Pulmonary epithelial markers in phenotypes of chronic lung allograft dysfunction

BACKGROUND

Airway epithelial injury is thought to be a key event in the pathogenesis of chronic lung allograft dysfunction (CLAD). We investigated whether markers of epithelial activity and injury in bronchoalveolar lavage fluid (BAL) correlate with CLAD diagnosis and major CLAD phenotypes: bronchiolitis obliterans syndrome (BOS) vs restrictive allograft syndrome (RAS)-related phenotypes (including RAS, mixed phenotype, and all other patients with RAS-like opacities).

METHODS

CLAD status and phenotypes were retrospectively determined in a cohort of all consecutive adult, first, bilateral lung transplants performed 2010-2015, with available BAL samples. All patients with RAS-related phenotypes were included and 1:1 matched with BOS patients based on the time from transplant to CLAD-onset. Subjects who were CLAD-free for a minimum of 3 years post-transplant were 1:1 matched to CLAD patients and included as controls. Proteins that maintain the barrier function of the airway epithelial mucosa (club cell secretory protein, surfactant protein-D and epithelial mucins: MUC1, MUC5AC, MUC5B, MUC16), as well as epithelial cell death markers (M30&M65 representing epithelial cell apoptosis and overall death, respectively), were measured in BAL obtained within 6-months post CLAD onset using a double-sandwich ELISA or a multiplex bead assay. Protein levels were compared using Mann-Whitney-U-test. Association between protein levels and graft survival was assessed using Cox proportional hazards models, adjusted for CMV serology mismatch status and CLAD phenotype.

RESULTS

Fifty-four CLAD (27 BOS, 11 RAS, 7 mixed, 9 others with RAS-like opacities) patients and 23 CLAD-free controls were included. Median BAL levels were significantly higher in patients with CLAD compared to CLAD-free controls for M30 (124.5 vs 88.7 U/L), MUC1 (6.8 vs 3.2 pg/mL), and MUC16 (121.0 vs 30.1 pg/mL). When comparing CLAD phenotypes, M30 was significantly higher in patients with RAS-related phenotypes than BOS (160.9 vs 114.6 U/L). In multivariable models, higher M30 and MUC5B levels were associated with decreased allograft survival after CLAD onset independent of phenotype (p < 0.05 for all).

CONCLUSIONS

Airway epithelial mucins and cell death markers are enhanced in the BAL of patients with CLAD and can assist in differentiating between CLAD phenotypes and post-CLAD outcomes. Abnormal airway mucin expression and epithelial cell death may be involved in the pathogenesis of CLAD, and therefore their detection may aid in future selection of targeted therapies.

Hypocellular Philadelphia chromosome-positive mixed-phenotype acute leukemia successfully treated with dasatinib: A case report

Both hypocellular leukemia and Philadelphia (Ph) chromosome-positive mixed-phenotype acute leukemia (MPAL) are rare subtypes of leukemia showing unfavorable outcomes and lacking established optimal management. Ph-positive leukemia most often presents with hypercellularity and hypoplasia is a rare condition. The present study reports an extremely rare case of hypocellular biclonal Ph-positive MPAL, which was diagnosed by biopsy and genetic analysis of bone marrow, and successfully treated with dasatinib and steroids. Briefly, a 77-year-old man presented with pancytopenia and flow cytometry of bone marrow could not be evaluated due to hypocellularity. The patient was finally diagnosed with hypocellular Ph-positive MPAL by genetic analysis and immunostaining of bone marrow biopsy. Although blood cells recovered with methylprednisolone pulse administration alone for concurrent optic neuritis, hematopoietic function rapidly normalized with dasatinib administered after definitive diagnosis of Ph-positive leukemia. Dasatinib and oral prednisolone were continued following methylprednisolone pulse administration and the patient achieved molecular complete remission (CR) on day 140 of treatment; molecular CR was maintained thereafter without any severe adverse events. In conclusion, the combination of dasatinib and a steroid may be one of the tolerable treatment options for elderly patients with hypocellular biclonal Ph-positive MPAL. Furthermore, genetic analysis and immunostaining of bone marrow biopsy can help with the diagnosis of leukemia with hypocellular bone marrow.

Clinical and histopathological features of myeloid neoplasms with concurrent Janus kinase 2 (JAK2) V617F and KIT proto-oncogene, receptor tyrosine kinase (KIT) D816V mutations

We report on 45 patients with myeloid neoplasms and concurrent Janus kinase 2 (JAK2) V617F and KIT proto-oncogene, receptor tyrosine kinase (KIT) D816V (JAK2^{pos .} /KIT^{pos .} ) mutations, which are individually identified in >60% of patients with classical myeloproliferative neoplasms (MPN) and >90% of patients with systemic mastocytosis (SM) respectively. In SM, the concurrent presence of a clonal non-mast cell neoplasm [SM with associated haematological neoplasm (SM-AHN)] usually constitutes a distinct subtype associated with poor survival. All 45 patients presented with a heterogeneous combination of clinical/morphological features typical of the individual disorders (e.g. leuco-/erythro-/thrombocytosis and elevated lactate dehydrogenase for MPN; elevated serum tryptase and alkaline phosphatase for SM). Overlapping features identified in 70% of patients included splenomegaly, cytopenia(s), bone marrow fibrosis and additional somatic mutations. Molecular dissection revealed discordant development of variant allele frequency for both mutations and absence of concurrently positive single-cell derived colonies, indicating disease evolution in two independent clones rather than monoclonal disease in >60% of patients examined. Overall survival of JAK2^{pos .} /KIT^{pos .} patients without additional somatic high-risk mutations [HRM, e.g. in serine and arginine-rich splicing factor 2 (SRSF2), additional sex combs like-1 (ASXL1) or Runt-related transcription factor 1 (RUNX1)] at 5 years was 77%, indicating that the mutual impact of JAK2 V617F and KIT D816V on prognosis is fundamentally different from the adverse impact of additional HRM in the individual disorders.

Mixed Phenotype of Emphysema and Airway Wall Thickening Is Associated with Frequent Exacerbation in Chronic Obstructive Pulmonary Disease Patients

Objective

The presence of both emphysema and airway wall thickening determined via volumetric computed tomography (CT) is defined as mixed phenotype. The long-term clinical course of this phenotype has not been studied in depth. This study compared the mixed phenotype to other phenotypes of chronic obstructive pulmonary disease (COPD) patients.

Methods

COPD patients enrolled in the Korean Obstructive Lung Disease (KOLD) study from June 2005 to October 2015 were evaluated. The emphysema index and the percentage of bronchial mean wall area were calculated from volumetric CT scans. Patients with COPD were classified into four phenotypes using two cutoffs: emphysema index of 15% and median value of mean wall area (MWA%).

Results

Of 435 patients with COPD, 99 (22.8%) were defined as CT-normal type, 119 (27.4%) as emphysema-dominant type, 113 (26.0%) as airway-dominant type, and 104 (23.9%) as mixed type. The mixed phenotype showed the highest baseline total COPD Assessment Test (CAT) and St. George’s Respiratory Questionnaire (SGRQ) scores. Moreover, it had the highest proportion of patients experiencing exacerbation of COPD (50.0%), and had the lowest baseline FEV1. Lower BMI, GOLD stages III–IV, and mixed phenotype were significant factors associated with severe exacerbation frequency in univariate analyses. Multivariate analyses showed that lower BMI and CT phenotype were significant factors associated with severe exacerbation frequency. Compared to the CT-normal phenotype, the mixed phenotype was significantly associated with more frequent severe exacerbation (IRR 4.134, 95% CI: 1.135–15.057, P=0.031).

Conclusion

Patients with mixed phenotype are more symptomatic, have poorer pulmonary function, and are associated with more frequent severe exacerbation.

Mexiletine rescues a mixed biophysical phenotype of the cardiac sodium channel arising from the SCN5A mutation, N406K, found in LQT3 patients

Introduction: Individual mutations in the SCN5A-encoding cardiac sodium channel α-subunit usually cause a single cardiac arrhythmia disorder, some cause mixed biophysical or clinical phenotypes. Here we report an infant, female patient harboring a N406K mutation in SCN5A with a marked and mixed biophysical phenotype and assess pathogenic mechanisms. Methods and Results: A patient suffered from recurrent seizures during sleep and torsades de pointes with a QTc of 530 ms. Mutational analysis identified a N406K mutation in SCN5A. The mutation was engineered by site-directed mutagenesis and heterologously expressed in HEK293 cells. After 48 hours incubation with and without mexiletine, macroscopic voltage-gated sodium current (I_Na) was measured with standard whole-cell patch clamp techniques. SCN5A-N406K elicited both a significantly decreased peak I_Na and a significantly increased late I_Na compared to wide-type (WT) channels. Furthermore, mexiletine both restored the decreased peak I_Na of the mutant channel and inhibited the increased late I_Na of the mutant channel. Conclusion: SCN5A-N406K channel displays both “gain-of-function” in late I_Na and “loss-of-function” in peak I_Na density contributing to a mixed biophysical phenotype. Moreover, our finding may provide the first example that mexiletine exerts a dual rescue of both “gain-of-function” and “loss-of-function” of the mutant sodium channel.

Early T-cell precursor acute lymphoblastic leukemia with KRAS and DNMT3A mutations and unexpected monosomy 7

Early T-cell precursor acute lymphoblastic leukemia/lymphoma (ETP-ALL) is a recently recognized subgroup of T lymphoblastic leukemia/lymphoma thought to be derived from lymphocytes at the ETP differentiation stage that have not irreversibly committed to the T-cell lineage. The definition of ETP-ALL is based on a unique immunophenotype that also expresses at least one myeloid or stem cell marker other than myeloperoxidase and monocytic markers. Correspondingly, ETP-ALLs are often found to express myeloid-associated mutations and have stem cell gene expression profiles. Because its morphology is nonspecific, recognizing the immunophenotype of this uncommon entity is important to separate it from other closely related acute leukemias. We report a case of ETP-ALL with KRAS and DNMT3A mutations and monosomy of chromosome 7 that did not initially respond to conventional ALL therapy but eventually responded to acute myeloid leukemia-type therapy, underscoring the interesting characteristics of this leukemia. Little information is available regarding monosomy 7 in this entity for the adult population.

Mixed phenotype acute leukemia contains heterogeneous genetic mutations by next-generation sequencing

Mixed phenotype acute leukemia (MPAL) is an uncommon manifestation of acute leukemia. The aim of this study is to further characterize the genetic landscape of de novo cases of MPAL that fulfill the 2016 World Health Organization (WHO) classification criteria for this entity. We identified 14 cases examined by next generation sequencing (NGS) using 28 (n = 10), 53 (n = 3) or 81 (n = 1) gene panels: 7 cases with a B-cell/myeloid (B/My) immunophenotype, 6 T-cell/myeloid (T/My) immunophenotype, and 1 B-cell/T-cell (B/T) immunophenotype. A total of 25 distinct mutations were identified in 15 different genes in 9/14 (64%) patients. FLT3-ITD was the only recurrent mutation in 2 patients. B/My MPAL cases less commonly harbored mutations compared with T/My MPAL cases (43% vs. 100%, p = 0.07). In contrast, B/My MPALs more commonly showed a complex karyotype compared to T/My MPALs (71% vs. 17%, p = 0.1). With NGS and karyotype combined, most (93%) MPAL cases had mutations or cytogenetic abnormalities. With a median follow-up of 12.5 months, there were no significant differences in median overall survival (OS) between patients with B/My or T/My MPAL (17.8 and 6.5 months, respectively, p = 0.81) or between patients with MPAL with versus without gene mutations (6.5 and 13.3 months, respectively, p = 0.86). Our data suggest that the distinguishing cases of MPAL according to immunophenotype has value because the underlying mechanisms of leukemogenesis might differ between B/My and T/My MPAL.

Successful acute lymphoblastic leukemia-type therapy in two children with mixed-phenotype acute leukemia

Mixed-phenotype acute leukemia (MPAL) is a rare type of leukemia expressing both myeloid and lymphoid markers. There is limited information, especially on pediatric cases. Therefore, the optimal therapeutic approach to pediatric MPAL has not been defined. Here, we report two pediatric cases of MPAL. According to the 2008 World Health Organization (WHO) classification and European Group for the Immunological Characterization of Leukemias (EGIL) criteria, patient 1 was diagnosed with overt MPAL positive for the myeloid marker myeloperoxidase (MPO), and B-lymphoid markers. Patient 2 was diagnosed with T-cell acute lymphoblastic leukemia (T-ALL) using EGIL criteria. According to the 2008 WHO classification, however, patient 2 was diagnosed with overt MPAL positive for CD3, T-lymphoid markers and MPO. We chose an ALL-type therapy consisting of both lymphoid- and myeloid-directed agents; these patients have maintained complete remission following treatment. Further information on pediatric MPAL is needed to establish an appropriate therapeutic strategy including stem cell transplantation for this rare condition.