Preserved granulocyte formation and function, as well as bone marrow innervation, in subjects with complete spinal cord injury.

Patients with a spinal cord injury are at risk of infections and is partly attributed to immobilization. Their lymphocyte-mediated immunity is impaired and the growth of blood progenitor cells is reduced. An adequate immune response depends on granulocytes being mobilized rapidly and activated properly, at the inflammatory site. Possibly this requires a coordinated interaction between the autonomous nervous system and cells within the haematopoietic bone marrow. Granulocyte function in the spinal cord injured has not been evaluated. Although there is evidence that the bone marrow in rodents is innervated, it is uncertain whether human bone marrow is similarly affected. Microscopy and immunolabelling followed by flow cytometry, showed that blood and bone marrow counts of leucocyte subsets were similar in paraplegic, tetraplegic and control subjects (P > 0.05). Neutrophilic migration and oxygen consumption, as well as eosinophil activation, assayed as release of eosinophilic cationic protein or CD69 expression, were not altered after spinal cord injury (P > 0.05). Cryostat sections of human bone marrow biopsies stained positive with glyoxylic acid, indicating the presence of catecholamine-containing nerves in both the patients and the controls. We conclude that terminal differentiation and formation of granulocytes, as well as their functional capacity, do not depend appreciably on supraspinal nervous regulation.