Histopathological analysis of four autopsy cases of HTLV-I-associated myelopathy/tropical spastic paraparesis: inflammatory changes occur simultaneously in the entire central nervous system

Abstract

Although brain lesions have been described in some cases with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), little is known about the nature of brain lesion and its relation to the spinal cord lesion. In the present study, we performed histopathological analysis of the brain and the spinal cord of four autopsied cases with HAM/TSP to clarify the relationship between the brain and the spinal cord lesions. In two cases with active-chronic inflammation in the spinal cord, perivascular inflammatory infiltration was also seen in the brain, and the composition of cell subsets was similar both in the spinal cord and in the brain. No active inflammatory change was seen in the brain in two cases with inactive-chronic spinal cord lesions. Inflamed vessels were distributed mainly in the deep white matter and in the area between cerebral cortex and white matter of the brain. In the spinal cord inflamed vessels were mainly seen in the bilateral lateral and the ventral posterior columns. Parenchymal infiltration was diffused in the spinal cord but very sparse in the brain, suggesting the importance of parenchymal infiltration in the destruction of tissues. These results suggest that inflammatory changes occurred simultaneously in the spinal cord and in the brain, and that distribution of inflamed vessels closely correlated with the characteristics of vascular architecture of the brain and the spinal cord, which lead to a slow blood flow. This study may help promote a better understanding of the pathogenesis of HAM/TSP.

HAM/TSP: association between white matter lesions on magnetic resonance imaging, clinical and cerebrospinal fluid findings

“…Cerebral atrophy was observed in 14% of our patients with HAM/TSP. In the study by Griffith et the mechanisms of brain atrophy are the same responsible for spinal cord atrophy secondary to degeneration of the parenchyma 26 . Cervilla et al did not show hyperintense lesions in the spinal cord of patients with HAM/TSP, but 87% had atrophy of the dorsal segment 18 .…”

The motor evoked potential in aids and HAM/TSP State of the evidence

“…Others suggested that the involvement of posterior and lateral columns is an independent degenerative process. We would favor the first hypotheses because it has been demonstrated, in recent neuropathological research that the entire CNS is affected simultaneously 46,52 . Thus, the lack of correlation between CMCT obtained by TMS and somatosensory evoked potentials, in some groups of patients, could be due more to disease duration than the anatomical distribution of the lesion.…”

Neuropathology of two Brazilian autopsied cases of tropical spastic paraparesis / HTLV-I associated myelopathy (TSP/HAM) of long evolution

“…The autopsied cases of long evolution are very few in the literature 8,[10][11][12]15,17 . The two Iwasaki's 8 cases of long evolution (19 and 28 years, respectively) were typical clinical TSP/HAM and, neuropathologically, "neither lymphocytic nor monocytic cell infiltration was seen in markedly devastated and shrunken parenchymal tissues".…”

“…Peripherally, the spinal ganglia exhibited slight lymphocytic infiltration, and the peripheral nerves and muscles were normal. Aye et al 17 analyzed four cases with, respectively, 7, 9, 15 and 24 years of illness duration, with incapacitating clinical signs in the three first ones, without, however, clinical cerebral signs. Their long evolutive cases (15 and 24 years, respectively) had degeneration of the lateral corticospinal tract and of the spinocerebellar or spinothalamic tracts.…”

“…There are around 34 autopsied TSP/HAM cases described in the world [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] . This number of cases is limited, since León et al 18 , in a world meta-analytical analysis, reported on 1261 cases of TSP/HAM.…”