The close interconnection between nervous system and the immune system is well known. Brain injuries lead to homeostasis disruption. On the one hand they result in increased brain inflammation contributing to tissue repair, at the expense of a possible extension of tissue damage. On the other hand, they lead to systemic down-regulation of innate and adaptive immunity, determining higher vulnerability to infections, responsible of death and comorbidities in the acute and subacute setting.

Aim of the study was to evaluate the role of immunosuppression in the neurorehabilitation pathway in patients with stroke.

The perfect balance between nervous and immune system could be severely impaired after brain injuries, such as strokes.

In the acute phase, inflammatory mediators are responsible of central nervous system inflammation, associated to tissue repair at the expense of possible secondary brain injury or damage expansions.

In the mean time, activation of hypothalamic-pituitary-adrenal axis and the autonomic nervous system determine downregulation of innate and adaptive immunity, with decreased circulating T cell count and reduced lymphocytic response. The degree of these changes is linked to the severity of brain damage and inevitably lead to higher vulnerability to infections, representing a negative prognostic factor in the acute phase.

Association between immunosuppression and functional outcome in the neurorehabilitation setting are missing.

Aim of this study was to evaluate the role of immunosuppression in the neurorehabilitation journey in patients with stroke.

We analyzed the neutrophil-to-lymphocyte ratio, a useful tool to investigate alterations in both the innate and adaptive immune systems. We correlated it to clinical and neurorehabilitation scales, investigating disability, functional status, as well as gait analysis and occurrence of infectious complications. All outcomes were measured on admission in Neurorehabilitation setting and at hospital discharge.

Inclusion Criteria:

• diagnosis of first episode of ischemic stroke or primary spontaneous intracerebral haemorrhage (both confirmed by proper neuroimaging)
• admission to the Neurorehabilitation ward within 30 days from the index event

Exclusion Criteria:

• medical history of immunodeficiency or immunoproliferative disease
• immunosuppressive or immunomodulating therapy in the year before the index event
• systemic steroids in the six months before the index event
• Glasgow Coma Scale < 8 at hospital admission
• other diagnosis of neurological diseases
• missing clinical/demographic data

Participants were selected from a single centre cohort admitted for stroke rehabilitation at the Neurorehabilitation Unit of the IRCCS Mondino Foundation (Pavia, Italy).

Raw data will be uploaded in the online Zenodo platform and available to other Researches upon reasonable request.