Human T cell lymphotropic virus type II (HTLV-II) infection is endemic in a number of indigenous populations in North, Central, and South America. In the present study we have employed serological and molecular methods to identify HTLV-II infection in Indian communities in the Amazon region of Brazil. Sera (1324) from 25 different Indian communities were analyzed by ELISA and Western blot. One hundred and four samples (7.8%) from a number of culturally distinct and geographically unrelated populations were found to have reactivities consistent with HTLV-II infection. Of these, 67 were from the Kayapo Indian communities, which had an overall seroprevalence rate of greater than 30%. In addition, high seroprevalence rates were observed in three other communities, the Munduruku, Arara do Laranjal and the Tyrio, suggesting that there are additional foci of endemic infection in the Amazon region. In the Kayapo, seroprevalence rates tended to increase with age, supporting the importance of sexual transmission of the virus, and family studies demonstrated that vertical transmission is also an important route of infection. Restriction fragment length polymorphism (RFLP) and nucleotide sequence analysis of a region of the env gene demonstrated that the Kayapo are infected with the HTLV-IIa subtype. Moreover, nucleotide sequence analysis of the LTR demonstrated that this belonged to a distinct HTLV-IIa phylogenetic group. The identification of HTLV-IIa in the Kayapo is, as far as we are aware, the first identified endemic focus of infection by this subtype of HTLV-II in the Americas.

Human T lymphotropic virus, type II (HTLV-II), infection has been shown to be endemic in a number of American Indian populations, and high rates of infection have also been documented in intravenous drug abusers in urban areas throughout the world. Although the role of HTLV-II in human disease has yet to be clearly defined, there is accumulating evidence that like HTLV-I, infection may also be associated with rare lymphoproliferative and neurological disorders. In this article we review and summarize the epidemiology, molecular properties and clinical features of HTLV-II infection.

To estimate the replication of the human T-cell leukemia virus type I (HTLV-I) in patients with HTLV-I-associated myelopathy (HAM), or tropical spastic paraparesis (TSP), HTLV-I DNA integrated into lymphocyte genomes was analyzed by Southern blot hybridization. HTLV-I DNA was detected in 125 (82%) of 153 patients and most showed random integration. This incidence was much higher than the 29% found in asymptomatic carriers. Therefore, HAM/TSP development is associated with a high level of HTLV-I replication. In addition, lymphocytes from 3 patients with HAM/TSP showed monoclonal integration of HTLV-I DNA, indicating adult T-cell leukemia.

Human T lymphotropic virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is one outcome of infection with HTLV-I. A population association study of 229 patients with HAM/TSP and 202 healthy carriers of HTLV-I in southern Japan showed that this outcome of HTLV-I infection and the HTLV-I provirus load are under polygenic control. Of 58 polymorphic sites studied in 39 non-HLA candidate gene loci, 3 new host genetic factors that influenced the risk of HAM/TSP or the provirus load of HTLV-I were identified. The promoter TNF -863A allele predisposed to HAM/TSP, whereas SDF-1 +801A 3'UTR, and IL-15 191C alleles conferred protection. Knowledge of HTLV-I-infected individuals' ages, sex, provirus load, HTLV-I subgroup, and genotypes at the loci HLA-A, HLA-C, SDF-1, and TNF-alpha allowed for the correct identification of 88% of cases of HAM/TSP in this Japanese cohort.

Neutropenia is a common laboratory finding in systemic lupus erythematosus (SLE). However, the molecular mechanism of SLE neutropenia has not been fully explained. In this study, we examined whether TNF-related apoptosisinducing ligand (TRAIL) is involved in the pathogenesis of SLE neutropenia using samples from SLE patients. Serum TRAIL levels in SLE patients with neutropenia were significantly higher than those of SLE patients without neutropenia and healthy volunteers. Serum TRAIL levels showed a significant negative correlation with neutrophil counts in SLE patients. The expression of TRAIL receptor 3 was significantly lower in SLE patients with neutropenia than in patients without neutropenia or in healthy volunteers. Treatment with glucocorticoids negated the decrease of TRAIL receptor 3 expression on neutrophils of SLE patients. TRAIL may accelerate neutrophil apoptosis of neutrophils from SLE patients, and autologous T cells of SLE patients, which express TRAIL on surface, may kill autologous neutrophils. IntroductionNeutropenia in systemic lupus erythematosus (SLE) was first described more than 70 years ago 1 and is found in about 50%-60% of patients with SLE. 2 Clinically, increased susceptibility to infections is a major cause of morbidity and mortality in patients with SLE. 3,4 In this regard, not only treatment with adrenal glucocorticoids and/or immunosuppressive drugs but also decreased numbers of polymorphonuclear neutrophils (PMNs) is obviously responsible for the increased incidence of infections. [5][6][7][8][9] However, the detailed molecular mechanism of neutropenia in SLE has not been fully elucidated.Traditionally, PMNs have been considered to be the first line cell component of the body defense mechanism against bacterial pathogens and were regarded as terminally differentiated cells incapable of protein synthesis and committed to death within 72 hours. [10][11][12] Recently, it was indicated that neutrophils were not only capable of receiving signals from different proinflammatory cytokines and chemokines, but also could synthesize many important proinflammatory cytokines and chemokines to modulate immune responses, such as interferon-gamma (IFN-␥), tumor necrosis factor alpha (TNF-␣), and interleukin-8 (IL-8). 13,14 And these proinflammatory mediators, relevant to the inflamed site in vivo, also act to modulate the constitutive death of neutrophils. 15,16 Regarding neutrophil apoptosis, Fas 17 and TNF-␣ 18 were reported to be able to shorten neutrophil lifespan at early time points. Recently, it was reported that TNF-related apoptosis-inducing ligand (TRAIL) could accelerate neutrophil apoptosis. 19 Also, TRAIL was reported to be involved in the monocyte apoptosis induced by T cells in SLE. 20 However, the role of TRAIL in neutropenia of SLE is still unclear.In this study, we have investigated the TRAIL receptors on neutrophils and TRAIL-induced neutrophil apoptosis using samples from SLE patients. A difference in the expression pattern of TRAIL receptors between SLE patients and healt...