HTLV-I-associated lymphoma involving the entire alimentary tract and presenting with an acquired immune deficiency

HTLV-1 and Co-infections

Human T lymphotropic virus type 1 (HTLV-1) is a retrovirus that causes lifelong T-cell infection in humans, impacting the host immune response. This virus causes a range of clinical manifestations, from inflammatory conditions, including neuronal damage (HTLV-1 associated myelopathy, HAM) to life-threatening leukemia (adult T-cell leukemia, ATL). Human T lymphotropic virus type 1 is also associated with increased risk of all-cause mortality, but the mechanisms remain unclear. As a blood-borne and sexually transmitted infection (STI), HTLV-1 shares transmission routes to many other pathogens and although it has worldwide distribution, it affects mainly those in low- and middle-income tropical areas, where the prevalence of other infectious agents is high. These factors contribute to a high incidence of co-infections in people living with HTLV-1 (PLHTLV). This comprehensive review addresses the impact of HTLV-1 on several co-infections and vice-versa. There is evidence of higher rates of HTLV-1 infection in association with other blood borne (HCV, HBV) and sexually transmitted (Syphilis, Chlamydia, HPV, HSV) infections but whether this represents increased susceptibility or opportunity is unclear. Higher frequency of Mycobacterium tuberculosis (MTb) and Mycobacterium leprae (M. leprae) is observed in PLHTLV. Reports of opportunistic infections and high frequency of crusted scabies in patients with HTLV-1 points to immune impairment in those individuals. Human T lymphotropic virus type 1 may influence the persistence of pathogens, exemplified by the higher rates of Schistosoma mansoni and Strongyloides stercoralis (St. stercoralis) treatment failure observed in PLHTLV. This retrovirus is also associated with increased tuberculosis (TB) severity with some evidence pointing to a deleterious impact on leprosy outcome as well. These findings are supported by immune alterations observed in those co-infected individuals. Although the role of HTLV-1 in HCV outcome is debatable, most data indicate that HTLV may negatively impact the clinical course of hepatitis C. Co-infections may also influence the risk of developing HTLV-1 associated disease, but data are still limited. The impact of HTLV-1 on the response to more common infections, might contribute to the increased mortality rate of HTLV-1. Large scale prospective controlled studies on the prevalence and impact of HTLV-1 in co-infections and vice-versa are needed. Human T lymphotropic virus type 1 impact in public health is broad. Measures to increase awareness and to prevent new infections are needed.

HTLV-I and Strongyloides in Australia: The worm lurking beneath

Strongyloidiasis and HTLV-I (human T-lymphotropic virus-1) are important infections that are endemic in many countries around the world with an estimated 370 million infected with Strongyloides stercoralis alone, and 5-10 million with HTVL-I. Co-infections with these pathogens are associated with significant morbidity and can be fatal. HTLV-I infects T-cells thus causing dysregulation of the immune system which has been linked to dissemination and hyperinfection of S. stercoralis leading to bacterial sepsis which can result in death. Both of these pathogens are endemic in Australia primarily in remote communities in Queensland, the Northern Territory, and Western Australia. Other cases in Australia have occurred in immigrants and refugees, returned travellers, and Australian Defence Force personnel. HTLV-I infection is lifelong with no known cure. Strongyloidiasis is a long-term chronic disease that can remain latent for decades, as shown by infections diagnosed in prisoners of war from World War II and the Vietnam War testing positive decades after they returned from these conflicts. This review aims to shed light on concomitant infections of HTLV-I with S. stercoralis primarily in Australia but in the global context as well.

Human T Lymphotropic virus-1 associated gastrointestinal histoplasmosis in Peru

We report a 72-year-old patient with chronic diarrhoea and histologic evidence of gastrointestinal histoplasmosis. He had no history of HIV or of taking immunosuppressive drugs. The patient was found to be a carrier of Human T-lymphotropic virus-1, a condition associated with inflammatory, lymphoproliferative, and opportunistic infectious diseases. To our knowledge, there are only three previous cases reporting this coinfection and this is the first documented case with gastrointestinal involvement.

Small Bowel Lymphoma

Treatment of small bowel lymphoma requires the expertise of medical and surgical subspecialists. The two most important factors that determine the optimal treatment are histology and staging of small bowel lymphoma. Other factors that may affect treatment include age, multiple areas of involvement, tumor size, and perforation. At present, the best treatment for gastrointestinal lymphoma (stage IE disease) is limited resection of the tumor, followed by postoperative radiotherapy. The cure rate is approximately 75% for stage IE patients, even for those with aggressive histologic types. Chemotherapy is reserved for advanced-staged tumors. In patients with regional nodal involvement or extranodal involvement confined to one side of the diaphragm (pathologic stage IIE disease), chemotherapy should be combined with radiation therapy. The best chemotherapy regimen depends on the histology of the tumor. For diffuse large B-cell lymphoma, the most frequently diagnosed subtype of non-Hodgkin's lymphoma (NHL), the CHOP regimen (cyclophosphamide, doxorubicin, vincristine, and prednisone) is still the gold standard. Clinical trials have been conducted evaluating the new monoclonal antibody rituximab, along with the CHOP regimen for primary NHL. Results have been promising. The use of rituximab in the treatment of extranodal lymphoma is still being evaluated. Low-grade lymphomas have a more indolent course and do not respond as well to combination chemotherapy agents as the high-grade tumors. Fludarabine alone or in combination with cyclophosphamide is effective as a first-line agent for patients with low-grade NHL. It has also been used to treat relapsed or refractory low-grade NHL. Some promising results have been reported using the chemoimmunotherapy agent rituximab alone or in combination with fludarabine for the treatment of low-grade NHL. However, clinical trials are still needed. In patients with nodal involvement on both sides of the diaphragm or other extranodal involvement such as bone marrow or liver (pathologic stages IIIE and IVE), the disease is managed primarily with combination chemotherapy. Radiation therapy is reserved for treatment of initially bulky tumor sites, treatment of residual disease following chemotherapy, or serious local problems. The disease can be controlled in 25% to 40% of patients with stage IIIE or IVE disease. As with stage IIE disease, the optimal chemotherapy regimen depends on the histologic subtype of NHL.

Reciprocal interactions between human cytomegalovirus and human T cell leukemia-lymphoma virus type I in monocyte-derived macrophages cultured in vitro

Infection of macrophages with human cytomegalovirus (HCMV) has been shown to be nonlytic and exclusively cell associated. Human T cell leukemia-lymphoma virus type I (HTLV-I) is capable of establishing productive infection in macrophages. We studied the interactions between HCMV and HTLV-I in monocyte-derived macrophages cultured in vitro. We found that coinfection of macrophages with HCMV and HTLV-I significantly enhanced HCMV replication, resulting in release of infectious HCMV from dually infected cells. On the other hand, HCMV inhibited HTLV-I replication in macrophages coinfected with both viruses. Reciprocal interactions between HCMV and HTLV-I were mediated by their trans-acting proteins. Results of transfection studies demonstrated that the tax gene product of HTLV-I alone was capable of upregulating HCMV production. In a transient gene expression assay the immediate-early 2 (IE2) protein of HCMV alone could inhibit HTLV-I replication, whereas the IE1 protein, which had no effect by itself, produced a synergistic inhibitory effect together with the IE2 protein. Results from this study suggest that in vivo double infection of macrophages with HCMV and HTLV-I may contribute to the dissemination of HCMV infection in patients suffering from HTLV-I-associated T cell leukemia-lymphoma.

Atypical human T-cell lymphotropic virus type-I-associated T-cell lymphoma in a low-prevalence Alaska Native population. Implications for disease surveillance

An atypical case of adult T-cell leukemia/lymphoma (ATL) associated with human T-cell lymphotropic virus type I (HTLV-I) occurred in a 46-year-old Inupiat Eskimo man with no behavioral risk factors for HTLV-I infection. The case was characterized by lack of atypical circulating lymphocytes, hypercalcemia, and opportunistic infections; and by complete remission of the initial renal parenchymal lymphoma. The lymphoma cells had a helper T-cell (CD4) immunophenotype. Serum antibodies to HTLV I/II, detected by Western immunoblot, were identified in specimens collected 31 months before the onset of illness, at the time of diagnosis, and up to 37 months later, shortly before the patient's death. Polymerase chain reaction was used to identify HTLV-I DNA in peripheral blood mononuclear cells and in lymphoma in involved skin. Clinicians should be alert to sporadic cases of both atypical and classic ATL, even in populations in which the prevalence of HTLV-I infection is low.

Strong trans activation of the human cytomegalovirus major immediate-early enhancer by p40tax of human T-cell leukemia virus type I via two repetitive tax-responsive sequence elements

The immediate-early 1 and 2 gene locus of human cytomegalovirus (HCMV) that encodes trans-activator proteins with effects on both homologous and heterologous promoters is expressed under control of a complex enhancer/promoter regulatory region. This enhancer contains four types of repetitive sequence elements with 17, 18, 19, and 21 bp that bind cellular transcription factors. Although the HCMV enhancer acts as a powerful stimulator of transcription in most cell types examined, human T cells do not support strong activity. The present study demonstrates that the tax gene product of human T-cell leukemia virus type I trans activates the major enhancer of HCMV more than 60-fold in the T-cell line Jurkat. When a series of chloramphenicol acetyltransferase expression plasmids containing synthetic oligonucleotides with the 17-, 18-, 19-, or 21-bp motif upstream of a minimal immediate-early 1 and 2 gene promoter was tested, two of the four repeat motifs could be identified as Tax-responsive elements. Both the 18- and the 19-bp motifs were able to act as strong Tax-responsive elements even when they were present as single copies. Thus, in addition to interacting with human immunodeficiency virus, HCMV is able to interact with a second retrovirus of clinical importance.

Case report: adult T-cell leukemia/lymphoma associated with recurrent strongyloides hyperinfection

Adult T-cell leukemia/lymphoma (ATLL) was demonstrated postmortem in a 47-year-old woman initially manifesting severe hypercalcemia and a vertebral compression fracture. Hyperinfection with Strongyloides stercoralis preceded the appearance of ATLL by several months and ultimately dominated the terminal course. Although HTLV-I and S. stercoralis commonly infect the same host, only three other cases of concomitant ATLL and hyperinfection have been reported in English. The apparent rarity of this association suggests that immunologic sequelae of ATLL do not predispose to dissemination and multiplication of Strongyloides. Observations pertinent to this conclusion are reviewed.

Acute T-cell leukemia/lymphoma mimicking Hodgkin's disease with secondary HTLV I seroconversion

The authors observed a pleiomorphic lymphoma mimicking Hodgkin's lymphoma in a French Guyana black woman lacking antibodies for human T-cell lymphoma/leukemia virus type I (HTLV I). After two courses of chemotherapy with either mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) or doxorubicin, bleomycin, vincaleukoblastine, and dacarbazine (ABVD), a typical acute T-cell leukemia/lymphoma developed with HTLV I seroconversion. Specific HTLV I DNA sequences were detected using the polymerase chain reaction (PCR) on a lymph node biopsy obtained before chemotherapy. The mechanisms of the seroconversion are discussed.

Transactivation of the transforming growth factor beta 1 (TGF-beta 1) gene by human T lymphotropic virus type 1 tax: a potential mechanism for the increased production of TGF-beta 1 in adult T cell leukemia

We examined the effect of the human T lymphotropic virus type 1 (HTLV-I) Tax gene product on the human transforming growth factor beta 1 (TGF-beta 1) promoter. Transfection of deleted constructs of the TGF-beta 1 promoter revealed regions homologous with AP-1 binding sites that were required for Tax-induced transactivation of the TGF-beta 1 promoter. In addition, we examined the expression and secretion of TGF-beta in fresh leukemic cells isolated from patients with adult T cell leukemia (ATL) and in HTLV-1-infected T cell lines. We report that fresh leukemic cells from ATL patients constitutively produce high levels of TGF-beta 1 mRNA and secrete TGF-beta 1 but not TGF-beta 2 into the culture medium. In addition, long-term ATL cell lines expressed significant amounts of TGF-beta 1 mRNA as well as detectable levels of TGF-beta 1 protein. These results suggest a role for Tax in the upregulation of TGF-beta 1 in HTLV-I-infected cells.