HAMの発生病理

HTLV-I-associated myelopathy: Clinical and neuropathological observations.

I．はじめに

　1986年，納ら^11）は成人男女に発症し，鹿児島地方に頻度の高い膀胱障害・感覚障害を伴う痙性脊髄麻痺について，患者の血清，髄液にhuman T-lymphotropic virustype I（HTLV-I）の抗体価が全例で高いことを指摘し，HTLV-I-associated myelopathy（HAM）として，新しい疾患概念を提唱した。以後，HTLV-Iの保有者の多い九州・沖縄地域を中心にこの疾患は全国的な広がりをもち，ミエロパチーの重要な鑑別疾患の一つとされるにいたった。一方，カリブ海地域・南インドなど熱帯地方に慢性の経過をとるtropical spastic paraparesis（TSP）の存在が知られ，この患者の多くは血清抗HT-LV-I抗体価が上昇しており，HAMと同一疾患である可能性が示唆され，HAMとの病理学的所見の対比が望まれた。本論文では，われわれが経験した臨床例と，本症最初の剖検所見につき論じたい。

　Eight cases of HTLV-I associated myelopathy (male: 1, female: 7) including an autopsy case were reported. The main clinical manifestations were spastic paraparesis with pyramidal signs, urinary disturbance and slight sensory disturbances. Examination of cerebrospinal fluid revealed slight increase of cell count, protein and γ-globulin levels and positive oligoclonal IgG bands. Serum and cerebrospinal fluid antibodies against HTLV-I were positive. ATL-like atypical lymphocytes were detected in both serum and cerebrospinal fluid.

　Neuropathology of one fatal case, which had blood transfusion 6 months prior to the onset, showed atrophy of spinal cord especially the thoracic cord. The most striking changes, in both the white and grey matter, were the marked proliferation of capillaries, perivascular cuffing with lymphocytes, and loss of myelin and axon. There were also proliferation of gemistocytic astrocytes and infiltration of foamy macrophages. These changes were severer in the lateral and anterior columns. Perivascular cuffing with lymphocytes were also seen in the medulla, pons, cerebellum and cerebral white matter. In the subarachnoid space, collagenous thickning and partial adhesion with lymphocytic infiltration were observed. Blood vessels, particularly small veins, in the cord and the subarachnoid space showed hyalinoid thickening of media and adventitia associated with intramedial and intra- and periadventitial lymphocytic infiltration.