Microcytosis in agnogenic myeloid metaplasia: Prevalence and clinical correlates

Prognostic implications of low transferrin saturation in patients with primary myelofibrosis

OBJECTIVES

Transferrin saturation (TSAT) 20% or less is considered to represent functional iron deficiency in the context of malignant disease, phenomenon mediated through inflammatory changes of iron homeostasis. We aimed to investigate clinical and prognostic significance of low TSAT in patients with primary (PMF) and secondary myelofibrosis (SMF), malignant diseases characterized by strong inflammatory milieu.

METHODS

We retrospectively analyzed 87 patients with myelofibrosis and compared TSAT with disease specific parameters.

RESULTS

One-third of patients had TSAT ≤20%. Lower TSAT was significantly associated with Janus-kinase-2 (JAK2) mutation (P = 0.007), transfusion independency (P = 0.003), higher platelets (P = 0.004), lower mean-corpuscular-volume (P < 0.001), lower ferritin (P < 0.001), higher absolute-neutrophil-count (P = 0.027), lower absolute-lymphocyte-count (P = 0.041) and lower albumin (P = 0.018). PMF patients presenting with low TSAT (≤20%) experienced significantly shorter overall-survival (OS) (HR = 2.43; P = 0.017), whereas TSAT did not affect OS of SMF patients (HR = 1.48; P = 0.623). Low TSAT remained significantly associated with inferior OS in PMF in a series of multivariate Cox regression models comparing its properties to anemia, transfusion dependency, ferritin and Dynamic-International-Prognostic-System (DIPSS).

CONCLUSIONS

Low TSAT has detrimental effect on survival of PMF patients. This effect is independent of anemia and of ferritin levels that seem to be better at representing iron overload in PMF patients.

Clinical significance of microcytosis in patients with primary myelofibrosis

Microcytosis is a relatively frequent finding in primary myelofibrosis (PMF); however its prognostic significance is unknown. We identified factors associated with microcytosis in PMF and measured its impact on outcomes. Among 725 patients with PMF, 140 (19%) showed microcytosis. In multivariate analysis, factors associated with microcytosis were absence of prior therapy, low iron, low transferrin saturation (satTF), and splenomegaly. Among 375 untreated patients, low satTF and splenomegaly were associated with microcytosis. Overall, microcytosis was associated with a higher risk of transformation to leukemia (p=0.03), but not shorter leukemia-free survival. Microcytosis in PMF may be related to dysregulation of iron homeostasis.

How I treat myelofibrosis

It is currently assumed that myelofibrosis (MF) originates from acquired mutations that target the hematopoietic stem cell and induce dysregulation of kinase signaling, clonal myeloproliferation, and abnormal cytokine expression. These pathogenetic processes are interdependent and also individually contributory to disease phenotype-bone marrow stromal changes, extramedullary hematopoiesis, ineffective erythropoiesis, and constitutional symptoms. Molecular pathogenesis of MF is poorly understood despite a growing list of resident somatic mutations that are either functionally linked to Janus kinase (JAK)-signal transducer and activator of transcription hyperactivation (eg JAK2, MPL, and LNK mutations) or possibly involved in epigenetic dysregulation of transcription (TET2, ASXL1, or EZH2 mutations). Current prognostication in primary MF is based on the Dynamic International Prognostic Scoring System-plus model, which uses 8 independent predictors of inferior survival to classify patients into low, intermediate 1, intermediate 2, and high-risk disease groups; corresponding median survivals are estimated at 15.4, 6.5, 2.9, and 1.3 years. Such information is used to plan a risk-adapted treatment strategy for the individual patient, which might include observation alone, conventional or investigational (eg, JAK inhibitors, pomalidomide) drug therapy, allogenic stem cell transplantation with reduced- or conventional-intensity conditioning, splenectomy, or radiotherapy. I discuss these treatment approaches in the context of who should get what and when.

Myelofibrosis in children: experience at a single tertiary care center in India

The authors describe 10 cases of myelofibrosis diagnosed and managed at their center over 16 years. There were 2 and 8 cases, respectively, of primary and secondary myelofibrosis. All patients presented with fever, pallor, hepatosplenomegaly, and/or lymphadenopathy. Hodgkin's lymphoma (n = 4), neuroblastoma (n = 1), thrombasthenic thrombopathy (n = 1), and retroperitoneal-mass (n = 1) were causal in 7 patients, whereas the diagnosis could not be established in a sole case of secondary myelofibrosis. Patients were managed with chemotherapy and appropriate care. However, outcome was poor. The authors emphasize variable clinical-laboratory spectrum of myelofibrosis, highlight management concerns, and demonstrate that prognosis/outcome depends upon appropriate management of the underlying condition.

Prevalence of erythrocyte haemoglobin H inclusions in unselected patients with clonal myeloid disorders

Patients with clonal myeloid disorders, especially myelodysplastic syndromes (MDS), may acquire alpha-thalassaemia. To estimate the prevalence of this erythrocyte phenotype, we examined brilliant cresyl blue-stained blood smears from 201 patients with neoplastic myeloid disorders and 282 controls (195 non-clonal anaemia, 62 with medical illnesses without anaemia and 25 healthy persons). Haemoglobin H inclusions were detected in 8/100 patients with MDS (8%) and 2/81 (2.5%) patients with myeloproliferative disorders, but in none of the acute leukaemia patients or controls. We conclude that the emergence of thalassaemic clones may be relatively common in the disordered marrow milieu of MDS.