HTLV-I/II survey on hemodialysis patients in Buenos Aires.

Abstract

To the Editor: In 1980, the human T-cell lymphotropic virus type I (HTLV-I) was first recognized as a human retrovirus. It has been considered the causative agent of adult T-cell leukemia or lymphoma and of tropical spastic paraparesis (1). This virus is endemic in several regions of Japan, central and northern South America, and Africa. An estimated 20 million people are infected with it world-wide (2). Human T-cell lymphotropic virus type II was originally isolated from two patients with hairy T cell leukemia (3). There is a wide variation in HTLV-I seroprevalence from one country to another, with the highest prevalence in Jamaica, Trinidad, and Tobago; the southern coastal regions of Colombia in South America; and the island of Kyushu in Japan (4), while HTLV-II has been shown to be endemic among Amerindian populations (5). Previous studies carried out in Buenos Aires, Argentina reported the presence of HTLV-I and HTLV-II in intravenous drug users with a prevalence of 4.2% for each retrovirus (6). Another survey performed in blood donors showed a prevalence of 0.046% and 0.023% for HTLV-I and HTLV-II, respectively (7). To determine the presence of HTLV-I/II, sera from 654 hemodialysis patients attending several hemodialysis centers in Buenos Aires, Argentina were collected during 1994. All sera specimens were screened for HTLV-I/II by particle agglutination (PA) test (Serodia HTLV-I, Fujirebio Inc, Tokyo, Japan). Reactive samples were retested by HTLV-I/II enzyme-linked immunosorbent assay (ELISA) technique (Vironostika HTLV-I Microelisa System, Organon Teknika Corporation, Durham, North Carolina, U.S.A.). Reactive and discordant results by both tests were assayed by an in-house indirect immunofluorescence assay (IFA), using an HTLV-I transformed human T-cell line (MT-2) and an HTLV-II cell line (MOT) to differentiate HTLV type I and type II (8,9). All samples were later confirmed by Western blot (WB) technique (HTLV BLOT 2.3, Diagnostic Biotechnology (Pte) Ltd., Singapore). A specimen was considered positive for HTLV-I when fulfilling the following criteria: reactivity to gag (p19 or p24), env (gp46 or rgp 46-I); and rpg 21; and for HTLV-II with gag (p24), env (rgp46-II), and rgp21. Of the 654 samples studied, 648 (99.47%) were negative; 5 (0.52%) indeterminate; and only 1 (0.10%) proved to be positive for HTLV-I. As shown in Table 1, PA test demonstrated many false-positive reactions. Although other studies show that this test is a sensitive and specific assay for the detection of HTLV-I/II, IFA results agreed with those of ELISA and WB tests. On the other hand, of the five indeterminate results by WB, four reacted with gp21. Interestingly, the other one showed a banding pattern with gp21 and rgp46-II, which could be an HTLV-II seroconversion. The finding of one patient infected with HTLV-I and a possible seroconversion for HTLV-II among the total patients studied, indicated that HTLV infection is rare in hemodialysis patients and suggests that hemodialysis is not a significant risk factor for HTLV infection. Claudia DeVito; Sandra Pampuro; Noemi Del Pino; Liliana Martinez Peralta; Osvaldo Libonatti National Reference Centre for Aids; Department of Microbiology; University of Buenos Aires; School of Medicine; Buenos Aires, Argentina