Depressed immunity and impaired proliferation of hematopoietic progenitor cells in patients with complete spinal cord injury

Abstract

The bone marrow is supplied with both sensory and autonomic neurons, but their roles in regulating hematopoietic and immunocompetent cells are unknown. Leukocyte growth and activity in patients with stable and complete spinal cord injuries were studied. The innervation of the bone marrow below the injury level lacked normal supraspinal activity, that is, a decentralized bone marrow. Lymphocyte functions were markedly decreased in injured patients. Long-term colony formation of all hematopoietic cell lineages, including dendritic cells, by decentralized bone marrow cells was substantially reduced. It was concluded that nonspecific and adaptive lymphocyte-mediated immunity and growth of early hematopoietic progenitor cells are impaired in patients with spinal cord injuries. Possibly, this reflects cellular defects caused by the malfunctioning neuronal regulation of immune and bone marrow function.

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

“…Hence it appears that the ability to mount a nonadaptive granulocytic response remains intact in the patients. This contrasts somewhat with our previous observation that the lymphocyte-mediated non-specific (NK cell) and adaptive (B and T lymphocyte) immunity were markedly reduced in otherwise healthy subjects with spinal cord injury (Iversen et al, 2000). The numbers of blood leucocyte subsets were apparently not different among the three study groups.…”

“…The numbers of the very immature, uncommitted CD34 + CD38 ) cells never exceeded 2% of the total number of CD34 + cells, and were similar among the three study groups (data not shown). Although the numbers of these early progenitor cells are apparently unchanged in spinal cord injured subjects, their proliferative capacity was found to be substantially reduced when assessed in vitro as the colony growth of long-term colony initiating cells (Iversen et al, 2000).…”

“…These patients lack supraspinal activity and develop a decentralized autonomous nervous system below the injury level. In these subjects we demonstrated impaired growth of haematopoietic progenitor cells, and reduced lymphocyte-mediated immunity (Iversen et al, 2000), suggesting that the nervous system can modify blood cell formation and function.…”

Spinal cord injury, immunodepression, and antigenic challenge

“…Yes [25,32,40] HLA-DR Reduced expression (blood) N/D [25,35] B lymphocyte Reduced number (immature and mature), genesis, and humoral function; more pronounce deficiency in centralized tissues (spleen, BM). Secondary humoral response is unaffected (spleen)…”

Factors implicated in pathogenesis of urinary tract infections in neurogenic bladders: some revered, few forgotten, others ignored

“…This reduced lymphocyte activity most likely reflects a qualitative defect. 21 Data on granulocyte function though, is more controversial, with some concluding that neutrophils have a significantly impaired phagocytic function, for example, in complete tetraplegics while others have reported that granulocyte function is normal in SCI patients. 22,23 Cerebral stroke may also result in immunosupression, possibly as a result of sympathetic signaling to the lymphoid organs.…”