Infection without antibody response in mother-to-child transmission of HTLV-I in rabbits

Adult T-cell leukemia/lymphoma in northeastern Brazil: a clinical, histopathologic, and molecular study

The state of Bahia in the northeastern coast of Brazil is a region in which HTLV-I infection is endemic. This study investigated the characteristics of 28 HTLV-I-associated lymphomas/leukemias in this region. HTLV-I-infection diagnosis was based on serologic study, Southern blot analysis, and polymerase chain reaction (PCR) in neoplastic tissue. The main clinical differences between these lymphomas and adult T-cell leukemia (ATL) cases from other endemic areas were as follows. The mean age was 47 years; 20% of the cases occurred in young adults; and a predominance was found among male subjects (2:1), blacks, and of those of mixed race (96%). Histologically, 20 cases were T-cell pleomorphic leukemia/lymphoma, 5 were Mycosis fungoides-like cutaneous lymphoma, and 3 were CD30+ large-cell anaplastic lymphoma. Immunohistochemistry demonstrated 4 cases of CD8+ lymphoma. Proviral genomic sequences were demonstrated by PCR in 9 lymph node biopsy specimens and in 3 skin biopsy specimens. Southern blot was performed and was positive in 8 cases.

Mother-to-child transmission of human T-lymphotropic virus type I (HTLV-I): an extended follow-up study on children between 18 and 22-24 years old in Okinawa, Japan

The significant difference observed between the seroprevalence of HTLV-I in adults and in children is as yet unexplained. To evaluate a hypothetical explanation of the existence of seroconversion cases of "seronegative carriers" for this phenomenon, 21 of 55 children who had been born to seropositive mothers and who remained seronegative until the age of 18 years were further followed up at the ages of 22 and/or 24 years. None of the 21 seronegative children born to seropositive mothers seroconverted, either at 22 years or at 24 years. In addition, the polymerase-chain-reaction (PCR) technique could not prove the existence of the HTLV-I provirus genome in peripheral mononuclear cells (PBMC) of 10 of these children. Our results fail to prove the possibility of viral latency of HTLV-I in mother-to-child transmission. Therefore, the hypothetical seroconversion of "seronegative carriers" after adulthood cannot be an explanation.

Comparative study of human and rabbit cell infection with cell-free HTLV-I

Infection of human and rabbit cells with cell-free HTLV-I was studied by PCR analysis. Both human and rabbit PBL were infected similarly by cell-free virus of both human and rabbit cell origin. Cells were infected with the cell-free virus without prior treatment and regardless of the concentration of the culture supernatant containing the virus. Human and rabbit cell lines were also infected similarly by the cell-free virus, the proviral DNA persisting for more than two months. The culture supernatants of HTLV-I-producing cells could thus be a potential cause of laboratory infections.