Suppression of tuberculin skin reaction in healthy HTLV‐I carriers from Japan

Abstract

Although it is thought that infection with human T‐lymphotropic virus type I (HTLV‐I) is immunosuppressive, this has not been clearly demonstrated among healthy carriers, and there are no data concerning delayed‐type hypersensitivity (DTH). To evaluate this hypothesis, DTH to purified protein derivative (PPD) of tuberculin was measured in 126 healthy adults from an endemic area for HTLV‐I infection in southern Japan. Among the 39 HTLV‐I carriers, only 15% had detectable induration following PPD exposure, compared to 46% of the 87 non‐carriers. In addition, the size of erythema among those carriers with a positive reaction was about 70% of that among non‐carriers. Overall, there was a significantly inverse association between the degree of DTH response and prevalence of antibody. In relation to subjects with strong to moderate reaction, those with negative or indefinite reaction were 6 times more likely to be a carrier. This association was much stronger among subjects aged 60 years or older than among younger persons. These findings indicate that there is subclinical immunosuppression among HTLV‐I carriers, which increases with age.

The relationship of FOXP3 expression and clinicopathological characteristics in adult T-cell leukemia/lymphoma

“…The immunodeficient state is also seen in HTLV-1 carriers and patients with HAM/TSP without malignancies and is associated with infections caused by various fungi, viruses and protozoa. 4,6,54 In one experiment, inoculation of rabbits with a cell line infected with HTLV-1 resulted in thymic atrophy, which was found to be associated with infiltration of HTLV-1-infected cells into the thymus. 55 Impaired production of naïve T lymphocytes in HTLV-1-infected individuals was reported recently.…”

Persistent oligoclonal expansion of human T-cell leukemia virus type 1-infected circulating cells in patients with Tropical spastic paraparesis/HTLV-1 associated myelopathy

“…An intense CTL response might impaired the physiological burst of expansion of the host HTLV-1 bearing CD45RO + cell as soon as viral expression occurs. Consequently, CTL control of cell proliferation may account for the impairment of immune responses in HTLV-1 infected individuals (Tachibana et al, 1988;Robinson et al, 1991). On the other hand, CTL response may have a positive eect on clonal proliferation and even permits expansion of some clones to the detriment of others depending upon their antigen speci®city.…”

Influence of human t-cell lymphotropic virus type 1 (HTLV-1) Infection on laboratory parameters of patients with chronic hepatitis C virus

“…Some evidences suggest that HTLV-1 causes a functional impairment of the cellular immune response among carriers 19,31,35 .…”

“…Although within the normal ranges, we have seen higher CD8 + T lymphocyte cells among co-infected patients, probably due to response to Tax protein of HTLV-1 33 . Despite this increased number of CD8 + T cell, there is a reduction of functional immune response, especially of cellular immunity in HTLV-1-infected carriers 19,31 . In persons co-infected with HTLV-1 and HCV, it is possible to infer that infection of T cells by HTLV-1 may interfere with the CTL response to HCV-infected hepatocytes 2 .…”