Functional characterization of the cells in chronic neutrophilic leukemia

Chronic Neutrophilic Leukemia: A Comprehensive Review of Clinical Characteristics, Genetic Landscape and Management

Chronic neutrophilic leukemia (CNL) represents a rare disease, that has been classified among the BCR/ABL-negative myeloproliferative neoplasms. The disease is characterized by marked leukocytosis with absolute neutrophilia and its clinical presentation may vary from asymptomatic to highly symptomatic with massive splenomegaly and constitutional symptoms. CNL prognosis remains relatively poor, as most patients succumb to disease complications or transform to acute myeloid leukemia. Recent studies have demonstrated that CSF3R mutations drive the disease, albeit the presence of other secondary mutations perplex the genetic landscape of the disease. Notably, the presence of CSF3R mutations has been adopted as a criterion for diagnosis of CNL. Despite the vigorous research, the management of the disease remains suboptimal. Allogeneic stem cell transplantation represents the only treatment that could lead to cure; however, it is accompanied by high rates of treatment-related mortality. Recently, ruxolitinib has shown significant responses in patients with CNL; however, emergence of resistance might perturbate long-term management of the disease. The aim of this review is to summarize the clinical course and laboratory findings of CNL, highlight its pathogenesis and complex genetic landscape, and provide the context for the appropriate management of patients with CNL.

Anti-inflammatory effects of ruxolitinib on chronic neutrophilic leukemia harboring CSF3R-T618I mutation with bilateral renal abscesses

Chronic neutrophilic leukemia (CNL) is a rare myeloproliferative neoplasm (MPN) characterized by sustained mature neutrophilic leukocytosis. Recently, presence of colony-stimulating factor 3 receptor (CSF3R) mutations has been added to the diagnostic criteria for CNL. Anti-inflammatory effects of the JAK1/2 inhibitor ruxolitinib relieve constitutional symptoms associated with MPN, such as fatigue, night sweats, and fever. We present a case of CNL harboring CSF3R-T618I mutation exacerbated by concomitant bilateral renal abscesses, which was refractory to antibiotics, at the time of initial diagnosis. In this case, ruxolitinib rapidly improved not only CNL but the infection, due to its anti-inflammatory potency.

Miliary tuberculosis associated with chronic neutrophilic leukemia

We report a case of miliary tuberculosis associated with chronic neutrophilic leukemia (CNL). A 70-year-old woman was referred to our hospital complaining of a 1-month history of persistent fever and anorexia. Chest and abdominal computed tomography images revealed diffuse small nodular lesions in the bilateral lung fields and extreme splenomegaly. Sputum cultures isolated Mycobacterium tuberculosis. After anti-tuberculous therapy for 1 year, the patient underwent splenectomy for massive splenomegaly and progressive leukocytosis. The presence of the homozygous JAK2 V617F tyrosine kinase mutation was also demonstrated in the peripheral blood. She was finally diagnosed as having miliary tuberculosis associated with CNL based on the histopathological examination of spleen. The patient was treated with a daily dose of 500 mg of hydroxyurea. As a result, 18 months after the splenectomy, her leukocyte count was decreased and her clinical condition was markedly improved; there was no relapse of the CNL.

Neoplastic involvement of granulocytic lineage, not granulocytic-monocytic, monocytic, or erythrocytic lineage, in a patient with chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a very rare myeloproliferative disorder. To determine the neoplastic origin of CNL, morphological and cytogenetical studies were made of colonies derived from hematopoietic progenitors of a patient with CNL. The patient's hematopoietic progenitors spontaneously formed colonies consisting of mature granulocytes, and cytogenetical study of the colonies indicated chromosome abnormalities identical to those in the patient's bone marrow cells. Analysis of colonies consisting of granulocytes and macrophages, macrophages, or erythrocytes disclosed a normal karyotype. These results demonstrated that the neoplastic process in this patient with CNL originated in hematopoietic progenitors capable of differentiating only into granulocytes, and not granulocytes and monocytes, monocytes, or erythrocytes.

Parallel tubular granules in human immature neutrophils--an electron microscopic study

Unique rounded granules consisting of clustered parallel tubules, 29-31 nm in diameter, with occasional, flocculent or amorphous electron-dense material (parallel tubular granules, PTGs) were found in immature neutrophils in the bone marrow in a case of chronic neutrophilic leukemia (CNL). PTGs were positive for electron microscopic myeloperoxidase. Since no structures similar to PTGs have been documented, we investigated the bone marrow of 65 adult patients with hematologic diseases, and 7 adult patients with miscellaneous non-hematologic diseases, by electron microscopy. The results showed that no PTGs were found in any cases other than the original CNL case. These findings suggest that PTGs are rare granules representing certain primary granules. In addition, the presence of PTGs might be helpful in diagnosing CNL.

Chronic neutrophilic leukemia. A study of four cases

Chronic neutrophilic leukemia (CNL) is a very rare entity, which has to be included among the chronic myeloid leukemias. Once an underlying cause of neutrophilia is excluded, the diagnosis of CNL is based on exclusion of chronic granulocytic and other types of chronic myeloid leukemias. The classification proposed by Sheperd et al. has proven to be helpful, but it must be completed by cytogenetic analysis and the search for bcr rearrangement by molecular biology methods, in order to confirm the absence of Philadelphia chromosome and of bcr-abl hybrid gene. We report here four cases of CNL, with confirmed absence of bcr rearrangement in two cases. Two patients died, 12 and 8 years after diagnosis, the second one following transformation into myelofibrosis with myeloid metaplasia. The other two died of acute myelogenous leukemia, the first one, 25 years after diagnosis of CNL, following a 3-year phase of acceleration. The last patient presented combined features of CNL and refractory anemia with excess of blasts, and was characterized by both progressive leukocytosis and severe thrombocytopenia; acute transformation into acute myelogenous leukemia occurred 6 months after diagnosis and death 1 month later. Among the 30 cases reported so far, plus the four presented here, combined myelodysplastic features were observed in five cases and transformation into acute myelogenous leukemia in six. Chronic neutrophilic leukemias should be reported regularity, in view of the uncertain and low frequency of this hematological disease.

Successful alpha-2b-interferon therapy for chronic neutrophilic leukemia

The authors report two patients with characteristic features of chronic neutrophilic leukemia (CNL) treated with alpha-2b-interferon (IFN) (Schering-Plough). At initiation of therapy, both patients had progressive disease and presented with large tumors. A rapid reduction of the tumor mass and a long-term stabilisation of the myeloproliferative disorder was obtained (therapy duration 16 and 26 months, respectively, and presently ongoing). In one patient, the dose of IFN could be significantly reduced during maintenance without relapse. Neither presented infectious or hemorrhagic complications under therapy. Alpha-2b-interferon is active and safe in CNL, even pretreated and progressive. It can also correct the neutrophil and natural killer functional defects frequently observed in CNL.

Elevated neutrophil function in chronic neutrophilic leukemia

A 65-year-old man with marked leukocytosis was admitted for diagnosis and treatment. His peripheral blood leukocyte count was 37,500/microliters and the leukocytes consisted of mature neutrophil-like cells. A high neutrophil alkaline phosphatase score and a normal bone marrow cell karyotype suggested that the patient had chronic neutrophilic leukemia rather than chronic myeloid leukemia. Several neutrophil functions, such as superoxide production, nitroblue tetrazolium reduction activity, and phagocytosis, were elevated. These data and the morphological features (toxic granules and Döhle bodies) indicated that the patient's neutrophils were in an activated stage.

Chronic neutrophilic leukemia and multiple myeloma. An association with lambda light chain expression

Two patients with plasma cell dyscrasia and IgG lambda paraproteinemia in association with the rare disorder, chronic neutrophilic leukemia (CNL), are described. Cytogenetic studies excluded Philadelphia + chronic myeloid leukemia and molecular analysis of the breakpoint cluster region (bcr) revealed no evidence of clonal gene rearrangement. Nine similar cases of coexistent CNL and paraproteinemia have been identified in the literature and attention is drawn to the disproportionate excess of lambda light chain restriction in this subset of patients. Evidence supporting a clonal origin of CNL is considered and the nature of the relationship between the chronic myeloid expansion and the development of multiple myeloma is discussed.

A case of chronic neutrophilic leukemia with original chromosomal abnormalities

We report a new case of the unusual myeloproliferative syndrome chronic neutrophilic leukemia (CNL) that met all the criteria generally required for the diagnosis of this entity. The patient presented abnormalities in platelet function not previously reported that may explain the bleeding tendency observed in these patients. The study of neutrophil function suggested also defective mobility and intracellular bactericidal activity. The chromosomal study revealed original abnormalities consisting of multiple chromosomal ruptures and figures. The disease was controlled with busulfan. After 20 months, the patient died of sepsis. An autopsy was performed confirming the diagnosis and ruling out the existence of a cause of a leukemoid reaction, such as cancer or granulomatous disease.

Lymph node involvement in chronic neutrophilic leukemia. An immunohistochemical study

An immunohistochemical study was performed on autopsy material from a patient with chronic neutrophilic leukaemia (CNL) using antibodies against various cell lineage-related antigens. Proliferation of immature neutrophils with occasional clusters of erythroblasts and megakaryocytes were noted in the retroperitoneal lymph nodes, spleen, and kidneys as well as in the bone marrow. Predominance of immature neutrophils in the lymph nodes suggested the emergence of a blast crisis, although there was no increase of blasts in the peripheral blood. Since immature myeloid cells are difficult to distinguish from malignant lymphoid cells on tissue sections, we suggest that immunohistochemical identification of cell lineage-related molecules on these cells is necessary for the more accurate interpretation of lymph node lesions in myeloid neoplasms.

Cytobiologic and clinical aspects in a patient with chronic neutrophilic leukemia after thorotrast exposure

A patient with fairly typical chronic neutrophilic leukemia, as represented by some two dozen such reported cases, had been given Thorotrast more than 20 years before. Typical myeloblastic crisis developed with remarkable terminal leukocytosis. Mature blood neutrophils had normal function with respect to phagocytosis, bacterial killing, metabolic activation, and chemotactic response. The number of cells producing colonies of neutrophils and monocytes in in vitro semisolid cultures was normal in the blood and increased in marrow. Colony size was smaller than is usually observed in normal patients or in typical patients with chronic myeloid leukemia. Termination in blast crisis, also seen in a few other patients with chronic neutrophilic leukemia, indicates that this is indeed a form of leukemia and not a "leukemoid" reaction of obscure cause. The differential diagnosis of extreme neutrophilia is discussed.