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Existence of escape mutant in HTLV-I tax during the development of adult T-cell leukemia.

Although Tax protein is the main target of cytotoxic T lymphocyte (CTL) on human T-cell lymphotropic virus type I (HTLV-I)-infected cells, and Tax peptide 11 through 19 binding to HLA-A*02 has been shown to elicit a strong CTL response, there are patients with adult T-cell leukemia (ATL) bearing HLA-A*02. To explore whether there is genetic variation in HTLV-I tax that can escape CTL recognition during the development of ATL, the HTLV-I tax gene was sequenced in 55 patients with ATL, 61 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and 62 healthy carriers, and it was correlated with the presence of HLA-A*02. First, a premature stop codon in the 5' half of the tax gene that looses transactivation activity on the viral enhancer was observed in 3 patients with acute and 1 patient with chronic ATL. This stop codon was revealed to emerge after the viral transmission to the patient from sequence analysis in family members with ATL. Second, amino acid change in Tax peptide 11-19 was observed in 3 patients with ATL. CTL assays demonstrated that this altered Tax 11-19 peptide, observed in ATL patients with HLA-A*02, was not recognized by Tax 11-19-specific CTL. Two patients with ATL had large deletions in tax by sequencing, and 5 patients with ATL had deletions in HTLV-I by Southern blotting. These findings suggest that at some stage of ATL development, HTLV-I-infected cells that can escape the host immune system are selected and have a chance to accumulate genetic alterations for further malignant transformation, leading to acute ATL.

Codon, Terminator↗

Limitations of Wada memory asymmetry as a predictor of outcomes after temporal lobectomy.

BACKGROUND: The intracarotid amobarbital (Wada) test can be used to evaluate hemispheric memory capacity before anterior temporal lobectomy (ATL). Most patients demonstrate better memory with injection ipsilateral to planned resection (expected asymmetry [EA]), but a substantial minority show better memory with contralateral injection (unexpected asymmetry [UA]). Both degree and direction of Wada memory asymmetry (WMA) have been associated with worse surgical outcome in small series. Reports also suggest that UA is associated with greater decline in verbal memory after left ATL (L-ATL). METHODS: The relationship between WMA and surgical outcome (at 3 months, 1 year, and last follow-up) was examined in a large group of ATL patients (108 L, 119 R) with both EA and UA. Also, memory in a subgroup (96 L, 108 R) was examined, comparing subscores of the Rey Auditory Verbal Learning Test obtained preoperatively, at 3 months, and at 1 year. RESULTS: Thirty-six percent of L-ATL and 8% of R-ATL patients had UA. UA was associated with worse surgical outcome at 1 year for R-ATL patients but was not associated with worse outcome for L-ATL patients. There was no correlation between WMA and persistent postoperative verbal memory change for patients with L- or R-ATL. CONCLUSIONS: Unexpected asymmetry is uncommon in patients with right anterior temporal lobectomy (R-ATL) and may be a risk marker of poor surgical outcome. This relationship may be obscured by language confounds in patients with L-ATL. The results suggest that Wada asymmetry (using mixed stimuli) does not predict postoperative verbal memory; it is unclear whether this finding is generalizable to centers using only nonverbal stimuli.

Adolescent↗

Delineation of immunoregulatory properties of adult T-cell leukemia cells.

We characterized leukemic cells from 20 adult T-cell leukemia (ATL) cases and 7 ATL-derived cell lines in terms of Foxp3 messenger RNA (mRNA) expression, cytokine production, cell surface markers associated with regulatory T-cells (Treg), and in vitro immunoregulatory activity and compared the results with those of cells from 3 T-cell-type chronic lymphocytic leukemia (T-CLL) patients and normal CD4+ T-cells. Real-time polymerase chain reaction analysis showed that cells from 10 ATL cases, 1 T-CLL case, and 1 ATL cell line had higher Foxp3 mRNA levels than CD4+ T-cells. In 5 ATL cases, Foxp3 levels were comparable to those of CD4+CD25+ T-cells. Flow cytometric analysis revealed that CTLA-4 expression correlated with Foxp3 mRNA level in ATL cells. The cells of all ATL cases examined produced no interleukin 2 or interferon gamma after iono-mycin and phorbolmyristate acetate stimulation. Cases with low Foxp3 expression (Foxp3-low) tended to express higher levels of transforming growth factor beta mRNA, but this trend was not statistically significant. An in vitro inhibition assay showed that the proliferation of normal CD4+CD25- T-cells stimulated with anti-CD3 monoclonal antibody and autologous dendritic cells was significantly suppressed by coculture with Foxp3-high ATL cells. These results indicate that Foxp3 expression is variable in ATL cases and that Foxp3-high ATL cells, which resemble Treg phenotypically as well as functionally, may be involved in immune suppression in ATL.

Aged↗

Increasing methylation of the CDKN2A gene is associated with the progression of adult T-cell leukemia.

In this study, we examined the methylation status of the CDKN2A gene in patients with different forms of adult T-cell leukemia (ATL) using Southern blot analysis, methylation-specific PCR (MSPCR), and nucleotide sequencing. We found that the CDKN2A gene was more frequently methylated in fresh tumor cells isolated from patients with acute ATL (47%) or lymphoma-type ATL (73%) than in those with less malignant chronic (17%) and smoldering (17%) ATL. In addition, deletions of the CDKN2A gene were found in 24% of acute ATL patients; thus, abnormalities of the CDKN2A gene totaled 71% in acute ATL patients. In contrast, no CDKN2A gene methylation was found in asymptomatic carriers or uninfected individuals. Methylation of the p15 gene was not found in any samples from 36 ATL patients. Direct sequencing of the CDKN2A gene after sodium bisulfite treatment of genomic DNA revealed that the methylation of CpG sites had occurred in 24 of 32 ATL cases (75%) including chronic and smoldering ATL, even when MSPCR and the Southern blot had failed to detect CDKN2A gene methylation. Among fresh ATL samples with methylation, methylation was detected in the promoter region and exon in 17 of 24 cases, and methylation in the exon without promoter region was detected in 7 of 24 cases. In one case, the pattern of methylation proved to be different between peripheral blood cells and lymph node cells, suggesting the presence of multiple subclones with regard to methylation patterns, despite the same HTLV-I integration site. Quantitative PCR showed a marked decrease in CDKN2A mRNA expression in the cells with a methylated CDKN2A gene, especially if the promoter region was methylated. These findings suggest that CpG methylation decreases CDKN2A expression and represents a critical factor in the disease progression of ATL.

Blotting, Southern↗

Constitutive activation of transcription factor AP-1 in primary adult T-cell leukemia cells.

Human T-cell leukemia virus type-I (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL). This study examined the status of the oncogenic transcription factor AP-1 in leukemic cells freshly isolated from patients with ATL. Leukemic cells from peripheral blood of all patients with ATL exhibited constitutive AP-1 DNA binding activity, whereas mononuclear cells from normal individuals did not. In agreement with previous studies, HTLV-I transforming protein, Tax, was found to stimulate the DNA binding activity of AP-1 in a T-cell line. However, HTLV-I genes, including Tax, were not significantly expressed in leukemic cells freshly obtained from patients with ATL. Moreover, all T-cell lines derived from leukemic cells of patients with ATL also displayed constitutive AP-1 DNA binding activity, but expressed little Tax protein. Thus, leukemic cells of patients with ATL appear to have Tax-independent mechanisms that induce AP-1 activity, both in vivo and in vitro. In antibody supershift experiments, AP-1 in fresh leukemic cells and ATL-derived cell lines were found to contain JunD. Consistently, all primary ATL cells and ATL-derived cell lines expressed high levels of JunD messenger RNA. Our results suggest that AP-1 is activated in leukemic cells of patients with ATL through a Tax-independent mechanism and this may play a role in the deregulated phenotypes of ATL leukemic cells. (Blood. 2000;95:3915-3921)

Adult↗

Calcium-dependent homotypic adhesion through leukocyte function-associated antigen-1/intracellular adhesion molecule-1 induces interleukin-1 and parathyroid hormone-related protein production on adult T-cell leukemia cells in vitro.

Adult T-cell leukemia (ATL) is a human T-cell leukemia virus type I (HTLV-I)-infected lymphoproliferative disorder that shows a characteristic nodular infiltration into various tissues, hypercalcemia, and subsequent rapid increase of peripheral ATL cell number. ATL cells and HTLV-I-infected T-cell lines also make cluster formation rapidly after the non-stimulative culture. However, the mechanism of the acute proliferation of ATL cells remains to be understood. We report the following novel features of homotypic adhesion via leukocyte function-associated antigen-1 (LFA-1)/intracellular adhesion molecule-1 (ICAM-1) pathway that suggest a role for it in cytokine production and rapid proliferation of ATL cells: (1) ATL cells show clustering in a calcium dependent manner, even at the higher concentration; (2) ATL cells consistently and highly express ICAM-1 and an active form of LFA-1, whereas integrin expression, except for LFA-1, is rather lower compared with that of normal CD4+ T cells; (3) ATL cells make conjugate formation within 6 minutes and clustering within 48 hours, both of which are inhibited by the addition of monoclonal antibodies (MoAbs) against LFA-1 and ICAM-1; (4) spontaneous mRNA transcription and protein secretion of both interleukin-1 and parathyroid hormone-related protein are observed consistently in ATL cells, and these productions are inhibited by anti-LFA-1 and anti-ICAM-1 MoAbs but are markedly increased by cross-linking of LFA-1 and ICAM-1 by the immobilized specific MoAbs; and (5) proliferative responses of ATL cells are also inhibited by these MoAbs. We propose that ATL cells proliferate in sequential events: the homotypic and calcium-dependent adhesion through LFA-1/ICAM-1, the signal transduction through these adhesion molecules, the production of cytokines, and the proliferation.

Bone Resorption↗

Clinical significance of beta 2-microglobulin in serum of adult T cell leukemia.

To clarify the clinical and biological significance of beta 2-microglobulin (beta 2-M) in serum of adult T cell leukemia (ATL) associated with human lymphotropic virus type-I (HTLV-I), beta 2-M was measured in 52 patients with ATL (acute ATL, 35 patients; lymphoma ATL, two patients; chronic ATL, 12 patients; smoldering ATL, three patients), and it was compared with serum lactic dehydrogenase (LDH). Statistical analysis disclosed a correlation between beta 2-M level and the percentage of abnormal lymphocytes (P < 0.05) and platelet count (P < 0.01). There was a correlation between LDH and platelet count (P < 0.01), and a tendency of correlation between LDH and the percentage of abnormal lymphocytes (P < 0.15). Significant difference was present in beta 2-M as well as LDH between acute ATL and chronic ATL (P < 0.01), and between acute ATL and smoldering ATL (P < 0.01). We also investigated a significant inverse correlation between beta 2-M level as well as LDH level and the length of survival after the initial diagnosis (P < 0.01). Thus, the beta 2-M level may indicate the aggressiveness of ATL cells and predict the length of survival.

Adult↗

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex.

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Adult↗

Expression of the intestinal T-lymphocyte-associated-molecule recognized by the HML-1 antibody on mononuclear cells from HTLV-I-infected subjects.

We investigated the expression of a monoclonal antibody (HML-1) defined antigen that appears on human intestinal T-lymphocytes in HTLV-I-related disease. We studied 25 ATL, and 24 healthy HTLV-I carriers. Patients with acute ATL showed a variety of the expression of the HML-1 antigen (range 0.4-74.8%). HML-1 expression on mononuclear cells (MNCs) in blood from patients with chronic ATL ranged from 1.7-43.6% (mean 13.5%). This level of expression was less than that of patients with acute ATL, but not significantly. In patients with smoldering ATL, the degree of patients with acute ATL, but not significantly. In patients with smoldering ATL, the degree of expression ranged from 1.6-13.3% (mean 8.0%). In contrast to patients with acute ATL, MNCs from patients with acute myelogenous leukemia (AML), acute lymphocytic leukemia (ALL), and B-cell type chronic lymphocytic leukemia (B-CLL) did not express the HML-1 antigen, except for the 2 patients with ALL. Healthy HTLV-I carriers and healthy controls also were negative for HML-1 reactivity. In acute ATL, patients with gastrointestinal tract infiltration tended to have high expression of the HML-1 epitope. After stimulation with phytohemagglutinin (PHA), healthy HTLV-I carriers showed significantly increased expression of the HML-1 epitope (P < 0.05). Recently, the beta 7 integrin family has been found to play a specific role in mucosal localization or adhesion, and HML-1 protein was found to match the deduced beta 7 N-terminal sequence. We propose that the cellular gene responsible for HML-1 epitope expression may, like IL-2, IL-2R, etc., be transactivated by infection with HTLV-I, and HML-1 antigen gene expression by HTLV-I infection may lead to infiltration of ATL cells with highly expressed HML-1 epitope into the gut mucosa.

Antigens, Neoplasm↗

Cytokine induction in HTLV-I associated myelopathy and adult T-cell leukemia: alternate molecular mechanisms underlying retroviral pathogenesis.

The human T-cell lymphotropic virus type I (HTLV-I) is capable of inducing a variety of host cellular genes including many of the cytokines responsible for immune regulation and osteoclast activation. This derangement in cytokine expression may contribute to the panoply of disease states associated with HTLV-I infection such as the adult T-cell leukemia (ATL) and HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/TSP). We wished to determine if there was a correlation between the expression of an array of cytokines and the diverse clinical manifestations of ATL and HAM/TSP. Utilizing the techniques of specific mRNA amplification by the polymerase chain reaction (PCR) as well as Northern blotting, we analyzed the ex vivo mRNA expression of gamma-interferon (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and transforming growth factor-beta 1 (TGF-beta 1) in the peripheral blood of HAM/TSP and ATL patients as well as asymptomatic seropositive carriers. IFN-gamma, TNF-alpha, and IL-1 beta transcripts were up-regulated in patients with HAM/TSP and seropositive carriers when compared to their levels in ATL and normal controls. In contrast, the ATL patients constitutively expressed higher levels of TGF-beta 1 mRNA than HAM/TSP and seropositive carriers. In addition, TNF-alpha and IL-1 beta serum levels were elevated in HAM/TSP, but not in ATL patients nor seropositive carriers. However, the circulating leukemic cells from ATL patients secreted increased levels of TGF-beta 1 protein into the culture medium than T-cells derived from HAM/TSP patients. Collectively these results suggest that induction of IFN-gamma, TNF-alpha, and IL-1 beta in HAM/TSP may initiate an inflammatory cascade with subsequent events leading to immune mediated destruction of the central nervous system in these patients. Expression of osteoclast activators such as TNF-alpha and IL-1 beta is not associated with hypercalcemia in ATL. Finally, impaired cellular and humoral immune responses present in ATL, but not in HAM/TSP, may be related to elevated levels of TGF-beta 1 produced by the leukemic cells. These differences in retroviral-induced host cytokine expression in ATL and HAM/TSP suggest alternate roles in disease pathogenesis.

Adult↗

Possible attenuation of fas-mediated signaling by dominant expression of caspase-8 aberrant isoform in adult T-cell leukemia cells.

The Fas up-regulated in adult T-cell leukemia (ATL) cells is usually the wild-type protein and is usually functional, at least in vitro. However, primary ATL cells, in contrast to ATL cell lines, are not necessarily susceptible to anti-Fas-induced apoptosis. To clarify the mechanism tuning the apoptotic signal transduction initiated by the activation caspase-8 in ATL cells and ATL cell lines, we examined the expression profile of caspase-8, of which there are at least 8 isoforms at the messenger RNA (mRNA) level with the potential to finely tune the signal transduction. Reverse transcription polymerase chain reaction disclosed the 2 major mRNA bands of 815 bp (casp-8S) and 951 bp (casp-8L) with different expression profiles among normal CD4 T-cells, primary ATL cells, and ATL cell lines. Casp-8L was the predominant form in primary ATL cells, whereas casp-8S was predominant in ATL cell lines. Casp-8S was structurally intact as shown by nucleotide analysis, whereas casp-8L was shown to be generated by a 136-bp insertion between exons 8 and 9 and to carry a frame shift in the transcript, introducing a premature stop codon and probably resulting in a truncated protein of approximately 30 kd deduced for the casp-8L transcript. These results suggest that an imbalanced expression of casp-8 isoforms, especially the dominant casp-8L in primary ATL cells, is in part responsible for tumor pathology through the modulation of cell death via Fas-mediated signaling.

Caspase 8↗

Current status of therapeutic approaches to adult T-cell leukemia.

More than 2 decades have elapsed since the proposal of adult T-cell leukemia (ATL). Since then, the discovery of the etiologic virus, human T-cell leukemia virus type I (HTLV-I), and the establishment of the diagnostic steps of serum test and molecular study have clearly defined ATL as a distinct disease entity. Because conventional chemotherapy, which is active against other lymphoid malignancies, was proven to be ineffective for treating aggressive forms of ATL, ATL has become the target of several clinical studies for the purpose of improving therapeutic outcomes. Combination chemotherapy exclusively designed for ATL has considerably elevated the treatment response rate in ATL patients, but it has not sufficiently extended the median survival time. The introduction of antiviral agents has led to surprising effects for patients with acute ATL. Monoclonal antibodies seem to be promising, especially for patients with chemotherapy-resistant disease. Unfortunately, these approaches did not prove to be sufficient for most patients with ATL to obtain long-term survival. Recent promising reports on allogeneic stem cell transplantation (allo-SCT) for ATL have suggested that allo-SCT could overcome the limitations that other treatment modalities have not surmounted. More efforts are clearly needed to clarify the usefulness of allo-SCT, especially with reduced-intensity conditioning regimens, for ATL patients.

Antineoplastic Combined Chemotherapy Protocols↗

Adenosine A2A receptor agonist improves cardiac dysfunction from pulmonary ischemia-reperfusion injury.

BACKGROUND: Ischemia-reperfusion (IR) injury negatively impacts patient outcome in lung transplantation. Clinically, we observed that lung transplant patients with ischemia-reperfusion injury tend to have cardiac dysfunction. Previous studies have shown that ATL-146e (4-{3-[6-amino-9-(5-ethylcarbamoyl-3,4-dihydroxy-tetrahydro-furan-2-yl)-9H-purin-2-yl]-prop-2-ynyl}-cyclohexanecarboxylic acid methyl ester), a selective adenosine A2A receptor agonist, reduces lung inflammation after ischemia-reperfusion. We hypothesized that pulmonary ischemia-reperfusion causes secondary heart dysfunction and ATL-146e will improve this dysfunction. METHODS: We utilized an in vivo rabbit lung ischemia-reperfusion model. The Sham group underwent 120 minutes single lung ventilation. The IR and ATL groups underwent 90 minutes right lung ischemia with 30 minutes right lung reperfusion. The ATL-146e was given intravenously to the ATL group during reperfusion. Cardiac output and arterial blood gases were monitored, and neutrophil sequestration was measured by myeloperoxidase activity. RESULTS: Upon reperfusion, cardiac output (mL/min) significantly dropped in the IR and ATL groups. By 15 minutes reperfusion, cardiac output in the ATL group improved significantly over the IR group and remained significant thereafter. Lung myeloperoxidase activity was significantly reduced by ATL-146e. Although never hypoxemic, arterial oxygenation was lower in the IR and ATL groups while central venous pressures and mean arterial pressures were similar among groups. A separate experiment demonstrated that reperfusion with the antioxidant N-(2-mercaptopropionyl)glycine prevented cardiac dysfunction. CONCLUSIONS: Pulmonary ischemia-reperfusion causes cardiac dysfunction independent of preload, afterload, and oxygenation. The ATL-146e improves this dysfunction presumably by the antiinflammatory effects of adenosine A2A receptor activation on neutrophils. One likely mechanism involves the release of oxidants from the ischemic lung upon reperfusion, which has immediate negative effects on the heart.

Adenosine A2 Receptor Agonists↗

Adenosine A2A receptor activation reduces inflammation and preserves pulmonary function in an in vivo model of lung transplantation.

BACKGROUND: Reperfusion injury continues to significantly affect patients undergoing lung transplantation. Isolated lung models have demonstrated that adenosine A 2A receptor activation preserves function while decreasing inflammation. We hypothesized that adenosine A 2A receptor activation by ATL-146e during the initial reperfusion period preserves pulmonary function and attenuates inflammation in a porcine model of lung transplantation. METHODS: Mature pig lungs preserved with Viaspan (Barr Laboratories, Pomona, NY) underwent 6 hours of cold ischemia before transplantation and 4 hours of reperfusion. Animals were treated with (ATL group, n = 7) and without (IR group, n = 7) ATL-146e (0.05 microg kg -1 . min -1 ATL-146e administered intravenously for 3 hours). With occlusion of the opposite pulmonary artery, the animal was maintained for the final 30 minutes on the allograft alone. Recipient lung physiology was monitored before tissue evaluation of pulmonary edema (wet-to-dry weight ratio), myeloperoxidase assay, and tissue tumor necrosis factor alpha by means of enzyme-linked immunosorbent assay. RESULTS: When the ATL group was compared with the IR group, the ATL group had better partial pressure of carbon dioxide (43.8 +/- 4.1 vs 68.9 +/- 6.3 mm Hg, P < .01) and partial pressure of oxygen (272.3 +/- 132.7 vs 100.1 +/- 21.4 mm Hg, P < .01). ATL-146e-treated animals exhibited lower pulmonary artery pressures (33.6 +/- 2.1 vs 47.9 +/- 3.5 mm Hg, P < .01) and mean airway pressures (16.25 +/- 0.08 vs 16.64 +/- 0.15 mm Hg, P = .04). ATL-146e-treated lungs had lower wet-to-dry ratios (5.9 +/- 0.39 vs 7.3 +/- 0.38, P < .02), lower myeloperoxidase levels (2.9 x 10 -5 +/- 1.2 x 10 -5 vs 1.3 x 10 -4 +/- 4.0 x 10 -5 DeltaOD mg -1 . min -1 , P = .03), and a trend toward decreased lung tumor necrosis factor alpha levels (57 +/- 12 vs 96 +/- 15 pg/mL, P = .06). The ATL group demonstrated significantly less inflammation on histology. CONCLUSION: Adenosine A 2A activation during early reperfusion attenuated lung inflammation and preserved pulmonary function in this model of lung transplantation. ATL-146e and similar compounds could play a significant role in improving outcomes of pulmonary transplantation.

Adenosine A2 Receptor Agonists↗

Impact of advanced trauma life support training on early trauma management.

To assess the impact of ATLS education on early trauma management, charts of patients with an ISS of 14 or greater were reviewed for a 1 year period before and after ATLS training of emergency room trauma care providers. There were 50 patients in the before ATLS group, with a mean age of 41.6 years and an ISS of 29.8, and 71 patients in the after ATLS group, with a mean age of 40.6 years and an ISS of 30.6. Of those parameters evaluated as measures of early assessment, only rectal examination was found to be performed significantly more frequently after ATLS training. The mortality rates of 26 percent before ATLS and 20 percent after ATLS were not significantly different. In evaluating assessment and management parameters in the patients who died, no airway management errors were found in the after ATLS group; however, there were more missed injuries in this group. We have concluded that ATLS instruction failed to produce a quantifiable improvement in patient assessment or outcome. Further studies directed at assessing the retention rate for ATLS education and determining the impact on clinical performance are needed.

Adult↗

Multi-clonal expansion of unique human T-lymphotropic virus type-I-infected T cells with high growth potential in response to interleukin-2 in prodromal phase of adult T cell leukemia.

We established a simple IL-2-dependent colony-forming assay for T cells infected with human T-lymphotropic virus type-I (HTLV-I). IL-2-dependent cell lines were subsequently established by expanding individual colonies in liquid cultures. Lymphocyte-rich fractions were prepared from 31 HTLV-I carriers, 12 patients with smoldering ATL, 11 chronic ATL, 12 crisis ATL and 10 acute ATL. Primary colonies of CD4+ p19+ T cells were formed in all cases of carriers, smoldering and chronic ATL, and in 10 of 12 crisis cases. In contrast, no colony was formed from cells of patients with acute ATL. The rate of establishment of cell lines in HTLV-I carriers was significantly lower than that in patients of prodromal phase ATL. Cell lines established from cells of three prodromal cases were clonally identical to the parent ATL cells, while others had clonally distinct cell lines. Our results indicated the presence of four components of HTLV-I-infected T cells: (1) normal carrier T cells capable of forming colonies but not cell lines; (2) pre-malignant T cells capable of forming colonies as well as cell lines; (3) malignant T cells capable of forming colonies as well as cell lines; (4) fully malignant T cells unresponsive to IL-2. Our results suggest the presence of a multiclonal expansion of unique T cells in the prodromal phase of ATL, which have a high growth potential in response to IL-2. The coexistence of multiclonality with a dominant ATL clone may be closely related to the underlying pathology in HTLV-I leukemogenesis.

Case-Control Studies↗

HLA-A*26, HLA-B*4002, HLA-B*4006, and HLA-B*4801 alleles predispose to adult T cell leukemia: the limited recognition of HTLV type 1 tax peptide anchor motifs and epitopes to generate anti-HTLV type 1 tax CD8(+) cytotoxic T lymphocytes.

Genetic risk for adult T cell leukemia (ATL) has been implicated by ethnic and familial segregation of ATL patients from HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). To clarify the genetic risk for ATL, we characterized HLA class I alleles of ATL patients and analyzed the anchor motifs of HTLV-1 peptides binding to HLA class I molecules, using 291 lines of anti-HTLV-1 CD8(+) cytotoxic T lymphocytes (CTLs) generated in vitro with a total of 165 synthetic peptides for HTLV-1 Tax and Env proteins. Allele frequencies of HLA-A*26, B*4002, B*4006, and B*4801 were significantly higher in ATL patients than in HAM/TSP patients and asymptomatic HTLV-1 carriers in southern Japan. CD8(+) CTL analysis revealed the HTLV-1 Tax peptide sequence to completely lack anchor motifs of peptides binding to HLA-A*26,B*4002, and B*4006 molecules but to possess one anchor for HLA-B*4801, while the HTLV-1 Env peptide sequence had many anchor motifs for HLA-A*26, B*4002, B*4006, and B*4801 molecules. Most ATL patients featured heterozygous HLA class I alleles composed of HLA-A*26, B*4002, B*4006, and B*4801, with a lower number of HTLV-1 Tax peptide anchor motifs and epitopes generating anti-HTLV-1 Tax CD8(+) CTLs than individuals possessing other HLA alleles. The relationship between Tax epitope and ATL incidence was verified by the significantly decreased number of HTLV-1 Tax epitopes in ATL patients compared with asymptomatic HTLV-1 carriers (p < 0.01) as well as late onset ATL patients (p < 0.001). These results indicate that HLA-A*26, B*4002, B*4006, and B*4801 alleles predispose to ATL because of the limited recognition of HTLV-1 Tax peptide anchor motifs and epitopes capable of generating anti-HTLV-1 Tax CD8(+) CTLs.

Adult↗

Immunohistochemical analysis of peripheral T-cell lymphoma in Japanese patients.

The authors immunohistochemically analyzed the phenotype of 40 cases of peripheral T-cell lymphoma, including 12 adult T-cell leukemia/lymphoma (ATL) cases. Molecular genetic analysis of the T-cell receptor beta-chain and immunoglobulin heavy chain genes were also applied to cases of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD)-like lymphoma and so-called Lennert's lymphoma. Twenty non-ATL lymphomas expressed a helper/inducer phenotype, whereas only one extranodal case expressed a suppressor/cytotoxic phenotype. Three cases had a CD4-CD8- phenotype, and two cases a CD4+CD8+phenotype. No specific relationship between morphologic characteristics (LSG classification) and phenotype was found among non-ATL lymphomas. Six of eight AILD-like lymphomas had a helper/inducer phenotype. Monoclonality of neoplastic T-cells was demonstrated in six of the seven cases of AILD-like lymphoma by molecular genetic analysis. Two cases of Lennert's lymphoma also showed a helper/inducer phenotype and rearrangement of the T-cell receptor beta-chain gene. Serologically defined ATL cases had a helper/inducer phenotype except in one case that expressed both CD4 and CD8. None of the ATL cases had the CD7 antigen in this study using WT 1 as a CD7 antibody, which is in contrast with the non-ATL lymphomas in which 13 of 25 cases expressed CD7. CD25, strongly detectable in all ATL cases, was negative or weakly expressed in non-ATL lymphomas. These facts suggest that non-ATL and ATL are in the different biologic state, probably resulting from the integration of human T-cell leukemia virus type I (HTLV-I), although both are derived from helper/inducer T-cells.

Antigens, Differentiation, T-Lymphocyte↗