Clinical immunogenicity outcomes from GENEr8-1, a phase 3 study of valoctocogene roxaparvovec, an AAV5-vectored gene therapy for hemophilia A.

Gene transfer therapies utilizing adeno-associated virus (AAV) vectors involve a complex drug design with multiple components that may impact immunogenicity. Valoctocogene roxaparvovec is an AAV serotype 5 (AAV5)-vectored gene therapy for the treatment of hemophilia A that encodes a B-domain-deleted human factor VIII (FVIII) protein controlled by a hepatocyte-selective promoter. Following previous results from the first-in-human phase 1/2 clinical trial, we assessed AAV5-capsid- and transgene-derived FVIII-specific immune responses with 2 years of follow-up data from GENEr8-1, a phase 3, single-arm, open-label study in 134 adult men with severe hemophilia A. No FVIII inhibitors were detected following administration of valoctocogene roxaparvovec. Immune responses were predominantly directed toward the AAV5 capsid, with all participants developing durable anti-AAV5 antibodies. Cellular immune responses specific for the AAV5 capsid were detected in most participants by interferon-γ enzyme-linked immunosorbent spot assay 2 weeks following dose administration and declined or reverted to negative over the first 52 weeks. These responses were weakly correlated with alanine aminotransferase elevations and showed no association with changes in FVIII activity. FVIII-specific cellular immune responses were less frequent and more sporadic compared with those specific for AAV5 and showed no association with safety or efficacy parameters.

Patient reported quality of life in young adults with sarcoma receiving care at a sarcoma center.

Background: Sarcomas are a diverse group of neoplasms that vary greatly in clinical presentation and responsiveness to treatment. Given the differences in the sites of involvement, rarity, and treatment modality, a multidisciplinary approach is required. Previous literature suggests patients with sarcoma suffer from poorer quality of life (QoL) especially physical and functional wellbeing. Adolescent and young adult (AYA) patients are an underrepresented population in cancer research and have differing factors influencing QoL. Methods: Retrospective analysis of Young Adult patients (age 18-39) enrolled in the Sarcoma Tissue Repository at University of Iowa. QoL was assessed using the self-report FACT-G questionnaire at enrollment and 12 months post-diagnosis; overall scores and the 4 wellbeing subscales (Physical, Emotional, Social, Functional) were calculated. Linear mixed effects models were used to measure the association between the rate of change in FACT-G subscale scores and baseline clinical, comorbidity, and treatment characteristics. Results: 49 patients were identified. 57.1% of patients had a malignancy involving an extremity. Mean FACT-G scores of overall wellbeing improved from baseline to 12 months (76.4 vs. 85.4, p < 0.01). Social and emotional wellbeing did not differ significantly between baseline and 12 months. Physical wellbeing (18.8 vs. 23.9, p < 0.01) and functional wellbeing (16.8 vs. 20.0, p< 0.01) scores improved from baseline to 12 months. No difference was seen for FACT-G overall scores for age, sex, laterality, marital status, performance status, having children, clinical stage, limb surgery, chemotherapy, or tumor size. A difference was demonstrated in physical wellbeing scores for patients with baseline limitation (ECOG 1-3) compared to those with no baseline limitation (ECOG 0) (p = 0.03). A difference was demonstrated in social wellbeing based on anatomical site (p = 0.02). Conclusion: Young adults with sarcoma treated at a tertiary center had improvements in overall reported QoL at 12 months from diagnosis. Overall baseline QoL scores on FACT-G were lower than the general adult population for YA patients with sarcoma but at 12 months became in line with general population norms. The improvements seen merit further investigation to evaluate how these change over the continuum of care. Quality of life changes may be useful outcomes of interest in sarcoma trials.

Associated comorbidities, healthcare utilization & mortality in hospitalized patients with haemophilia in the United States: Contemporary nationally representative estimates.

INTRODUCTION: Current in-hospital burden and healthcare utilization patterns for persons with haemophilia (PWH) A and B, including both children (ages < 18 years) and adults (ages ≥ 18 years), in the United States (US) are lacking. AIM: To evaluate healthcare utilization, the prevalence of comorbidities, and mortality in hospitalized paediatric and adult PWH using a contemporary nationally representative cohort. METHODS: Hospitalizations of PWH either as the primary reason for admission (principal diagnosis) or one of all listed diagnoses were identified using ICD-10 codes from the 2017 Nationwide Inpatient Sample (NIS), the largest publicly available all-payer inpatient discharge database in the US. Sampling weights were applied to generate nationally representative estimates. RESULTS: The contemporary cohort included 10,555 hospitalizations (paediatrics, 18.3%; adults, 81.7%) among PWH as one-of-all listed diagnoses (n = 1465 as principal diagnosis). Median age (interquartile range) was 46 (24-66) years overall; adults, 54 (35-70) years and paediatric, 4 (1-11). The most common comorbidities in adults were hypertension (33.4%), hyperlipidaemia (23.6%), and diabetes (21.1%). In children, hemarthrosis (11.4%), contusions (9.6%), and central line infections (9.3%) were the most common. The overall mortality rate was 2.3%. Median hospital charges per haemophilia admission were $52,616 ($24,303-$135,814) compared to $26,841 ($12,969-$54,568) for all-cause admissions in NIS. CONCLUSION: Bleeding and catheter-related infections are the significant reasons for paediatric haemophilia admissions. Adult haemophilia admissions tend to be associated with age-related comorbidities. Costs for haemophilia-related hospitalizations are higher than the national average for all-cause hospitalizations.

Perspectives on Follicular Lymphoma Treatment From New and Experienced Clinicians: New, Old, & Old Is New

Jonathan R. Day, MD, PharmD, and Brian K. Link, MD, give their perspective on emerging treatments for follicular lymphoma.

Epidemiology of Hospitalized Patients with Babesiosis, United States, 2010-2016.

Babesia spp. are tickborne parasites that cause the clinical infection babesiosis, which has an increasing incidence in the United States. We performed an analysis of hospitalizations in the United States during 2010-2016 in which babesiosis was listed as a diagnosis. We used the National Inpatient Sample database to characterize the epidemiology of Babesia-associated admissions, reflecting severe Babesia-related disease. Over a 7-year period, a total of 7,818 hospitalizations listed babesiosis as a primary or secondary admitting diagnosis. Hospitalizations were seasonal (71.2% occurred during June-August) and situated overwhelmingly in the Northeast and Midwest. The patients were predominantly male and of advanced age, which is consistent with the expected epidemiology. Despite a higher severity of illness in more than (58.5%), the mortality rate was low (1.6%). Comparison with state reporting data suggests that the number of hospitalized persons with babesiosis increased modestly during the observation period.

Evidence of feedback regulation of C-type natriuretic peptide during Vosoritide therapy in Achondroplasia.

Evidence from genetic disorders of CNP signalling suggests that plasma concentrations of CNP are subject to feedback regulation. In subjects with Achondroplasia (Ach), CNP intracellular activity is suppressed and plasma concentrations are raised but the therapeutic impact of exogenous CNP agonists on endogenous CNP is unknown. In this exploratory dose finding and extension study of 28 Ach children receiving Vosoritide over a 5 year period of treatment, endogenous CNP production was assessed using measurements of plasma aminoterminal proCNP (NTproCNP) adjusted for age and sex and normalised as standard deviation score (SDS), and then related to skeletal growth. Before treatment NTproCNP SDS was raised. Within the first 3 months of accelerating growth, levels were significantly reduced. Across the 5 years of sustained growth, levels varied widely and were markedly increased in some subjects during adolescence. Plasma NTproCNP was suppressed at 4 h post-injection in proportion to the prevailing level of hormone resistance as reflected by SDS before injection. We conclude CNP remains subject to regulation during growth promoting doses of Vosoritide. Fall in CNP during accelerating growth is consistent with an indirect feedback whereas the fall at 4 h is likely to be a direct effect from removal of intra cellular CNP resistance.

Safe and persistent growth-promoting effects of vosoritide in children with achondroplasia: 2-year results from an open-label, phase 3 extension study.

PURPOSE: Achondroplasia is caused by pathogenic variants in the fibroblast growth factor receptor 3 gene that lead to impaired endochondral ossification. Vosoritide, an analog of C-type natriuretic peptide, stimulates endochondral bone growth and is in development for the treatment of achondroplasia. This phase 3 extension study was conducted to document the efficacy and safety of continuous, daily vosoritide treatment in children with achondroplasia, and the two-year results are reported. METHODS: After completing at least six months of a baseline observational growth study, and 52 weeks in a double-blind, placebo-controlled study, participants were eligible to continue treatment in an open-label extension study, where all participants received vosoritide at a dose of 15.0 µg/kg/day. RESULTS: In children randomized to vosoritide, annualized growth velocity increased from 4.26 cm/year at baseline to 5.39 cm/year at 52 weeks and 5.52 cm/year at week 104. In children who crossed over from placebo to vosoritide in the extension study, annualized growth velocity increased from 3.81 cm/year at week 52 to 5.43 cm/year at week 104. No new adverse effects of vosoritide were detected. CONCLUSION: Vosoritide treatment has safe and persistent growth-promoting effects in children with achondroplasia treated daily for two years.

Characteristics of dyspnoea and associated clinical outcomes in the CHAMPION PHOENIX study.

Dyspnoea may be induced by some reversibly-binding P2Y12 inhibitors, including cangrelor and ticagrelor. Dyspnoea was not associated with any compromise to the efficacy of ticagrelor in the PLATO study. The CHAMPION PHOENIX study (NCT01156571) compared initial treatment with cangrelor versus initial treatment with clopidogrel in patients undergoing PCI. We investigated the incidence, characteristics, and associated clinical outcomes in patients with dyspnoea in CHAMPION PHOENIX. Adverse events (AEs) of dyspnoea to 48 hours were recorded in patients randomised to cangrelor or clopidogrel in CHAMPION PHOENIX. The composite primary endpoint of death, myocardial infarction, ischaemia-driven revascularisation, or stent thrombosis as well its individual components were assessed in patients who did or did not report dyspnoea. A total of 68 (1.2 %) cangrelor-treated patients and 18 (0.3 %) clopidogrel-treated patients reported dyspnoea (p<0.001). Most dyspnoea events in cangrelor-treated patients were considered mild (71 %) or moderate (28 %) and only one event was considered severe and led to discontinuation of cangrelor. The dyspnoea events in the clopidogrel-treated patients were mild (78 %) or moderate (22 %). Characteristics of dyspnoea were consistent with those seen in the CHAMPION programme as a whole. In the modified intention-to-treat population, rates of the composite primary outcome and its individual components were not affected by the presence of dyspnoea in cangrelor-treated patients. Cangrelor-related dyspnoea is transient, usually mild or moderate, and unlikely to lead to discontinuation of therapy. The occurrence of dyspnoea does not seem to be associated with any reduction in the efficacy of cangrelor compared with clopidogrel as initial therapy in PCI patients.

Patient-centered care as value-added service by compounding pharmacists.

The term "value-added" is widely used to describe business and professional services that complement a product or service or that differentiate it from competing products and services. The objective of this study was to determine compounding pharmacists' self-perceptions of the value-added services they provide. A web-based survey method was used. Respondents' perceptions of their most important value-added service frequently fell into one of two categories: (1) enhanced pharmacist contribution to developing and implementing patient therapeutic plans and (2) providing customized medications of high pharmaceutical quality. The results were consistent with a hybrid community clinical practice model for compounding pharmacists wherein personalization of the professional relationship is the value-added characteristic.

Effect of cangrelor on periprocedural outcomes in percutaneous coronary interventions: a pooled analysis of patient-level data.

BACKGROUND: Cangrelor is a potent, rapid-acting, reversible intravenous platelet inhibitor that was tested for percutaneous coronary intervention (PCI) in three large, double-blind, randomised trials. We did a pooled analysis of data from three trials that assessed the effectiveness of cangrelor against either clopidogrel or placebo in PCI. METHODS: This prespecified, pooled analysis of patient-level data from three trials (CHAMPION-PCI, CHAMPION-PLATFORM, and CHAMPION-PHOENIX) compared cangrelor with control (clopidogrel or placebo) for prevention of thrombotic complications during and after PCI. Trial participants were patients undergoing PCI for ST-elevation myocardial infarction (11.6%), non-ST-elevation acute coronary syndromes (57.4%), and stable coronary artery disease (31.0%). Efficacy was assessed in the modified intention-to-treat population of 24,910 patients, with a prespecified primary efficacy composite of death, myocardial infarction, ischaemia-driven revascularisation, or stent thrombosis at 48 h. The primary safety outcome was non-coronary artery bypass graft-related GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) severe or life-threatening bleeding at 48 h. FINDINGS: Cangrelor reduced the odds of the primary outcome by 19% (3.8% for cangrelor vs 4.7% for control; odds ratio [OR] 0.81, 95% CI 0.71-0.91, p=0.0007), and stent thrombosis by 41% (0.5% vs 0.8%, OR 0.59, 95% CI 0.43-0.80, p=0.0008). Cangrelor reduced the odds of the secondary triple composite (all-cause death, myocardial infarction, or ischaemia-driven revascularisation at 48 h) by 19% (3.6% vs 4.4%, OR 0.81, 95% CI 0.71-0.92, p=0.0014). Efficacy outcomes were consistent across the trials and main patient subsets. These benefits were maintained at 30 days. There was no difference in the primary safety outcome (0.2% in both groups), in GUSTO moderate bleeding (0.6% vs 0.4%), or in transfusion (0.7% vs 0.6%), but cangrelor increased GUSTO mild bleeding (16.8% vs 13.0%, p<0.0001). INTERPRETATION: Compared with control (clopidogrel or placebo), cangrelor reduced PCI periprocedural thrombotic complications, at the expense of increased bleeding. FUNDING: The Medicines Company.

Advanced laboratory techniques for sample processing and immunolabeling using microwave radiation.

A better understanding of improved microwave technology has increased the benefits and versatility of the technique as it applies to all aspects of immunohistochemistry. The role of continuous magnetron power output (wattage) combined with precise control of sample heating demonstrated their significance to complex labeling protocols. Here, we present results for microwave-assisted formaldehyde fixation and its effect on GFP expression in transfected HeLa cells. Rat brain sections and cultured hippocampal cells were labeled with 11 different primary antibodies using a unified microwave protocol. Microwave-assisted immunohistochemistry made it possible to sequentially label tissues and cells with several primary antibodies in a very short period of time with excellent labeling characteristics.

Aprotinin inhibits proinflammatory activation of endothelial cells by thrombin through the protease-activated receptor 1.

OBJECTIVE: Thrombin is generated in significant quantities during cardiopulmonary bypass and mediates adverse events, such as platelet aggregation and proinflammatory responses, through activation of the high-affinity thrombin receptor protease-activated receptor 1, which is expressed on platelets and endothelium. Thus antagonism of protease-activated receptor 1 might have broad therapeutic significance. Aprotinin, used clinically to reduce transfusion requirements and the inflammatory response to bypass, has been shown to inhibit protease-activated receptor 1 on platelets in vitro and in vivo. Here we have examined whether aprotinin inhibits endothelial protease-activated receptor 1 activation and resulting proinflammatory responses induced by thrombin. METHODS: Protease-activated receptor 1 expression and function were examined in cultured human umbilical vein endothelial cells after treatment with alpha-thrombin at 0.02 to 0.15 U/mL in the presence or absence of aprotinin (200-1600 kallikrein inhibitory units/mL). Protease-activated receptor 1 activation was assessed by using an antibody, SPAN-12, which detects only the unactivated receptor, and thrombin-mediated calcium fluxes. Other thrombin-dependent inflammatory pathways investigated were phosphorylation of the p42/44 mitogen-activated protein kinase, upregulation of the early growth response 1 transcription factor, and production of the proinflammatory cytokine interleukin 6. RESULTS: Pretreatment of cultured endothelial cells with aprotinin significantly spared protease-activated receptor 1 receptor cleavage (P < .0001) and abrogated calcium fluxes caused by thrombin. Aprotinin inhibited intracellular signaling through p42/44 mitogen-activated protein kinase (P < .05) and early growth response 1 transcription factor (P < .05), as well as interleukin 6 secretion caused by thrombin (P < .005). CONCLUSIONS: This study demonstrates that endothelial cell activation by thrombin and downstream inflammatory responses can be inhibited by aprotinin in vitro through blockade of protease-activated receptor 1. Our results provide a new molecular basis to help explain the anti-inflammatory properties of aprotinin reported clinically.

Effect of aprotinin and recombinant variants on platelet protease-activated receptor 1 activation.

BACKGROUND: Thrombin generated during cardiopulmonary bypass activates the high-affinity thrombin receptor, protease-activated receptor 1 (PAR1), causing platelet dysfunction and excessive bleeding. The serine protease inhibitor aprotinin protects platelets against thrombin-mediated PAR1 activation in vitro and in vivo. Here we have investigated three novel recombinant aprotinin variants with specific modifications to the active site lysine at amino acid position 15 (arginine-15, arginine-15-alanine-17, and valine-15-leucine-17) for their effect on PAR1-mediated platelet aggregation in vitro. METHODS: Aggregation studies were carried out using washed human platelets (n = 9) or platelet rich plasma (n = 7) from healthy volunteers activated with 1 or 5 nM thrombin. Recombinant aprotinin variants were used at the molar equivalent to 50 KIU/mL of the parent compound. The PAR1-specific antagonist peptide, FLLRN, was used at 500 microM. RESULTS: Platelet aggregation at low concentrations of thrombin (1 nM) was mediated exclusively through PAR1, as shown by inhibition of aggregation in the presence of FLLRN. At 1 nM thrombin, the mean percentage +/- SD aggregation of washed platelets was 68.6% +/- 12.3%. This was suppressed by each aprotinin variant at the 50 KIU/mL equivalent dose: arginine-15 (23.0% +/- 17.5%, p < 0.001); arginine-15-alanine-17 (33.3% +/- 22.9%, p < 0.01); aprotinin (37.5% +/- 19.4%, p < 0.05); valine-15-leucine-17 (50.0% +/- 16.1%, not significant)). At 5 nM thrombin, which activates both high (PAR1) and low-affinity (PAR4) thrombin receptors on platelets, FLLRN and aprotinin failed to block aggregation: this finding indicates that aprotinin selectively targeted PAR1. In platelet-rich plasma, aggregation at 1 nM thrombin was 77.1% +/- 10.0%, and this was inhibited in the following order: arginine-15 (30.1% +/- 9.6%, p < 0.001); arginine-15-alanine-17 (52.3% +/- 9.7%, p > 0.001); aprotinin (55.9% +/- 6.2%, p > 0.001); valine-15-leucine-17 (73.7% +/- 7.1%, not significant). CONCLUSIONS: Aprotinin variants differentially inhibit PAR1-mediated platelet aggregation. With more understanding of the mechanisms of action of aprotinin and its derivatives, safer and more efficacious aprotinin variants may become available for clinical use.

Microwave-assisted immunostaining: a new approach yields fast and consistent results.

Advances in microwave technology permitted the development of new antigen labeling techniques. The recent microwave development of a true variable wattage unit designed for laboratory use and an apparatus for dampening standing wave radiation patterns have allowed investigators to better control the conditions within a microwave cavity. Thus, operating limits thought to be endemic to microwave-assisted protocols could be effectively mitigated. Standard protocols for histochemistry call for prolonged incubations and numerous rinses that add considerable time to the procedure. Here, we present microwave-assisted staining protocols for floating rat brain sections and cultured rat hippocampal cells. Acetylcholinesterase (ACHE) histochemistry and immunocytochemistry were conducted inside a specially designed and configured laboratory microwave oven. As a control additional tissue sections were stained on the bench and treated in the same manner as those in the microwave. Labeling was minimal in the control tissue, but specific, high contrast staining was present in the microwave group. Tissues were evenly stained with minimal background, and anatomical structures were easily detected. Also, the differences between lesioned and intact sides of the brain were obvious and agreed with previous observations. Microwave-assisted methods resulted in significantly shorter protocol times (approximately 10-fold) resulting in staining patterns of equal or superior quality to those obtained using conventional methods.

Seven cDNAs enriched following hippocampal lesion: possible roles in neuronal responses to injury.

Synaptic plasticity is important for formation of long-term memories and in re-establishment of function following injury. Seven cDNAs enriched following lesion in the hippocampus of the rat have been isolated using a PCR-based cDNA suppression subtraction hybridization. Sequence analysis resulted in the identification of two genes with known roles in synaptic development and neuronal activities: astrotactin and calcineurin. These two neuron-specific genes have established roles in development or synaptogenesis. Sequence analysis of the other five additional genes shows that two are likely to be involved in G-protein signaling pathways, one is a WD repeat protein, and the remaining two are entirely novel. All seven candidates are expressed in the hippocampus and, in some cases, cortical layers of adult brains. RT-PCR data show that expression increases following synaptogenic lesion. Immunocytochemical analysis in primary hippocampal neurons showed that Calcineurin immunoreactivity was redistributed in neurons during 2 weeks in culture. This redistribution suggests that Calcineurin's role changes during neurite outgrowth immediately prior to synapse formation in vitro. In addition, inhibiting Calcineurin activity with cyclosporin A enhanced neurite outgrowth, suggesting that Calcineurin has a regulatory role in axon sprouting. The discovery of previously unknown genes involved in the response to neurodegeneration will contribute to our understanding of neural development, responses to CNS trauma, and neurodegenerative diseases.

Castleman's disease associated with myasthenia gravis.

Castleman's disease presents as a peculiar type of lymph node hyperplasia. Traditionally, the disease has been classified on clinical grounds (solitary or multicentric) and by histologic appearance (hyaline vascular pattern, plasma cell predominance, or mixed lesions). It is now increasingly clear that there are different etiologies for each of these different subtypes. Reported associations include POEMS syndrome (polyneuropathy, organomegally, endocrinopathy, monoclonal gammopathy, and skin changes), paraneoplastic pemphigus, Hodgkin's disease, and follicular dendritic cell sarcoma. We present a case of Castleman's disease associated with myasthenia gravis, the third reported case in the literature. We discuss Castleman's disease and review the literature.

Gene expression of transferrin and transferrin receptor in brains of control vs. iron-deficient rats.

The mechanism of the regulation of transferrin (Tf) and transferrin receptor (TfR) levels in rat brain by dietary iron status is not fully elucidated. We examined Tf and TfR protein and mRNA contents in various brain regions affected by dietary iron deficiency, and analyzed the relationships between protein and mRNA contents in brains of control vs. iron-deficient rats. In a region-specific fashion, iron-deficient diet decreased significantly brain iron concentration by 22-63%, and increased Tf level by 22-130% and TfR level by 74% in thalamus and 40% in cortex. Tf mRNA content decreased by 20-50% in most brain regions demonstrating inverse correlation of Tf and its mRNA in response to iron deficiency. TfR mRNA levels remained unaffected by iron status. The corpus callosum, white matter of the cerebellum and lateral ventricles expressed highest levels of Tf mRNA, whereas TfR mRNA levels was lowest in these regions, but highest in cortex, hippocampus, and the gray matter of the cerebellum. The data demonstrate that the cells in brain have the capacity to maintain minimum iron levels during iron deficiency. This capacity may be associated with increased iron-Tf uptake from plasma, stabilization of TfR mRNA, or increased Tf mRNA translation efficiency in specific cell types within the brain.

Heparin-induced hyperkalemia after cardiac surgery.

Surgeons are increasingly faced with patients suffering from complicated pathology in multiple organ systems, to which multiple therapeutic agents with complex adverse effects are often prescribed. We face a daily challenge in maintaining an up-to-date knowledge of these complications. Heparin is widely used in surgical practice, yet our awareness of its adverse effects, other than bleeding and thrombocytopenia, remains poor. We will present an example of heparin-induced hyperkalemia following administration for cardiopulmonary bypass and intraaortic balloon pump prophylaxis. This is a rare but serious complication of heparin therapy, not usually reported in the context of a cardiac surgical patient. We will also discuss the renal physiology leading to hyperkalemia and the options available for its management.

H and L ferritin subunit mRNA expression differs in brains of control and iron-deficient rats.

The mRNA expression of ferritin subunits has not been studied thoroughly in the brain regions of iron-deficient rats. Sprague-Dawley rats (n = 26; 21 d old) were randomly assigned to an iron-deficient (3.5 mg Fe/kg diet) or a control diet (35 mg Fe/kg diet) for 6 wk. Ferritin protein and mRNA contents were quantified and the cellular expression of ferritin subunits in brain was determined. H and L ferritin had the same mRNA locations in nearly all brain regions. Both ferritin subunit mRNAs had heterogeneous distributions and there was a regional effect across brain regions. Iron deficiency did not affect the amount of ferritin mRNA in most brain regions, suggesting the post-transcriptional regulation of messengers by iron status. H ferritin protein was predominant in neurons and oligodendrocytes, whereas L ferritin protein and iron predominated in microglia cells and astrocytes as well as in oligodendrocytes and neurons. Ferritin mRNA was detectable only in neurons. Iron deficiency did not induce new types of cells containing either ferritin protein or mRNA. The fact that ferritin protein was found in four types of cells whereas mRNA was found in only one type of cell suggests that the site of ferritin synthesis is different from protein location in the brain. All of these data suggest that regulation of ferritin subunits is cellular and/or regional specific.