Clinical features and treatment outcomes of liver involvement in paediatric Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder in children, and liver involvement in LCH is rare. This retrospective study reported the clinical features and prognosis of patients with hepatic LCH. Liver involvement was defined by histopathological findings, liver dysfunction or abnormalities, or ultrasound imaging. A total of 130 patients (14.5%) with hepatic LCH out of 899 in the LCH population were enrolled. Patients with liver involvement had greater frequencies of skin, lung, hearing system, and haematologic system involvement, and hemophagocytic lymphohistiocytosis (P<0.001, 0.001, 0.002, 0.009, and <0.001, respectively). Overall survival and progression-free survival were lower in LCH patients with liver involvement than in those without liver involvement (P<0.001 and <0.001). In patients with liver involvement, the overall survival (OS) and progression-free survival (PFS) rates were lower in patients with cholangitis than in those without cholangitis (P<0.020 and 0.030). For the treatment response, the response rate of hepatic LCH patients to initial first-line therapy (n=89) was 22.5%. However, there was no significant difference in the response rate or recurrence rate between patients who shifted from first-line treatment to second-line treatment (n=29) or to targeted therapy (n=13) (P=0.453 and 1.000). The response rate of hepatic LCH patients who received initial second-line therapy (n=13) was 38.5%. Two of these patients subsequently experienced bone recurrence. The response rate of hepatic LCH patients who received initial targeted therapy (n=16) was 75.0%. Three patients subsequently experienced recurrence, including 2 in the bone and 1 in the liver and skin. A total of 39.3% of patients who received second-line treatment had severe myelosuppression (grade III-IV), and 50.8% had varying degrees of gastrointestinal events, whereas there was no severe toxicity in patients who received first-line treatment and targeted therapy. Four patients underwent liver transplantation because of liver cirrhosis. The patients' liver disease improved within a follow-up period of 18-79 months. This study demonstrated that LCH with liver involvement, especially cholangitis, indicates a poor prognosis. Targeted therapy provides a good treatment response and less toxicity. However, it may relapse after withdrawal. Liver transplantation is still a reliable salvage option for patients with end-stage liver disease.

Nationwide Study of Factors Impacting Survival Outcome and Consequences in Children with Reactivation/Refractory Langerhans Cell Histiocytosis.

BACKGROUND: Disease reactivation/refractory remains a major challenge in managing Langerhans cell histiocytosis (LCH). Outcomes and late sequelae should be explored. METHODS: A multi-institutional retrospective study was conducted to describe clinical characteristics, predictive factors, outcomes and late sequelae of pediatric reactivation/refractory LCH in Thailand. RESULTS: In all, 47 patients were studied, 25 (53.2%) patients had disease reactivation and 22 (46.8%) patients had refractory LCH. The median reactivation and refractory time were 1.59 and 0.33 years from diagnosis, respectively (p <0.001). The most common site of reactivation/refractory was the bone (n = 26, 55%), and 20 (42.6%) patients developed late sequelae. The 5-year overall survival (OS) was 76.1%. Patients with reactivation and refractory LCH performed similarly in 5-year OS (88% vs. 63%, p = 0.055). Prognostic factors associated with mortality were liver, spleen, hematopoietic system and lung reactivation (p <0.05). Lung reactivation was the only independent risk factor associated with the survival outcome (p = 0.002). CONCLUSIONS: The outcomes of pediatric patients between reactivation and refractory LCH in Thailand were similarly desirable and mortality was minimal although late sequelae may evolve. Pulmonary reactivation/refractory was an independent risk factor associated with survival.

Clinical and prognostic characteristics of 95 cases of Langerhans cell histiocytosis in children: a single-institute experience from 2013 to 2020.

BACKGROUND: This study aimed to understand the clinical characteristics and outcomes of children with Langerhans cell histiocytosis (LCH) in China. METHODS: We conducted a retrospective study of 95 paediatric patients with LCH in West China Second University Hospital of Sichuan University between July 2013 and August 2020. RESULTS: The onset age of multisystem LCH (MS-LCH) patients with risk organ (RO) involvement was younger than that of MS-LCH without RO involvement (p = .002) and single system LCH (p < .001) patients; bone was the most frequently involved organ, followed by the skin. Of all, the BRAF-V600E mutation was detected in 48 out of 84 patients who underwent gene analysis. Additionally, in our study, BRAF p.N486_T491 > K, BRAF p.L485_P490delinsF, BRAF p.R506_K507insLLR, ARAF p.Q349_F351delinsL and MAP2K1 p.Q58_E62del were known mutations in the mitogen-activated protein kinase (MAPK) pathway. The BRAF-V600E genotype in the tissue and plasma prior to therapy were detected in 16 patients, and the concordance was only 37.5% (6/16). According to the modified LCH-III-based-protocol, JLSG-02 protocol chemotherapy, and vemurafenib, the estimated five-year overall survival, event-free survival (EFS) and cumulative reactivation rates of 95 patients were 98.8%, 74.6% and 24.5%, respectively. The EFS rate in good responders was better than that in poor responders at 12-week (HR = 0.022, 95%CI 0.002-0.231, p = .002), and EFS was not affected by age, RO involvement or BRAF-V600E mutation. Regarding sequelae, nine patients had central diabetes insipidus and two had growth retardation. CONCLUSIONS: In this study, LCH was a highly heterogeneous disease characterized molecularly by MAPK-pathway activating mutations. Vincristine, prednisone and cytarabine-based chemotherapy combined with vemurafenib improved the prognosis of childhood LCH. In future, prospective clinical trials and novel therapeutic strategies should be developed to improve outcomes in paediatric patients with LCH.KEY MESSAGEChildren with Langerhans cell histiocytosis in China present highly heterogeneous clinical characteristics, with up to 60% of cases harbouring mutations in MAPK pathway.Treatment response at 12-week is associated with EFS in our study.Vincristine, prednisone and cytarabine-based chemotherapy combined with vemurafenib improved the prognosis of Chinese childhood LCH, but the reactivation rate is still high.

Additive Prognostic Impact of Gastrointestinal Involvement in Severe Multisystem Langerhans Cell Histiocytosis.

OBJECTIVE: To evaluate the prognostic impact of gastrointestinal involvement on the survival of children with Langerhans cell histiocytosis (GI-LCH) registered with the international clinical trials of the Histiocyte Society. STUDY DESIGN: This was a retrospective analysis of 2414 pediatric patients registered onto the consecutive trials DAL-HX 83, DAL-HX 90, LCH-I, LCH-II, and LCH-III. RESULTS: Among the 1289 patients with single-system LCH, there was no single case confined to the GI tract; 114 of 1125 (10%) patients with multisystem LCH (MS-LCH) had GI-LCH at initial presentation. GI-LCH was significantly more common in children aged <2 years at diagnosis (13% vs 6% in those aged >2 years; P < .001) and in those with risk organ involvement (15% vs 6% in those without risk organ involvement; P < .001). The 5-year overall survival (OS) in patients without risk organ involvement was excellent irrespective of GI disease (98% vs 97% in patients with GI-LCH; P = .789). In patients with risk organ involvement, the 5-year OS was 51% in 70 patients with GI-LCH vs 72% in 394 patients without GI-LCH (P < .001). CONCLUSIONS: GI-LCH has an additive unfavorable prognostic impact in children with MS-LCH and risk organ involvement. The emerding need for more intensive or alternative treatments mandates prospective evaluation.

BRAF V600E Mutation in Cell-Free DNA, Rather than in Lesion Tissues, at Diagnosis Is An Independent Prognostic Factor in Children with Langerhans Cell Histiocytosis.

The aim of this study was to investigate the prognostic significance of BRAFV600E in cell-free (cf) DNA (cfBRAFV600E) and lesion tissues (ltBRAFV600E) in pediatric Langerhans cell histiocytosis (LCH). This study included a total of 140 patients with successfully detected cfBRAFV600E and ltBRAFV600E at diagnosis. Treatment response at week 6 was correlated with both cfBRAFV600E and ltBRAFV600E Moreover, the patients with positive cfBRAFV600E had a much lower 3-year progression-free survival (PFS) rate and a higher progression/reactivation rate than those with negative cfBRAFV600E (47.1% ± 7.6% vs. 78.4% ± 5.1%, P < 0.0001; 44.6% vs. 19.0%, P = 0.001, respectively). However, no significant difference was found in the 3-year PFS rate or progression/reactivation rate between patients with positive and negative ltBRAFV600E (P = 0.348 and 0.596, respectively). In addition, after patients were divided into group A (both cfBRAFV600E and ltBRAFV600E positive, n = 56), group B (ltBRAFV600E positive and cfBRAFV600E negative, n = 28), and group C (both cfBRAFV600E and ltBRAFV600E negative, n = 56), there was a significant difference in the 3-year PFS rate and progression/reactivation rate among the three groups (47.1% ± 7.6%, 92.9% ± 6.1%, and 72.2% ± 6.1%, P < 0.001; 44.6%, 3.6%, and 26.8%, P < 0.001, respectively). In the multivariate analysis, cfBRAFV600E and age at diagnosis remained independent prognostic factors for 3-year PFS in childhood LCH. Therefore, cfBRAFV600E was more closely associated with important clinical characteristics, treatment response at week 6, and prognosis than ltBRAFV600E.

[The Clinical and Laboratory Characteristics of Adult Langerhans Cell Histiocytosis Patients and the Influencing Factors of Prognosis].

OBJECTIVE: To observe the clinical and laboratory characteristics of adult Langerhans cell histiocytosis(LCH) patients and to analyze the influencing factors of its prognosis. METHODS: The clinical and laboratory charac-teristics of 38 adult LCH patients treated in our hospital from January 2010 to August 2019 were retrospective analyzed, and the clinical prognosis of the patients was analyzed. RESULTS: The median age of 38 patients was 41 (21-65) years old, and the ratio of male and female was about 2∶1. Among 38 patients, 44.7% (17/38) were involved in multiple systems, and 31.6% (12/38) were involved in high-risk organs (including liver, lung, hematopoietic system or spleen). The bone involvement was the most common (21/38, 55.3%), and the most common clinical symptom was pain (19/38, 50.0%). The result of laboratory showed that anemia (4/38，10.5%), thrombocytopenia (1/38，2.6%), neutropenia (2/38，5.3%), lymphopenia (6/38，15.8%), monocytosis (11/38，28.9%), C-reactive protein increasing (6/21，28.6%), erythrocyte sedimentation rate increasing (10/18, 55.3%), and ferritin protein increasing (9/17, 55.3%). The median follow-up time was 53 months, and a total of 5 patients were died. The 10-year overall survival rate of patients with single-system involvement was 100%, which was significantly higher than that of patients with multiple-system involvement (70.1%) (P=0.0078). The prognosis of patients without risk-organ involvement was better than that of patients with risk-organ involvement (10-year overall survival rate: 100% vs 60.6%) (P=0.0007). Further analysis showed that in addition to multiple-system involvement and risk-organ involvement, the increase of peripheral blood monocyte cells and the increase of ferritin protein were also associated with poorer prognosis of the patients. CONCLUSION: The multiple system involve-ment and risk-organ involvement, the increasing of monocyte cells and the increasing of ferritin protein were the independent risk factors of adult LCH patients.

Clinical presentation and prognostic analysis of adult patients with Langerhans cell histiocytosis with pulmonary involvement.

BACKGROUND: The study aimed to investigate the clinical features and prognosis factors of adult patients with Langerhans cell histiocytosis (LCH) with pulmonary involvement, especially multisystem (MS) LCH with pulmonary involvement. METHODS: We retrospectively analyzed the demographic materials, clinical features and treatment outcomes of 119 adult LCH patients with pulmonary involvement at our center from January 1990 to November 2019. RESULTS: Among 119 patients, 13 (10.9%) had single-system (SS) LCH, and 106 (89.1%) had MS-LCH with pulmonary involvement. SS-LCH patients had higher smoking rate (84.6% vs 52.8%, P = 0.026) and smoking index (300 vs 200, P = 0.019) than MS-LCH patients. The percentage of respiratory symptoms of SS-LCH patients was higher than MS-LCH patients (84.6% vs 53.8%, P = 0.034). Pulmonary function was impaired in 83.8% of the patients, and DLCO was the parameter most frequently impaired, accounting for 81.1%. The median DLCO was 65.1% predicted. Patients with pneumothorax had significantly worse DLCO (P = 0.022), FEV1 (P = 0.000) and FEV1/FVC (P = 0.000) than those without pneumothorax. During the follow-up, 72.4% of the patients had stable pulmonary function, and 13.8% showed improvements after chemotherapy. The estimated 3-year OS and EFS were 89.7 and 58.3%, respectively. Patients with a baseline FEV1 ≤ 55% predicted had worse OS. A history of pneumothorax indicated worse EFS and cytarabine based therapy predicted better EFS. CONCLUSIONS: An FEV1 ≤ 55% predicted and a history of pneumothorax at diagnosis indicated a poor prognosis. Cytarabine based regimen may arrest the decline in pulmonary function in LCH patients with pulmonary involvement and improve EFS.

Long-term follow-up of children with risk organ-negative Langerhans cell histiocytosis after 2-chlorodeoxyadenosine treatment.

The nucleoside analogue, 2-chlorodeoxyadenosine (2CDA), was reported to be an active treatment for childhood Langerhans cell histiocytosis (LCH) without risk organ (RO-) involvement. However, we lack data on long-term effects of 2CDA treatment, including the disease reactivation rate, permanent sequelae and long-term tolerance. This study included 44 children from the French LCH registry, treated for a RO- LCH with 2CDA monotherapy (median number of six courses). The median age at the beginning of 2CDA was 3·6 years (range, 0·3-19·7 years) and the median follow-up after was 5·4 years (range, 0·6-15·1 years). Objective response to 2CDA was observed in 25 patients (56·8%), while six patients (13·6%) had stable disease and 13 patients (29·5%) exhibited progressive disease. Among patients without progression, only two experienced disease reactivation after 2CDA discontinuation. The five-year cumulative incidence of disease progression or reactivation after 2CDA therapy initiation was 34·3%. The lymphopenia reported in all cases [72% below absolute lymphocyte count (ALC) of 0·5 G/l], was addressed with appropriate prophylactic measures. Other toxicities above grade 2 were uncommon, and no second malignant neoplasm or neuropathy was reported. The five-year overall survival was 97·7%. In conclusion, we could confirm that 2CDA monotherapy was a beneficial long-term therapy for treating patients with RO- LCH. Appropriate management of induced immune deficiency is mandatory.

Egyptian experience in Langerhans cells histiocytosis: frequent multisystem affection and reactivation rates.

Background: Histiocytoses are unique disorders; their clinical presentations vary from self-healing lesions to life-threatening disseminated disease. Objectives: We aimed to evaluate the different clinical presentations, frequency of reactivations, and treatment outcome of Langerhans cell histiocytosis among Egyptian children. Methods: we restrospectively analyzed the data of 37 Langerhans cell histiocytosis patients (LCH) registered at Ain Shams University Children's Hospital for clinicopathological features, treatment modalities and their outcomes. Results: Twenty seven (73%) of the studied patients with LCH had multisystem disease (MS), 24 (88.9%) of them had risk organ involvement (MS RO+) and only 3 without risk organ (MS RO-). Most of the patients received LCH III protocols. Eleven patients (29.7%) had reactivations with median time till reactivation of 17 months (IQR 5-23).Reactivation rates were 40% and 50% in patients with no evidence of active disease (NAD) and those with active disease better (AD better) at week 6 evaluation respectively (p = 0.71).We report 9 deaths (all had MS RO+, two died after reactivation and 7 had progressive disease. The 5 years EFS and OS were 49.4% and 81.2% respectively. Risk stratification did not significantly affect the EFS or OS (p = 0.64 and p = 0.5 respectively). Conclusion: A high reactivation rate was encountered in children with LCH and MS-RO + irrespective of 6 weeks response to induction therapy. A high mortality in patients with progressive disease necessitates a possible earlier aggressive salvage in such group.

Clinical features and outcomes of adult Langerhans cell histiocytosis: a single-center experience.

Langerhans cell histiocytosis (LCH) is a clonally expanding neoplasm characterized by the accumulation of CD1a + CD207 + myeloid dendritic cells. As LCH is a rare disease and is presumed to mainly affect children, the clinical features and treatment outcomes of adult LCH have been poorly documented. We retrospectively reviewed 53 adult patients with LCH who were referred to the Institute of Medical Science, the University of Tokyo from 2005 to 2018. The median age at diagnosis was 42 years with a slight female predominance (57%). The time between onset and diagnosis varied among patients (median, 8 months; range, 0-144 months). In total, 40% of the patients had single organ involvement and 60% had multiple organ involvement. Overall, the most frequently affected organ was bone (62%), followed by the central nervous system (34%), and the lung (28%). Twenty-six patients required systemic treatment, and 25 patients underwent the Special C regimen. Twenty patients (80%) who underwent Special C regimen showed a partial response or better with favorable toxicity. All but one patient is still alive. Median progression-free survival has not been reached despite a median follow-up of 35.5 months. Immunohistochemistry revealed that 39% of patients were positive for BRAF-V600E, which was a lower proportion than in previous reports from North America and Europe.

Long-term efficacy and safety of 2CdA (cladribine) in extra-pulmonary adult-onset Langerhans cell histiocytosis: analysis of 23 cases from the French Histiocytosis Group and systematic literature review.

Langerhans cell histiocytosis (LCH) is a rare protean disease that usually affects children. Few data are available for management of adult-onset cases. A complete picture of the efficacy and safety of 2CdA (2-chlorodeoxyadenosine, cladribine) is lacking. We report a retrospective multicentre study of 23 adult LCH (a-LCH) patients who received single-agent 2CdA and a systematic literature review. All had previously received systemic therapy (vinblastine, n = 19). Response to 2CdA was evaluable in 22 cases. Overall response rate (ORR) was 91%. Complete response (CR) occurred in 11 cases (50%). Nine patients (39%) developed grade 3-4 neutropenia and/or severe infection. A literature review yielded 48 additional cases. A pooled analysis confirmed our findings (ORR: 88%, CR: 49%). CRs were rare with cumulative dose <50 mg/m2 . Disease progression rates were 20% and 30% at two and five years, respectively. Partial response (PR) to 2CdA was predictive of disease progression. Among eight re-treated patients, five went into CR, two in PR, and one died. Single-agent 2CdA is effective in reactivated a-LCH, including at intermediate doses. Toxicity, significant but acceptable, warrants infectious prophylaxis. Complete responders may enter prolonged remission. Further studies are needed to determine 2CdA sequencing with other agents (vinblastine, cytarabine).

BRAF V600E mutation in childhood Langerhans cell histiocytosis correlates with multisystem disease and poor survival.

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia of children with systemic involvement and poor outcome. The altered RAS-RAF-MEK-ERK cell signalling pathway due to somatic mutation of BRAF V600E is the most common genetic abnormality associated with the disease. In the current study, we highlight the frequency of BRAF V600E in our cohort of LCH cases (n = 31) and its relation with clinical outcome. On Real-Time PCR and Sanger sequencing, BRAF V600E was detected in 6/31 (19%) patients. All cases positive for BRAF V600E mutation had multisystem involvement/disseminated disease compared to BRAF mutation negative cases (100% v/s 41%, p = 0.0348). Univariate analysis also revealed significant correlation of mutation positivity with risk category (p = 0.09). The event free survival and overall survival at 36 months for BRAF mutation positive group compared to mutation negative group was 17% v/s 72% (Log rank test p = 0.0110) and 32.5% v/s 82% (p = 0.0330), respectively. In our study, BRAF V600E positivity was low (19%) however, all positive cases had multisystem involvement and a poor three year survival confirming BRAF V600E to be a poor prognostic marker.

Nationwide retrospective review of hematopoietic stem cell transplantation in children with refractory Langerhans cell histiocytosis.

The efficacy of and indications for hematopoietic stem cell transplantation (HSCT) in pediatric Langerhans cell histiocytosis (LCH) remain undetermined. This retrospective study analyzed 30 children with refractory LCH who underwent HSCT in Japan between 1996 and 2014. Eleven patients received a myeloablative conditioning (MAC) regimen, while 19 patients received a reduced-intensity conditioning (RIC) regimen. Among the 26 patients with complete data, 23 patients had risk organ (RO) involvement during clinical course. Disease status at HSCT was no active disease (NAD) (4), active disease-regression (AD-r) (2), active disease-stable (AD-s) (4), and active disease-progressive (AD-p) (16). Seventeen of the 30 patients (57%) were alive with a median follow-up of 433 days (range 9-5307) after HSCT. Death occurred within 3 months after HSCT in eight of 13 patients. RIC and MAC patients were similar in both overall survival (OS) (56.8% vs. 63.6%, respectively, p = 0.789) and failure-free survival (56.8% vs. 54.6%, respectively, p = 0.938). Regarding disease status at HSCT, the six patients with NAD/AD-r experienced better outcomes than the 20 with AD-s/AD-p (5-year OS, 100% vs. 54.5%, respectively, p = 0.040). Disease state at the time of HSCT was the most important prognostic factor.

Langerhans Cell Histiocytosis of the Gastrointestinal Tract: Evidence for Risk Organ Status.

OBJECTIVE: To investigate the "risk status" of Langerhans cell histiocytosis (LCH) of the gastrointestinal tract. STUDY DESIGN: Outcomes from 43 published cases of patients with LCH and gastrointestinal tract involvement were matched to 43 patients with LCH without gastrointestinal tract involvement cared for at our institution. Comparisons were made of the 5-year overall survival rates determined from Kaplan-Meier survival curves for the entire cohort of patients, as well as subgroups defined by lack of risk organ involvement and later era of treatment (to control for temporal changes in LCH treatment regimens). In addition, an association between LCH-gastrointestinal tract and risk organ involvement was investigated. RESULTS: The 5-year overall survival for children with LCH-gastrointestinal tract (45.3%) was significantly worse than for those without gastrointestinal tract involvement (94.6%; P = .001). This difference remained significant after we excluded risk organ involvement (53.6%% vs 100%; P = .001), and analyzing subjects diagnosed after 2000 (75% vs 100%; P = .012). A 4-fold increase in risk organ involvement with LCH-gastrointestinal tract was observed (OR 4.359; 95% CI 1.75-10.82, P = .001). CONCLUSIONS: This limited retrospective study suggests that patients with LCH-gastrointestinal tract involvement may have decreased survival, independent of risk organ involvement, and provides evidence to support a prospective study to evaluate risk organ status of LCH-gastrointestinal tract. LCH-gastrointestinal tract may be associated with a 4-fold risk for risk organ involvement. Attention to gastrointestinal symptoms and LCH-gastrointestinal tract in young children diagnosed with LCH is warranted.

Outcome of High-risk Langerhans Cell Histiocytosis (LCH) in Egyptian Children, Does Intermediate-dose Methotrexate Improve the Outcome?

High-risk multisystem organ (RO+) Langerhans cell histiocytosis (LCH) has the least survival. We present the outcome of RO+ LCH in a pediatric single center. Fifty RO+ LCH patients, treated between 07/2007 and 07/2015, were retrospectively analyzed. Induction vinblastine (VBL) and prednisone (PRED) with intermediate-dose methotrexate (idMTX) was adopted until 2012 (n=20) wherein idMTX was omitted (n=30). The 3-year overall survival (OS) of MTX and non-MTX groups was 75% and 63%, respectively, P=0.537, while the event-free survival (EFS) was 36.9% and 13.2%, respectively, P=0.005. At week 12 of induction, "better status" was obtained in 80% of those receiving MTX, and 55% of those who were not. The statistically significant factors associated with both poor OS and EFS were trihemopoietic cytopenias, hepatic dysfunction, tri RO+ combination, and single induction. The factors associated with disease progression (DP) on induction were trihemopoietic cytopenias, hepatic dysfunction, and lack of idMTX, while those for disease reactivations (REA), the season of autumn/winter, lung disease, male sex, and idMTX were the associated factors. The 1-year OS was remarkably affected with the occurrence of DP versus REA versus none, wherein it was 47%, 93%, and 95%, respectively, P=0.001. In conclusion, idMTX is associated with better EFS. DP on induction remains of dismal prognosis in relation to disease REA afterwards. Risk stratification should highlight the role of trihemopoietic cytopenias, hepatic dysfunction, tri RO+, central nervous system risk site, and lung association.

Morphometric Study of Pulmonary Arterial Changes in Pulmonary Langerhans Cell Histiocytosis.

CONTEXT: - Pulmonary hypertension (PHT) is a complication of pulmonary Langerhans cell histiocytosis (PLCH); however, the pathogenesis remains largely unknown. Few studies have evaluated histopathologic changes in pulmonary arteries (PAs) of patients with PLCH; systematic quantification of arterial remodeling has yet to be undertaken. OBJECTIVE: - To quantify the extent of arterial remodeling among patients with PLCH through morphometry and to correlate these results with pertinent clinical parameters. DESIGN: - Patients with PLCH were identified from institutional files (1995-2015) along with age-, sex-, and smoking status-matched controls. Morphometric analysis of intimal and medial thickness of small to medium PAs was performed in patients with PLCH (within PLCH lesions [lesional] and away from PLCH lesions [nonlesional]) and controls. Paired measures were compared with Wilcoxon signed rank tests. RESULTS: - Twenty-five patients with PLCH (14 men: median age, 46 years; interquartile range, 37-55 years) and 25 controls were included. The lesional arteries of patients with PLCH demonstrated thicker PA intima and media than controls ( P < .001 and P < .001, respectively), as did PLCH nonlesional arteries compared to controls ( P < .001 and P < .001, respectively). The PA intima and media were thicker within the PLCH lesions than nonlesional arteries ( P = .02 and P = .002, respectively). Patients with PLCH-related PHT had a worse prognosis than those without PHT ( P = .04; hazard ratio, 4.5 [1.1, 22.2]). Echocardiography parameters including right atrial size ( P = .007), estimated right atrial pressure ( P = .01), and right ventricular systolic pressure ( P = .01) were inversely associated with survival. CONCLUSIONS: - Our findings suggest that factors other than direct vascular obstruction or inflammatory cell infiltration contribute, at least in part, to the vascular remodeling in PLCH.

[BRAF-V600E mutation and its clinical significance in children with Langerhans cell histiocytosis].

OBJECTIVE: To investigate the clinical significance of BRAF-V600E mutation in children with Langerhans cell histiocytosis (LCH). METHODS: Real-time fluorescence quantitative PCR was used to detect BRAF-V600E mutation in paraffin-embedded tissue samples from 26 children with LCH. A retrospective analysis was performed for the association of BRAF-V600E mutation with clinical features and prognosis of children with LCH. RESULTS: Of the 26 children, 25 received standard chemotherapy, with a 2-year overall survival (OS) rate of 100% and a 2-year event-free survival (EFS) rate of 88%. Of the 26 pathological samples, 18 (70%) came from bone tissue, and the positive rate of BRAF-V600E mutation reached 50% (13/26). The positive rate of BRAF-V600E gene mutation was not associated with age, sex, affected organ, clinical classification, early treatment response, recurrence, and 2-year OS and EFS rates of the children with LCH (P>0.05), but it was associated with clinical grouping of LCH (P<0.05). CONCLUSIONS: Children with LCH tend to have a high OS rate and a high incidence rate of BRAF-V600E mutation. BRAF-V600E mutation is associated with clinical grouping of LCH.

Intensification of induction therapy and prolongation of maintenance therapy did not improve the outcome of pediatric Langerhans cell histiocytosis with single-system multifocal bone lesions: results of the Japan Langerhans Cell Histiocytosis Study Group-02 Protocol Study.

Langerhans cell histiocytosis (LCH) with single-system (SS) multifocal bone (MFB) lesions is rarely fatal, but patients may experience relapses and develop LCH-associated sequelae. To evaluate effect on outcomes of pediatric multifocal LCH, we tested a treatment protocol modified from the Japan Langerhans Cell Histiocytosis Study Group (JLSG)-96 study. We assessed the outcomes of all consecutive newly diagnosed pediatric patients with LCH with SS-MFB lesions who were treated with JLSG-02 protocol in 2002-2009. JLSG-02 was modified from JLSG-96 as follows: increased prednisolone dosage at the induction phase and extension of maintenance therapy duration from 24 to 48 weeks. In total, 82 patients with a median follow-up duration of 8.0 years were eligible for analysis. At 6 weeks, 92.7% responded to induction; however, 27.6% of responders experienced relapses. In total, 4.8% developed central nervous system-related sequelae, including central diabetes insipidus and neurodegeneration, which were associated with relapse. None of the patients died. The 5-year event-free survival rates were not different between JLSG-02 and -96 cohort (66.7 vs. 65.1%; p = 0.697). Modification of previous treatment protocol did not contribute to improvement of outcomes in LCH with SS-MFB lesions.

Treatment of Langerhans cell histiocytosis with a modified risk-adapted protocol-experience from a tertiary cancer institute in India.

BACKGROUND: Involvement of risk-organs (RO+) in Langerhans cell histiocytosis (LCH) and inadequate early response identifies patients at high risk for relapse and mortality requiring intensive salvage therapy including stem cell transplant, adding cost and toxicity. To mitigate this, we used a standard induction, augmented with metronomic etoposide, and prolonged maintenance-similarly augmented for RO+, and retrospectively analyzed its impact. PROCEDURE: LCH patients from 2009 through 2014 were included. Patients received standard vinblastine and prednisolone therapy weekly till week 25 for RO+. Single site (SS) and multisystem (MS) without risk organ involvement (RO-) received 3-weekly pulses from week 13 till week 25. Maintenance was 3-weekly vinblastine and 5-day prednisolone pulses, daily 6-mercaptopurine (60 mg/m2 ) and weekly methotrexate (15 mg/m2 ) for 18 and 9 months for RO+ and MSRO-, respectively. RO+ also received oral etoposide (50 mg/m2 ) for 21 of every 28-day cycle for the first year. RESULTS: Fifty consecutive patients were analyzed. Median age was 36 months (4-189 months). SS, MSRO-, and RO+ were 29 (58%), 12 (24%), and nine (18%), respectively. Four were lost to follow-up and excluded from further evaluation. On response evaluation at week 6, 24 (52%) had no active disease (NAD), 17 (37%) had AD-better (where AD is active disease), and one (2%) had AD-worse. In RO+, eight (66.6%) had AD-better and three (25%) had NAD. Forty-five patients had NAD by week 12. Three patients relapsed. With median follow-up of 39 months (8-84), 5-year event free survival was 85.6% (RO- and SS), and 100% for RO+. One patient's death in remission from unrelated causes resulted in overall survival of 97%. CONCLUSIONS: RO+LCH receiving oral etoposide augmented induction and maintenance had early and durable responses. Prolonging maintenance lowered reactivation rates in RO+ and RO-LCH, resulting in excellent survival.