3D CNN-based Deep Learning Model-based Explanatory Prognostication in Patients with Multiple Myeloma using Whole-body MRI.

Although magnetic resonance imaging (MRI) data of patients with multiple myeloma (MM) are used to predict prognosis, few reports have applied artificial intelligence (AI) techniques for this purpose. We aimed to analyze whole-body diffusion-weighted MRI data using three-dimensional (3D) convolutional neural networks (CNNs) and Gradient-weighted Class Activation Mapping (Grad-CAM), an explainable AI, to predict prognosis and explore the factors involved in prediction. We retrospectively analyzed the MRI data of a total of 142 patients with MM obtained from two medical centers. We defined the occurrence of progressive disease after MRI evaluation within 12 months as a poor prognosis and constructed a 3D CNN-based deep learning model to predict prognosis. Images from 111 cases were used as the training and internal validation data; images from 31 cases were used as the external validation data. Internal validation of the AI model with stratified 5-fold cross-validation resulted in a significant difference in progression-free survival (PFS) between good and poor prognostic cases (2-year PFS, 91.2% versus [vs.] 61.1%, P = 0.0002). The AI model clearly stratified good and poor prognostic cases in the external validation cohort (2-year PFS, 92.9% vs. 55.6%, P = 0.004), with an area under the receiver operating characteristic curve of 0.804. According to Grad-CAM, the MRI signals of the spleen and bones of the vertebrae and pelvis contributed to prognosis prediction. This study is the first to show that image analysis of whole-body MRI using a 3D CNN without any other clinical data is effective in predicting the prognosis of patients with MM.

Loss of or decrease in CD30 expression in four patients with anaplastic large cell lymphoma after brentuximab vedotin-containing therapy.

Brentuximab vedotin (BV), CD30 specific antibody drug conjugate, has been used to treat anaplastic large cell lymphoma (ALCL) and classic Hodgkin lymphoma (CHL); it is also used in the treatment of other CD30-positive peripheral T-cell lymphomas. We aimed to investigate the incidence and clinicopathological characteristics of patients with ALCL or CHL with loss of or decrease in CD30 expression after BV-containing therapy. Twelve and nine patients with refractory/relapsed CHL and ALCL, respectively, were analyzed after receiving BV-containing therapy. In four ALCL patients (44%), CD30 expression was lost/decreased in re-biopsy materials, including one with complete loss and three with a reduction of less than 20%. All 12 CHL patients showed consistent CD30 expression levels after BV treatment. Compared with five ALCL patients with consistent CD30 expression, four ALCL patients with a loss of/decrease in CD30 expression received a higher cumulative dose of BV (P = 0.014) and revealed a lower intensity of CD30 expression in initial biopsy materials (P = 0.017). The subtypes of ALCL (ALK positive, ALK negative, and primary cutaneous) were not related to the loss of/decrease in CD30 expression. In conclusion, 44% of ALCL patients, regardless of histological subtypes, showed a loss of/decrease in CD30 expression after receiving BV-containing therapy, but this phenomenon was not observed in CHL patients. A higher cumulative dose of BV and a lower amount of CD30 antigen in tumor cells in the initial biopsy materials might be predictors of a loss of/decrease in CD30 expression in ALCL patients.

Pathogenesis of Gastrointestinal Follicular Lymphomas: Consideration Based on Histopathology and Endoscopic Findings.

Gastrointestinal (GI) follicular lymphoma (FL) is the most frequently diagnosed extranodal FL; however, its pathogenesis is debatable. We investigated the distribution, endoscopic, and histopathologic findings of 366 GI FL samples obtained from 298 patients. FLs were most frequently observed in the small intestine (71%), including the duodenum (52%), but were also commonly found in the stomach (15%) and colon (12%). The proportion of granular lesions in the duodenum, terminal ileum, colon, and stomach was 74%, 39%, 24%, and 0%, respectively. Submucosal or ulcerated tumors were frequently observed in the stomach (48%) and colon (52%). Most GI FL showed grade 1 to 2 histology (89%) as well as CD10 + (93%) and BCL2 + (98%) positivity. There were no significant differences in the endoscopic or histologic findings between primary and secondary GI FLs. As known, the mucosa of the small intestine is thin and villous, while the mucosa of the stomach and colon is thicker and has a smooth surface. Granular lesions corresponding to very small FL were detected in the former but rarely in the latter. Nine (7%) patients with primary GI FL developed histologic transformation to diffuse large B-cell lymphoma (n=8) or high-grade B-cell lymphoma (n=1) 10 months to 14 years after the diagnosis of FL. Two patients died of lymphoma. In conclusion, the incidence and endoscopic findings differed, but the histopathology was similar in FLs in each site. These differences might be attributed to variations in each GI site's mucosal structure and the neoplastic follicles' size. Due to its characteristic structure, very small classic FLs might be detectable mainly in the small intestine.

Diagnostic clues of BCL2-negative, faint, or controversial follicular lymphomas: a study of 103 cases.

BCL2 positivity by immunohistochemistry is helpful for the diagnosis of follicular lymphoma (FL); however, a minority of FL cases are BCL2-negative, and the diagnosis is thus challenging. We retrospectively analyzed the incidence, morphology, immunophenotype, and genetic status of BCL21+ (weakly/focally positive by clone 124), BCL20 (negative), and BCL2controversial FLs compared with BCL22+ (strongly positive) FLs to clarify diagnostic clues. In 1068 FL cases, 103 (10%) with BCL21+ (37 cases, 4%), BCL20 (61 cases, 6%), or BCL2controversial (5 cases, 0.5%) were included in the final analysis. BCL21+ and BCL20 FLs tended to have limited stage disease, nodal disease, and grades 3A/3B histology and showed a higher complete response rate than BCL22+ FLs. Among 103 BCL20, BCL21+, or BCL2controversial FL cases, 34 (33%) had a diffuse area composed of CD20-positive small-to medium-sized lymphoid cells, a feature of low-grade B-cell lymphoma. Interfollicular dense CD20-positive cells and interfollicular clusters of CD10-positive cells were observed in 59% and 37% of cases, respectively. In remaining 13/40 cases (33%), BCL2 was converted to BCL22+ by other clones E17/SP66. CD23 and MUM1 were positive in 10/40 (25%) and 1/40 (3%) cases, respectively. IGH/BCL2 fusion and clonality were detected in 6/37 (16%) and 31/34 (91%) cases, respectively. In conclusion, morphological examination of the distribution of CD20-and/or CD10-positive cells and the presence of diffuse area could be used to diagnose FL in most cases. The majority of the remaining FL cases could be diagnosed using other BCL2 clones and clonality analyses.

Clinical characteristics and outcomes of Castleman disease: a multicenter Consortium study of 428 patients with 15-year follow-up.

Castleman disease (CD) has been reported as a group of poorly understood lymphoproliferative disorders, including unicentric CD (UCD) and idiopathic multicentric CD (iMCD) which are human immunodeficiency virus (HIV) negative and human herpes virus 8 (HHV-8) negative. The clinical and independent prognostic factors of CD remain poorly elucidated. We retrospectively collected the clinical information of 428 patients with HIV and HHV-8 negative CD from 12 large medical centers with 15-year follow-up. We analyzed the clinicopathologic features of 428 patients (248 with UCD and 180 with iMCD) with a median age of 41 years. The histology subtypes were hyaline-vascular (HV) histopathology for 215 patients (56.58%) and plasmacytic (PC) histopathology for 165 patients (43.42%). Most patients with UCD underwent surgical excision, whereas the treatment strategies of patients with iMCD were heterogeneous. The outcome for patients with UCD was better than that for patients with iMCD, 5-year overall survival (OS) rates were 95% and 74%, respectively. In further analysis, a multivariate analysis using a Cox regression model revealed that PC subtype, hepatomegaly and/or splenomegaly, hemoglobin ≤ 80 g/L, and albumin ≤ 30 g/L were independent prognostic factors of CD for OS. The model of iMCD revealed that age > 60 years, hepatomegaly and/or splenomegaly, and hemoglobin ≤ 80 g/L were independent risk factors. In UCD, single-factor analysis identified two significant risk factors: hemoglobin ≤ 100 g/L and albumin ≤ 30 g/L. Our study emphasizes the distinction of clinical characteristics between UCD and iMCD. The importance of poor risk factors of different clinical classifications may direct more precise and appropriate treatment strategies.

Two-year outcomes of tirabrutinib monotherapy in Waldenström's macroglobulinemia.

The phase II study of tirabrutinib monotherapy at a daily dose of 480 mg under fasting conditions for treatment-naïve and relapsed/refractory Waldenström's macroglobulinemia (ONO-4059-05 study) demonstrated a promising efficacy and tolerable safety profile. We conducted an unplanned analysis with a median follow-up of 24.8 months to update the efficacy and safety results and to report patient-reported quality of life. Of 27 enrolled patients, 22 patients continued receiving the study drug. The major response assessed by an independent review committee was observed in 25 patients (93%), including one and five patients who newly achieved complete response and very good partial response, respectively, after the primary analysis. The progression-free and overall survival rates at 24 months were 92.6% and 100%, respectively. Serum IgM levels in all patients except one declined and were maintained at low levels, although transient increases occurred after temporal interruption of the study drug. The disease-related symptoms including recurrent fever and hyperviscosity mostly disappeared. Health-related quality of life, assessed by cancer-specific questionnaires, was mostly maintained. Grade 3-4 neutropenia, lymphopenia, and leukopenia were newly recognized in three, two, and one patient, respectively. Grade 3 treatment-related hypertriglyceridemia was also recognized. Nine patients experienced grade 1-2 bleeding events (33%), one patient experienced grade 2 treatment-related atrial fibrillation, and one patient experienced grade 1 treatment-related hypertension. Treatment-related skin adverse events were observed in 14 patients (52%). Taken together, tirabrutinib has durable efficacy with an acceptable safety profile for treatment-naïve and refractory/relapsed Waldenström's macroglobulinemia.

CD3-and CD20-negative extramedullary non-Hodgkin leukemia/lymphoma: a histopathological study of 118 cases.

Histopathological diagnoses are challenging for rare CD3-and CD20-negative extramedullary leukemias/lymphomas. We report 118 cases of CD3- CD20-extramedullary leukemias/lymphomas (2.4% of 4977 cases). CD45 was positive in 68% of cases. Forty-nine (41%) cases were anaplastic large cell lymphomas. Thirty-five (30%) cases were large B-cell lymphomas/plasmablastic lymphomas positive for at least one of the following markers: CD79a, PAX5, CD19, CD138, and MUM1. Nine (8%) cases were peripheral T/NK-cell lymphomas, where at least CD43, CD45RO, or cytotoxic molecules were positive; 4, 3, and 2 cases were extranodal NK/T-cell lymphoma, nasal type, peripheral T-cell lymphoma-not otherwise specified, and adult T-cell leukemia/lymphoma, respectively. The remaining 25 (21%) cases included 11, 8, and 6 cases of myeloid sarcoma, blastic plasmacytoid dendritic cell neoplasm, and B- or NK-cell lymphoblastic leukemia/lymphoma, respectively. For large B-cell lymphoma/plasmablastic lymphoma diagnosis, MUM1 (92%) was the most sensitive marker, followed by CD79a (63%), PAX5 (52%), CD138 (42%), and CD19 (36%). EBER 1 and HHV8 were positive in 32% and 0% of the cases. For peripheral T/NK-cell lymphomas other than ALCL, CD45RO and CD43 were positive in nine cases; however, cytotoxic molecules (TIA1, 86%; granzyme B, 71%) were the most sensitive markers. In conclusion, most cases of the 118 (2.4%) CD3- CD20- extramedullary leukemia/lymphoma were represented by anaplastic large cell lymphomas (41%). The second most frequent group of neoplasia, large B-cell lymphoma/plasmablastic lymphoma (30%), characterized a special diagnostic challenge when B-cell markers were not expressed, requiring immunohistochemistry for multiple B-cell markers and molecular analysis in some cases.

PD-L1 expression is associated with the spontaneous regression of patients with methotrexate-associated lymphoproliferative disorders.

BACKGROUND: Most patients with methotrexate-associated lymphoproliferative disorder (MTX-LPD) show diffuse large B-cell lymphoma (DLBCL) or classic Hodgkin lymphoma (CHL) types. Patients with MTX-LPD often have spontaneous remission after MTX discontinuation, but chemotherapeutic intervention is frequently required in patients with CHL-type MTX-LPD. In this study, we examined whether programmed cell death-ligand 1 (PD-L1) expression levels were associated with the prognosis of MTX-LPD after MTX discontinuation. METHODS: A total of 72 Japanese patients diagnosed with MTX-LPD were clinicopathologically analyzed, and immunohistochemical staining of PD-L1 was performed in 20 DLBCL-type and 24 CHL-type MTX-LPD cases to compare with the clinical course. RESULTS: PD-L1 was expressed in 5.0% (1/20) of patients with DLBCL-type MTX-LPD, whereas it was expressed in 66.7% (16/24) of the patients with CHL-type MTX-LPD in more than 51% of tumor cells. Most CHL-type MTX-LPD patients with high PD-L1 expression required chemotherapy owing to exacerbations or relapses after MTX discontinuation. However, no significant differences in clinicopathologic findings at diagnosis were observed between PD-L1 high- and low-expression CHL-type MTX-LPD. CONCLUSION: PD-L1 expression was significantly higher in patients with CHL-type than DLBCL-type MTX-LPD, suggesting the need for chemotherapy in addition to MTX discontinuation in CHL-type MTX-LPD patients to achieve complete remission. No association was observed between PD-L1 expression levels and clinical findings at diagnosis, suggesting that PD-L1 expression in tumor cells influences the pathogenesis of CHL-type MTX-LPD after MTX discontinuation.

Validated international definition of the thrombocytopenia, anasarca, fever, reticulin fibrosis, renal insufficiency, and organomegaly clinical subtype (TAFRO) of idiopathic multicentric Castleman disease.

Thrombocytopenia, anasarca, fever, reticulin fibrosis, renal insufficiency, and organomegaly (TAFRO) syndrome is a heterogeneous entity manifesting with a constellation of symptoms described above that can occur in the context of idiopathic multicentric Castleman disease (iMCD) as well as infectious diseases, malignancies, and rheumatologic disorders. So, iMCD-TAFRO is an aggressive subtype of iMCD with TAFRO syndrome and often hyper-vascularized lymph nodes. Since we proposed diagnostic criteria of iMCD-TAFRO in 2016, we have accumulated new insights on the disorder and additional cases have been reported worldwide. In this systematic review and cohort analysis, we established and validated a definition for iMCD-TAFRO. First, we searched PubMed and Japan Medical Abstracts Society databases using the keyword "TAFRO" to extract cases. Patients with possible systemic autoimmune diseases and hematologic malignancies were excluded. Our search identified 54 cases from 50 articles. We classified cases into three categories: (1) iMCD-TAFRO (TAFRO syndrome with lymph node histopathology consistent with iMCD), (2) possible iMCD-TAFRO (TAFRO syndrome with no lymph node biopsy performed and no other co-morbidities), and (3) TAFRO without iMCD or other co-morbidities (TAFRO syndrome with lymph node histopathology not consistent with iMCD or other comorbidities). Based on the findings, we propose an international definition requiring four clinical criteria (thrombocytopenia, anasarca, fever/hyperinflammatory status, organomegaly), renal dysfunction or characteristic bone marrow findings, and lymph node features consistent with iMCD. The definition was validated with an external cohort (the ACCELERATE Natural History Registry). The present international definition will facilitate a more precise and comprehensive approach to the diagnosis of iMCD-TAFRO.

Detection of Antibodies Against Human Leukocyte Antigen Class II in the Sera of Patients Receiving Intravenous Immunoglobulin.

IVIG is occasionally used for preventing and treating severe infections of patients who are to undergo transplantation. Administration of IVIG, which includes high-titer antibodies (Abs) against HLA class I and II, might have a substantial influence on the HLA Ab test results of these patients. However, this issue has remained unreported. METHODS: Anti-HLA Ab titers were determined in 4 types of IVIG preparations, fresh frozen plasma, and the sera of 11 patients with hematological diseases before and after IVIG administration. RESULTS: Although anti-HLA Abs were not detected in any of the fresh frozen plasma products, various anti-HLA class I and II Abs were detected in all 4 IVIG preparations. Six out of 11 patients who had received IVIG showed a low titer of anti-HLA class II Abs, which were not detected before IVIG administration. Conversely, no anti-HLA class I Abs were detected in any of the 11 patients. Furthermore, all 4 (100%) patients who were positive for anti-HLA class II Abs initially and were assessable became negative for anti-HLA Abs after the discontinuation of IVIG treatment (median, d 79; range, d 22-192). CONCLUSIONS: IVIG preparations consist of high-titer anti-HLA class I and II Abs, but the latter can be transiently detected in the sera of patients who had received IVIG. When these patients are screened for the presence of donor-specific Abs, some may be incorrectly deemed positive for HLA class II Abs. Thus, caution is necessary when only donor-specific Abs specific to class II HLAs are detected in patients.

Effectiveness of hyperbaric oxygen therapy for virus-associated hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation.

Although some studies have suggested the effectiveness of hyperbaric oxygen (HBO) therapy for hemorrhagic cystitis (HC) after allogeneic hematopoietic stem cell transplantation (HSCT), the role of HBO has not been established. We compared the treatment outcomes of 8 patients with viral HC (adenovirus [ADV], n = 2; BK virus [BKV], n = 6) treated with HBO (HBO[+]) and 8 patients (ADV, n = 2; BKV, n = 6) treated with conventional therapy (HBO[-]), such as urinary catheterization and intravenous cidofovir. HBO therapy was performed at 2.1 atmospheres for 90 min/day until clinical improvement was achieved. The median number of HBO treatments was 10 (range 8-12). The median duration of HBO treatment was 19.5 days (range 10-23 days). All 8 HBO(+) patients achieved complete remission (CR) at a median of 14.5 days (range 5-25 days). Of the 8 HBO(-) patients, 5 (62.5%) obtained CR and 3 remained symptomatic for 2-6 months. The cumulative incidence of transplant-related mortality at day 100 after allogeneic HSCT was significantly higher in the HBO(-) patients than in the HBO(+) patients (14.2 vs. 0%, P < 0.05). No severe HBO-related adverse effects were observed. In conclusion, HBO is a feasible option for treating viral HC after allogeneic HSCT.

Multiple Malignant Lymphomas of the Bile Duct Developing after Spontaneous Regression of an Autoimmune Pancreatitis-like Mass.

We herein report a 67-year-old woman with malignant lymphomas of the bile duct that developed after regression of a pancreatic head mass. Computed tomography suggested the mass was pancreatic head cancer. Endoscopic ultrasonography showed a low-echoic mass with hyperechoic strands resembling autoimmune pancreatitis. Her serum IgG4 concentration was elevated to 674 mg/dL. After the pancreatic head mass spontaneously diminished, three masses were detected in the common bile duct. A biopsy of the major papilla revealed high-grade B-cell lymphoma with MYC, BCL2 and/or BCL6 rearrangement. Systemic chemotherapy with rituximab plus etoposide, prednisolone, vincristine, cyclophosphamide and doxorubicin resulted in complete remission.

A Novel Predictive Model for Idiopathic Multicentric Castleman Disease: The International Castleman Disease Consortium Study.

BACKGROUND: Patients with multicentric Castleman disease (MCD) who are negative for human immunodeficiency virus and human herpesvirus 8 are considered to have idiopathic MCD (iMCD). The clinical presentation of iMCD varies from mild constitutional symptoms to life-threatening symptoms or death. The treatment strategy varies from "watchful waiting" to high-dose chemotherapy. This diverse clinical presentation calls for a classification stratification system that takes into account the severity of the disease. SUBJECTS, MATERIALS, AND METHODS: We analyzed the clinical, laboratory, and pathologic abnormalities and treatment outcomes of 176 patients with iMCD (median follow-up duration 12 years) from the U.S. and China to better understand the characteristics and prognostic factors of this disease. This discovery set of iMCD results was confirmed from the validation set composed of additional 197 patients with iMCD organized from The International Castleman Disease Consortium. RESULTS: Using these data, we proposed and validated the iMCD international prognostic index (iMCD-IPI), which includes parameters related to patient characteristics (age > 40 years), histopathologic features (plasma cell variant), and inflammatory consequences of iMCD (hepatomegaly and/or splenomegaly, hemoglobin <80 g/L, and pleural effusion). These five factors stratified patients according to their performance status and extent of organ dysfunction into three broad categories: low risk, intermediate risk, and high risk. The iMCD-IPI score accurately predicted outcomes in the discovery study cohort, and the results were confirmed on the validation study cohort. CONCLUSION: This study represents the largest series of studies on patients with iMCD in the field and proposed a novel risk-stratification model for iMCD-IPI that could be used to guide risk-stratified treatment strategies in patients with iMCD. IMPLICATIONS FOR PRACTICE: Patients with idiopathic multicentric Castleman disease (iMCD) can benefit from care based on clinical symptoms and disease severity. This study in 176 patients with iMCD constructed an iMCD-IPI score based on five clinical factors, including age >40 years, plasmacytic variant subtype, hepatomegaly and/or splenomegaly, hemoglobin <80 g/L, and pleural effusion, and stratified patients into three risk categories: low risk, intermediate risk, and high risk. The predictive value was validated in an independent set of 197 patients with iMCD from The International Castleman Disease Consortium. The proposed novel model is valuable for predicting clinical outcome and selecting optimal therapies using clinical parameters.

A multicenter, open-label, phase II study of tirabrutinib (ONO/GS-4059) in patients with Waldenström's macroglobulinemia.

Tirabrutinib is a second-generation Bruton's tyrosine kinase inhibitor with greater selectivity than ibrutinib. Here, we conducted a multicenter, phase II study of tirabrutinib in patients with treatment-naïve (Cohort A) or with relapsed/refractory (Cohort B) Waldenström's macroglobulinemia (WM). Patients were treated with tirabrutinib 480 mg once daily. The primary endpoint was major response rate (MRR; ≥ partial response). Secondary endpoints included overall response rate (ORR; ≥ minor response), time to major response (TTMR), progression-free survival (PFS), overall survival (OS), and safety. In total, 27 patients (18 in Cohort A; 9 in Cohort B) were enrolled. The median age was 71 y, and the median serum immunoglobulin M level was 3600 mg/dL. Among the patients, 96.2% had the MYD88L265P mutation. MRR and ORR were 88.9% and 96.3%, respectively (Cohort A: MRR, 88.9%; ORR, 94.4%; Cohort B: MRR, 88.9%; ORR, 100%). Median TTMR was 1.87 mo. PFS and OS were not reached with a median follow-up of 6.5 and 8.3 mo for Cohorts A and B, respectively. The most common adverse events (AEs) were rash (44.4%), neutropenia (25.9%), and leukopenia (22.2%), with most AEs classified as grade 1 or 2. Grade ≥ 3 AEs included neutropenia (11.1%), lymphopenia (11.1%), and leukopenia (7.4%). No grade 5 AEs were noted. All bleeding events were grade 1; none were associated with drug-related atrial fibrillation or hypertension. Although the follow-up duration was relatively short, the study met the primary endpoint. Therefore, tirabrutinib monotherapy is considered to be highly effective for both untreated and relapsed/refractory WM with a manageable safety profile. (JapicCTI-173646).

A case of hepatosplenic T-cell lymphoma successfully treated by HLA haploidentical stem cell transplantation.

We report a case of hepatosplenic T-cell lymphoma (HSTL) transplanted from an HLA-haploidentical daughter. A 51-year-old man was referred due to liver function test abnormalities and fever. He was confirmed to have γδ-type HSTL by bone marrow and liver biopsies. He was treated with five cycles of a CHOP regimen. Although metabolic complete response (CR), as defined by positron emission tomography, was achieved, his bone marrow still contained tumor cells on polymerase chain reaction (PCR). He underwent transplantation using unmanipulated peripheral blood stem cells from his HLA-haploidentical daughter. The preconditioning regimen consisted of fludarabine, melphalan, busulfan and antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and short-term methotrexate. Neutrophil engraftment was achieved on day 14. His bone marrow exhibited a completely female phenotype by fluorescence in situ hybridization, and no lymphoma cells were detected by PCR on day 30. Although he developed grade II acute GVHD on day 47, it was successfully treated by prednisolone. He has a limited type of skin chronic GVHD and still receives oral immunosuppressive therapy. He remains in CR four years after transplantation.

Epidemiological analysis of multicentric and unicentric Castleman disease and TAFRO syndrome in Japan.

Castleman disease is a polyclonal lymphoproliferative disease which is clinically classified into unicentric (UCD) and multicentric (MCD). TAFRO syndrome is a relatively new concept that partly overlaps with MCD. Due to their rarity, their incidence remains unknown. This study investigated the incidence and prevalence of UCD, MCD, and TAFRO syndrome in Japan using a fixed-point observation method based on their incidence in Ishikawa prefecture. The annual incidences of MCD, UCD, and TAFRO syndrome in Japan were 309-731, 71-542, and 110-502, respectively, yielding annual incidence rates per million individuals of 2.4-5.8, 0.6-4.3, and 0.9-4.9, respectively, and nationwide prevalence of 4,180-14,900, 1,350-10,300, and 860-7,240, respectively. In conclusion, MCD, UCD and TAFRO syndrome may not be as rare as previously estimated in Japan.

Hepatic Campylobacter jejuni infection in patients with Castleman-Kojima disease (idiopathic multicentric Castleman disease with thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly (TAFRO) syndrome).

Castleman-Kojima disease, also known as idiopathic multicentric Castleman disease with TAFRO syndrome (iMCD-TAFRO), is a recently recognized systemic inflammatory disorder with a characteristic series of clinical symptoms, including thrombocytopenia (T), anasarca (A), fever (F), reticulin fibrosis (R), and organomegaly (O). Patients with iMCD-TAFRO often develop severe abdominal pain, elevated alkaline phosphatase levels, and systemic inflammation, but the etiological factors are unknown. To investigate the potential role of bacterial infection in the pathogenesis of iMCD-TAFRO, we performed polymerase chain reaction (PCR) for the bacterial 16S rRNA gene with DNA extracted from liver specimens of three patients with iMCD-TAFRO, four patients with amyotrophic lateral sclerosis, and seven patients with inflammatory conditions. Sequencing of the PCR product showed 99% DNA sequence identity with Campylobacter jejuni in all three patients with iMCD-TAFRO and in two patients with inflammatory conditions. Immunohistochemical and electron microscopy analyses could not identify C. jejuni in patients with iMCD-TAFRO. The findings indicated that C. jejuni infection is not the pathological cause of iMCD-TAFRO; however, this ubiquitous bacterium may play a role in uncontrolled systemic hypercytokinemia, possibly through the development of cross-reactive autoantibodies.

Tentative diagnostic criteria and disease severity classification for Castleman disease: A report of the research group on Castleman disease in Japan.

OBJECTIVES: To determine the tentative diagnostic criteria and disease severity classification for Castleman disease (CD) and describe the clinical and pathologic features among human herpesvirus 8 (HHV-8) negative idiopathic multicentric CD (iMCD) in the Japanese population. METHODS: We established the working groups for the research of CD in Japan and had meetings to discuss and define the tentative diagnostic criteria and disease severity classification for CD. We subsequently analyzed 142 patients classified into iMCD by using the nationwide Japanese patient registry. RESULTS: We proposed the preliminary diagnostic criteria and disease severity classification for CD based on our discussion. In addition, we made a proposal for the disease activity score. We identified clinical and pathological features of patients with iMCD diagnosed by these diagnostic criteria. In the disease severity classification, 37, 33 and 30% patients were categorized into mild, moderate and severe diseases, respectively. CONCLUSION: This is the first proposal for diagnosis and classification of CD by the Japanese group. Further studies are required to validate whether they can distinguish CD from other inflammatory diseases and to determine their sensitivity and specificity.