Screening blood products for HTLV-I: what is the best approach?

A recent concern for disease transmission by blood transfusion is T-lymphotropic virus type I (HTLV-I). This virus is endemic in Japan, the Caribbean basin, subsaharan Africa, and, to a lesser extent, the southeastern United States and parts of Central and South America. HTLV-I, which has been shown to be transmitted via transfusion, is associated with adult T-cell leukemia (ATL) and certain degenerative neurological disorders. Antibodies to HTLV-I, an indicator of exposure to the virus, have been demonstrated in 0.025% of healthy U.S. donors. This study, using the Decision Tree Model, presents an approach to a donor screening policy which should be cost-effective and yet ensure a safe blood supply.     

Clinico-pathological aspects of adult T-cell leukemia/lymphoma(ATL)

Adult T-cell leukemia/lymphoma(ATL) was first discovered and reported in Japan, where it has a high incidence in the southwestern region of the country. The retrovirus human T-cell leukemia virus type I(HTLV-I) is considered to be related to its etiology. ATL shows divers clinical features. It can be divided into four types of smoldering, chronic, acute, and lymphoma. ATL cells originate from the CD4-positive subset of peripheral T cells showing a characteristic notch in the nucleus and a tendency for lobulation. A definit diagnosis of ATL is made by documenting the presence of HTLV-I proviral DNA in the DNA of leukemic or lymphoma cells. Crinico-Pathological aspects of ATL are more complexed than other types of lymphoma because of the verity of the disease type, state of immunodeficiency, hypercalcemia, cytokine activation, and so on.     

HTLV-I/II prevalence in different geographic locations

Human T-cell lymphotropic virus (HTLV) type I (HTLV-I) is the etiological agent of adult T-cell leukemia and HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-II is a closely related virus, and this infection is not clearly associated with clinical disease, although neurologic disorders are observed resembling HAM/TSP. Prevalence rates for HTLV-I infection in the general population are greater than 1% in the Caribbean Basin, Central Africa, and South Japan. In most other areas in the world, as far as we know, HTLV-I/II infections are mainly found in high-risk groups (ie, immigrants from endemic areas, their offspring, their sexual contacts and in patients and intravenous injection users attending sexually transmitted disease clinics). Also, a high rate of infection for both HTLV-I and HTLV-II infection was observed in the native Amerindian population in North America as well as South America. Blood donors are routinely screened for HTLV-I/II in North America, several countries in Europe, Japan, and Taiwan.     

Epidemiologic comparison of human T-lymphotropic virus type I-infected blood donors from endemic and nonendemic regions over a 3-year period

BACKGROUND: Screening for human T-lymphotropic virus type I (HTLV-I) infection became systematic in 1989 in the French West Indies for blood from all donors and in France for blood from natives of endemic areas; in 1990, it was extended to blood from donors with at-risk sex partners and in July 1991 to blood from all donors. STUDY DESIGN AND METHODS: The epidemiologic characteristics of individuals found through the screening of donated blood to be HTLV-I infected were compared for an endemic region (Guadeloupe, French West Indies) and a nonendemic region (Paris area) over a 3-year period (1989 through 1991). RESULTS: In Guadeloupe, 131 HTLV-I-infected individuals were detected in the screening of 28,801 units; in the Paris area, 38 HTLV-I-infected donors were detected in the screening of 109,824 units. All Guadeloupean HTLV- I-infected donors were natives of endemic areas. Among the 38 Parisian HTLV-I-infected donors, 21 were natives of endemic areas, 10 were natives of endemic areas and had received transfusions, 2 were whites who had received transfusions, and 5 were whites who had had heterosexual contact with natives of endemic areas. The percentage of HTLV-I-infected individuals whose blood would have been excluded because of positivity for one or more markers for other viruses did not significantly change over the study period and did not significantly differ between regions (41%). Among the eight Parisian HTLV-I-infected blood donors detected after July 1991, six would not have been detected without the biologic screening. CONCLUSION: The generalization of biologic screening of HTLV-I-infected donated blood in France was useful for the prevention of HTLV-I and HTLV type II infections through transfusion.     

Human T-cell leukemia virus type I (HTLV-I) and blood transfusion

Human T-cell leukemia (or T-lymphotropic) virus type I (HTLV-I) is a human exogenous infectious retrovirus of the family Retroviridae. This virus has been associated with adult T-cell leukemia and endemic myelopathies (tropical spastic paraparesis and HTLV-I associated myelopathy). HTLV-I is transmitted by sexual contact, from mother to child, by intravenous drug abuse, and by blood transfusion. The estimated lifetime risk of developing disease in antibody-positive patients is 1 in 80, and a latency period as long as 20 years can intervene. No case of transfusion-transmitted disease has been reported to date. Currently, no testing of blood donors for HTLV-I is required in the United States, and no such test has been approved by the Food and Drug Administration. Because data on the natural history of this virus may take years to accumulate, it is probably wise to begin excluding anti-HTLV-I-positive units from the blood supply in the United States as soon as a licensed test is available.     

献血员血清中成人嗜T淋巴细胞病毒的血清学调查

目的 了解HTLV-I在汕头地区献血人群中的感染情况。方法 应用ELISA和Western Blot法对随机抽样的献血进行HTLV-I感染调查。结果 在3123名献血员中用ELISA法检出3名呈阳性反应,Western Blot检出1名具有特殊性的HTLV-I毒株。结论 中国的东南沿海一带确实存在HTLV-I小流行区,应在已发现有散在HTLV携带的区域或小流行区的献血员中做HTLV-I抗体检测,防止因输血感染ATL。     

Elevated serum levels of soluble interleukin-2 receptors in HTLV-I--associated myelopathy

Using an enzyme-linked immunosorbent assay, we measured the level of soluble interleukin-2 receptors (sIL-2Rs) in the serum of 50 normal controls, 48 human carriers of T cell leukemia virus type I (HTLV-I) antibody who had no symptoms, 11 patients with HTLV-I-associated myelopathy (HAM), and 39 patients with adult T cell leukemia (ATL) (four smoldering, 10 chronic, nine lymphoma, and 16 acute type). The highest levels of sIL-2R were observed in patients with acute and lymphoma-type ATL, as opposed to those with chronic and smoldering-type ATL. The levels of sIL-2R in patients with HAM were roughly between those of smoldering ATL and healthy HTLV-I carriers. Serum sIL-2R levels in healthy carriers were also elevated compared with those in normal controls. These observations suggest that the measurement of sIL-2R levels in patients with ATL can be useful as a noninvasive measure of tumor burden and should aid in the understanding of the natural history of HTLV-I infection leading to the development of ATL.     

NIK-333 inhibits growth of human T-cell leukemia virus type I-infected T-cell lines and adult T-cell leukemia cells in association with blockade of nuclear factor-kappaB signal pathway

Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type I (HTLV-I) and remains incurable. NIK-333, a novel synthetic retinoid, prevents the recurrence of human hepatoma after surgical resection of primary tumors. We explored the effects of NIK-333 on HTLV-I-infected T-cell lines and ATL cells. NIK-333 inhibited cell proliferation, induced G1 arrest, and resulted in massive apoptosis in all tested HTLV-I-infected T-cell lines and ATL cells, whereas little effect was observed on normal peripheral blood mononuclear cells. NIK-333 treatment decreases the levels of cyclin D1, cyclin D2, cIAP2, and XIAP proteins. Further analysis showed that NIK-333 inactivated nuclear factor-kappaB in HTLV-I-infected T-cell lines. In animal studies, treatment with NIK-333 (100 mg/kg given orally every other day) produced partial inhibition of growth of tumors of a HTLV-I-infected T-cell line transplanted s.c. in severe combined immunodeficient mice. Our results indicate that NIK-333 is a potentially useful therapeutic agent for patients with ATL.     

Origin of human T-lymphotrophic virus I-positive T cell lines in adult T cell leukemia. Analysis of T cell receptor gene rearrangement

Using the clone-specific rearrangement of the T cell receptor gene as the genetic marker of the clonotype, we analyzed the clonal origin of the interleukin 2 (IL-2)-dependent human T-lymphotrophic virus I (HTLV-I)-positive T cell lines established from various adult T cell leukemia (ATL) patients. From a patient with chronic ATL, whose leukemic cells proliferated in vitro in response to IL-2, we repeatedly established leukemic T cell clones having the same rearrangement profile of the T beta chain gene as the leukemic cells. By contrast, established cell lines from acute ATL patients had different beta chain gene rearrangements from those of the leukemic cells. These HTLV-I+ T cell lines might not be the direct progeny of the leukemic cells, but that of T cells infected either in vivo or in vitro. These IL-2-reactive nonleukemic T cells might have been selected in vitro, because their leukemic cells failed to respond to IL-2, despite the expression of IL-2 receptor. The analysis of the T cell receptor gene rearrangement may give a new approach for the elucidation of the mechanism of leukemogenesis and the origin of the HTLV-I+ T cell lines in ATL.     

Human T-lymphotropic virus type I and type II infections and correlation with risk factors in blood donors from Sao Paulo, Brazil

BACKGROUND: Little is known about the prevalence of and risk factors for human T-lymphotropic virus type I and type II (HTLV-I, HTLV-II) infections in Brazil. STUDY DESIGN AND METHODS: Sera from 17,063 healthy Brazilian donors were screened by enzyme-linked immunosorbent assay for antibody to HTLV-I/II between August 1991 and July 1993. Repeatedly reactive samples were confirmed by Western blot, and discrimination between HTLV-I and HTLV-II was made by polymerase chain reaction or synthetic peptide enzyme-linked immunosorbent assay. A univariate analysis was performed on demographic and serologic data. RESULTS: HTLV-I infection was demonstrated in 83 percent of the 30 donors with reactive serologic tests (0.15% of the total tested [17,063]; 95% CI, 0.09-0.20) and HTLV-II infection in 17 percent (0.03% of the total tested [17,063]; 95% CI, 0.01-0.05). HTLV-I-positive donors were more likely than reference groups to be of Asian ethnicity (odds ratio [OR] 15.1; reference group: whites), more than 50 years old (OR 4.2; reference group: 20–29 years old), and positive for antibody to hepatitis C virus (anti-HCV) (OR 21.8) or to hepatitis B core (antigen) (anti-HBc) (OR 5.7). HTLV-II showed a significant association with anti-HCV (OR 75.2) and anti-HBc (OR 21.8). Eleven of the 25 HTLV-I- positive donors were counseled. Family origin in endemic areas of Japan (n = 4), prior blood transfusion (n = 3), or sexual contact with prostitutes (n = 1) were the risk factors reported by 8 donors. In 3 white men, no risk factors could be identified. CONCLUSION: Both HTLV-I and HTLV-II occur among Brazilian blood donors. HTLV-I is associated with Asian ethnicity, greater age, and the presence of anti-HCV and anti-HBc. Three HTLV-I-positive donors had a history of blood transfusion, which emphasizes the need for HTLV-I/II screening in Brazil.     

Transfusion-associated transmission of human T-lymphotropic virus types I and II: experience of a regional blood center

During a 22-month period, 78,000 blood donors were screened for human T- lymphotropic virus types I and II (HTLV-I/II) at Belle Bonfils Memorial Blood Center (Denver, Colorado). Positive donors and the living recipients of their previously donated blood components were evaluated for risk factors and symptoms related to HTLV-I infection, were screened by enzyme immunoassay, confirmed by Western blot for HTLV- I/II, and subsequently tested by polymerase chain reaction and peptide enzyme immunoassay to distinguish between HTLV-I and -II infection. Six seropositive blood donors (0.008%) were identified; four were typed as having HTLV-I infection and two as having HTLV-II. Of 18 living recipients of components from seropositive donors, none had risk factors for HTLV-I infection prior to transfusion and none had signs or symptoms of HTLV-I infection at follow-up. The mean time from transfusion to testing was 6.4 years. Seven recipients of HTLV-I- infected components were HTLV seropositive; all were typed as having HTLV-I. A possible case of posttransfusion HTLV-I-associated myelopathy was identified in one patient who died before complete evaluation. One possible case of transfusion-associated HTLV-II was identified. These data further support the continued screening of blood donors for HTLV- I/II.     

Interleukin-2 receptor (Tac antigen) expressed on adult T cell leukemia cells.

We studied the expression of the interleukin-2 (IL-2) receptor and the proliferative response to exogenous IL-2 of peripheral blood leukemic cells from patients with adult T cell leukemia (ATL) in order to see whether IL-2 receptor expressed on ATL cells is different from normal IL-2 receptor and whether it plays a role in the neoplastic growth in ATL. Peripheral blood leukemic cells from 42 patients with ATL examined expressed IL-2 receptors that were detected by anti-Tac monoclonal antibody when examined immediately after the separation of cells or after the culture for 24 or 48 h. The number of anti-Tac binding sites ranged from 3,100 to 11,400 in fresh cells and from 3,600 to 96,000/cell in short-term cultured leukemic cells, whereas phytohemagglutinin-P (PHA-P)-stimulated normal T cells exhibited 6,900-35,000 anti-Tac binding sites per cell. ATL-derived and human T cell leukemia/lymphoma virus, type I (HTLV-I)-infected cell lines such as MT-1 and Hut102 expressed a much higher number of anti-Tac binding sites. Leukemic cells from 15 patients with ATL examined showed no or very poor proliferative response to various concentrations of immunoaffinity-purified IL-2, although they expressed Tac antigen (Ag). Radiolabeled IL-2 binding experiments demonstrated that ATL leukemic cells could bind IL-2, and they expressed both high and low affinity IL-2 receptors, although the number of high affinity IL-2 receptor was much less than that of low affinity IL-2 receptor and that of anti-Tac binding sites. In contrast, leukemic T cells from a patient with T cell chronic lymphocytic leukemia (CLL), in whom HTLV-I infection was not demonstrated, responded as well as PHA-P-stimulated normal T cells, and their IL-2 receptors, unlike ATL cells, were modulated (down regulated) by anti-Tac antibody. No differences were noted between ATL cells and normal activated T cells in one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the IL-2 receptor. Thus, leukemic cells in ATL spontaneously and continuously express IL-2 receptor, which appears to be abnormally regulated and unresponsive to IL-2. These results, taken together with those on normal IL-2 receptors on HTLV-I-negative T-CLL cells, suggest that abnormal expression of the IL-2 receptor in ATL is closely associated with HTLV-I infection and may play a role in the neoplastic growth of ATL cells.     

Prevalence of antibodies to human T-lymphotropic virus types I and II in volunteer blood donors and high-risk groups in northwestern Greece

BACKGROUND: In addition to human immunodeficiency virus, human T- lymphotropic virus types I and II (HTLV-I/II) is prevalent among blood donors in the United States. In Greece, there are no epidemiologic data regarding the prevalence of HTLV-I/II among volunteer blood donors and high-risk groups. STUDY DESIGN AND METHODS: To determine the prevalence of HTLV-I/II infections in northwestern Greece, a seroepidemiologic study was conducted among volunteer blood donors, multiply transfused patients, heroin addicts, and chronic hemodialysis patients. The subjects were tested for serologic evidence of HTLV-I/II infection by enzyme immunoassays and specific protein immunoblot confirmatory test. RESULTS: None of the volunteer blood donors and heroin addicts had detectable antibodies to HTLV-I/II. Only 1 (1.45%) of the 69 multiply transfused patients had indeterminate results, while 2 (1.2%) of 163 hemodialysis patients were positive. CONCLUSION: In northwestern Greece, routine screening for HTLV-I and HTLV-II infections does not appear to be required. However, the finding of seropositivity among hemodialysis patients requires further evaluation of the origin of the infection, as its zero prevalence in this population seems to exclude transfusion transmission.     

九例成人T淋巴细胞白血病的临床与实验研究

目的探讨成人Ｔ淋巴细胞白血病（ＡＴＬ）的临床、细胞学、免疫学、细胞遗传学、血清学及分子生物学等特征。方法采用间接免疫荧光法及酶联免疫吸附法检测血清ＨＴＬＶⅠ抗体,建立ＰＣＲ和液相杂交法检测前病毒基因序列,结合ＭＩＣ特征确诊ＡＴＬ。结果和结论确诊９例ＡＴＬ,其临床特征主要为淋巴结肿大,皮损及溶骨改变少见,外周血及骨髓出现典型的花瓣状核淋巴细胞,胞体大,核畸形,免疫表型为ＣＤ－１、ＣＤ＋２、ＣＤ３＋、ＣＤ４＋、ＣＤ－８,还表达ＣＤ２５等激活标记,染色体核型及ＨＬＡ分型未发现有规律性的变化。８例ＡＴＬ中有７例血清ＨＴＬＶⅠ抗体阳性,应用ＰＣＲ及液相杂交法可检出整合到宿主细胞ＤＮＡ中的ＨＴＬＶⅠ病毒序列,表明在我国ＨＴＬＶⅠ也是ＡＴＬ的病因。９例中１例为淋巴瘤型,１例为慢性型,７例为急性型ＡＴＬ,治疗效果及预后均不良     

北京地区部分献血员嗜人T细胞病毒I型血清抗体调查

目的 进一步了解北京地区献血员HTLV-I感染状况。方法 应用明胶颗粒凝集试验(GPAT)检测本院的749份北京地区献血员血清HTLV-I抗体。结果 均为阴性。结论 研究结果可能与近年来北京地区对献血员的严格筛选有关,其它病毒检测项目的增加可能也会减少血清HTLV-I的阳性率。     

佛山市地区HTLV-I感染的血清流行病学研究

目的调查佛山市献血人群人类嗜T淋巴细胞白血病病毒I(HTLV-I)的感染状况。方法分别按地区及职业分组。用酶联免疫吸附试验方法(ELISA)筛查2006~2007年佛山市地区的献血人群血清标本26608份。双孔试验确认阳性者采用免疫印迹法(WB)进行确证。结果献血人群中HTLV-I抗体阳性率为0.03%,本地组未检出阳性,而外来组人群检出33例确认阳性,确证阳性为9例,占该组0.05%,两组存在显著性差异(p<0.05)。固定职业组和学生组未检出阳性,而不固定职业组人群检出确认阳性33例,确证阳性为9例,占该组0.05%,与其它两组存在显著性差异(p<0.05)。结论提示在佛山市地区HTLV-I的流行水平很低。不同地区及职业分布可能是影响其流行的一个因素。     

Cellular immune response to hepatitis C virus (HCV) in nonviremic blood donors with indeterminate anti-HCV reactivity

BACKGROUND: Blood donors with indeterminate hepatitis C virus antibody (anti-HCV) reactivity are rejected from blood donation. As they are mostly nonviremic, the source of these reactions remains unclear. Reasons for such findings can be resolved HCV infections as well as unspecific antibody reactions. The aim of this study was to investigate HCV-specific T-cell response in blood donors to determine the reason for the weak antibody detection.
STUDY DESIGN AND METHODS: Anti-HCV reactivity was tested in 72 blood donors initially diagnosed with an indeterminate HCV result by enzyme-linked immunosorbent assay and immunoblot. Cellular immune response was measured by proliferation assay and enzyme-linked immunosorbent spot analysis after stimulation with viral proteins core, NS3, and NS4.
RESULTS: In 56% of donors anti-HCV reactivity was detectable in the screening assay whereas 72% had a reaction in the confirmation immunoblot. Forty-six percent of donors had a cellular immune response against HCV proteins. The response was most frequent to NS3 protein.
CONCLUSION: In almost half of donors the indeterminate result in serologic testings could be explained by a previous resolved HCV infection as the pattern of T-cell response was similar to these patients. These findings indicate that HCV-specific antibodies disappear more rapidly after resolved infection than HCV-specific T cells. These results are important for counseling blood donors and patients with indeterminate serologic results.     

Evaluation of a new third-generation ARCHITECT rHTLV-I/II assay for blood screening and diagnosis

In comparison to current on-market assays, the ARCHITECT rHTLV-I/II assay is the first fully automated assay that simultaneously detects human T-cell lymphotropic virus type I (HTLV-I) and type II (HTLV-II) in human serum and plasma. Specificity was assessed on 5646 blood donors and 692 clinical specimens. For sensitivity determination, 301 HTLV-I–positive and 105 HTLV-II–positive specimens were tested. Precision was between 3.98% and 4.31% coefficient of variation (CV) for specimens with 1 to 6 sample to cutoff. Specificity was 99.95% and 99.86% on specimens from blood donors and hospitalized patients, respectively. Sensitivity evaluation showed 100% detection on 301 HTLV-I and 105 HTLV-II specimens. HTLV-I and HTLV-II viruses are still circulating among general populations even in the low prevalence areas. To control the further spread of these retroviruses, we need to know that it is important to continue screening of blood. The performance evaluation data from this study demonstrate that the high throughput and fully automated ARCHITECT rHTLV-I/II chemiluminescence immunoassay effectively serves this purpose.     

Close association between interleukin 2 receptor mRNA expression and human T cell leukemia/lymphoma virus type I viral RNA expression in short-term cultured leukemic cells from adult T cell leukemia patients.

Human T cell leukemia/lymphoma (T-lymphotropic) virus type I (HTLV-I) infection has been considered to be closely associated with the leukemogenesis of adult T cell leukemia (ATL), in which interleukin 2 (IL-2) receptors are abnormally expressed. In this study, however, Southern blot analysis revealed no gross rearrangement or obvious amplification of the IL-2 receptor gene in ATL leukemic cells, indicating that abnormal IL-2 receptor expression in ATL is not due to the structural change of its gene. Hence, we studied the expression of the IL-2 receptor and HTLV-I at the RNA level during short-term cultures of leukemic cells from 9 ATL patients. Cytoplasmic dot hybridization and Northern hybridization revealed that fresh leukemic cells from seven of nine patients expressed a small amount of IL-2 receptor mRNA but HTLV-I RNA was undetectable in all cases. After cultures for up to 7 d, both IL-2 receptor mRNA and HTLV-I RNA (including pX message) expression concomitantly increased, whereas the amounts of other cellular genes, except for beta-actin, did not. The increases in their RNA expression were inhibited by early addition (within 12 h after the beginning of the culture) of cycloheximide, indicating that these increases are mediated by newly synthesized protein(s). These results strongly suggested that IL-2 receptor expression is closely associated with HTLV-I expression in leukemic cells from ATL patients.     

Use of PCR amplification for diagnosis of HTLV-I infection after blood transfusion.

We studied the seroconversion to human T-cell leukemia virus type-1 (HTLV-I) in two immunocompromised patients after transfusions of cellular blood components. One patient produced IgM antibodies against the viral p19 protein 149 days post-transfusion (a serum on day 43 was negative). Both patients showed indeterminate Western-blots (IgG anti-p19 and anti-gp46 but no anti-p24). Using the polymerase chain reaction (PCR) with two primer pairs (SK43/44 and SK54/56), we demonstrated HTLV-I infection prior to seroconversion. This infection was confirmed by Southern blot.