aim 2. Identify the transcriptional profile and TCRVb repertoire of CSF--enriched
IL--11+CD4+ cells from CIS patients.

2. A. Characterize the phenotype and transcriptional profile of CSF--enriched IL--11+CD4+
cells. Flow cytometry phenotyping and RNA sequencing will be performed on IL--11+CD4+
cells from CSF and matched blood samples.

2.B. Determine the TCRVb repertoire of CSF IL--11+CD4+ cells. Identify whether they can be
tracked to the peripheral circulation.

Aim 3. Characterize the role of IL--11 in the induction of encephalitogenic CD4+ cells.

3.A. Determine the capacity of IL--11 to induce encephalitogenic CD4+ cells. In vivo
experiments will test the effect of IL--11 on the encephalitogenic capacity of CD4+ cells.

3.B. Determine the efficacy of anti IL--11R mAb in preventing and suppressing RREAE. Mice
with RREAE will be treated prior to and during the clinical flare--ups and the remission of
the disease. The therapeutic effect of anti IL--11R mAb will be characterized via the
clinical response, immunohistochemistry, and flow cytometry studies of CNS infiltrating
cells.

Inclusion Criteria:

First clinical presentation and at least two central nervous system MRI lesions consistent
with demyelinating disease;

Age 18-65 inclusive;

Extended disability status score (EDSS) 1.5-5.5;

No immunomodulatory or immunosuppresive therapy prior to the enrollment in the study.

Exclusion Criteria:

Concomitant infection;

Significant medical and psychiatric condition at the disgression of principal investigator;

Pregnant women;

Children and patients participating in research trials will not be enrolled in this study.