Human T-cell leukemia virus type I tax/rex DNA and RNA in cutaneous T- cell lymphoma

Abstract

Peripheral blood mononuclear cells (PBMCs) and T-cell lines from patients with Sezary syndrome (SS) and skin lesions from patients with mycosis fungoides (MF) were examined by polymerase chain reaction (PCR) for DNA sequences homologous to the human retroviruses human T- lymphotropic virus (HTLV)-I and -II. Results obtained using primers and probes from the tax/rex region of HTLV-I indicate that 72% (18/25) of SS patients PBMCs, 80% (20/25) of T-cell lines established from SS- PBMC, and 30% (3/10) of skin lesions from MF patients were positive for HTLV-I tax/rex region DNA. Sequence analysis of the 127-bp fragment amplified by the tax/rex primers from 4 of these individuals was found to be identical to that in prototypic HTLV-I. Negative results were obtained using primers and probes from the HTLV-I gag region and the HTLV-II gag and tax regions. No PCR products were obtained using all primers and probes using DNA from 9 healthy blood donors and 10 cord bloods. Expression of HTLV-I tax/rex mRNA was found in 4 of 8 Sezary patients, as determined by RNA-PCR, indicating that this viral region is being transcribed in vivo. Exposure to Tax/Rex protein in SS- patients is supported by the fact that serum antibodies against p27rex and p40tax was observed in 43% and 29% of these SS patients, respectively. Although the causal relationship between the HTLV-I tax/rex region and cutaneous T-cell lymphoma (CTCL) remains unclear, these findings support the presence of a truncated HTLV-I retrovirus in CTCL patients.

Defective Human T-Cell Lymphotropic Virus Type I (HTLV-I) Provirus in 10 Chilean Seronegative Patients with Tropical Spastic Paraparesis or HTLV-I-Associated Myelopathy

“…Yonaha-Nagato and Sumida found only the HTLV-I tax gene but not the gag, pol, or env gene in labial salivary gland samples from 29% of patients with Sjögren's syndrome (23). Others researchers demonstrated the presence of a truncated HTLV-I genome from 72% of patients with Sezary's syndrome (11). Our results showed the detection of tax but did not confirm ltr in 10 patients with TSP-HAM.…”

Defective human T‐lymphotrophic virus type I provirus in T‐cell prolymphocytic leukaemia

“…The presence of the HTLV‐I tax with no monoclonal integration could be explained in one of two ways: (1) HTLV‐I genome insertion only triggered T‐PLL, and no monoclonal proliferation was detected; or (2) latent HTLV‐I infection suppressed the host's antitumour immunity, resulting in the development of T‐PLL. The defective HTLV tax ‐like sequence without amplification of other parts of the genome has been previously reported in seronegative patients with cutaneous T‐cell lymphoma (CTCL) (Ghosh et al , 1994; Pancake et al , 1995), which is another post‐thymic T‐cell neoplasm. Since seronegative individuals rarely have HTLV‐I provirus (Miyata et al , 1995), consistent findings of no induction of HTLV‐I antibodies in patients with T‐PLL or CTCL and the defective HTLV‐I provirus raise the possibility that there may be alternative mechanisms involved in HTLV‐associated leukaemogenesis.…”

Canine cutaneous epitheliotropic T‐cell lymphoma: a review

“…Two reports document the isolation of a type C retrovirus (related to FeLV) in leukaemic dogs affected by SS, but a causal relationship between virus and disease was not proven 10,11 . In man, sequences of human T‐lymphotropic virus‐1 have been isolated from some patients with CETL 12,13 . Human herpes virus 8 (HHV‐8) has also been found in cutaneous lymphoproliferative lesions 14 .…”