The lymphocyte/monocyte ratio predicts the efficacy of isatuximab plus pomalidomide in multiple myeloma patients.

BACKGROUND: Isatuximab, an anti-CD38 antibody, has been widely used in treatments for patients with relapsed/refractory multiple myeloma (MM). Despite its high efficacy, not all patients achieve a lasting therapeutic response with isatuximab. OBJECTIVE: We tried to identify biomarkers to predict the effectiveness of isatuximab by focusing on the host's immune status before treatment. METHODS: We retrospectively analyzed the cases of 134 relapsed/refractory MM patients in the Kansai Myeloma Forum database who had received only a first isatuximab treatment. RESULTS: Among the 134 patients, an isatuximab, pomalidomide and dexamethasone (Isa-PD) regimen, isatuximab, carfilzomib and dexamethasone (Isa-KD) regimen and isatuximab and/or dexamethasone (Isa-D) regimen were used in 112, 15 and 7 patients, respectively. The median age at treatment, number of prior treatment regimens, and progression-free survival (PFS) were 71, 6, and 6.54 months, respectively. Multivariate analysis showed that the PFS under the Isa-PD regimen was longer in patients with higher lymphocyte/monocyte ratio (LMR ≥ 4), fewer prior treatment regimens (< 6), and no use of prior daratumumab treatment. The OS under the Isa-PD regimen was longer in patients with higher white blood cell counts (WBC counts ≥ 3000/µL) and higher LMR. The PFS under the Isa-D regimen was longer in patients with fewer prior treatment regimens in univariate analysis, but no parameters were correlated with PFS/OS under the Isa-KD regimen. CONCLUSION: We found that the patients with higher LMR (≥ 4) could obtain longer PFS and OS under the Isa-PD regimen. Other cohort studies of isatuximab treatment might be necessary to substantiate our results.

Systemic inflammatory autoimmune disease before allogeneic hematopoietic stem cell transplantation is a risk factor for death in patients with myelodysplastic syndrome or chronic myelomonocytic leukemia.

Myelodysplastic syndrome (MDS) is well known to be complicated by systemic inflammatory autoimmune disease (SIADs). However, it remains unclear how the prognosis after allogenic hematopoietic stem cell transplantation (allo-HSCT) in patients with MDS is impacted by SIADs that occur before allo-HSCT. Therefore, we hypothesized that SIADs before allo-HSCT may be a risk factor for negative outcomes after allo-HSCT in patients with MDS. We conducted a single-center, retrospective, observational study of sixty-nine patients with MDS or chronic myelomonocytic leukemia who underwent their first allo-HCT. Fourteen of the patients had SIADs before allo-HSCT. In multivariate analysis, the presence of SIADs before allo-HSCT was an independent risk factor for overall survival (HR, 3.36, 95% confidence interval: 1.34-8.42, p = 0.009). Endothelial dysfunction syndrome was identified in five of 14 patients with SIADs who required immunosuppressive therapy or intensive chemotherapy, and notably, all patients with uncontrollable SIADs at allo-HSCT developed serious endothelial dysfunction syndrome and died in the early phase after allo-HSCT. The development of SIADs in the context of MDS is thought to reflect the degree of dysfunction of hematopoietic cells in MDS and suggests a higher risk of disease progression. In addition, MDS patients with SIADs before allo-HSCT are considered to be at higher risk of endothelial dysfunction syndrome because of preexisting vascular endothelial dysfunction due to SIADs. In conclusion, SIADs before allo-HSCT constitute an independent risk factor for death in MDS patients undergoing allo-HSCT.

Autotaxin is a potential predictive marker for the development of veno-occlusive disease/sinusoidal obstruction syndrome after allogeneic hematopoietic cell transplantation.

Veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a life-threatening complication after allogeneic hematopoietic cell transplantation (allo-HCT), and stratification of the high-risk group before transplantation is significant. Serum autotaxin (ATX) levels have been reported to increase in patients with liver fibrosis caused by metabolic inhibition from liver sinusoidal endothelial cells. Considering that the pathophysiology of VOD/SOS begins with liver sinusoidal endothelial cell injury, an increase in serum ATX levels may precede the onset of VOD/SOS. A retrospective study with 252 patients, including 12 patients with VOD/SOS, who had received allo-HCT was performed. The cumulative incidence of VOD/SOS was higher in the group with serum ATX levels before conditioning (baseline ATX) above the upper reference limit (high ATX group, p < 0.001), and 1-year cumulative incidences were 22.7% (95% confidence interval [95%CI], 3.1-42.4%) and 3.5% (95%CI, 1.1-5.8%), respectively. In the multivariate analysis, elevated baseline ATX was identified as an independent risk factor for VOD/SOS development and showed an additive effect on the predictive ability of known risk factors. Furthermore, the incidence of VOD/SOS-related mortality was greater in the high ATX group (16.7% vs. 1.3%; p = 0.005). Serum ATX is a potential predictive marker for the development of VOD/SOS.

Efficacy of elotuzumab for multiple myeloma deteriorates after daratumumab: a multicenter retrospective study.

Elotuzumab-based regimens are sometimes selected for multiple myeloma treatment after daratumumab-based regimens. However, there has been insufficient discussion on the efficacy of elotuzumab after daratumumab. We used Kansai Myeloma Forum registration data in a multicenter retrospective evaluation of the efficacy of elotuzumab after daratumumab. Overall survival (OS) rate and time to next treatment (TTNT) were significantly worse in the cohort given elotuzumab after daratumumab (Dara cohort, n = 47) than in the cohort with no history of daratumumab administration before elotuzumab (No-Dara cohort, n = 80, OS: P = 0.03; TTNT: P = 0.02; best response: P < 0.01). In the Dara cohort, OS and TTNT rates were worse with sequential elotuzumab use after daratumumab than with non-sequential (OS: P = 0.02; TTNT: P = 0.03). In patients given elotuzumab < 180 days after daratumumab, OS (P = 0.08) and best response (P = 0.21) tended to be worse, and TTNT was significantly worse (P = 0.01), than in those given elotuzumab after ≥ 180 days. These findings were confirmed by subgroup analyses and multivariate analyses. Monoclonal-antibody-free treatment might be preferable after daratumumab-based regimens. If possible, elotuzumab-based regimens should be considered only ≥ 180 days after daratumumab use.

Posttransplantation cyclophosphamide mediates effective reconstitution of memory B cells after allogeneic hematopoietic cell transplantation.

OBJECTIVES: Impaired B-cell reconstitution after allogeneic hematopoietic cell transplantation (allo-HCT) contributes to the pathogenesis of chronic graft-versus-host disease (cGVHD). Therefore, methods to consistently achieve effective B cell lymphogenesis are required. We assessed the long-term effects of posttransplantation cyclophosphamide (PTCy) use on immune reconstitution in clinical settings, an emerging strategy to suppress allogeneic immunological inflammation early after allo-HCT and prevent subsequent GVHD. METHODS: We comprehensively analyzed peripheral immune cell subsets and measured serum immunoglobulin G (IgG) or cytokine levels in 39 patients who survived for >1 year after allo-HCT. RESULTS: The absolute counts of B1 and IgM memory B cells were significantly lower in patients with severe cGVHD than in those without. The absolute count and percentage (among total CD19+ B cells) of switched memory B cells and serum IgG levels were significantly higher in patients transplanted with PTCy than in those transplanted with conventional GVHD prophylaxis. Interestingly, increased percentages of switched memory B cells and serum IgG levels were observed only in patients transplanted with PTCy and not in those transplanted with umbilical cord blood. CONCLUSIONS: PTCy administration can mediate favorable memory B-cell reconstitution long after allo-HCT and may therefore suppress cGVHD.

Impacts of Posttransplant Cyclophosphamide Dose on Graft-versus-leukemia Effects via HLA-B Leader in HLA-haploidentical Peripheral Blood Stem Cell Transplantation.

INTRODUCTION: The graft-versus-leukemia effect of HLA-B leader dimorphism, i.e. methionine (M) or threonine (T) at position -21 of the leader sequence, has been observed in HLA-haploidentical hematopoietic cell transplantation with posttransplant cyclophosphamide (PTCy-haplo). However, the biological mechanism has been unclear, and the contributions of HLA-B leader genotype to risk reduction of relapse might be dependent on posttransplant cyclophosphamide (PTCy) doses. METHODS: To investigate whether the effect of HLA-B leader dimorphism was modified by the PTCy dose, we retrospectively analyzed 99 patients who received PTCy-haplo. RESULTS: In the low-dose PTCy group, the patient M+ HLA-B leader genotype did not significantly affect the cumulative incidence of relapse (CIR) but negatively impacted the overall survival (OS) compared to the M- genotype. In contrast, in the high-dose PTCy group, patients with the M+ genotype had a decreased CIR, but no significant difference in the OS was observed between patients with the M+ and M- genotypes. Regardless of PTCy doses, the patient M+ genotype had detrimental effects on nonrelapse mortality. CONCLUSION: Our findings suggest that the effect of the patient HLA-B leader genotype is modified by the PTCy dose, providing immunological insight into the PTCy dosage and supporting further studies to investigate the underlying mechanisms.

Invasive fungal infection caused by Blastobotrys mokoenaii in an immunocompromised patient with acute myeloid leukemia: A case report.

Blastobotrys is a genus of rare yeast that is increasingly recognized as a cause of fungal infections in humans. However, there have been no reports of fungal infections in humans caused by Blastobotrys mokoenaii. We describe a case of invasive fungal infection (IFI) caused by B. mokoenaii in an immunocompromised patient with acute myeloid leukemia (AML). A 46-year-old man with relapsed/refractory AML underwent a second allogeneic peripheral blood hematopoietic stem cell transplantation (allo-PBSCT) during remission. The patient had prolonged neutropenia and received systemic steroid therapy for graft-versus-host disease before the second allo-PBSCT. Uncommon yeast was isolated from the blood cultures obtained on day 4. We initially suspected that the uncommon yeast was Trichosporon spp. based on its morphology. However, unlike Trichosporon spp., in vitro antifungal susceptibility tests showed that this yeast isolate was resistant to micafungin, caspofungin, voriconazole, itraconazole, and fluconazole. We performed DNA sequencing and identified it as B. mokoenaii. B. mokoenaii was persistently isolated from blood cultures taken during combination therapy with liposomal amphotericin B and voriconazole. The patient died of multiorgan failure on day 24. B. mokoenaii can cause severe IFI in immunocompromised patients; however, it may not be correctly identified by routine clinical microbiology testing in a hospital laboratory and DNA sequencing is useful for diagnosis.

[Usefulness of web-based application for health surveys before and after peripheral blood stem cell harvest from healthy donors].

Health surveys to assess adverse events after peripheral blood stem cell harvest (PBSCH) have conventionally been conducted by phone, but phone calls are suboptimal for conducting frequent surveys. We developed a web-based application (donor app) that enables donors to inform healthcare professionals (HCPs) of their health status as an electronic patient-reported outcome (ePRO). In this prospective observational study, we compared the usefulness of this donor app to phone calls for conducting health surveys. App users reported ePRO daily, and patients called by HCPs reported their health status at least once a week when called. The observation period was from the first administration of granulocyte colony-stimulating factor to the first follow-up visit after PBSCH, excluding the hospitalization period. Each group consisted of eight donors with a median age of 32 years (range: 19-58). Nine (56.3%) were female. There were eight related donors in the phone call group and four in the donor app group. During the observation period, HCPs obtained health status reports more frequently from app users than from phone call recipients (mean proportion of days with reports made during the observation period, 27.0% vs 53.5%; p<0.05). Average time spent by the HCPs for one follow-up and total follow-ups were both significantly shorter when the donor app was used. There were no differences in donor burden or satisfaction with donation. Our study suggests that use of a donor app could provide more detailed health survey data without increasing the burden on donors and HCPs.

Recapitulated Late-Onset Inflammatory Toxicities and Progressive Dysautonomia with Persistence of Central Memory CD4+ Chimeric Antigen Receptor T Cells in a Case of Transformed Follicular Lymphoma: Case Report.

CD19-directed chimeric antigen receptor (CAR) T-cell therapy has been widely used and is highly effective for B-cell lymphoid malignancies. Immune-mediated adverse effects such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) occur in the acute phase and are monophasic after CAR T-cell therapy. However, late-onset inflammatory and neurological toxicities have not been well studied. We encountered a patient with recurrent late-onset inflammatory toxicities and progressive dysautonomia after CD19-directed CAR T-cell therapy. A 69-year-old man was treated with CD19-directed CAR T-cell therapy for transformed follicular lymphoma. Triphasic inflammation with stomatitis, cytopenia, and noninfectious pneumonia was first observed 7 months after CAR T-cell infusion. Progressive dysautonomia was also observed and eventually fatal. Residual CAR T cells, predominantly central memory CD4+ cells, were detectable in peripheral blood approximately 1 year after CAR T-cell infusion. The cytokine profile with the lack of tumor necrosis factor-α, interferon-γ, and interleukin-1ß elevation in the peripheral blood and cerebrospinal fluid was inconsistent with that of typical CRS or ICANS. The persistence of central memory CD4+ CAR T cells might be associated with unique manifestations of late-onset immune-mediated adverse effects. More cases should be accumulated to elucidate the mechanism and establish the optimal management strategy of late-onset immune-mediated toxicities previously unrecognized.

Sinusoidal obstruction syndrome associated with disseminated toxoplasmosis involving the liver after allogeneic hematopoietic stem cell transplantation: A case report.

Sinusoidal obstruction syndrome (SOS) is a fatal complication after hematopoietic stem cell transplantation (HSCT). Only a few complications after HSCT have been reported as risk factors for SOS, including sepsis. Here, we report the case of a 35-year-old male diagnosed with Philadelphia chromosome-positive acute lymphoblastic leukemia who underwent peripheral blood HSCT from a human leukocyte antigen-matched unrelated female donor in remission. Graft-versus-host disease prophylaxis contained tacrolimus, methotrexate, and low-dose anti-thymoglobulin. The patient was treated with methylprednisolone for engraftment syndrome from day 22. On day 53, he presented worsening fatigue, breathlessness, and abdominal pain in the right upper quadrant that had persisted for 4 days. Laboratory tests showed severe inflammation, liver dysfunction, and positive for Toxoplasma gondii PCR. He died on day 55. An autopsy showed SOS and disseminated toxoplasmosis. Hepatic infection with T. gondii was identified in zone 3 of the liver, which overlapped with the pathological features of SOS. In addition, the timing of the exacerbation of hepatic dysfunction coincided with the onset of systemic inflammatory symptoms and T. gondii reactivation. This rare case of toxoplasmosis is the first to suggest that hepatic infection with T. gondii is strongly associated with SOS after HSCT.

Successful treatment of proven coronavirus disease 2019-associated pulmonary aspergillosis with liposomal amphotericin B in a patient with bronchiolitis obliterans syndrome after allogeneic hematopoietic stem cell transplantation.

Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is being increasingly recognized as a severe complication that contributes to poor prognoses among patients with COVID-19. However, little is known regarding the clinical course of CAPA with hematological malignancies, especially after allogeneic hematopoietic stem cell transplantation (HSCT). A 29-year-old woman was diagnosed with proven CAPA with an Aspergillus fumigatus identified by cultures of bronchoalveolar lavage and lung biopsy four years after haploidentical HSCT for acute myelogenous leukemia. She had been taking oral prednisolone for bronchiolitis obliterans syndrome that developed after HSCT. Although prolonged RT-PCR positivity for SARS-CoV-2 (133 days after the onset of COVID-19) without shedding of viable virus was observed, the COVID-19 was treated with favipiravir, remdesivir, dexamethasone, and enoxaparin. However, the CAPA did not respond to combination therapy, which included triazole (voriconazole, itraconazole, posaconazole) and echinocandin (caspofungin, micafungin), even though the Aspergillus fumigatus isolate was found to be susceptible to these agents in vitro. Nevertheless, a total of 16 weeks of liposomal amphotericin B (L-AMB) therapy led to a favorable response, and the patient was discharged from the hospital on day 213. This case provided essential experience of CAPA treated with L-AMB in a recipient with chronic respiratory disease after HSCT.

[AL amyloidosis presenting with fluminant multiorgan failure accompanied by rapid progression from MGUS to multiple myeloma].

Monoclonal gammopathy of undermined significance (MGUS) is usually asymptomatic, and untreated follow-up is the standard treatment. However, MGUS progresses to multiple myeloma or related malignancy at a frequency of 1.5% per year. It is sometimes difficult to diagnose the progression of the disease via usual examinations. We herein report a case wherein rapid renal dysfunction led to a diagnosis of disease progression to multiple myeloma in a patient with MGUS that was asymptomatic for a long time. A 66-year-old woman developed rapid renal dysfunction requiring continuous hemodiafiltration 8 years after the diagnosis of IgA-κ type MGUS. A complete examination led to the diagnosis of IgA-κ type multiple myeloma. Chemotherapy was not effective, and she died due to sepsis on the 19th day of admission. A pathological autopsy revealed systemic amyloidosis and multiple abscesses positive for Staphylococcus aureus. An abnormal free light chain κ/λ ratio and M protein other than IgG are reportedly risk factors of disease progression of MGUS. In cases with these risk factors, it is important to always keep in mind the possibility of disease progression and to monitor the patient carefully for an early diagnosis.

[Warm autoimmune hemolytic anemia and IgM-monoclonal gammopathy following BNT162b2 COVID-19 vaccine in a patient with splenic marginal zone lymphoma].

There is currently no evidence that a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine might be associated with the development of autoimmune hemolytic anemia or disease progression in patients with mature B-cell neoplasm. Our patient was a 71-year-old man with indolent mature B-cell neoplasm who had been monitored for many years without treatment. After receiving the second dose of the BNT162b2 mRNA COVID-19 vaccine, he developed severe warm autoimmune hemolytic anemia. Although steroid therapy improved his anemia, he continued to develop IgM-monoclonal gammopathy, renal insufficiency, and splenomegaly. He was diagnosed with splenic marginal zone lymphoma after undergoing splenectomy. The splenectomy improved the patient's symptoms. We assessed his SARS-CoV-2 specific antibody response, but the patient's serologic response to the vaccine was impaired. In patients with mature B-cell neoplasm, a non-specific immune response after vaccination might be associated with paraneoplastic syndromes.

Plateau is a prognostic factor of lenalidomide therapy for previously treated multiple myeloma.

The plateau phase emerging during the treatment of multiple myeloma (MM) is known to last steadily for a certain period, even without treatment. Therefore, the treatment started at plateau phase is expected to be associated with a better outcome. In this study, this hypothesis was evaluated retrospectively for previously treated MM patients in Kansai Myeloma Forum database who received lenalidomide (LEN) with or without dexamethasone for the first time. Disease stability index (DSI) was defined as (maximum - minimum values of M protein during the 90 days before the start of LEN) divided by M-protein values at the start of LEN. The patients were classified into three groups: stable (S), DSI ≤ 0.25; increasing (I), DSI > 0.25 with increasing M protein; decreasing (D), DSI > 0.25 with decreasing M protein. In univariate analysis of 352 patients, DSI group "I", non-IgG type, serum albumin<3.5 g/dL, and age≥70 were statistically significant prognostic factors for both progression-free survival and overall survival. In multivariate analysis, the former 3 risk factors were statistically significant for poor overall survival. Thus, DSI is an independent prognostic factor for the treatment with LEN for previously treated MM.

Outcomes of ixazomib/lenalidomide/dexamethasone for multiple myeloma: A multicenter retrospective analysis.

OBJECTIVES: This study aimed to investigate real-world data of ixazomib plus lenalidomide and dexamethasone (IRd) therapy for patients with relapsed and refractory multiple myeloma (RRMM). METHODS: We retrospectively analyzed 122 patients treated with IRd at 16 centers from May 2017 to January 2019 by using the Kansai Myeloma Forum database. RESULT: At the start of IRd, the median age was 72 years, 66.7% of patients had IgG type, and the median number of prior therapies was 4, comprising bortezomib (85.4%) and lenalidomide (89.3%)-based regimens. Disease progression and adverse events accounted for treatment discontinuation in 46 and 32 patients, respectively. The median overall survival (OS) was not reached, and the median progression-free survival (PFS) was 11.9 months. Sensitivity to bortezomib did not affect the PFS, whereas lenalidomide-refractory patients had significantly lower PFS than lenalidomide-sensitive patients, who were comparable to TOURMALINE-MM1 study. The patients with IgG type had significantly better PFS and OS than those with non-IgG type. CONCLUSION: This study presents the largest real-world data of patients treated with IRd in Asia. However, in real clinical practice, the patient background is different from the TOURMALINE-MM1 study, and IRd showed poor efficacy, especially in the non-IgG type and lenalidomide-refractory patients with RRMM.

Isatuximab plus Pomalidomide and Dexamethasone in a Patient with Dialysis-Dependent Multiple Myeloma.

The phase 3 ICARIA-MM trial showed that the addition of isatuximab improved the progression-free survival compared with pomalidomide/dexamethasone. However, the safety and efficacy of isatuximab for end-stage renal failure remains unclear. A 67-year-old man who started hemodialysis 5 years ago for diabetic nephropathy was diagnosed with International Staging System stage III multiple myeloma (MM) of IgD-λ type 3 years ago. After receiving a total of 7 treatment regimens, his free light chain (FLC) λ level increased from 419 to 2,070 mg/L, indicating progressive disease. Twelve days after starting isatuximab plus pomalidomide (3 mg daily) and dexamethasone (IsaPd), his FLC λ level rapidly decreased to 412 mg/L. The patient has now completed 7 courses of IsaPd with no adverse events, including infusion reactions and neutropenia. Isatuximab requires a lower dilution volume than daratumumab and can be safely and effectively administered to hemodialysis-dependent MM patients.

[Diffuse large B-cell lymphoma with markedly improved chylothorax by lymphangiography].

Chylothorax is a rare clinical sign in patients with diffuse large B-cell lymphoma (DLBCL), which is often challenging to manage and has a poor prognosis. We report the case of a 59-year-old woman who presented with right pleural effusion at the time of DLBCL diagnosis. Lymphadenopathy rapidly improved in response to chemotherapy. However, the pleural effusion progressed and was identified as chylothorax by thoracentesis. Because attempts to manage the condition with fasting and central venous nutrition were unsuccessful, we performed ultrasound-guided intranodal lipiodol lymphangiography from the inguinal lymph node. Although leak sites were not detected, the pleural effusion markedly improved on the day after the examination and resolved after 2 months. Lymphangiography is a minimally invasive examination with few complications. It contributes not only to the identification of leak sites but also to the improvement and resolution of chylothorax. Therefore, lymphangiography should be considered for refractory chylothorax that is unresponsive to chemotherapy or nutritional management.

[Retrospective Analysis of Bortezomib or Lenalidomide for Very Elderly Patients with Newly Diagnosed Multiple Myeloma].

In elderly patients aged≥80 with newly diagnosed multiple myeloma(NDMM), the optimal initial doses of bortezomib (Bor)and lenalidomide(Len)remain unclear. We performed a retrospective analysis that included 20 patients with NDMM aged≥80 years who underwent treatment with Bor or Len at our hospital from July 2010 to December 2019. Among the patients treated with Bor, the median time to next treatment(TTNT)was 4.2 months, and the median dose was 1.0 mg/m2 per injection. While patients with International Staging System(ISS)Ⅲ or an estimated glomerular filtration rate of < 40 mL/ min/1.73 m2 required dose reductions, dose intensity did not significantly affect TTNT. Among the patients treated with Len, the median TTNT was 14.6 months, and the median dose of Len was 10.0 mg/day. All patients who started with6le;10 mg Len continued the initial dose; the others required a dose reduction. Treatment was discontinued in 2 patients because of disease progression and in other 15 patients because of adverse events(AEs). In conclusion, initial doses of Bor at 1.0 mg/ m2 per injection and Len at 10 mg per day may provide potent disease control and permit continuing treatment with few AEs in elderly patients with MM.

Acquired Factor V Inhibitor with Hemorrhagic Symptoms after Prasugrel Hydrochloride Treatment.

Acquired factor V inhibitor (AFVI) is a rare coagulopathy. It may be triggered by specific antigens such as antibiotics. We herein report the first case of AFVI after treatment with prasugrel hydrochloride (prasugrel) in an 80-year-old male who underwent percutaneous coronary intervention because of angina pectoris 6 years ago and was initiated on aspirin and ticlopidine hydrochloride. He was switched from ticlopidine hydrochloride to prasugrel before undergoing percutaneous coronary intervention for myocardial infarction. Fifteen days later, he developed sudden nasal hemorrhage, hematuria, and systemic purpura. Coagulation tests revealed prolonged prothrombin time-international normalized ratio (11.35) and activated partial thromboplastin time (170 s). The coagulation factor profile revealed a decreased FV activity (1%). The Bethesda assay for FV inhibitor was positive. AFVI was diagnosed; prasugrel was immediately discontinued, and administration of recombinant activated factor VII and prednisolone were initiated. Hemorrhagic symptoms immediately disappeared; FV activity improved, and the FV inhibitor titer was normalized.

[Erythrocytosis following allogeneic hematopoietic stem cell transplantation].

Post-transplant erythrocytosis (PTE) following allogeneic hematopoietic stem cell transplantation (alloHSCT) is rare, and the clinical characteristics of this condition remain unknown. In this study, we examined the clinical characteristics of three PTE cases among 321 patients who received allo HSCT from January 1992 to December 2011 at our institution. All three patients exhibited normal levels of white blood cell and platelet counts when their hemoglobin levels reached their peak. Two patients exhibited normal levels of erythropoietin. No thrombosis or hemorrhage was observed in any of the three patients without cytoreductive therapy or an antiplatelet agent. All three patients tested negative for JAK2V617F mutations. Two patients had high levels of IL-13, an upstream signal for the JAK/STAT pathway. JAK2 is known to significantly contribute to the pathology of polycythemia vera; however, this pathology may differ from that of PTE. We believe that it is necessary to construct a more appropriate management structure for PTE by analyzing more case data in the future.