Patients with Chronic Spinal Cord Injury Display a Progressive Alteration over the Years of the Activation Stages of the T Lymphocyte Compartment

Abstract

Spinal cord injury (SCI) is a serious medical condition associated with severe morbidities and disability. Chronic SCI patients present an enhanced susceptibility to infections and comorbidities with inflammatory pathogenesis. Chronic SCI appears to be associated with a systemic dysfunction of the immune system. We investigated the alteration of the pivotal CD4+ and CD8+ T lymphocytes in patients with chronic SCI at different years of evolution. A clinically homogenous population of 105 patients with chronic SCI (31 with time of evolution less than 5 years (SCI SP); 32 early chronic (SCI ECP) with time of evolution between 5 and 15 years; and 42 late chronic (SCI LCP) with time of evolution more than 15 years) and 38 healthy controls were enrolled. SCI ECP and SCI LCP patients showed significant CD4+ and CD8+ T lymphopenia, ascribed to a reduction in naïve and CM subsets. Furthermore, SCI ECP and SCI LCP patients showed a significant reduction in the expression of CD28 on CD8+ T lymphocytes. The expression of CCR6 by CD4+ T lymphocytes was decreased during the evolution of chronic SCI, but on CD8+ T lymphocytes, it was observed during the first 15 years of evolution. In conclusion, the chronic SCI course with severe damage to T lymphocytes mainly worsens over the years of disease evolution.