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Although somatic mutations influence the pathogenesis, phenotype, and outcome of myeloproliferative neoplasms (MPNs), little is known about their impact on molecular response to cytoreductive treatment. We performed targeted next-generation sequencing (NGS) on 202 pretreatment samples obtained from patients with MPN enrolled in the DALIAH trial (A Study of Low Dose Interferon Alpha Versus Hydroxyurea in Treatment of Chronic Myeloid Neoplasms; #NCT01387763), a randomized controlled phase 3 clinical trial, and 135 samples obtained after 24 months of therapy with recombinant interferon-alpha (IFNα) or hydroxyurea. The primary aim was to evaluate the association between complete clinicohematologic response (CHR) at 24 months and molecular response through sequential assessment of 120 genes using NGS. Among JAK2-mutated patients treated with IFNα, those with CHR had a greater reduction in the JAK2 variant allele frequency (median, 0.29 to 0.07; P < .0001) compared with those not achieving CHR (median, 0.27 to 0.14; P < .0001). In contrast, the CALR variant allele frequency did not significantly decline in those achieving CHR or in those not achieving CHR. Treatment-emergent mutations in DNMT3A were observed more commonly in patients treated with IFNα compared with hydroxyurea (P = .04). Furthermore, treatment-emergent DNMT3A mutations were significantly enriched in IFNα–treated patients not attaining CHR (P = .02). A mutation in TET2, DNMT3A, or ASXL1 was significantly associated with prior stroke (age-adjusted odds ratio, 5.29; 95% confidence interval, 1.59-17.54; P = .007), as was a mutation in TET2 alone (age-adjusted odds ratio, 3.03; 95% confidence interval, 1.03-9.01; P = .044). At 24 months, we found mutation-specific response patterns to IFNα: (1) JAK2- and CALR-mutated MPN exhibited distinct molecular responses; and (2) DNMT3A-mutated clones/subclones emerged on treatment.

Previous seroprevalence studies have demonstrated higher anti-SARS-CoV-2 IgG seroprevalence in healthcare workers (HCWs) than in the background population during the first phase of the 2020 COVID-19 pandemic. These studies, however, focussed mainly on hospital employees. To perform a cross-sectional study comparing the seroprevalence of hospital-based HCWs with those employed in elderly care (home care and nursing homes). Employees (n = 4955) in the county of Värmland, Sweden, were recruited between weeks 27 and 42 and tested for IgG antibodies against SARS-CoV-2. Serological results were combined with self-reported questionnaire data. IgG seroprevalence was 5.7% in the total group of HCWs, and was higher among those employed in hospital-based healthcare than among those working in elderly care (8.4% vs. 3.7%, p The difference in seroprevalence between HCWs in the two settings suggests that not only the profession but also factors in the workplace environment may be of importance. As all studied exposures were associated with IgG seropositivity, and asymptomatic infection was detected in 7.5% of participants, preventing outbreaks among HCWs is challenging. Adequate use of personal protective equipment when working with patients regardless of COVID-19 status, source control in situations with co-workers in which distancing is not possible, and routines enabling symptomatic staff to isolate pending PCR results are required to prevent healthcare-associated outbreaks of COVID-19.

Background Erythema migrans (EM) is the most common manifestation of Lyme borreliosis. Here, we examined EM patients in Norwegian general practice to find the proportion exposed to tick-transmitted microorganisms other than Borrelia, and the impact of co-infection on the clinical manifestations and disease duration. Methods Skin biopsies from 139/188 EM patients were analyzed using PCR for Neoehrlichia mikurensis, Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Follow-up sera from 135/188 patients were analyzed for spotted fever group (SFG) Rickettsia, A. phagocytophilum and Babesia microti antibodies, and tested with PCR if positive. Day 0 sera from patients with fever (8/188) or EM duration of ≥ 21 days (69/188) were analyzed, using PCR, for A. phagocytophilum, Rickettsia spp., Babesia spp. and N. mikurensis. Day 14 sera were tested for TBEV IgG. Results We detected no microorganisms in the skin biopsies nor in the sera of patients with fever or prolonged EM duration. Serological signs of exposure against SFG Rickettsia and A. phagocytophilum were detected in 11/135 and 8/135, respectively. Three patients exhibited both SFG Rickettsia and A. phagocytophilum antibodies, albeit negative PCR. No antibodies were detected against B. microti. 2/187 had TBEV antibodies without prior immunization. There was no significant increase in clinical symptoms or disease duration in patients with possible co-infection. Conclusions Co-infection with N. mikurensis, A. phagocytophilum, SFG Rickettsia, Babesia spp. and TBEV is uncommon in Norwegian EM patients. Despite detecting antibodies against SFG Rickettsia and A. phagocytophilum in some patients, no clinical implications could be demonstrated.

Rickettsia spp. can be found across the globe and cause disease of varying clinical severity, ranging from life-threatening infections with widespread vasculitis to milder, more localized presentations. Vector and, to some degree, reservoir are hematophagous arthropods, with most species harboured by ticks. In Denmark, rickettsiae are known as a cause of imported travel-related infections, but are also found endemically in ticks across the country. Data are, however, lacking on the geographical origin and clinical features of diagnosed cases. In this study, we have examined the travel history and clinical features of two groups of patients; 1) hospital-patients diagnosed with rickettsioses in the years 2010–2015 and 2) patients from primary health care (PHC) centers in Denmark having demonstrated anti-rickettsia antibodies in the years 2012–2015. The patients were identified using the Danish National Patient Registry (DNPR) and through the serological database at the State Serum Institute, where the laboratory diagnosis of rickettsioses is currently centralized. Data were collected for 86 hospital patients and 26 PHC center patients by reviewing hospital medical records and performing telephone interviews with PHC centers. Of the hospital patients, 91% (78/86) had a history of international travel 14 days prior to symptom start, with most having imported their infection from southern Africa, South Africa in particular (65%), and presenting with a clinical picture most compatible with African tick-bite fever caused by R. africae. Only two patients presented with a CRP > 100 mg/L and no mortalities were reported. At the PHC centers, most patients presented with mild flu-like symptoms and had an unknown (50%) or no history (19%) of international travel, raising the possibility of endemic rickettsioses. In view of our findings, rickettsioses do not appear to constitute a major public health problem in Denmark, with most cases being imported infections and potential endemic cases presenting as mild infections.

Tick-borne encephalitis (TBE) is a tick-borne infection with an increasing presence in many European countries. It is caused by the TBE virus (TBEV), a flavivirus transmitted by the Ixodes ricinus tick in northern Europe. In Denmark, the virus exists endemically on the island of Bornholm. However, a large proportion of Danish cases are also imported from Sweden, where the incidence of TBE has steadily been increasing during the last few decades. With the prospect of expanding risk areas due to climate change, TBE surveillance data exchange between countries could facilitate the identification of new TBEV microfoci and thereby aid healthcare workers in the issuing of vaccination recommendations. We present data from a collaborative effort between Denmark and Sweden on the surveillance of TBEV that resulted in the uncovering of a previously unrecognized possible TBEV microfocus in central Sweden.

Background Recombinant Interferon Alpha-2a (r-IFNα) is a potent immunomodulating agent, which has been used off-label for the treatment of polycythemia vera (PV) for more than three decades and has been demonstrated to induce high rates of clinical, hematological and molecular responses. Only few studies have compared efficacy and safety of r-IFNα vs. hydroxyurea (HU), which is considered first line therapy for PV patients > 60 years in most parts of the world. However, recent studies have provided encouraging results for the treatment of PV with r-IFNα compared to HU irrespective of age (R. Hoffmann 2016; H. Gisslinger 2018). Aims To examine the difference in efficacy and safety of low-dose r-IFNα in PV patients ≤ 60 or > 60 years of age compared to HU > 60 years of age. Methods Ninety newly diagnosed or previously phlebotomized PV patients only (WHO 2008) were enrolled in the DALIAH trial (NCT01387763). All patients provided written informed consent. Patients ≤ 60 years were randomized (I:I) to r-IFNα-2a (Pegasys®) or to r-IFNα-2b (PegIntron®) whereas patients > 60 years were randomized (I:I:I) to either r-IFNα-2a, r-IFNα-2b or to HU. The starting dose of r-IFNα-2a and r-IFNα-2b was 45 or 35 µg/week, respectively. The HU dose was 500 to 2000 mg/day. Patients randomized to r-IFNα who presented with major thrombosis or platelets > 1500 109/L received HU from inclusion and until normalization of the platelet count. Efficacy assessment consisted of the clinicohematological and the molecular response rates by intention to treat analysis (ITT) using the European Leukemia Net (ELN) 2009 criteria. JAK2V617F analysis was performed by qPCR. Groups were compared by Fisher's Exact Test. Results Three-year analysis was available in all but five patients (n=85) at time of abstract submission (Table 1). The analysis was performed after a median of 36 months (range: 33-39 months). The median treatment dose was 684 mg/day (IQR: 131 - 942) for HU, 51 μg/week (IQR: 30-90 μg/week) and 54 μg/week (IQR: 30-66 μg/week) for r-IFNα-2a age ≤ 60 and > 60, respectively, and 41 μg/week (IQR: 29-45 μg/week) and 36 μg/week (IQR: 31-37 μg/week) for r-IFNα-2b age ≤ 60 and > 60. The overall clinicohematological response rate (ORR) was 68% (13/19) for HU, 42% (14/33) for r-IFNα ≤ 60 years and 39% (13/33) for r-IFNα > 60 years. The partial clinicohematological response rate (PHR) and the complete clinicohematological response rate (CHR) was 53% (10/19) and 16% (3/19) for HU, 9% (3/33) and 33% (11/33) for r-IFNα ≤ 60 years and 9% (3/33) and 30% (10/33) for r-IFNα > 60 years. Neither the ORR, CHR nor the PHR was significantly different between the three groups. Maintenance of CHR from first occurrence to data analysis after 36 months was 11% (2/19) for HU, 21% (7/33) for r-IFNα ≤ 60 years and 18% (6/33) for r-IFNα > 60 years. Forty-seven JAK2V617F positive patients were available for molecular response analysis after 36 months of therapy. A partial molecular response (PMR) was detected in 21% (4/19) of HU treated patients and in 24% (7/29) of r-IFNα treated patients ≤ 60 years and 18% (6/33) of r-IFNα > 60 years. Notably, 7% (2/29) of the r-IFNα treated patients ≤ 60 years obtained a complete molecular response (CMR). The median JAK2V617F reduction from baseline was 38% (IQR: 31-63%) for HU, 79% (IQR: 59-92%) for r-IFNα ≤ 60 years and 73% (IQR: 49-97%) for r-IFNα > 60 years. There was no statistically significant difference in the PMR between groups. Discontinuation of treatment for any reason after 36 months of therapy was 21% (4/19) for HU, 52% (17/33) for r-IFNα ≤ 60 years and 45% (15/33) for r-IFNα > 60 years. Toxicity related discontinuation was 5% (1/19) for HU and 30% (10/33) for both r-IFNα ≤ 60 and > 60 years. Grade 3-4 AEs occurred in 32% (6/19) of HU treated patients, 27% (9/33) in r-IFNα treated patients ≤ 60 years and in 42% (14/33) r-IFNα treated patients > 60 years. SAEs were reported in 21% (4/19) for HU, 9% (3/33) for r-IFNα ≤ 60 years and 24% (8/33) for r-IFNα > 60 years. The numbers of grade 3-4 AEs as well as SAEs were comparable between groups. Conclusion After 36 months of therapy CHR was non-significantly higher in PV patients treated with r-IFNα compared to HU by ITT, irrespective of age. Also, maintenance of CHR was longer for r-IFNα. However, ORR was non-significantly higher for HU. PMR was almost similar between the three groups but the median JAK2V617F reduction was greater for r-IFNα. Toxicity related discontinuation from study therapy was higher for r-IFNα compared to HU. Disclosures Stentoft: Bristol-Myers Squibb: Research Funding; Merck Sharp&Dohme: Research Funding. Hasselbalch:Novartis: Research Funding.

The castor bean tick, Ixodes ricinus, is common in woodlands in most of Denmark. Besides Borrelia burgdorferi, it can harbour a number of pathogenic microorganisms such as tick-borne encephalitis virus, Anaplasma phagocytophilum, Rickettsia helvetica, Francisella tularensis, Candidatus Neoehrlichia mikurensis, Bartonella spp., Borrelia miyamotoi and Babesia spp. These tick-borne infections should be a differential diagnostic consideration during the tick season in Denmark. We review the distribution, clinical manifestations, diagnosis and treatment of these microorganisms.

Lyme borreliosis is an infection caused by the Borrelia burgdorferi sensu lato complex and transmitted by Ixodes ricinus ticks in Denmark. It can manifest itself in several different forms of which erythema migrans is the most common and is diagnosed by clinical assessment of the characteristic erythema. Laboratory support for the clinical diagnosis of other manifestations rests on the measurement of Borrelia-specific antibodies. Treatment is straight-forward with antibiotics such as penicillin. This paper reviews the clinical manifestations, diagnosis and treatment of this infection.

Despite the presence of several microorganisms, other than Borrelia burgdorferi sensu lato (Bbsl) and TBE virus, in Ixodes ricinus ticks from the Nordic countries, data is lacking on their pathogenic potential in humans. In this study, we wanted to investigate the aetiology and clinical manifestations of tick-transmitted infections in individuals seeking medical care following a tick-bite. The sampling frame was participants of a large-scale, prospective, multi-centre, follow-up study of tick-bitten volunteers recruited in Sweden, Finland and Norway in the years 2007-2015. Participants who sought medical care during the three-month follow-up period and from whom blood samples were collected during this healthcare visit (n=92) were tested, using PCR, for exposure to spotted fever group (SFG) Rickettsia spp., Anaplasma phagocytophilum and Babesia spp. Moreover, 86 of these individuals had two serum samples, collected three months apart, tested serologically for six tick-borne microorganisms. The selected organisms-Bbsl, SFG rickettsiae, Anaplasma phagocytophilum, TBE virus, Babesia microti and Bartonella henselae-have all been detected in field-collected ticks from the Nordic countries. Medical records were reviewed and questionnaires were completed to determine clinical manifestations. We found Lyme borreliosis to be the most common tick-transmitted infection as seen in 46 (54%) of the 86 participants with available medical records. Among the 86 participants with paired sera, serological or molecular evidence of recent exposure to other microorganisms than Bbsl could be demonstrated in eight (9%). Five participants (6%) exhibited serological evidence of recent concomitant exposure to more than one tick-borne microorganism. Clinical presentations were mild with one exception (TBE). In conclusion, our data suggest a low risk of infection with tick-borne microorganisms, other than Bbsl, in immunocompetent tick-bitten persons from the examined regions, a low occurrence of co-infection and mostly mild or no overt clinical signs of infection in immunocompetent persons exposed to the studied agents. Funding Agencies|EUEuropean Union (EU) [20200422]; Swedish Research Council Branch of MedicineSwedish Research Council [K2008-58X-14631-06-3]; Medical Research Council of Southeast Sweden; County Council of Ostergotland [LIO-56191]; Independent Research Fund Denmark [8020-00344B]; Wilhelm and Else Stockmann Foundation; Foundation for Aland Medical Research of the Aland Culture Foundation

Background: To investigate the role of genomics in determining response and resistance to front line treatment in MPN, we performed somatic mutational profiling of the DALIAH trial, a randomized controlled phase III trial of interferon versus hydroxyurea in newly diagnosed MPN patients. Methods: We performed genomic analyses on 202 pre-treatment primary MPN samples obtained from patients enrolled on the DALIAH trial (NCT01387763) and 135 samples obtained after 24 months of treatment. Genomic profiling comprised targeted next generation sequencing (NGS) of 100 genes, selected on the basis of their known or suspected involvement in the pathogenesis of myeloid malignancies, and 1609 informative single nucleotide polymorphisms (SNPs) on chromosome 9p. Clinicohematological response was determined by central review using ELN 2009 (ET, PV and pre-MF) and EUMNET 2005 (PMF) criteria. We evaluated the association of somatic mutations with clinical parameters and with attainment of clinicohematological complete response (CR) at 24 months. Results: Prior to treatment, 191 of 202 (95%) patients had somatic mutations, including 93% with canonical MPN phenotypic drivers: JAK2 (74%), CALR (14%), and MPL (5%). Among those with JAK2 mutations 37% had JAK2 copy-neutral loss of heterozygosity (JAK2 CN-LOH). Patients with PV were more likely to have JAK2 CN-LOH (p = 0.0001) as compared with patients with other MPN subtypes. At baseline, patients with JAK2 CN-LOH had significantly higher hemoglobin (p = 0.0001), higher white blood cell count (WBC, p = 0.002) and lower platelet count (p=0.0001) than patients without JAK2 CN-LOH. Mutations in TET2 (24%), DNMT3A (16%), and ASXL1 (10%) were the most frequent co-occurring non-MPN phenotypic driver mutations and they occurred across all MPN subtypes. In addition, 5% of patients had spliceosome gene mutations, and 6% had mutations in genes involved in RAS/MAPK signaling. Patients with TET2, DNMT3A or ASXL1 mutations were significantly older than patients without these mutations (p= 0.0001) and there was a significant association between the presence of a TET2, DNMT3A or ASXL1 mutation and prior stroke (p = 0.004). There were no other significant associations between somatic mutation status and baseline clinical characteristics. The probability of attaining clinicohematological CR at 24 months was independent of baseline somatic mutations. Among patients with JAK2 mutations who remained on interferon treatment at 24 months, those with CR had a greater reduction in mean variant allele fraction (VAF) (28% to 8%, p Among patients who remained on treatment for 2 years, 44 mutations in 35 patients were newly detected or expanded on serial sampling. DNMT3A mutations were the most frequently acquired, accounting for 41% of new mutations. ASXL1, TET2, PPM1D, TP53, IDH2, and CBL mutations were also recurrently acquired. 97% of patients who acquired new mutations were JAK2-mutant. Among those with acquired DNMT3A mutations, 85% were treated with interferon, and 23% had CR at 24 months. Among those that acquired non-DNMT3A mutations, 38% were treated with interferon and 47% had CR at 24 months. The VAF of newly detected mutations was low (median 1.5%), and half of the patients with newly acquired mutations had at least 50% reduction in JAK2V617F VAF, suggesting that new mutations could either have arisen independently or be subclonal to the dominant JAK2-mutant clone. Conclusions: Using sequential genomic analyses of a phase III clinical trial of interferon versus hydroxyurea in MPN patients, we found mutation-specific and treatment-specific patterns of response. We uncovered distinct patterns of response to interferon in JAK2-mutant MPN as compared with CALR-mutant MPN. We found that DNMT3A mutations were the most frequent acquired mutations at 24 months and that these were enriched in patients treated with interferon. In aggregate, these results provide insights into molecular response and resistance to interferon and inform the clinical use of interferon in MPN patients. Disclosures Hansen: Alexion: Research Funding. Neuberg:Pharmacyclics: Research Funding; Madrigal Pharmaceuticals: Equity Ownership; Celgene: Research Funding. Hasselbalch:Novartis: Research Funding; AOP Orphan Pharmaceuticals: Other: Data monitoring board. Lindsley:Jazz Pharmaceuticals: Research Funding; Takeda Pharmaceuticals: Consultancy; Medlmmune: Research Funding. Mullally:Janssen: Research Funding.

BACKGROUND: The number of hematological malignancies is expected to increase as the Danish population ages within the next few decades. Despite this, data on the course of hematological cancers among the oldest patients are sparse with many intervention studies focusing on younger age groups. The aim of this study is to present Danish incidence and mortality rates among older patients with non-Hodgkin lymphomas (NHL), multiple myeloma (MM), chronic lymphocytic leukemia (CLL), and acute myeloid leukemia (AML).MATERIAL AND METHODS: Nationwide population-based study presenting the incidence, prevalence and mortality rates of NHL, MM, and AML with a focus on the elderly population in Denmark during the last few decades. Data were drawn from the NORDCAN database.RESULTS: Incidence rates of NHL, MM, CLL and AML were 10-50 times higher among the population aged 70 years or more than among the younger population. An increasing incidence with stable or decreased mortality rates was seen mainly among elderly patients with NHL during the last few decades, leading to increased survival and a greater prevalence of patients with NHL. Increased relative survival and prevalence could also be seen among elderly patients with MM and CLL, while the trends of the incidence rates were inconclusive for these diseases. Survival among patients with AML improved most notably in those aged below 70 years leading to an increased prevalence of AML patients predominantly in this age group.CONCLUSION: Improvements in diagnostics and treatment have led to increased survival and therefore prevalence of elderly patients with NHL, MM, CLL and AML during the past decades.

Patients with the classical Philadelphia chromosome-negative chronic myeloproliferative neoplasms including essential thrombocythemia, polycythemia vera and primary myelofibrosis often suffer from comorbidities, in particular, cardiovascular diseases and thrombotic events. Apparently, there is also an increased risk of osteoporotic fractures among these patients. However, the true prevalence, mechanisms involved and therapeutic implications are not well described. In this review, we summarize what is currently known about possible associations between bone disease and chronic myeloproliferative neoplasms. Chronic inflammation has been suggested to explain the initiation of clonal development and progression in chronic myeloproliferative neoplasms. Decreased bone mineral density and enhanced fracture risk are well-known manifestations of many chronic systemic inflammatory diseases. As opposed to systemic mastocytosis (SM) where pathogenic mechanisms for bone manifestations probably involve effects of mast cell mediators on bone metabolism, the mechanisms responsible for increased fracture risk in other chronic myeloproliferative neoplasms are not known.

The chaperone and calcium storing protein calreticulin is coded by CALR, and newly identified mutations in CALR are found in respectively 49-70% and 56-88% of JAK2- and MPL-negative patients with essential thrombocytaemia (ET) and primary myelofibrosis (PMF). A total of 41 mutations have been identified, all located to exon 9 which codes the protein's C-terminal. CALR mutations are present only in myeloid malignancies and confer a more indolent disease than JAK2-mutated ET and PMF. CALR mutations as a diagnostic and prognostic tool are promising and the mutations are potential targets for immune therapy.

Polycythaemia vera, essential thrombocytosis and primary myelofibrosis are closely related, clonal myeloproliferative neoplasms. Our knowledge of the underlying molecular mechanisms driving these diseases has increased dramatically during the latest ten years. Traditionally, treatment of these malignancies has focused on lowering their inherent thromboembolic risk but with the discovery of the JAK2-V617F mutation and most recently the calreticulin mutations new therapeutic options such as interferon-alpha, JAK2-inhibitors and statins are being contemplated. This article reviews these new treatment options.

Background Treatment of Philadelphia chromosome negative chronic myeloproliferative neoplasms (MPNs) with recombinant pegylated interferon alpha2a/b (rIFN-alpha) has proven effective. It is well known that prolonged therapy with recombinant type 1 interferons (IFN-alpha and IFN-beta) may induce neutralizing antibodies (nAbs) against the drug leading to treatment failure. Most data on type 1 IFN immunogenicity are available from studies of patients with multiple sclerosis treated with rIFN-beta, and patients with hepatitis C treated with rIFN-alpha. A few reports have demonstrated nAbs in MPN patients not responding adequately to rIFN-alpha treatment, but the phenomenon has not been thoroughly investigated in MPNs. Patients and Methods Newly diagnosed patients with MPNs enrolled in the Danish multicenter trial - DALIAH (Low-dose rIFN-alpha versus Hydroxyurea in The Treatment of Ph-Negative MPNs) were included. Patients were randomized to treatment with either rIFN-alpha 2a or 2b at a starting dose of 45 and 35 mikrograms once weekly, respectively. The occurrence of neutralizing Abs (nAbs) against rIFN-alpha was investigated at baseline, month 12 and month 24 by reporter gene assays (iLiteTM alphabeta and iLiteTM antialpha, Biomonitor A/S, Copenhagen, Denmark). JAK2 V617F quantitative mutation analyses were performed as previously described (Larsen TS, BJH 2007). Statistical analyses were performed using STATA version 9.0. Results Ninety-two patients on sustained treatment with rIFN-alpha2a (n=48) and rIFN-alpha2b (n=44) for 12 months were analyzed for this study. Forty-five patients had ET, 39 patients had PV and 8 patients had proliferative PMF. Thirty-six out of 39 (92%) PV patients, 22 out of 45 (49%) ET patients and 4 out of 8 (50%) PMF patients were JAK2V617F mutated. Hematological responses at 12 months: ET: 67% CR, 29 % PR; PV: 64% CR, 31% PR (ELN 2009 criteria); PMF: 50% had at least a minor response (EUMNET). The median serum concentration of bioactive IFN-alpha at 12 months was 12,4 (range Conclusions Development of nAbs in MPN patients completing treatment for 12 months with rIFN-alpha seems exceedingly rare as no patients, neither complete responders nor patients not meeting criteria for complete hematological remission developed nAbs after 12 (24) months of therapy. Its apparent rarity does not justify a routine investigation of nAbs in patients not responding to rIFN-alpha treatment. There was no significant correlation between serum concentration of rIFN-alpha 2a and -2b and clinical or molecular responses. The intriguing finding that one of 24 patients had pre-existing cross reacting nAbs against rIFN-alpha 2a and 2b before commencing rIFN-alpha treatment is interesting and was associated with an insufficient response. Disclosures Off Label Use: Recombinant interferon-alpha 2a and -2b in the treatment of chronic Philadelphia-negative myeloproliferative neoplasms.. El Fassi:Novartis Denmark: Honoraria, Other: Have conducted an educational session for Novartis Denmark, regarding MPNs and ruxolitinib, for this a honorarium was received.. Bjerrum:Bristoll Myers Squibb, Novartis and Pfizer: Other: educational activities. Hasselbalch:Novartis: Research Funding. Bendtzen:Pfizer: Honoraria; Eurodiagnostica AB: Equity Ownership; Novo-Nordisk: Equity Ownership.

A 33-year-old man treated with azathioprine for 12 years for Crohn's disease presented with headache, nausea and vomiting accompanied by difficulty in putting words together and slight mental confusion. Prednisolone and antibiotics were without effect. MRI of the brain showed multiple focal lesions with surrounding oedema. There was cerebrospinal fluid pleocytosis, and Epstein-Barr virus (EBV) DNA was detected in the spinal fluid by PCR. A brain biopsy confirmed the suspicion of primary brain lymphoma. EBV-associated primary brain lymphoma is a relevant differential diagnosis in patients with long-standing immune suppression presenting with neurological symptoms. Detection of EBV DNA in the spinal fluid together with characteristic radiological findings may serve as a diagnostic clue for a quick diagnosis.

The chaperone and calcium storing protein calreticulin is coded by CALR, and newly identified mutations in CALR are found in respectively 49-70% and 56-88% of JAK2- and MPL-negative patients with essential thrombocytaemia (ET) and primary myelofibrosis (PMF). A total of 41 mutations have been identified, all located to exon 9 which codes the protein's C-terminal. CALR mutations are present only in myeloid malignancies and confer a more indolent disease than JAK2-mutated ET and PMF. CALR mutations as a diagnostic and prognostic tool are promising and the mutations are potential targets for immune therapy.