Antimicrobial susceptibility and prevalence of resistance genes in Bacteroides fragilis isolated from blood culture bottles in two tertiary care hospitals in Japan.

The in vitro susceptibilities of Bacteroides fragilis to antimicrobial agents, especially to carbapenem, are a major concern in the treatment of patients with bloodstream infections. In this study, 50 isolates of B. fragilis were obtained from positive blood bottles from 2014 to 2019 in Saitama, Japan. Their susceptibility to ampicillin/sulbactam was reduced to 70.0% compared with a previous report, whereas they were still sufficiently susceptible to piperacillin/tazobactam (94.0%). Five cfiA-positive isolates (5/50, 10.0%) were identified that were resistant to doripenem and meropenem, and two of them carried an insertion sequence located upstream of the cfiA-coding region. In particular, imipenem should be considered as a first-line carbapenem for the empirical treatment of B. fragilis infection because only insertion sequence and cfiA double-positive strains showed resistance to imipenem. Thirty-six percent of the isolates had a reduced minimum inhibitory concentration for moxifloxacin. In addition, metronidazole should still be considered as an active agent for B. fragilis because all isolates were susceptible to this antibiotic and the prevalence of the nim gene was low in Japan.

Elevated Periostin Concentrations in the Bronchoalveolar Lavage Fluid of Patients with Eosinophilic Pneumonia.

BACKGROUND: Eosinophilic pneumonia (EP) is characterized by massive pulmonary infiltration by eosinophils. Although serum periostin is a novel marker for eosinophil-dominant asthma, the upregulation of periostin in the airway of asthmatics is controversial. In this study, we examined whether periostin concentrations are elevated in the bronchoalveolar lavage fluid (BALF) of patients with EP. METHODS: BAL was performed in healthy volunteers and in patients with acute eosinophilic pneumonia (AEP), chronic eosinophilic pneumonia (CEP), and sarcoidosis. The periostin concentrations in the BALF were measured. RESULTS: The periostin concentration in the BALF increased significantly with pulmonary eosinophil ia and was higher in AEP and CEP patients than in healthy volunteers and sarcoidosis patients, even after adjusting the albumin concentration. In pulmonary eosinophilia, the periostin concentration correlated with the eosinophil and lymphocyte counts, the concentration of albumin, and the concentration of cytokines such as IL-5, IL-13, and transforming growth factor ß1. CONCLUSIONS: Although some blood leakage may be involved in the elevation of periostin in the BALF of EP, periostin can be induced locally, at least in part. Therefore, periostin may play a role in the development of EP.

Clinical characteristics in blood stream infections caused by Klebsiella pneumoniae, Klebsiella variicola, and Klebsiella quasipneumoniae: a comparative study, Japan, 2014-2017.

BACKGROUND: Klebsiella variicola and K. quasipneumoniae are new species distinguishable from K. pneumoniae but they are often misidentified as K. pneumoniae in clinical settings. Several reports have demonstrated the possibility that the virulence factors and clinical features differ among these three phylogroups. In this study, we aimed to clarify whether there were differences in clinical and bacterial features between the three phylogroups isolated from patients with bloodstream infections (BSIs) in Japan. METHODS: Isolates from all patients with BSIs caused by K. pneumoniae admitted to two hospitals between 2014 and 2017 (n = 119) were included in the study. Bacterial species were identified via sequence analysis, and their virulence factors and serotypes were analyzed via multiplex PCR results. Clinical data were retrieved from medical records. RESULTS: Of the 119 isolates, 21 (17.7%) were identified as K. variicola and 11 (9.2%) as K. quasipneumoniae; K1 serotype was found in 16 (13.4%), and K2 serotype in 13 (10.9%). Significant differences in the prevalence of rmpA, iutA, ybtS, entB and kfu (p < 0.001), and allS genes (p < 0.05) were found between the three phylogroups. However, there were no significant differences in clinical features, including the 30-day mortality rate, between the three organisms, although K. variicola was more frequently detected in patients over 80 years old compared with other Klebsiella species (p < 0.005), and K. quasipneumoniae more frequently occurred in patients with malignancy (p < 0.05). CONCLUSIONS: Our findings demonstrated the differences in bacterial pathogenicity and clinical features among these three phylogroups. Further epidemiological studies into BSI caused by Klebsiella species are warranted.

False-positive blood culture results in patients with hematologic malignancies.

Blood cultures are the most valuable tool when bacteremia is clinically suspected. Technical advances have led to the development of automated blood culture systems to detect bacterial infections. Usually positive signals in automated blood culture systems result from the proliferation of microorganisms. Cases are classified as false-positive when the automated blood culture system produces a positive signal but no microorganisms are detected on Gram-stained smears and no microorganism growth is observed in blood subcultures. False-positive blood culture results are very rare in patients with hematologic malignancies. Recently, we encountered four patients who had false-positive blood culture results. Two of the patients were diagnosed with acute leukemia, involving hyperleukocytosis and an excess of blasts. The other two patients were diagnosed with acute leukemia and diffuse large B cell lymphoma with leukocytopenia. Although hypercapnia or acidosis, apart from hyperleukocytosis, might also cause false-positive results, our cases clearly did not have these conditions. We should be aware of the possibility that false-positive blood culture results can occur in patients with leukocytopenia, as well as hyperleukocytosis. To understand the mechanisms responsible for the observed false-positive results, additional studies are needed after the accumulation of similar cases.

Hepatic gas gangrene caused by Clostridium novyi.

We report the case of a patient with advanced gastric cancer and multiple liver metastases, who presented with bacteremia and hepatic gas gangrene caused by Clostridium novyi (C. novyi). The gas gangrene caused abscesses to form within metastatic lesions. This case highlights the antitumor effects of C. novyi in human.

Wernicke encephalopathy without delirium in patients with cancer.

OBJECTIVE: Wernicke encephalopathy (WE) is a neuropsychiatric disorder caused by thiamine deficiency. Several reports of WE in cancer patients are known. WE is sometimes overlooked because most patients do not exhibit its typical symptoms (e.g., delirium, ataxia, ocular palsy). If delirium is not present, a diagnosis of WE is difficult because delirium is the hallmark symptom of WE. METHOD: Taken from a series on WE in cancer, we report two patients who developed WE without delirium during periodic psycho-oncology outpatient visits. RESULTS: Case 1. A 61-year-old woman with non-Hodgkin lymphoma who was periodically attending a psycho-oncology outpatient clinic developed an unsteady gait. WE was suspected because she also developed appetite loss for two weeks, and we could find no other laboratory findings to explain her unsteady gait. Our diagnosis was supported by abnormal serum thiamine and disappearance of the gait disturbance after intravenous thiamine administration. Case 2. A 50-year-old woman with breast carcinoma with bone metastasis developed an unsteady gait. WE was suspected because she also developed loss of appetite for two weeks, and no other laboratory findings could explain her unsteady gait. The diagnosis was supported by abnormal serum thiamine and disappearance of the gait disturbance after administration of intravenous thiamine. SIGNIFICANCE OF RESULTS: Our report emphasizes the importance of being aware of WE, even when patients do not present with delirium. The presence of loss of appetite for more than two weeks may be the key to a diagnosis of WE.

Subclinical thiamine deficiency in patients with abdominal cancer.

OBJECTIVE: Thiamine is an essential coenzyme for oxidative metabolisms; however, it is not synthesized in the human body, and the average thiamine storage capacity is approximately 18 days. Therefore, thiamine deficiency (TD) can occur in any condition of unbalanced nutrition. If TD is left untreated, it causes the neuropsychiatric disorder Wernicke encephalopathy (WE). Although WE is a medical emergency, it is sometimes overlooked because most patients with WE do not exhibit all of the typical symptoms, including delirium, ataxia, and ophthalmoplegia. If all of the typical clinical symptoms of WE are absent, diagnosis of TD or WE becomes more difficult. METHOD: From a series of cancer patients, we reported three patients who developed TD without the typical clinical symptoms of WE.ResultA 69-year-old woman with pancreatic body cancer receiving chemotherapy with paclitaxel and gemcitabine for six months. Her performance status (PS) was 1. A detailed interview revealed that she had appetite loss for six months. Another 69-year-old woman with ovarian cancer received nedaplatin; her PS was 0. A detailed interview revealed that she had appetite loss for three months. A 67-year-old woman with colon cancer receiving ramucirumab in combination with second-line fluorouracil with folinic acid and irinotecan. Her PS was 1. A detailed interview revealed that she had appetite loss for three weeks. None exhibited typical clinical signs of WE, but they developed appetite loss for six months, three months, and three weeks, respectively. The diagnosis of TD was supported by abnormally low serum thiamine levels.Significance of the resultsThis report emphasizes the possibility of TD in cancer patients even when patients do not develop typical clinical signs of WE. The presence of appetite loss for more than two weeks may aid in diagnosing TD. Patients receiving chemotherapy may be at greater risk for developing TD.

Wernicke encephalopathy without delirium that appeared as agitation in a patient with lung cancer.

OBJECTIVE: Wernicke encephalopathy (WE) is a neuropsychiatric disorder caused by thiamine deficiency, and is sometimes overlooked because of the diversity of clinical symptoms. METHOD: From a series of WE patients with cancer, we report a lung cancer patient who developed WE, the main symptom of which was agitation.ResultA 50-year-old woman with lung cancer was referred to our psycho-oncology clinic because of agitation lasting for three days. No laboratory findings or drugs explaining her agitation were identified. Although the patient did not develop delirium, ophthalmoplegia, or ataxia, WE was suspected because she experienced a loss of appetite loss lasting 5 weeks. This diagnosis was supported by abnormal serum thiamine and disappearance of agitation one hour after intravenous thiamine administration.Significance of resultsThis report emphasizes the clinical diversity of WE and indicates the limits of the ability to diagnose WE from typical clinical symptoms. The presence of a loss of appetite for more than two weeks may be the key to the accurate diagnosis of WE.

Early detection and successful treatment of Wernicke's encephalopathy in outpatients without the complete classic triad of symptoms who attended a psycho-oncology clinic.

OBJECTIVE: Wernicke's encephalopathy (WE) is a neuropsychiatric disorder caused by a thiamine deficiency. Although WE has been recognized in cancer patients, it can be overlooked because many patients do not exhibit symptoms that are typical of WE, such as delirium, ataxia, or ocular palsy. Furthermore, outpatients with WE who intermittently present at psycho-oncology clinics have not been described as far as we can ascertain. METHOD: This report describes two patients who did not exhibit the complete classic triad of symptoms among a series with cancer and WE, and who attended a psycho-oncology outpatient clinic.ResultCase 1, a 76-year-old woman with pancreatic cancer and liver metastasis, periodically attended a psycho-oncology outpatient clinic. She presented with delirium and ataxia as well as appetite loss that had persisted for 8 weeks. We suspected WE, which was confirmed by low serum thiamine levels and the disappearance of delirium after thiamine administration. Case 2, a 79-year-old man with advanced stomach cancer, was referred to a psycho-oncology outpatient clinic with depression that had persisted for about 1 month. He also had appetite loss that had persisted for several weeks. He became delirious during the first visit to the outpatient clinic. Our initial suspicion of WE was confirmed by low serum thiamine levels and the disappearance of delirium after thiamine administration. The key indicator of a diagnosis of WE in both patients was appetite loss.Significance of resultsThis report emphasizes awareness of WE in the outpatient setting, even when patients do not exhibit the classical triad of WE. Appetite loss might be the key to a diagnosis of WE in the absence of other causes of delirium.

Diagnostic performance of procalcitonin, presepsin, and C-reactive protein in patients with hematological malignancies.

INTRODUCTION: Infections represent a major complication of hematological malignancies. C-reactive protein (CRP) and procalcitonin (PCT) have been used as diagnostic biomarkers of infections, but do not produce definitive findings. Recently, a new biomarker, presepsin, has been used as a diagnostic tool for detecting infections in the fields of emergency and neonatal medicine. However, the usefulness of presepsin for identifying infections in patients with hematological malignancies, including those who develop febrile neutropenia, remains unclear. METHODS: In this study, we retrospectively analyzed the utility of PCT, presepsin, and CRP as biomarkers of infections during 49 febrile episodes that occurred in 28 patients with hematological malignancies. RESULTS: The levels of PCT, but not those of CRP or presepsin, were significantly higher in the infection group than in the uninfected group (P<.03), indicating that PCT might be a more sensitive biomarker of infections. No differences in presepsin levels were detected between the patients with and without neutropenia, or between the infected and uninfected patients with neutropenia, indicating that presepsin might have less diagnostic value in patients with neutropenia. CONCLUSIONS: We conclude that PCT might provide additional information and could be used in combination with other biomarkers to detect infections in patients with hematological malignancies.

Elevated uric acid and adenosine triphosphate concentrations in bronchoalveolar lavage fluid of eosinophilic pneumonia.

BACKGROUND: Recent evidence has suggested that the innate immune response may play a role in the development of eosinophilic airway inflammation. We previously reported that uric acid (UA) and adenosine triphosphate (ATP), two important damage-associated molecular pattern molecules (DAMPs), activate eosinophil functions, suggesting that these molecules may be involved in the development of eosinophilic airway inflammation. The objective of this study was to measure the concentrations of DAMPs including UA and ATP in the bronchoalveolar lavage fluid (BALF) of patients with eosinophilic pneumonia (EP). METHODS: BAL was performed in patients with EP including acute and chronic eosinophilic pneumonia, and in patients with hypersensitivity pneumonia, and sarcoidosis. UA, ATP, and cytokine concentrations in the BALF were then measured. RESULTS: The UA concentration was increased in the BALF of EP patients. UA concentrations correlated with eosinophil numbers, and with eosinophil-derived neurotoxin and interleukin (IL)-5 concentrations. Furthermore, the ATP concentration was increased in the BALF of EP patients and ATP concentrations correlated with UA concentrations. Moreover, IL-33 was increased in EP patients and IL-33 concentrations correlated with UA and ATP concentrations. CONCLUSIONS: The UA and ATP concentration was increased in the BALF of EP patients. UA concentrations correlated with eosinophil numbers, and with ATP and IL-33 concentrations. Our findings suggest that DAMPs such as UA and ATP play a role in the pathogenesis of EP.

Utility of the MALDI-TOF MS method to identify nontuberculous mycobacteria.

In comparison to the conventional real-time polymerase chain reaction method (PCR method) or the DNA-DNA hybridization method (DDH method), the utility of NTM identification by the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) method has seldom been reported. In this study, 75 clinical NTM isolates from our hospital between April 2013 and July 2014 were identified and analyzed using PCR, DDH, and MALDI-TOF MS methods, and the results for the MALDI-TOF MS method were compared with the others. Identification at the species level was in agreement for 71 (94.5%) of the 75 isolates. For further details, identification was possible for 23 (95.8%) of 24 Mycobacterium avium, 11 (100%) of 11 Mycobacterium intracellulare, and 1 (50%) of 2 isolates mixed with M. avium and M. intracellulare. Mycobacterium ksansasii, Mycobacterium abscessus, Mycobacterium fortuitum, Mycobacterium gordonae, and Mycobacterium chelonae identified by DDH method were same result by MALDI-TOF MS. Additionally, Mycobacterium mucogenicum, which could not be identified by the DDH method, was identified by the MALDI-TOF MS method. However, two isolates identified as Mycobacterium terrae by DDH method could not be identified by the MALDI-TOF MS method and were determined to be Mycobacterium arupense by 16S ribosomal RNA (rRNA) sequence analysis. The present findings show that, for rare bacterial species, identification is sometimes not possible, but, in most cases, the results of identification by the MALDI-TOF MS method have a high concordance rate with the results of the PCR and DDH methods.

Coagulation factors in whole blood collected from pregnant women and stored at 4°C.

The present study aimed to measure the levels of coagulation factors in stored whole blood of pregnant women and to determine their usefulness in treating pregnant women who developed coagulopathy. A prospective study to measure coagulation factors in stored donated whole blood from pregnant and non-pregnant women was conducted. Fibrinogen, FV, FVII, FVIII, FXIII, and von Willebrand factor were measured in blood stored at 4°C for 0, 1, 3, and 5 weeks. All coagulation factors except for factor XIII decreased during storage. Fibrinogen and factor VII in the blood collected from pregnant women gradually decreased over time and their levels were significantly higher after 5 weeks of storage than those of non-pregnant women at week 0. Whole blood donated by pregnant women for autologous blood transfusion and stored at 4°C may be expected being effectively for the prevention of coagulopathy and the treatment of circulatory blood volume loss.

Early detection and successful treatment of Wernicke encephalopathy in a patient with advanced carcinoma of the external genitalia during chemotherapy.

OBJECTIVE: Few reports of Wernicke encephalopathy in oncological settings have been published. Some cases of Wernicke encephalopathy are related to appetite loss; however, the degree to which loss of appetite leads to thiamine deficiency is not known. METHOD: A 63-year-old female with advanced cancer of the external genitalia was referred for psychiatric consultation because of disorientation, insomnia, and bizarre behaviors. Her symptoms fulfilled the diagnostic criteria for delirium. Routine laboratory examinations did not reveal the cause of the delirium. Thiamine deficiency was suspected because appetite loss had continued for 19 days since she had been admitted to hospital. RESULTS: Intravenous administration of thiamine resulted in recovery from the delirium within three days. Serum thiamine level was found to be 16 ng/ml (normal range: 24-66 ng/ml). The clinical findings, the low level of thiamine in the serum, and the effective alleviation of delirious symptoms after thiamine administration fulfilled Francis's criteria for delirium induced by thiamine deficiency. SIGNIFICANCE OF RESULTS: Clinicians must be aware of the possibility of Wernicke encephalopathy in cancer patients, especially in those with loss of appetite for longer than 18 days. The degree of appetite loss in such patients might serve as a reference. Early detection and intervention may alleviate the symptoms of delirium and prevent irreversible brain damage.

[Benign Subcutaneous Nodules for the Diagnosis of Which Ultrasonography Is Useful].

OBJECTIVE: We analyzed sonographic appearance of dermatofibroma, schwannoma, small-sized venous mal- formation, glomus tumor, nodular fasciitis, and thrombus for effective use in the diagnosis. METHODS: We evaluated with sonography 44 subcutaneous nodules in histopathologically proven cases. RESULTS AND DISCUSSION: 1) Sonography was the most useful for diagnosing schwannoma. Six of 8 lesions were diagnosed correctly from sonographic appearance. They had increased posterior echo and Doppler flow signals. 2) Sonography was helpful in diagnosis of subungual glomus tumor, though malignant melano- ma should be excluded. One of 6 glomus tumors was not detected but all of the other had well-defined mar- gins and showed internal vascularity. Three subungual glomus tumors were diagnosed from sonographic appearance although 2 nonsubungual tumors were not. 3) It was difficult to diagnose nodular fasciitis with sonography. Two of 5 cases were not detected. The other 3 lesions were ill-defined, and 2 were hy- perechoic and 2 showed internal vascularity. Interval between emergence of the lesion and sonography ex- amination was important. This duration was more than 50 days in lesions not detected with sonography, about 20 days in 2 hyperechoic lesions, and 6 days in a hypoechoic lesion. 4) Dermatofibromas (n =14) were also difficult to be diagnosed. The region was very characteristic, that is, in the upper dermis. Other find- ings, such as hypoechoic appearance and well-defined margin, were nonspecific. CONCLUSION: Sonography was more useful for diagnosing schwannoma and glomus tumor. We have to know their characteristic appearance on sonography to use sonography effectively. [Original].

[Sonographic appearance of benign subcutaneous nodules--including color Doppler sonography].

OBJECTIVE: Color Doppler sonography is used to distinguish malignant from benign subcutaneous nodules because many malignant tumors show an increased number of vessels. But benign lesions, such as inflammatory epidermal cysts, pilomatricomas, palmoplantar fibromatoses show vascular flow signals. We analyze diagnostic factors for subcutaneous nodules on the basis of ultrasonographic appearance including color Doppler sonography. METHODS: We evaluated with sonography 79 subcutaneous nodules in histopathologically proven cases. RESULTS AND DISCUSSION: The diagnostic findings for 28 epidermal cysts were increased posterior echo(sensitivity 77%, specificity 90%). Vascular flow signals were seen in 7 cases(25%). The signals were seen from periphery to adjacent zone of the mass. They were accompanied by inflammatory granulation tissues histologically. The percentage of blood flow may be related to the percentage of "ruptured" epidermal cysts. Pilomatricomas (n = 9) had internal echogenic foci or Doppler flow signals, and no posterior enhancement (sensitivity 89%, specificity 78%). Seven pilomatricomas showed Doppler flow signals in the mass. The percentage of flow signals is explained by the degree of internal echogenic foci because remarkable calcium deposits producing posterior acoustic shadowing prevent us from flow signals. Palmoplantar fibromatoses (n = 5) were ill-defined margins and showed internal vascularity with no posterior enhancement (sensitivity 80%, specificity 94%). CONCLUSION: More benign lesions showed vascular flow signals than reported previously. We have to diagnose subcutaneous nodules referring to not only color Doppler but also gray scale sonography.

Fibrinogen concentrate substitution therapy for obstetric hemorrhage complicated by coagulopathy.

AIM: The aim of this study was to assess the efficacy and safety of fibrinogen concentrate therapy for women with obstetric hemorrhage complicated by dilutional or consumptive coagulopathy by retrospectively reviewing the medical records of relevant patients from a single tertiary center. MATERIAL AND METHODS: Eighteen cases of coagulopathy (8 dilutional, 10 consumptive) administered fibrinogen concentrate at our center over the past 5 years for treating hypofibrinogenemia were identified. Hemoglobin levels, platelet counts, fibrinogen levels, prothrombin time, activated partial thromboplastin time, and D-dimer levels were examined before and after fibrinogen substitution. Units of red blood cells, fresh frozen plasma, and pooled platelet concentrates transfused; blood loss volume; patient outcomes; and adverse events were obtained from medical and laboratory records. RESULTS: The overall response to fibrinogen concentrate was considered good in 12 cases, moderate in four, and poor in two. The response rate was good or moderate in 88% (7/8) of dilutional coagulopathy cases and 89% (9/10) of consumptive coagulopathy cases. Fibrinogen levels significantly increased after fibrinogen substitution therapy (approximately 40 mg/L per g fibrinogen concentrate) in both groups. Although prothrombin time and activated partial thromboplastin time improved after substitution, hemoglobin levels, platelet counts, and D-dimer levels remained unchanged. No serious adverse event was causally associated with fibrinogen substitution therapy. CONCLUSION: Fibrinogen concentrate substitution therapy for obstetric hemorrhage increases fibrinogen levels and appears to be effective in managing dilutional or consumptive coagulopathy.

[Emergency incompatible red cell transfusion to a patient whose blood type was suspended from identification].

We report a case of a 59-year-old woman who presented with hypovolemic shock and compensated acidosis (preoperative arterial blood gases: pH 7.3, P(CO2) 31.9 mmHg, Pa(O2) 112.3 mmHg, base excess -9.8, Hb 6.4 g x dl(-1)) due to perforated descending colon, necessitating emergency surgery. Tracheal intubation had been performed preoperatively. Prior to induction of anesthesia, blood pressure was 106/74 mmHg, heart rate 119 beats x min(-1), and Sp(O2) 100% breathing room air. Anesthesia was induced with remifentanil influsion at a rate of 0.05 mg x kg(-1) x min(-1), sevoflurane 1% and rocuronium bromide 30mg, and was maintained with oxygen, air, remifentanil and sevoflurane. For a critical hypovolemia, in accordance to the guidelines for intraoperative critical hemorrhage and the Japanese practical guidelines for blood components therapy, we started to transfuse incompatible red cell (O+) since the identification of blood typing was suspended. The duration of surgery was 104 min, with an intraoperative total bleeding of 125 ml. Four units of total blood transfusion and 3,050 ml of infusion of Ringer's acetate solution were administered. The patient was transferred to ICU with tracheal intubation. No adverse reactions associated with blood type incompatibility were recognized.

A novel mutation of ALK2, L196P, found in the most benign case of fibrodysplasia ossificans progressiva activates BMP-specific intracellular signaling equivalent to a typical mutation, R206H.

Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant congenital disorder characterized by progressive heterotopic ossification in muscle tissues. Constitutively activated mutants of a bone morphogenetic protein (BMP) receptor, ALK2, have been identified in patients with FOP. Recently, a novel ALK2 mutation, L196P, was found in the most benign case of FOP reported thus far. In the present study, we examined the biological activities of ALK2(L196P) in vitro. Over-expression of ALK2(L196P) induced BMP-specific activities, including the suppression of myogenesis, the induction of alkaline phosphatase activity, increased BMP-specific luciferase reporter activity, and increased phosphorylation of Smad1/5 but not Erk1/2 or p38. The activities of ALK2(L196P) were higher than those of ALK2(G356D), another mutant ALK2 allele found in patients with FOP and were equivalent to those of ALK2(R206H), a typical mutation found in patients with FOP. ALK2(L196P) was equally or more resistant to inhibitors in comparison to ALK2(R206H). These findings suggest that ALK2(L196P) is an activated BMP receptor equivalent to ALK2(R206H) and that ALK2(L196P) activity may be suppressed in vivo by a novel molecular mechanism in patients with this mutation.