Identifying hearing impairment in infants and young children.

important problem in serological screening is the tendency for false positive results to arise owing to "sticky serum" or "ccross reactivity." This problem with specificity can now be overcome by using such tests as the western blot or the polymerase chain reaction. In the study of Brennan and colleagues 2-5% of the 96720 blood donors initially were positive for HTLV-I; only 35 of those were positive on one of two enzyme linked immunosorbent assays (but not true positives) and only five were truly infected with HTLV-I.' Of these five, four were white women with sexual contact as a risk factor, and one a drug misuser. The authors argue that selective screening based solely on ethnic origins would not exclude HTLV-I infection. Additionally , they discuss the risks of blood borne HTLV-I infection and developing diseases against the costs of screening and counselling, as well as the cost per infection prevented and diseases contracted. Screening does not seem to be cost effective in Britain at present. Nevertheless, the issues of what other countries are doing, consumer protection, and product liability make the decision to screen blood donors non-selectively extremely complex. The incidence of infection in Britain so far is too low and the incubation time too long to justify screening all blood samples. As far as product liability and consumer protection are concerned, achieving zero risk is impossible given the remote chance that a seronegative specimen may give a positive result on testing with the polymerase chain reaction and that testing every specimen in this way could be prohibitively expensive. Meanwhile, the situation should be kept under regular review. Trends in seroprevalence may be more important indications for action than absolute values. Search for human T-cell leukemia virus type 1 (HTLV-1) proviral sequences by polymnerase chain reaction in the central nervous system tissue ofHTLV-1-associated myelopathy. tropical spastic paraparesis virus culture and serological responses. High human T cell lymphotrophic virus type 1 (HTLV-1) specific precursor cytotoxic T lymphocyte frequencies in patients with HTLV-1-associated neurological disease. Abnormal in vitro proilferation and differentiation of T cell colony-forming cells in patients with tropical spastic paraparesis/human T lymphocyte virus type 1 (HTLV-1)-associated myeloencephalopathy and healthy HTLV-1 carriers. Activated, HTLV-1-specific cytotoxic T-lymphocytes are found in healthy seropositives as well in patients with tropical spastic paraparesis. HTLV-1 in vivo infected T cells clones IL-2-independent growth of nontransformed T cells. Dendritic cells infected in vitro with human T cell …