Recurrent Facial Erythema with Cytotoxic T Cell Infiltration as a Possible Reactive Eruption in a Human T-Cell Lymphotropic Virus Type 1 Carrier.

Human T-cell lymphotropic virus type 1 (HTLV-1) induces adult T cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and carrier. Approximately half of ATLL patients have direct skin involvement of neoplastic cells. However, there exist HTLV-1-associated reactive eruptions with a predominant infiltrate of non-neoplastic CD8+ T cells in ATLL, HAM/TSP and carrier. A 50-year-old Japanese female HTLV-1 carrier had several episodes of itchy, indurated erythema that occurred diffusely on the face and neck, lasted for 2 weeks and spontaneously subsided without sequelae. Histopathologically, CD3+ T cells infiltrated the upper dermis, and part of the infiltrating cells were CD4+CD25+, sharing the phenotype with ATLL neoplastic cells. An aggregate of CD8+ T cells bearing the cytotoxic molecule TIA-1 was also present. It is possible that skin-affinitive HTLV-1+CD4+ T cells propagated and subsequently disappeared as a result of cytotoxic T cell attack.

A "possible" involvement of TNF-alpha in apoptosis induction in peripheral blood lymphocytes of cats with feline infectious peritonitis.

Feline infectious peritonitis (FIP) cats show a decrease in peripheral blood lymphocyte counts, and a particularly marked decrease in T cells including CD4+ and CD8+ cells. In this study, we showed that lymphopenia observed in FIP cats was due to apoptosis, and that the ascitic fluid, plasma, and culture supernatant of peritoneal exudate cells (adherent cells with macrophage morphology, or PEC) from FIP cats readily induced apoptosis in specific pathogen-free cat peripheral blood mononuclear cells, particularly CD8+ cells. In addition, TNF-alpha released from macrophages and TNF-receptor (TNFR) 1 and TNFR2 mRNA expression in lymphocytes were closely involved in this apoptosis induction. In particular, in CD8+ cells cultured in the presence of the PEC culture supernatant, the expression levels of TNFR1 and TNFR2 mRNA were increased, indicating that CD8+ cells are more susceptible to apoptosis induction by TNF-alpha than other lymphocyte subsets, particularly B cells (CD21+ cells). The results of this study suggest that TNF-alpha, produced by virus-infected macrophages, is responsible for induction of apoptosis in uninfected T cells, primarily CD8+ T cells.