Exploring olfactory receptor family 7 subfamily C member 1 as a novel oral cancer stem cell target for immunotherapy.

The mortality rate of oral cancer has not improved over the past three decades despite remarkable advances in cancer therapies. Oral cancers contain a subpopulation of cancer stem cells (CSCs) that share characteristics associated with normal stem cells, including self-renewal and multi-differentiation potential. CSCs are tumorigenic, play a critical role in cancer infiltration, recurrence, and distant metastasis, and significantly contribute to drug resistance to current therapeutic strategies, including immunotherapy. Cytotoxic CD8+ T lymphocytes (CTLs) are key immune cells that effectively recognize peptide antigens presented by the major histocompatibility complex class I molecules. Increasing evidence suggests that cancer antigen-specific targeting by CTLs effectively regulates CSCs that drive cancer progression. In this study, we utilized data from public domains and performed various bioassays on human oral squamous cell carcinoma clinical samples and cell lines, including HSC-2 and HSC-3, to investigate the potential role of olfactory receptor family 7 subfamily C member 1 (OR7C1), a seven transmembrane G-protein-coupled olfactory receptor that is also expressed in nonolfactory tissues and was previously reported as a novel marker and target of colon cancer initiating cell-targeted immunotherapy, in CSC-targeted treatment against oral cancer. We found that the OR7C1 gene was expressed only in oral CSCs, and that CTLs reacted with human leukocyte antigen-A24-restricted OR7C1 oral CSC-specific peptides. Taken together, our findings suggest that OR7C1 represents a novel target for potent CSC-targeted immunotherapy in oral cancer.

Identification of characteristic subepithelial surface granulomatosis in immune-related adverse event-associated enterocolitis.

Immune checkpoint inhibitors (ICIs) have provided an additional treatment option for various types of human cancers. However, ICIs often induce various immune-related adverse events (irAEs). Enterocolitis is a major irAE with poorly understood histopathological characteristics. In this study, we retrospectively investigated the histopathology of colon tissue samples from 17 patients treated with ICIs. There were two major histological patterns of colitis: an ulcerative colitis-like pattern and a graft vs host disease-like pattern. Although these two patterns of colitis were mutually exclusive, both patterns often showed a characteristic that we call "subepithelial surface granulomatosis" (SSG), which has not been reported in other types of colitis. SSG was found even in colon tissue without symptoms or endoscopic findings of colitis. Given the increasing reports of sarcoid reaction or exacerbation of tuberculosis after treatment with ICIs, granuloma formation could be a histological hallmark of systemic immune activation by ICIs. Although statistical significance was not obtained, probably because of the small sample size, SSG may be a surrogate biomarker of systemic anticancer immune activation. We propose that a prospective study with larger sample size be performed.

Less correlation between mismatch repair proteins deficiency and decreased expression of HLA class I molecules in endometrial carcinoma: a different propensity from colorectal cancer.

Mismatch repair protein deficiency (dMMR) is a favorable prognostic factor in colorectal cancer. It is also associated with aberrant expression of HLA class I molecules, which are required for cytotoxic T lymphocyte-mediated cancer immunotherapy. Because dMMR is frequently also found in endometrial cancers (ECs), we retrospectively investigated the expression of mismatch repair proteins and HLA class I molecules in 127 EC patients. In this study, EC patients being treated in our hospital were recruited from 2005 to 2009 and observed until December 2017. Lesion specimens were evaluated via immunohistochemistry for MSH6 and PMS2 (mismatch repair proteins) and HLA class I molecules. Expression of these molecules was statistically related to clinical and pathological factors and prognosis. dMMR was detected in 33 patients and did not correlate with the expression level of HLA class I molecules (P = 0.60). On the other hand, unexpectedly, multivariate analysis revealed that intact expression of HLA class I molecules was associated with p53 overexpression (P = 0.004). Neither dMMR nor decreased expression of HLA class I molecules were prognostic factors. These results are inconsistent with previous findings for colorectal cancer. A distinctive local tissue immune microenvironment would underlie the discrepancy in the results between EC and colorectal cancer.

[Successful Total Resection with Preceding Arterial Coil Embolization of Intradural Extramedullary Tumor at Craniovertebral Junction Encasing Dominant-side Vertebral Artery].

OBJECTIVE: The surgical resection of craniovertebral junction(CVJ)meningioma is challenging because of the neighboring brainstem, lower cranial nerves, and vertebral artery(VA). Moreover, encasement of the VA by the tumor can raise the risk of complications and require cautious manipulation during surgery. CASE: A 46-year-old woman presented with a one-year history of neck pain. She had temporal hemiplegia and numbness on her left side. Magnetic resonance imaging(MRI)showed a CVJ meningioma pushing the brainstem from the right vertebral side and encasing the right VA. Digital subtraction angiography(DSA)showed two feeding arteries arising from the right VA and a sunburst sign. The right VA was the dominant side but did not have the right posterior inferior cerebellar artery(PICA). The anterior spinal artery(ASA)was dominant in the left VA. We performed a balloon test occlusion(BTO)for 20 min and it did not cause any complications;therefore, we occluded the VA using endovascular coils. After 4 days, we removed the meningioma in the prone position, using a far-lateral approach and C1-laminectomy. The laterally located meningioma pushed the brainstem. After detaching the tumor from the dura, we cut the encased VA and the tumor was resected safely(Simpson grade II). Postoperatively, she developed temporal thermal hypoalgesia on the left side of her body. Magnetic resonance imaging showed a microinfarction in the medulla. CONCLUSION: If the VA test occlusion provides a clear result, pre-operative endovascular sacrifice of the VA encased by CVJ meningioma is a feasible treatment strategy.

Heat shock protein DNAJB8 is a novel target for immunotherapy of colon cancer-initiating cells.

The aim of the present study was to establish cancer stem-like cell/cancer-initiating cell (CSC/CIC)-targeting immunotherapy. The CSC/CIC are thought to be essential for tumor maintenance, recurrence and distant metastasis. Therefore they are reasonable targets for cancer therapy. In the present study, we found that a heat shock protein (HSP) 40 family member, DnaJ (Hsp40) homolog, subfamily B, member 8 (DNAJB8), is preferentially expressed in CSC/CIC derived from colorectal cancer (CRC) cells rather than in non-CSC/CIC. Overexpression of DNAJB8 enhanced the expression of stem cell markers and tumorigenicity, indicating that DNAJB8 has a role in CRC CSC/CIC. A DNAJB8-specific cytotoxic T lymphocyte (CTL) response could be induced by a DNAJB8-derived antigenic peptide. A CTL clone specific for DNAJB8 peptide showed higher killing activity to CRC CSC/CIC compared with non-CSC/CIC, and CTL adoptive transfer into CRC CSC/CIC showed an antitumor effect in vivo. Taken together, the results indicate that DNAJB8 is expressed and has role in CRC CSC/CIC and that DNAJB8 is a novel target of CRC CSC/CIC-targeting immunotherapy.

Restoration of ARID1A Protein in ARID1A-deficient Clear Cell Carcinoma of the Ovary Attenuates Reactivity to Cytotoxic T Lymphocytes.

BACKGROUND/AIM: Clear cell carcinoma is a prevalent histological type of ovarian cancer in East Asia, particularly in Japan, known for its resistance to chemotherapeutic agents and poor prognosis. ARID1A gene mutations, commonly found in ovarian clear cell carcinoma (OCCC), contribute to its pathogenesis. Recent data revealed that the ARID1A mutation is related to better outcomes of cancer immunotherapy. Thus, this study aimed to investigate the immunotherapy treatment susceptibility of OCCC bearing ARID1A mutations. MATERIALS AND METHODS: Expression of ARID1A was analyzed using western blotting in ovarian cancer cell lines. OCCC cell lines JHOC-9 and RMG-V were engineered to overexpress NY-ESO-1, HLA-A*02:01, and ARID1A. Sensitivity to chemotherapy and T cell receptor-transduced T (TCR-T) cells specific for NY-ESO-1 was assessed in ARID1A-restored cells compared to ARID1A-deficient wild-type cells. RESULTS: JHOC-9 cells and RMG-V cells showed no expression of ARID1A protein. Overexpression of ARID1A in JHOC-9 and RMG-V cells did not impact sensitivity to gemcitabine. While ARID1A overexpression decreased sensitivity to cisplatin in RMG-V cells, it had no such effect in JHOC-9 cells. ARID1A overexpression reduced the reactivity of NY-ESO-1-specific TCR-T cells, as observed by the IFNγ ESLIPOT assay. CONCLUSION: Cancer immunotherapy is an effective approach to target ARID1A-deficient clear cell carcinoma of the ovary.

Aldehyde Dehydrogenese-1 High Cancer Stem-like Cells/Cancer-initiating Cells Escape from Cytotoxic T Lymphocytes due to Lower Expression of Human Leukocyte Antigen Class 1.

BACKGROUND/AIM: Human gastric cancer stem-like cells (CSCs)/cancer-initiating cells can be identified as aldehyde dehydrogenase-high (ALDHhigh) cells. Cancer immunotherapy employing immune checkpoint blockade has been approved for advanced gastric cancer cases. However, the effectiveness of cancer immunotherapy against gastric CSCs/CICs remains unclear. This study aimed to investigate the susceptibility of gastric CSCs/CICs to immunotherapy. MATERIALS AND METHODS: Gastric CSCs/CICs were isolated as ALDHhigh cells using the human gastric cancer cell line, MKN-45. ALDHhigh clone cells and ALDHlow clone cells were isolated using the ALDEFLUOR assay. ALDH1A1 expression was assessed via qRT-PCR. Sphere-forming ability was evaluated to confirm the presence of CSCs/CICs. A model neoantigen, AP2S1, was over-expressed in ALDHhigh clone cells and ALDHlow clone cells, and susceptibility to AP2S1-specific TCR-T cells was assessed using IFNγ ELISPOT assay. RESULTS: Three ALDHhigh clone cells were isolated from MKN-45 cells. ALDHhigh clone cells exhibited a stable phenotype in in vitro culture for more than 2 months. The High-36 clone cells demonstrated the highest sphere-forming ability, whereas the Low-8 cells showed the lowest sphere-forming ability. High-36 cells exhibited lower expression of HLA-A24 compared to Low-8 cells. TCR-T cells specific for AP2S1 showed lower reactivity to High-36 cells compared to Low-8 cells. CONCLUSION: High-36 cells and Low-8 cells represent novel gastric CSCs/CICs and non-CSCs/CICs, respectively. ALDHhigh CSCs/CICs evade T cells due to lower expression of HLA class 1.

DNA methyltransferase 1 is essential for initiation of the colon cancers.

DNA methyltransferase 1 (Dnmt1) is essential for the maintenance of hematopoietic and somatic stem cells in mice; however, its roles in human cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are still elusive. In the present study, we investigated DNMT1 functions in the maintenance of human colon CSCs/CICs using the human colon cancer cell line HCT116 (HCT116 w/t) and its DNMT1 knockout cell line (DNMT1(-/-)). The rates of CSCs/CICs were evaluated by side population (SP) analysis, ALDEFLUOR assay and expression of CD44 and CD24. SP, ALDEFLUOR-positive (ALDEFLUOR(+)) and CD44-positive and CD24-positive (CD44(+)CD24(+)) cell rates were lower in DNMT1(-/-) cells than in HCT116 w/t cells. Since CSCs/CICs have higher tumor-initiating ability than that of non-CSCs/CICs, the tumor-initiating abilities were addressed by injecting immune deficient (NOD/SCID) mice. DNMT1(-/-) cells showed less tumor-initiating ability than did HCT116 w/t cells, whereas the growing rate of DNMT1(-/-) cells showed no significant difference from that of HCT116 cells both in vitro and in vivo. Similar results were obtained for cells in which DNMT1 had been transiently knocked-down using gene-specific siRNAs. Taken together, these results indicate that DNMT1 is essential for maintenance of colon CSCs/CICs and that short-term suppression of DNMT1 might be sufficient to disrupt CSCs/CICs.

Cytotoxic T lymphocytes efficiently recognize human colon cancer stem-like cells.

Cancer stem-like cells (CSCs) and tumor-initiating cells (TICs) are a small population of cancer cells that share three properties: tumor initiating ability, self-renewal, and differentiation. These properties suggest that CSCs/TICs are essential for tumor maintenance, recurrence, and distant metastasis. Here, we show that cytotoxic T lymphocytes (CTLs) specific for the tumor-associated antigen CEP55 can efficiently recognize colon CSCs/TICs both in vitro and in vivo. Using Hoechst 33342 dye staining, we isolated CSCs/TICs as side population (SP) cells from colon cancer cell lines SW480, HT29, and HCT15. The SP cells expressed high levels of the stem cell markers SOX2, POU5F1, LGR5, and ALDH1A1 and showed resistance to chemotherapeutic agents such as irinotecan or etoposide.To evaluate the susceptibility of SP cells to CTLs, we used CTL clone 41, which is specific for the CEP55-derived antigenic peptide Cep55/c10orf3_193 (10) (VYVKGLLAKI). The SP cells expressed HLA class I and CEP55 at the same level as the main population cells. The SP cells were susceptible to CTL clone 41 at the same level as main population cells. Furthermore, adoptive transfer of CTL clone 41 inhibited tumor growth of SW480 SP cells in vivo. These observations suggest that Cep55/c10orf3_193(10) peptide-based cancer vaccine therapy or adoptive cell transfer of the CTL clone is a possible approach for targeting chemotherapy-resistant colon CSCs/TICs.

Immunopathological basis of immune-related adverse events induced by immune checkpoint blockade therapy.

Despite the considerable success of cancer immunotherapy with immune checkpoint inhibitors, their nonspecific release of the immunosuppressive mechanism is often associated with immune-related adverse events (irAEs). irAEs significantly disturb patients' quality of life and can even be life-threatening. Therefore, the appropriate management of irAEs is crucial for the development of further reliable cancer immunotherapies. irAEs have the appearance of ordinary autoimmune diseases in one aspect but often have distinct features. Although the detailed pathogenesis of irAEs remains unclear, increasing numbers of studies have provided numerous clues. Here, we review the current knowledge on irAEs, particularly from an immunopathological basis.

SOX2 is overexpressed in stem-like cells of human lung adenocarcinoma and augments the tumorigenicity.

Recently, the SOX2 gene has been reported to be amplified in human lung squamous cell carcinomas. However, its roles in human lung adenocarcinomas are still elusive. In this study, we analyzed the functions of SOX2 in cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) derived from human lung adenocarcinoma. Human lung CSCs/CICs were isolated as higher tumorigenic side population (SP) cells using Hoechst 33342 dye from several lung cancer cell lines. Four of nine lung cancer cell lines were positive for SP cells (LHK2, 1-87, A549, Lc817). The ratios of SP cells ranged from 0.4% for Lc817 to 2.8% for LHK2. To analyze the molecular aspects of SP cells, we performed microarray screening and RT-PCR analysis, and isolated SOX2 as one of a SP cell-specific gene. SOX2 was expressed predominantly in LHK2 and 1-87 SP cells, and was also expressed in several other cancer cell lines. The expression of SOX2 protein in primary human lung cancer tissues were also confirmed by immunohistochemical staining, and SOX2 was detected in more than 80% of primary lung cancer tissues. To address SOX2 molecular functions, we established a SOX2-overexpressed LHK2 and A549 cell line (LHK2-SOX2 and A549-SOX2). LHK2-SOX2 cells showed higher rates of SP cells and higher expression of POU5F1 compared with control cells. LHK2-SOX2 and A549-SOX2 cells showed relatively higher tumorigenicity than control cells. On the other hand, SOX2 mRNA knockdown of LHK2 SP cells by gene-specific siRNA completely abrogated tumorigenicity in vivo. These observations indicate that SOX2 has a role in maintenance of stemness and tumorigenicity of human lung adenocarcinoma CSCs/CICs and is a potential target for treatment.

The feasibility of Cep55/c10orf3 derived peptide vaccine therapy for colorectal carcinoma.

In our previous study, we demonstrated that a peptide derived from the novel centrosome residing protein Cep55/c10orf3 can be targeted by the cytotoxic T lymphocytes (CTLs) in peripheral blood mononuclear cells (PBMCs) of breast carcinoma patients. In this report, we evaluated the feasibility of cancer immunotherapy using Cep55/c10orf3 peptide for colorectal carcinoma (CRC). To evaluate the expression of Cep55/c10orf3 in CRC tissues, we performed immunohistochemical staining of using anti-Cep55/c10orf3 monoclonal antibody. Sixty-three percent cases showed weak positive for Cep55/c10orf3 in total 70 CRC cases. The Cep55/c10orf3 expression intention was collated with high histological grade of CRC. Thus, we hypothesized that Cep55/c10orf3 can also be the target of CTLs in CRC cases. We generated CTLs from PBMCs of human leukocyte antigen (HLA)-A24-positive colorectal carcinoma patients using HLA-A24-restricted Cep55/c10orf3 peptides. Two of 6 colorectal cancer patients were reactive for the Cep55/c10orf3_193(10) peptide, which was the only immunogenic peptide in breast carcinoma patients. CTL clone specific for Cep55/c10orf3_193(10) recognized and lysed HLA-A24 (+) and Cep55/c10orf3 (+) colorectal carcinoma cell lines. In addition, 1 of 6 colorectal carcinoma patients was reactive for the Cep55/c10orf3_402(11) and Cep55/c10orf3_283(12) peptides, but not for Cep55/c10orf3_193(10) with the ELISPOT assay. These observations suggest that the antigenic peptide repertoire presented by HLA-A24 in colorectal carcinoma might be different from that in breast carcinoma. Thus, these peptide vaccination peptide mixture of Cep55/c10orf3_193(10), Cep55/c10orf3_402(11) and Cep55/c10orf3_283(12) might be more effective than a single peptide in the treatment of colorectal carcinoma patients.

Immunoglobulin G4-related autoimmune hepatitis simultaneously concomitant with autoimmune pancreatitis: a case report.

Thus far, there have been limited case reports on immunoglobulin G4-related autoimmune hepatitis (IgG4-AIH), and its clinical features have not been elucidated. We herein report a rare case of IgG4-AIH simultaneously concomitant with autoimmune pancreatitis (AIP). A 73-year-old female was admitted to our hospital for further investigation of elevated levels of liver transaminase and pancreatic enzymes. Her serological tests showed a high antinuclear antibody titer, and elevated IgG and IgG4 levels. Liver biopsy revealed interface hepatitis and bridging necrosis with IgG4-positive lymphoplasmacytic infiltration in the portal area. Moreover, contrast-enhanced computed tomography (CECT) showed pancreatic tail enlargement, and magnetic resonance cholangiopancreatography showed skipped narrowing of the main pancreatic duct in the pancreatic tail. Endoscopic ultrasonography-fine needle aspiration specimens showed no malignant cells. Based on these results, we diagnosed her with IgG4-AIH simultaneously concomitant with probable type 1 AIP. She was started on prednisolone (PSL) at 35 mg/d, and her symptoms and liver transaminase levels improved. One month after starting treatment, CECT showed improvement of pancreatic tail enlargement. She is maintained on 5 mg PSL/d and has been in remission for two years.

Fatal fulminant hepatitis induced by combined ipilimumab and nivolumab therapy despite favorable histologic response and confirmed by autopsy in a patient with clear cell renal cell carcinoma.

Effective management of immune-related adverse events in patients receiving immunotherapy for cancer is problematic. In this report, we present the case of a 58-year-old man with advanced clear cell renal cell carcinoma who responded well to a combination of ipilimumab and nivolumab. However, after two courses of treatment, he developed fulminant hepatitis and died. An autopsy confirmed that the primary lesion in the left kidney was more than 99% necrotic with only six small residual tumor lesions. These lesions were infiltrated by large numbers of CD8-positive/TIA-1-positive lymphocytes. However, a metastatic lesion in the right kidney harbored few lymphocytes. Furthermore, the tumor cells in the metastatic lesion and one of the residual lesions showed decreased expression of HLA class I molecules, which are a prerequisite for cytotoxic T-lymphocyte-mediated immunotherapy in tumor cells. In this patient, more than 80% of hepatocytes were destroyed and the parenchyma was infiltrated with CD8-positive/TIA-1-positive lymphocytes. The patient had polyuria, which was attributed to neurohypophysitis caused by the infiltration of CD8-positive/TIA-1-positive lymphocytes. We believe that this is an instructive case for immuno-oncologists.

Borderline Microenvironment Fibrosis Is a Novel Poor Prognostic Marker of Oral Squamous Cell Carcinoma.

BACKGROUND/AIM: The tumor microenvironment (TME) balances tumor growth and suppression through humoral factors and cell-cell interactions. In oral squamous cell carcinoma (OSCC), TMEs have been associated with prognosis of cancer patients and are evaluated by microscopy; however, these methods of evaluation vary among studies. MATERIALS AND METHODS: To evaluate the TME, borderline microenvironment fibrosis (bMF) was evaluated histologically in 236 OSCC cases and used to determine the clinicopathological status. RESULTS: bMF was observed in 47% (110 in 236 cases) of OSCC cases and associated with higher T category, N category, stage, histological grade and mode of invasion. bMF-positive was related to overall survival (OS) and progression-free survival (PFS). Multivariate analysis revealed that bMF-positive was an independent factor for OS in all cases [n=226; HR=1.683 (1.018-2.781); p=0.042], especially in T1+T2 cases [n=186; HR=1.926 (1.079-3.440); p=0.024], and PFS in all cases [n=226; HR=2.254 (1.397-3.637); p=0.001]. CONCLUSION: bMF may act as a novel biomarker for OSCC.

Non-bacterial cystitis with increased expression of programmed death-ligand 1 in the urothelium: An unusual immune-related adverse event during treatment with pembrolizumab for lung adenocarcinoma.

INTRODUCTION: Immune checkpoint inhibitors are now a standard therapeutic option for lung adenocarcinoma. However, Immune checkpoint inhibitors often induce various immune-related adverse events. CASE PRESENTATION: The patient was a 78-year-old woman with lung adenocarcinoma who had a partial response to pembrolizumab. During treatment, she complained of pollakiuria and nocturia with painful micturition. Histological analysis revealed infiltration of CD8-positive and/or TIA-1 cytotoxic granule-associated RNA binding protein-positive lymphocytes and programmed death-ligand 1 expression in the urothelium. A diagnosis of immune-related adverse event cystitis was made based on these clinical and pathological findings. The patient's subjective symptoms and findings on cystoscopy improved dramatically after treatment with prednisolone. CONCLUSION: Immune checkpoint inhibitors-induced cystitis is extremely rare. This report is the first to include an immunohistochemical analysis of the urothelial epithelium in immune-related adverse event cystitis and describes an instructive case.

[Hypogammaglobulinemia with a clinical course similar to that of drug-induced hypersensitivity syndrome].

A 30-year-old man consulted a local hospital because of upper abdominal pain and tarry stool and was admitted because of duodenal ulcer and hepatic dysfunction. On the fifth hospital day, he developed fever and erythema on the upper body. Liver biopsy demonstrated giant cell hepatitis, and interferon alpha was therefore administered. Liver function improved, though total bilirubin increased to 22.3 mg/dl. The eruption and fever improved in the 3rd hospital week, deteriorated again in the 5th hospital week, and then improved again in the 8th hospital week. Thereafter, he was transferred to our hospital for detailed examination of atypical lymphocytosis, lymphopenia, and hypogammaglobulinemia. Many lymph nodes measuring about 1 cm were detected by palpation. After admission to our hospital, lymphoadenopathy and fever improved. We measured the level of HHV-6 antibody since the clinical course was similar to that of drug-induced hypersensitivity syndrome (DIHS). HHV-6 IgG was x2,560, although it had been x160 at the previous hospital. The clinical course appeared similar to that of DIHS, but drugs known to cause DIHS had not been administered.

Iron deficiency anemia successfully treated by Helicobacter pylori eradication in a patient with idiopathic thrombocytopenic purpura.

A 53-year-old woman had demonstrated idiopathic thrombocytopenic purpura (ITP) and iron deficiency anemia (IDA) since 1978. Although she was treated with prednisolone for ITP and oral iron compounds for IDA, neither ITP nor IDA showed any improvement. Since her (13)C-urea breath test was positive, Helicobacter pylori (H. pylori) eradication therapy was performed in 2001. The therapy was effective for IDA but not for ITP. Analysis of cases such as this will be useful for clarifying the mechanisms underlying the development of ITP and IDA associated with H. pylori.

HB vaccination in the prevention of viral reactivation in allogeneic hematopoietic stem cell transplantation recipients with previous HBV infection.

Hepatitis B virus (HBV)-reverse seroconversion (RS) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a frequent late-onset complication in recipients with previous HBV infection. We followed 38 allo-HSCT recipients with previous HBV infection, and conducted posttransplant HB vaccine intervention in 13 recipients. First, we followed the recipients without any intervention (historic control) until 2003; hence, we commenced HB vaccination. Out of the patients who underwent transplantation after 2003, 13 recipients were immunized by a standard three-dose regimen after immunosuppressant cessation (vaccine group), whereas 12 recipients were observed without any intervention (nonvaccine group). Eight of the 13 historic control group recipients and 3 of the 12 nonvaccine group recipients, but none of the 13 vaccine group recipients, suffered HBV-RS. Cumulative risks of HBV-RS at 3 years post-HSCT in the historic control, nonvaccine and vaccine groups were 41%, 39%, and 0% respectively (P=.022). We therefore conclude that intervention with HB vaccines is significantly effective in preventing post-HSCT HBV-RS.

A retrospective analysis of allogeneic hematopoietic stem cell transplantation for adult T cell leukemia/lymphoma (ATL): clinical impact of graft-versus-leukemia/lymphoma effect.

Adult T cell leukemia/lymphoma (ATL) is a highly aggressive T cell malignancy, and has a poor prognosis. Recently, allogeneic-hematopoietic stem cell transplantation (allo-HSCT) has been suggested to improve the outcome. We retrospectively analyzed 15 patients with ATL who had received allo-HSCT in 2 institutions in Hokkaido, Japan. The median age of the patients was 57 years. The estimated 3-year overall survival (OS) and progression-free survival (PFS) rates were 73.3% and 66.7%, respectively. Calcineurin inhibitor dosage was reduced and administration was discontinued abruptly in 6 of the 15 patients for disease control; as a result, 4 (66.7%) of the 6 patients achieved complete response (CR) or partial response. Therefore, a graft-versus-leukemia/lymphoma (GVL) effect might be induced by discontinuation of immunosuppression. Thirteen of the 15 patients were followed up by monitoring HTLV-1 proviral DNA levels. In 10 of the 11 patients with positive HTLV-1 proviral DNA before allo-HSCT, HTLV-1 proviral DNA became undetectable at least once after allo-HSCT, and only 1 of the 5 patients in whom HTLV-1 proviral DNA became detectable after allo-HSCT relapsed. Compared to the results of past studies, these results show that allo-HSCT greatly improved the prognosis of ATL and suggest a contribution of the induction of a GVL effect.