title: Peripheral neuropathy associated with chronic natural killer cell lymphocytosis.
abstract: We report a patient with steroid-responsive peripheral neuropathy which developed with chronic natural killer cell lymphocytosis (CNKL). A 70-year-old female with a 2-week history of progressive motor and sensory neuropathy showed a marked increase of natural killer (NK) cells in the blood, and was diagnosed as having CNKL. Nerve conduction studies (NCS) revealed a mixed axonal and demyelinating neuropathy. A sural nerve biopsy revealed infiltration of NK cells into the nerve fascicles, and demyelinating changes with axonal degeneration. The infiltrating NK cells were adjacent to myelinated fibers, showing damage of Schwann cell membrane. Treatment with oral prednisolone resulted in rapid improvement of the sensory disturbance and weakness with a significant decrease of NK cells in the blood and disappearance of the conduction blocks in NCS. This is the first case of CNKL associated neuropathy in which infiltration of NK cells was demonstrated in the nerve fascicles. Our observations suggest that the infiltrating NK cells may directly damage myelin and Schwann cells, thus causing demyelination.
authors.affiliation: Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Science, 13-1 Takara-machi, Kanazawa 920-8641, Japan. noguchim@med.kanazawa-u.ac.jp
authors.forename: Moeko
authors.initials: M
authors.lastname: Noguchi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshita
authors.forename: Kenji
authors.initials: K
authors.lastname: Sakai
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Masahisa
authors.initials: M
authors.lastname: Arahata
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ontachi
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takami
authors.forename: Shinji
authors.initials: S
authors.lastname: Nakao
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Sato
authors.forename: Masahito
authors.initials: M
authors.lastname: Yamada
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000368:Aged; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D003711:Demyelinating Diseases / Q000473:pathology; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural; D018655:Lymphocyte Count; D008218:Lymphocytosis / Q000150:complications* / Q000473:pathology; D009431:Neural Conduction; D009460:Neurologic Examination; D010523:Peripheral Nervous System Diseases / Q000209:etiology* / Q000473:pathology; D011241:Prednisone / Q000627:therapeutic use; D013497:Sural Nerve / Q000473:pathology
chemical_list: D000893:Anti-Inflammatory Agents; D011241:Prednisone