PROGRESSION OF NEUROLOGICAL DISABILITY IN HTLV-I-ASSOCIATED MYELOPATHY TROPICAL SPASTIC PARAPARESIS (HAM TSP)/

HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is apparently a disease with a chronic evolution without spontaneous rem issions. The real profile of its natural history and of the progressio n of the neurological disability, however, awaits confirmation. We dev ised the present study to evaluate the progression profile of the neur ological disability of HAM/TSP in a series of 43 patients who have nev er received any kind of previous immune therapy. Patients were divided into different groups according to the duration of their disease. Age , gender and the Kurtzke's disability status scale (DSS) at the time o f the first examination were compared. There were no statistically sig nificant differences among groups with different disease duration. The present study suggests that the evolution of the neurological disabil ity in HAM/TSP occurs mainly during the first year of the disease and becomes relatively stable after that. Therefore we speculate that the variable therapeutic success rates observed in many series of the lite rature could be due to the timing in the beginning of the pharmacologi cal immunessupression. Probably the therapeutic window in HAM/TSP lies within the first year of the disease. Thus it might be of utmost impo rtance that future therapeutical trials take into consideration the du ration of the disease since this factor can play an important role in the results of the trial.