Clinical and immunological features in ACKR1/DARC-associated neutropenia.

ABSTRACT: ACKR1/DARC-associated neutropenia (NP; ADAN; Online Mendelian Inheritance in Man 611862), caused by a variation in the ACKR1/DARC gene (rs2814778), is common in persons of African or Middle Eastern descent. In a cohort of 66 genetically confirmed subjects with ADAN, we show that absolute neutrophil counts (ANCs) may occasionally be lower than previously recognized (0.1 × 109-0.49 × 109/L for 9% of the subjects), which is similar to ANCs in severe congenital NP (SCNP). ANCs often normalized during inflammation, even mild. Individuals with ADAN (of 327 observed person-years) showed no cases of myelodysplastic syndrome (MDS), which is frequently encountered in SCNP. Unexpectedly, 22% presented with autoantibodies to neutrophils, compared with <1% in controls. Compared with healthy donors, subjects with ADAN demonstrated significantly lower human cationic antimicrobial protein-18/pro-leucin leucin-37 plasma levels; higher levels of nonclassical, proinflammatory, 6-sulfo LacNac-expressing monocytes; and differentially expressed plasma levels of 28 of the 239 analyzed cytokines related to immunity/inflammation, cell signaling, neutrophil activation, and angiogenesis. Collectively, more severe neutropenia in ADAN than previously assumed may complicate differential diagnoses compared with other SCNPs, and various (auto)immune/inflammatory reactions with a distinct profile may be a cause or consequence of this hereditary neutropenia.

HAX1-related congenital neutropenia: Long-term observation in paediatric and adult patients enrolled in the European branch of the Severe Chronic Neutropenia International Registry (SCNIR).

HAX1-related congenital neutropenia (HAX1-CN) is a rare autosomal recessive disorder caused by pathogenic variants in the HAX1 gene. HAX1-CN patients suffer from bone marrow failure as assessed by a maturation arrest of the myelopoiesis revealing persistent severe neutropenia from birth. The disorder is strongly associated with severe bacterial infections and a high risk of developing myelodysplastic syndrome or acute myeloid leukaemia. This study aimed to describe the long-term course of the disease, the treatment, outcome and quality of life in patients with homozygous HAX1 mutations reported to the European branch of the Severe Chronic Neutropenia International Registry. We have analysed a total of 72 patients with different types of homozygous (n = 68), compound heterozygous (n = 3), and digenic (n = 1) HAX1 mutations. The cohort includes 56 paediatric (<18 years) and 16 adult patients. All patients were initially treated with G-CSF with a sufficient increase in absolute neutrophil counts. Twelve patients required haematopoietic stem cell transplantation for leukaemia (n = 8) and non-leukaemic indications (n = 4). While previous genotype-phenotype reports documented a striking correlation between two main transcript variants and clinical neurological phenotypes, our current analysis reveals novel mutation subtypes and clinical overlaps between all genotypes including severe secondary manifestations, e.g., high incidence of secondary ovarian insufficiency.

The European Guidelines on Diagnosis and Management of Neutropenia in Adults and Children: A Consensus Between the European Hematology Association and the EuNet-INNOCHRON COST Action.

Neutropenia, as an isolated blood cell deficiency, is a feature of a wide spectrum of acquired or congenital, benign or premalignant disorders with a predisposition to develop myelodysplastic neoplasms/acute myeloid leukemia that may arise at any age. In recent years, advances in diagnostic methodologies, particularly in the field of genomics, have revealed novel genes and mechanisms responsible for etiology and disease evolution and opened new perspectives for tailored treatment. Despite the research and diagnostic advances in the field, real world evidence, arising from international neutropenia patient registries and scientific networks, has shown that the diagnosis and management of neutropenic patients is mostly based on the physicians' experience and local practices. Therefore, experts participating in the European Network for the Innovative Diagnosis and Treatment of Chronic Neutropenias have collaborated under the auspices of the European Hematology Association to produce recommendations for the diagnosis and management of patients across the whole spectrum of chronic neutropenias. In the present article, we describe evidence- and consensus-based guidelines for the definition and classification, diagnosis, and follow-up of patients with chronic neutropenias including special entities such as pregnancy and the neonatal period. We particularly emphasize the importance of combining the clinical findings with classical and novel laboratory testing, and advanced germline and/or somatic mutational analyses, for the characterization, risk stratification, and monitoring of the entire spectrum of neutropenia patients. We believe that the wide clinical use of these practical recommendations will be particularly beneficial for patients, families, and treating physicians.

Perturbed NK-cell homeostasis associated with disease severity in chronic neutropenia.

Neutrophils have been thought to play a critical role in terminal differentiation of NK cells. Whether this effect is direct or a consequence of global immune changes with effects on NK-cell homeostasis remains unknown. In this study, we used high-resolution flow and mass cytometry to examine NK-cell repertoires in 64 patients with neutropenia and 27 healthy age- and sex-matched donors. A subgroup of patients with chronic neutropenia showed severely disrupted NK-cell homeostasis manifesting as increased frequencies of CD56bright NK cells and a lack of mature CD56dim NK cells. These immature NK-cell repertoires were characterized by expression of the proliferation/exhaustion markers Ki-67, Tim-3, and TIGIT and displayed blunted tumor target cell responses. Systems-level immune mapping revealed that the changes in immunophenotypes were confined to NK cells, leaving T-cell differentiation intact. RNA sequencing of NK cells from these patients showed upregulation of a network of genes, including TNFSF9, CENPF, MKI67, and TOP2A, associated with apoptosis and the cell cycle, but different from the conventional CD56bright signatures. Profiling of 249 plasma proteins showed a coordinated enrichment of pathways related to apoptosis and cell turnover, which correlated with immature NK-cell repertoires. Notably, most of these patients exhibited severe-grade neutropenia, suggesting that the profoundly altered NK-cell homeostasis was connected to the severity of their underlying etiology. Hence, although our data suggest that neutrophils are dispensable for NK-cell development and differentiation, some patients displayed a specific gap in the NK repertoire, associated with poor cytotoxic function and more severe disease manifestations.

The role of BAFF and G-CSF for rituximab-induced late-onset neutropenia (LON) in lymphomas.

Mechanisms for late-onset neutropenia (LON) after rituximab treatment are poorly defined both for non-Hodgkin lymphoma (NHL) and for autoimmune disorders. We performed a case-control analysis of a prospective cohort of 169 evaluable consecutive rituximab-treated NHL patients to assess cytokines involved in neutro- and lymphopoiesis (G-CSF, SDF1, BAFF, APRIL) and inflammation (CRP) as possible LON mechanisms. Fifteen patients (9%) developed LON (peripheral blood /PB/ absolute neutrophil counts /ANC/ < 0.5 G/L, all with marked depletion of CD20+ B-lymphocytes in bone marrows); they were compared with 20 matched NHL controls without LON. At start of LON, significantly higher PB G-CSF and BAFF levels (P = 0.0004 and 0.006, respectively), as well as CRP rises were noted compared to controls; these G-CSF and BAFF and most CRP values returned to levels of the controls in post-LON samples. G-CSF (but not BAFF) changes correlated to CRP rises (but not to ANC levels). BAFF levels correlated significantly to absolute monocyte counts and PB large granular lymphocyte counts (but not to ANC, C-CSF or CRP values). No changes of SDF1 or APRIL levels were noted. Neither LON cases nor controls displayed anti-neutrophil autoantibodies. Collectively, LON in NHL patients was timewise related to transient bursts of blood G-CSF and BAFF concentrations, suggesting that these neutro- and lymphopoiesis growth factors play a role in emergence of rituximab-induced LON, and that inflammation may be a trigger for G-CSF production during LON.

Age-related prevalence and clinical significance of neutropenia - isolated or combined with other cytopenias: Real world data from 373 820 primary care individuals.

Neutropenia (NP), that is, an absolute blood neutrophil count (ANC) <1.5 g/L, accompanies various diseases. However, the clinical significance of NP, detected in routine complete blood cell counts (CBC) in primary care, is poorly characterized. Here, from a primary care resource with ANCs from >370 000 individuals, we identified and followed neutropenic subjects for the next 4 years for novel ICD-10 based diagnoses of viral infections and hematological malignancies (ie, previously identified major outcomes in NP individuals) in Danish nationwide health registers. Risk estimates were assessed for children/adolescents (1-18 years) and adults (19-90 years) in relation to NP severity, and for isolated NP, bi- or pancytopenias. We found that NP was observed in 4.9% of children and in 1.9% of adults. The lower the ANC, the likelier was a diagnosis of viral infections or hematological malignancies established during the ensuing 4 years. Among neutropenic children, unspecified viral infections predominated, followed by mononucleosis (with other cytopenias in only 7% and 25% of the cases, respectively). All NP children with acute leukemia presented with bi- or pancytopenia from start of follow-up. In NP adults, hepatitis, followed by HIV, were the most common infections, and acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDSs) the predominating hematological malignancies. Adult NP patients, subsequently diagnosed with hepatitis, HIV or AML, MDS, were bi- or pancytopenic in 42%, 47%, 90% and 91% of cases, respectively. Thus, presence of NP in even one CBC may be the first sign of a latent viral or hematological disorder requiring careful follow-up.

Ethnic benign neutropenia: A phenomenon finds an explanation.

Ethnic benign neutropenia (ENP) is the most common form of neutropenia (NP) worldwide, if an absolute blood neutrophil count (ANC) of < 1.5 G/L is used as definition. In 2009, ENP was associated with a gene variation in the ACKR1/DARC gene, the same variation that also confers the Duffy-null trait. In 2017, a novel mechanism for ENP was introduced, questioning if ENP is a true neutropenic state, when the body's total neutrophil count (TBNC) is concerned. Here, we summarize the current knowledge of ENP, asking (1) How well does the peripheral blood ANC predict the TBNC? (2) Can we improve methods for assessing TBNC? (3) Will estimates of TBNC predict infection propensity and reduce the need for further, costly workup?

Cytokine Measurements for Diagnosing and Characterizing Leukemoid Reactions and Immunohistochemical Validation of a Granulocyte Colony-Stimulating Factor and CXCL8-Producing Renal Cell Carcinoma.

BACKGROUND: Various paraneoplastic syndromes are encountered in renal cell carcinomas. This case report illustrates that a paraneoplastic leukemoid reaction may precede the diagnosis of renal cell carcinoma and be explained by cytokine production from the cancer cells. CASE PRESENTATIONS: A 64-year-old man was referred for hematology workup due to pronounced leukocytosis. While being evaluated for a possible hematologic malignancy as the cause, he was found to have a metastasized renal cell carcinoma, and hyperleukocytosis was classified as a leukemoid reaction. A multiplex panel for measurement of 25 serum cytokines/chemokines showed highly elevated levels of granulocyte colony-stimulating factor (G-CSF) and CXCL8 (C-X-C-motif chemokine ligand 8, previously known as interleukin [IL]-8). By immunohistochemistry it was shown that the renal carcinoma cells expressed both these cytokines. Two additional, consecutive patients with renal cell carcinoma with paraneoplastic leukocytosis also showed elevated serum levels of CXCL8, but not of G-CSF. Nonparametric statistical evaluation showed significantly higher serum concentrations of CXCL8, IL-6, IL-10, monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor, but lower interferon gamma (IFN-γ) and IL-1α, for the 3 renal cell carcinoma cases compared with healthy blood donors. CONCLUSIONS: In suspected paraneoplastic leukocytosis, multiplex serum cytokine analyses may facilitate diagnosis and provide an understanding of the mechanisms for the reaction. In the index patient, combined G-CSF and CXCL8 protein expression by renal carcinoma cells was uniquely documented. A rapidly fatal course was detected in all 3 cases, congruent with the concept that autocrine/paracrine growth signaling in renal carcinoma cells may induce an aggressive tumor phenotype. Immune profiling studies could improve our understanding for possible targets when choosing therapies for patients with metastatic renal cell carcinoma.

Aberrant bone marrow vascularization patterns in untreated patients with Gaucher disease type 1.

Bone marrow (BM) in subjects with Gaucher disease (GD) displays accumulation of Gaucher cells (GC), i.e. glucocerebroside-laden macrophages. Following the assumption that macrophage proliferation and perturbation in GD modulates local inflammation-associated phenomena including angiogenesis, BM biopsies from 11 untreated GD patients and 36 controls were investigated for morphology and angiogenesis-associated features. These included microvascular density, (MVD), vessel structure and pericyte coverage, expression of VEGF-A and angiopoietins (ANGPT1 and 2). In GD BM, cellularity was higher, and GC clustered in cohesive but poorly demarcated areas, leaving irregular islands with normal hematopoiesis. MVD was 2.6-fold higher in GD marrows than in controls (p<0.001). In GC-rich areas, MVD was 1.4-fold higher (p=0.026), and vessel architecture was abnormal compared with GC-poor areas. MVD correlated with BM cellularity, particularly in GC-rich areas. Moreover, 30±17% of GD BM vessels were pericyte-coated, significantly fewer than in controls (48±16%; p<0.001). Expression of ANGPT1 and 2 was significantly higher in GD BM vessel walls than in controls (7.2- and 13.2-fold higher), whereas VEGF expression was 20-fold lower (p<0.05 for all). Thus, human GD BM shows increased angiogenesis with defective pericyte coating and skewed VEGF/ANGPT1 and 2 balances, presumably related to local accumulation of GC.

X-linked thrombocytopenia with thalassemia displays bone marrow reticulin fibrosis and enhanced angiogenesis: comparisons with primary myelofibrosis.

X-linked thrombocytopenia with thalassemia (XLTT) is caused by the mutation 216R > Q in exon 4 of the GATA1 gene. Male hemizygous patients display macrothrombocytopenia, splenomegaly, and a ß-thalassemia trait. We describe two XLTT families where three males were initially misdiagnosed as having primary myelofibrosis (PMF) and all five investigated males showed mild-moderate bone marrow (BM) reticulin fibrosis. Comparative investigations were performed on blood samples and BM biopsies from males with XLTT, PMF patients and healthy controls. Like PMF, XLTT presented with high BM microvessel density, low GATA1 protein levels in megakaryocytes, and elevated blood CD34+ cell counts. But unlike PMF, the BM microvessel pericyte coverage was low in XLTT, and no collagen fibrosis was found. Further, as evaluated by immunohistochemistry, expressions of the growth factors VEGF, AGGF1, and CTGF were low in XLTT megakaryocytes and microvessels but high in PMF. Thus, although the reticulin fibrosis in XLTT might simulate PMF, opposing stromal and megakaryocyte features may facilitate differential diagnosis. Additional comparisons between these disorders may increase the understanding of mechanisms behind BM fibrosis in relation to pathological megakaryopoiesis.

Low pericyte coverage of endometrial microvessels in heavy menstrual bleeding correlates with the microvessel expression of VEGF-A.

A prospective clinical study was carried out to investigate whether endometrial microvessels in patients with idiopathic heavy menstrual bleeding (HMB) of endometrial origin (HMB-E) are fragile due to low pericyte coverage. Idiopathic HMB-E is characterized by large endothelial cell gaps related to the microvascular overexpression of vascular endothelial growth factor (VEGF)-A and VEGF receptors 1-3. A total of 10 women with a normal menstrual cycle and a history of HMB of <5 years, and 17 healthy women with a normal menstrual cycle were recruited from the Karolinska University Hospital. Blood samples were obtained for hormone analysis and coagulation tests. Endometrial biopsies were collected in the proliferative or in the secretory phase. Pericyte coverage was assessed using immunohistochemical staining for smooth muscle actin-α (SMAα) and by image analysis (microvascular density) of endometrial biopsies from 10 patients with HMB-E and 17 healthy ovulating women (control subjects). Previously published data on endothelial cell gap size and the expression of VEGF receptors were used. Although microvascular density did not differ between the patients with HMB-E and the control subjects, the number of SMAα-positive microvessels in the proliferative phase was significantly (P=0.005) lower in the patients with HMB-E than in the control subjects. Moreover, the number of SMAα-positive microvessels in the control subjects was significantly fewer in the secretory (P=0.04) than in the proliferative phase, whereas this number did not differ among the patients with HMB-E regardless of phase. A significant negative correlation was observed between the number of VEGF-A-positive microvessels and microvessels with pericyte coverage (r=0.8; P=0.04). Finally, the endothelial cell layer was significantly thicker in the patients with HMB-E than in the control subjects. Thus, the upregulation of VEGF-A in idiopathic HMB-E is associated with a low pericyte coverage during the proliferative phase of intense angiogenesis, which may confer vessel fragility, possibly leading to excessive blood loss.

Angiogenesis is increased in advanced haemophilic joint disease and characterised by normal pericyte coverage.

BACKGROUND: Repeated intra-articular bleedings in patients with haemophilia results in a crippling arthropathy for which no specific treatment is currently available. Recent studies have shown that neoangiogenesis is involved in the pathologic process. The aim of this study was to determine whether angiogenesis is dysregulated in haemophilic joint disease (HJD). METHODS: Synovial tissue and synovial fluid were collected from patients with severe haemophilia undergoing knee or hip replacement and from a control group consisting of non-haemophilic patients undergoing diagnostic procedures. In a second set of patients, blood samples were collected in patients with mild, moderate and severe haemophilia A when free from current bleeding. Analysis of microvascular density, vascular endothelial growth factor (VEGF) expression and pericyte coverage was performed by immunofluorescence. Analyses of VEGF concentrations in plasma, platelet lysates and synovial fluid were performed by ELISA. RESULTS: Microvascular density and VEGF expression were significantly increased in synovial tissue from haemophilic patients compared with controls (P = 0.005 and P = 0.02, respectively). There was no difference in pericyte coverage of synovial vessels or levels of VEGF in plasma, platelet lysates or synovial fluid. CONCLUSIONS: Angiogenesis observed as synovial microvascular density, and VEGF expression is increased in HJD. As pericyte coverage was similar in synovial vessels from haemophilic and non-haemophilic patients, we assume that the vessels were mature, suggesting that the rate of new vessel formation is low in the chronic phase of haemophilic joint disease.

Omega-3 fatty acids enhance phagocytosis of Alzheimer's disease-related amyloid-ß42 by human microglia and decrease inflammatory markers.

The use of supplements with omega-3 (ω3) fatty acids (FAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) is widespread due to proposed beneficial effects on the nervous and cardiovascular systems. Many effects of ω3 FAs are believed to be caused by down-regulation and resolution of inflammation. Alzheimer's disease (AD) is associated with inflammation mediated by microglia and astrocytes, and ω3 FAs have been proposed as potential treatments for AD. The focus of the present study is on the effects of DHA and EPA on microglial phagocytosis of the AD pathogen amyloid-ß (Aß), on secreted and cellular markers of immune activity, and on production of brain-derived neurotrophic factor (BDNF). Human CHME3 microglial cells were exposed to DHA or EPA, with or without the presence of Aß42. Phagocytosis of Aß42 was analyzed by flow cytometry in conjunction with immunocytochemistry using antibodies to cellular proteins. Secreted proteins were analyzed by ELISA. Both DHA and EPA were found to stimulate microglial phagocytosis of Aß42. Phagocytosis of Aß42 was performed by microglia with a predominance of M2 markers. EPA increased the levels of BDNF in the culture medium. The levels of TNF-α were decreased by DHA. Both DHA and EPA decreased the pro-inflammatory M1 markers CD40 and CD86, and DHA had a stimulatory effect on the anti-inflammatory M2 marker CD206. DHA and EPA can be beneficial in AD by enhancing removal of Aß42, increasing neurotrophin production, decreasing pro-inflammatory cytokine production, and by inducing a shift in phenotype away from pro-inflammatory M1 activation.

Diagnosis according to World Health Organization determines the long-term prognosis in patients with myeloproliferative neoplasms treated with anagrelide: results of a prospective long-term follow-up.

OBJECTIVES: During long term follow-up of a cohort of patients with essential thrombocythemia (ET) and polycythemia vera (PV) a higher than expected incidence of myelofibrosis (MF) was noted. In order to test if the explanation could be found in the diagnostic criteria a re-evaluation of diagnosis using the 2008 WHO diagnostic criteria for ET and MF was performed. METHODS: This prospective study of 60 patients with ET and PV was set up in 1998 to evaluate the long-term efficacy and tolerability of anagrelide treatment. Bone marrow trephine biopsies were requested from study start, after 2 and 7 years of follow-up. A blinded re-evaluation of the bone marrow trephines was performed. The 2008 WHO bone marrow criteria were used for diagnosis and fibrosis grading. RESULTS: Of 40 patients with an initial diagnosis of ET, 21 were confirmed as 'true ET' whereas 17 were reclassified as primary myelofibrosis (PMF) (12 PMF-0, 3 PMF-1, 2 PMF-2) and 2 as myeloproliferative neoplasms of uncertain origin. After 7 years of follow-up, 19 of 21 patients with 'true ET' were alive, none had transformed to MF, leukemia, or myelodysplastic syndrome. In contrast, 4/17 patients reclassified as PMF had died, two patients transformed to myelodysplastic syndrome and 7 patients progressed to overt MF. DISCUSSION: We conclude that a blinded re-evaluation of bone marrow trephines from study start and after 7 years of follow-up using 2008 World Health Organization criteria was able to differentiate between true ET and PMF with a marked difference in follow-up outcome.

Incidence of severe congenital neutropenia in Sweden and risk of evolution to myelodysplastic syndrome/leukaemia.

Severe congenital neutropenia (SCN) is characterized by low blood neutrophil counts, early bacterial infections, and risk of leukaemia development. As yet, no population-based incidence estimates of SCN have been reported. Children less than 16 years of age with SCN were sought in Sweden during the 20-year period 1987-2006 by a questionnaire to all Swedish Departments of Paediatrics and by reviewing the Swedish Health and Welfare Statistical Databases. Thirty-two patients were diagnosed with congenital neutropenia during this period. All received treatment with recombinant granulocyte-colony stimulating factor (G-CSF). Twenty-one patients were diagnosed as SCN or probable SCN, corresponding to 1·0 per 100,000 live births. Nine (43%) had ELANE mutations, four (19%) HAX1 mutations and eight (38%) were children with disease of unknown genetic aetiology. Four out of 21 patients (19%) developed myelodysplastic syndrome/leukaemia and three (14%) died, all with leukaemia. The cumulative incidence of myelodysplastic syndrome/leukaemia was 31%. The observed incidence of SCN in this population-based study was higher than previously estimated, possibly because genetic testing now can identify SCN cases previously thought to be idiopathic or benign neutropenia. The risk of developing myelodysplastic syndrome/leukaemia is considerable. ELANE mutations are the most commonly identified genetic defects.

Late-onset neutropenia following rituximab therapy: incidence, clinical features and possible mechanisms.

Late-onset neutropenia (LON) is emerging as a common adverse effect to rituximab therapy owing to widespread use of this drug in the treatment of B-cell lymphomas and autoimmune diseases. However, the true incidence and mechanisms are not fully understood. LON has been reported in 5?27% of rituximab-treated lymphoma patients. Similar figures apply for autoimmune patients but they appear to have more infections during the neutropenic period. Recent reports imply that host factors may play an intriguing role for development of LON, for example, polymorphisms in FCGR3. Pronounced B-lymphocyte depletion and lower serum IgM, as reported in LON patients during the period of neutropenia compared with matched controls, may play a role for understanding the mechanisms and risk stratification for emergence of LON.

Predictive factors for the occurrence of idiopathic menorrhagia: evidence for a hereditary trait.

The aim of the present study was to assess predictive factors for occurrence of idiopathic menorrhagia (IM), a disease characterized by abnormal endometrial blood vessel morphology. It was hypothesized that IM exhibits familial clustering (suggesting inheritance) and is associated with other vascular abnormalities, primarily cutaneous hemangiomas. Women with IM (n=152) and healthy, regularly menstruating (n=56) women answered a questionnaire concerning menstrual pattern, susceptibility to bleeding and family history of abnormal gynecological bleeding. Factor analysis with principal component extraction was used to separate predictive factors that may be associated with IM. A total of 35 different items were analyzed. A strong association was found between IM and a family history of heavy menstrual bleeding (r=0.68), but not with cutaneous vascular abnormalities. Our results revealed that a family history of heavy menstrual bleeding may have the highest predictive value for the diagnosis of IM, indicating a hereditary trait.