AB1135 RESPONSE TO SARS-COV-2 VACCINATION IN SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASE DEPENDS ON IMMUNOSUPPRESSIVE REGIMEN: A MATCHED, PROSPECTIVE COHORT STUDY

Background

Vaccination efficiency has been demonstrated to be reduced in patients with systemic autoimmune rheumatic disease (SARD) compared with the general population.

Objectives

To assess the humoral response to mRNA vaccine in patients with (SARD) and the effect of immunosuppressive medication in a matched cohort study.

Methods

Patients with SARD were enrolled and matched 1:1 for gender and age with healthy control subjects (HC). Differences in the humoral response to two doses of mRNA vaccine BNT162b2 in terms of seroconversion rate and SARS-COV-2 antibody titer between the two groups and impact of treatment within SARD patients was assessed using Fisher’s exact test, Student’s t-test, Mann-Whitney test and Kruskal-Wallis test, adjusting for multiple testing.

Results

We enrolled 82 patients with SARD and 82 matched HC (Table 1). Among patients the seroconversion rate was significantly lower after the 1st dose (65% compared to 100% in HC, p<0.0001) but levelled up after the 2nd dose (94% vs. 100%). While the difference in seroconversion rate was independent of treatment regime (no disease modifying anti-rheumatic drug (DMARD), DMARD monotherapy, DMARD combination therapy), the seroconversion rate of SARD patients on mono- or combination DMARD therapy was also significantly lower as compared to those receiving no DMARD therapy (56% for monotherapy and 57% for combination therapy compared to 77% for no DMARD therapy, p=0.002 and p=0.004 respectively; Figure 1A). Seroconversion rate after the 2nd dose was significantly lower for patients on combination DMARD therapy compared to all other groups (81% compared to 95% for monotherapy, and 100% for both no DMARD therapy and HC respectively, all p<0.0001); also antibody titers after the 2nd dose were lower when comparing patients on combination DMARD therapy to all other groups (49 binding antibody units (BAU)/ml versus 1673 BAU/ml in HC, p<0.0001; 2500 BAU/ml in those on no DMARD therapy, p<0.0001; and 687 BAU/ml in those on DMARD monotherapy, p=0.0072; Figure 1B). Considering effects of individual compounds, mycophenolate mofetil in mono- or combination therapy led to lower antibody titers after the 2nd dose as compared to HC or patients receiving no DMARDs (2 BAU/ml versus 1673 BAU/ml and 2500 BAU/ml respectively, both p<0.0001).

Figure 1.

Seroconversion rate (A) and anti-SARS-Cov 2 S antibody levels (B) after the 1stand 2ndvaccination between the healthy control (HC) group and patients according to therapy

Table 1.

Study subject characteristics

SARD (n=82)HC (n=82)Age, mean (±SD)52.05 (±14.06)52.15 (±13.42)Female, n (%)65 (79%)65 (79%)Different disease entity, n (%):33 (40%) Systemic lupus erythematosus Systemic sclerosis13 (16%) Other connective tissue diseases*15 (18%) Vasculitides#17 (21%) Miscellaneous$4 (5%)Treatment groups, n (%):43 (52%) csDMARD or b/tsDMARD monotherapy csDMARD and/or b/tsDMARD combination therapy16 (20%) No therapy23 (28%)Treatment agents, n (%):13 (16%) Methotrexate Mycophenolate14 (17%) Hydroxychloroquine28 (34%) Azathioprine13 (10%) Belimumab3 (4%) Tocilizumab3 (4%) Tacrolimus2 (2%) Olumiant1 (1%)

*dermato-/polymyositis (n=4), mixed connective tissue disease (n=2), primary Sjögren’s syndrome (n=6), undifferentiated connective tissue disease (n=3)

#antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (n=3), Behcet’s disease (n=1), large-vessel vasculitis (n=3), polymyalgia rheumatica (n=10)

$ adult-onset Still’s disease (n=1), immune deficiency (n=2), sarcoidosis (n=1)

b/tsDMARD: biological/targeted synthetic disease modifying antirheumatic drug; csDMARD: conventional synthetic disease modifying antirheumatic drug; HC: healthy control; n: number; SARD: systemic autoimmune rheumatic disease; SD: standard deviation;

Conclusion

Patients with SARD showed a good response after the 2nd vaccination with the mRNA vaccine. However, the choice of immunosuppressive regimen has a marked effect on both seroconversion rate and overall antibody titer.

Acknowledgements

We thank Sylvia Taxer and Zoltan Vass for their support.

Disclosure of Interests

Peter Mandl Speakers bureau: AbbVie, Janssen, Novartis, Consultant of: AbbVie, Janssen, Novartis, Grant/research support from: AbbVie, BMS, Lilly, Novartis, MSD, UCB, Selma Tobudic: None declared, Helmut Haslacher: None declared, Daniel Mrak: None declared, Thomas Nothnagl: None declared, Thomas Perkmann: None declared, Helga Radner Speakers bureau: Gilead, Merck Sharp, Pfizer, Abbvie, Consultant of: Gilead, Merck Sharp, Pfizer, Abbvie, Judith Sautner Speakers bureau: Otsuka, Novartis, Consultant of: Lilly, Astro Pharma, UCB, Abbvie, Elisabeth Simader Grant/research support from: Pfizer, Bristol-Myers Squibb, Florian Winkler: None declared, Heinz Burgmann: None declared, Daniel Aletaha Speakers bureau: Abbvie, Amgen, Lilly, Janssen, Merck, Novartis, Pfizer, Roche, Sandoz, Consultant of: Abbvie, Amgen, Lilly, Janssen, Merck, Novartis, Pfizer, Roche, Sandoz

, Grant/research support from: Abbvie, Amgen, Lilly, Novartis, Roche, SoBi, Sanofi, Stefan Winkler: None declared, Stephan Blüml Speakers bureau: Novartis, Abbvie, Consultant of: Gilead, Merck, Novartis, Abbvie

POS1243 ACCELERATED WANING OF PROTECTIVE IMMUNITY AFTER SARS-CoV-2 mRNA VACCINATION IN PATIENTS TREATED WITH BIOLOGICAL AND TARGETED SYNTHETIC DISEASE MODIFYING ANTIRHEUMATIC DRUGS

Background

Little is known about the duration of humoral antibody levels after two SARS-CoV-2 mRNA vaccinations in patients with immunosuppression. During this ongoing global epidemic, it is of essential interest to gather information about the time of protection after initial immunization in the vulnerable patients receiving either conventional synthetic disease modifying antirheumatic drugs (csDMARD) or biological/ targeted drugs (b/tsDMARDs).

Objectives

In this study we compared the antibody level development after vaccination and after six months in patients with inflammatory arthritis, inflammatory bowel disease (IBD) and healthy controls. Furthermore, we assessed factors affecting the quality and quantity of the humoral response.

Methods

We enrolled 85 healthy controls (HC), 75 patients with rheumatoid arthritis and spondyloarthritis and 41 patients suffering from IBD. Patients treated with B-cell depleting therapies were excluded from this study. Binding antibody units were measured after vaccination and 6 or more months. Neutralizing antibodies were measured after 6 months. Multivariate regression analyses analyzing factors associated with low titers after 6 months was performed.

Results

We found that patients with inflammatory arthritis or IBD showed reduced anti-SARS-CoV-2 S titers compared to HC. When we stratified for therapies, we found that patients receiving conventional synthetic disease modifying antirheumatic dugs (csDMARDs) had comparable anti-SARS-CoV-2 S titers to HC. In contrast, patients receiving biological or targeted synthetic (b/tsDMARDs) showed reduced anti-SARS-CoV-2 Igs as well as neutralizing antibody titers compared with healthy controls (HC) or patients receiving conventional synthetic (cs)DMARDs. We further show that anti-SARS-CoV-2 titers declined more rapidly in patients receiving b/tsDMARDs compared to HC, leading to a 50 percent reduction in vaccination-associated protection time in patients receiving b/tsDMARDs when compared to those receiving csDMARDs or even HC. In multivariate regression analyses, we found that in addition to the type of treatment, also age as well as corticosteroid use were associated with reduced anti-SARS-CoV-2 S titers.

Conclusion

Patients under ongoing b/tsDMARDs therapy exposed an accelerated waning of anti-SARS-CoV-2 S titers and therefore decreased immunity and protection against severe Covid-19 infections over time. These results may lead to more personalized approaches for further vaccination strategies in this group of immunosuppressed patients.

Figure 1.

A, Analysis of anti-SARS-CoV-2 S titers 6 months after the second vaccination in patients with inflammatory arthritis, inflammatory bowel disease and HC (** p ≤ 0.01; *** p ≤ 0.005, **** p ≤ 0.001). B, Determination of neutralizing antibody activity in sera of HC and patients with inflammatory arthritis receiving the indicated therapies.

Disclosure of Interests

Selma Tobudic: None declared, Elisabeth Simader Grant/research support from: Pfizer, Bristol-Myers Squibb, Thomas Deimel: None declared, Peter Mandl Speakers bureau: AbbVie, Janssen, Bristol-Myers Squibb, Merck Sharp & Dohme, Celgene, Novartis, Pfizer, Roche, Sanofi, UCB, Consultant of: Novartis, Celgene, Grant/research support from: Novartis, Celgene, Abbvie, Roche, Bristol-Myers Squibb

, Helmuth Haslacher Grant/research support from: Glock Health, BlueSky Immunotherapies and Neutrolis;, Thomas Perkmann: None declared, Lisa Schneider: None declared, Thomas Nothnagl: None declared, Helga Lechner-Radner: None declared, Florian Winkler: None declared, Heinz Burgmann Speakers bureau: Shionogi, Pfizer, MSD, Paid instructor for: Valneva, MSD, Gilead, Consultant of: from MSD, Pfizer, Takeda, Gilead, Karin Stiasny Grant/research support from: Pfizer, Gottfried Novacek: None declared, Walter Reinisch: None declared, Daniel Aletaha Speakers bureau: Abbvie, Amgen, Lilly, Novartis, Roche, SoBi, Sanofi

Merck, Pfizer, Roche, Sandoz, Stefan Winkler: None declared, Stephan Blüml Speakers bureau: Abbvie, personal fees from Novartis

Effects of Tissue Temperature and Injury on ADC during Therapeutic Hypothermia in Newborn Hypoxic-Ischemic Encephalopathy

BACKGROUND AND PURPOSE

ADC changes are useful in detecting ischemic brain injury, but mechanisms other than tissue pathology may affect the kinetic movement and diffusion of water molecules. We aimed to determine the effects of brain temperature on the corresponding ADC in infants undergoing therapeutic hypothermia.

MATERIALS AND METHODS

Brain temperature and ADC values in the basal ganglia, thalamus, cortical GM, and WM were analyzed during and after therapeutic hypothermia. The study cohort was categorized as having no-injury or injury. Among infants without injury, the correlation between ADC values and temperature was analyzed using the Pearson correlation. Intrasubject comparison of ADC changes during and after therapeutic hypothermia were analyzed, excluding patients who had an MR image interval of >5 days to minimize the effects of injury evolution.

RESULTS

Thirty-nine infants with hypoxic-ischemic encephalopathy were enrolled (23 no-injury; 16 injury). The median ADC was significantly lower during therapeutic hypothermia (837; interquartile range, 771-928, versus 906; interquartile range, 844-1032 ×10^-6mm²/s; P < .001). There was no difference in the ADC between the no-injury and injury groups during therapeutic hypothermia (823; interquartile range, 782-868, versus 842; interquartile range, 770-1008 ×10^-6mm²/s; P  = .4). In the no-injury group, in which ADC is presumed least affected by the evolution of injury, the median ADC was significantly lower during therapeutic hypothermia (826; interquartile range, 771-866, versus 897; interquartile range, 846-936 ×10^-6mm²/s; P  < .001). There was a moderate correlation between temperature and ADC in the no-injury group (during therapeutic hypothermia: Spearman ρ, 0.48; P  < .001; after therapeutic hypothermia: ρ, 0.4; P  < .001).

CONCLUSIONS

Aside from brain injury, reduced tissue temperature may also contribute to diffusion restriction on MR imaging in infants undergoing therapeutic hypothermia.

The First Examination of Diagnostic Performance of Automated Measurement of the Callosal Angle in 1856 Elderly Patients and Volunteers Indicates That 12.4% of Exams Met the Criteria for Possible Normal Pressure Hydrocephalus

BACKGROUND AND PURPOSE

Many patients with dementia may have comorbid or misdiagnosed normal pressure hydrocephalus, a treatable neurologic disorder. The callosal angle is a validated biomarker for normal pressure hydrocephalus with 93% diagnostic accuracy. Our purpose was to develop and evaluate an algorithm for automatically computing callosal angles from MR images of the brain.

MATERIALS AND METHODS

This article reports the results of analyzing callosal angles from 1856 subjects with 5264 MR images from the Open Access Series of Imaging Studies and the Alzheimer's Disease Neuroimaging Initiative databases. Measurement variability was examined between 2 neuroradiologists (n = 50) and between manual and automatic measurements (n = 281); from differences in simulated head orientation; and from real-world changes in patients with multiple examinations (n = 906). We evaluated the effectiveness of the automatic callosal angle to differentiate normal pressure hydrocephalus from Alzheimer disease in a simulated cohort.

RESULTS

The algorithm identified that 12.4% of subjects from these carefully screened cohorts had callosal angles of <90°, a published threshold for possible normal pressure hydrocephalus. The intraclass correlation coefficient was 0.97 for agreement between neuroradiologists and 0.90 for agreement between manual and automatic measurement. The method was robust to different head orientations. The median coefficient of variation for repeat examinations was 4.2% (Q1 = 3.1%, Q3 = 5.8%). The simulated classification of normal pressure hydrocephalus versus Alzheimer using the automatic callosal angle had an accuracy, sensitivity, and specificity of 0.87 each.

CONCLUSIONS

In even the most pristine research databases, analyses of the callosal angle indicate that some patients may have normal pressure hydrocephalus. The automatic callosal angle measurement can rapidly and objectively screen for normal pressure hydrocephalus in patients who would otherwise be misdiagnosed.

POS0485 TRAJECTORY CLUSTERS OF RADIOGRAPHIC PROGRESSION IN RHEUMATOID ARTHRITIS PATIENTS: ASSOCIATIONS WITH CLINICAL VARIABLES

Background:

Joint damage is a defining feature of rheumatoid arthritis (RA), a major driver of functional impairment and of reduction of quality of life. Many factors are associated with damage accrual however, the course of structural damage of individual patients over time and factors associated with such trajectories have not been investigated.

Objectives:

Identification of trajectories of radiographic damage in RA by clustering patients according to the shape of their curve of Sharp-van der Heijde scores (SHS) over time. Developing models to predict their progression cluster from baseline characteristics.

Methods:

Patient-level data over a two-year period from 5 large randomized controlled trials on TNF-inhibitors in RA (ERA, PREMIER, TEMPO, GO-BEFORE and GO-FORWARD) were used. SHSs were clustered in a shape-respecting manner to identify distinct clusters of radiographic progression. Characteristics of patients within different progression clusters were compared at baseline and over time. Logistic regression models were developed to predict trajectory of radiographic progression using information at baseline.

Results:

In total 1887 patients with 7738 x-rays were used for cluster analyses. We identified 4 distinct clusters with characteristic shapes of radiographic progression: one with a stable SHS over the whole 2-year period (C0/lowChange; 86%); one with relentless progression (C1/rise; 5.8%); one with decreasing SHS (C2/improvement; 6.9%); and one going up and down (C3/bothWays; 1.4%) of the SHS. Robustness of clusters and shapes of progression over time were confirmed using different clustering methods and cut-offs to define radiographic progression (Figure 1). Regression models identified disease duration, baseline CRP and SHS and treatment status as predictors for cluster assignment (Table 1), showing good performance (PCC 87.5%; Nagelkerke r2 0.36).

Conclusion:

We were able to identify 4 different clusters of radiographic progression over time in patients with RA, most remarkably one with relentless progression and another one with amelioration of joint damage over time, suggesting the existence of distinct patterns of joint damage accrual in RA. The nature of the identified trajectories is mostly explained by inflammatory load, disease duration and especially type of treatment.

Figure 1.

Representations of the major three clusters of radiologic progression curves. (A) shows the curves of all patients with a SHS-range >= 10, colored by their cluster. Values between visits were linearly interpolated. Big dotted line is the median of particular cluster, thinner lines represent single patient values. Cluster C0 /lowChange are patients without enough variation in SHS to be seen as a curve, therefor not shown in the diagrams.

Table 1.

Simple logistic regression models to predict assignment to clusters of radiologic progression using information at baseline. Variables entered but not selected by a stepwise approach were: rheumatoid factor, age, gender, tender joint count;

c0/low change vs:C1/rise ClusterC2/improve ClusterparametersOR95%CIOR95%CIX-ray Score1.021.01-1.031.031.02-1.03CRP (mg/dl)1.121.07-1.160.980.90-1.07Duration (years)0.870.80-0.951.091.05-1.12TreatmentCombinationREFREFREFREFcsDMARD4.982.88-8.630.050.01-0.23bDMARD Mono2.281.29-4.040.640.38-1.08

Disclosure of Interests:

Stephan Blüml Speakers bureau: Novartis, MSD, Abvie, Pfizer, Consultant of: MSD, Lilly, Novartis, Alexander Platzer: None declared, Farideh Alasti: None declared, Daniel Aletaha Speakers bureau: Abbvie, Amgen, Lilly, Merck, Novartis, Pfizer, Roche, Sandoz, Consultant of: Abbvie, Amgen, Lilly, Merck, Novartis, Pfizer, Roche, Sandoz, Grant/research support from: Abbvie, Amgen, Lilly, Novartis, Roche, SoBi, Sanofi, Josef S. Smolen Speakers bureau: AbbVie, Amgen, AstraZeneca, Astro, Bristol-Myers Squibb, Celgene, Celltrion, Chugai, Gilead, ILTOO Pharma, Janssen, Lilly, Merck Sharp & Dohme, Novartis-Sandoz, Pfizer, Roche, Samsung, Sanofi, and UCB., Consultant of: AbbVie, Amgen, AstraZeneca, Astro, Bristol-Myers Squibb, Celgene, Celltrion, Chugai, Gilead, ILTOO Pharma, Janssen, Lilly, Merck Sharp & Dohme, Novartis-Sandoz, Pfizer, Roche, Samsung, Sanofi, and UCB., Grant/research support from: Dr Smolen received grants to his institution from Abbvie, AstraZeneca, Janssen, Lilly, Merck Sharpe & Dohme, Pfizer, and Roche, Helga Radner: None declared

Pediatric Atypical Teratoid/Rhabdoid Tumors of the Brain: Identification of Metabolic Subgroups Using In Vivo 1H-MR Spectroscopy

BACKGROUND AND PURPOSE

Atypical teratoid/rhabdoid tumors are rare, aggressive central nervous system tumors that are predominantly encountered in very young children. Our aim was to determine whether in vivo metabolic profiles correlate with molecular features of central nervous system pediatric atypical teratoid/rhabdoid tumors.

MATERIALS AND METHODS

Twenty confirmed patients with atypical teratoid/rhabdoid tumors who underwent MR spectroscopy were included in this study. In vivo metabolite levels of atypical teratoid/rhabdoid tumors were compared with molecular subtypes assessed by achaete-scute homolog 1 expression. Additionally, brain-specific creatine kinase levels were determined in tissue samples.

RESULTS

In vivo creatine concentrations were higher in tumors that demonstrated achaete-scute homolog 1 expression compared with those without achaete-scute homolog 1 expression (3.42 ± 1.1 versus 1.8 ± 0.8 IU, P < .01). Additionally, levels of myo-inositol (mI) (9.0 ± 1.5 versus 4.7 ± 3.6 IU, P < .05) were significantly different, whereas lipids approached significance (44 ± 20 versus 80 ± 30 IU, P = .07) in these 2 cohorts. Higher brain-specific creatine kinase levels were observed in the cohort with achaete-scute homolog 1 expression (P < .05). Pearson correlation analysis showed a significant positive correlation of brain-specific creatine kinase with absolute creatine (P < .05) and myo-inositol (P < .05) concentrations.

CONCLUSIONS

In vivo MR spectroscopy may predict key molecular features of atypical teratoid/rhabdoid tumors at initial diagnosis, leading to timely patient risk stratification and accelerating the development of targeted therapies.

Myeloid PTEN deficiency impairs tumor-immune surveillance via immune-checkpoint inhibition

Tumor-host interaction is determined by constant immune surveillance, characterized by tumor infiltration of myeloid and lymphoid cells. A malfunctioning or diverted immune response promotes tumor growth and metastasis. Recent advances had been made, by treating of certain tumor types, such as melanoma, with T-cell checkpoint inhibitors. This highlights the importance of understanding the molecular mechanisms underlying the crosstalk between tumors and their environment, in particular myeloid and lymphoid cells. Our aim was to study the contribution of the myeloid PI3K/PTEN-signaling pathway in the regulation of tumor-immune surveillance in murine models of cancer. We made use of conditional PTEN-deficient mice, which exhibit sustained activation of the PI3K-signaling axis in a variety of myeloid cell subsets such as macrophages and dendritic cells (DCs). In colitis-associated colon cancer (CAC), mice deficient in myeloid PTEN showed a markedly higher tumor burden and decreased survival. We attributed this observation to the increased presence of immune-modulatory conventional CD8α(+) DCs in the spleen, whereas other relevant myeloid cell subsets were largely unaffected. Notably, we detected enhanced surface expression of PD-L1 and PD-L2 on these DCs. As a consequence, tumoricidal T-cell responses were hampered or redirected. Taken together, our findings indicated an unanticipated role for the PI3K/PTEN-signaling axis in the functional regulation of splenic antigen-presenting cells (APCs). Our data pointed at potential, indirect, tumoricidal effects of subclass-specific PI3K inhibitors, which are currently under clinical investigation for treatment of tumors, via myeloid cell activation.

Pristane-induced lupus as a model of human lupus arthritis: evolvement of autoantibodies, internal organ and joint inflammation

OBJECTIVE

Arthritis is frequently seen in human lupus, but rarely in lupus models. Pristane-induced lupus (PIL) can be induced in various mouse strains such as BALB/c and C57BL/6. We herein characterize clinical and histological features of arthritis in the context of systemic lupus and provide a prudent comparison with models of rheumatoid arthritis (RA).

METHODS

A total of 57 BALB/c mice received pristane (PIL group) and were analyzed for serum autoantibodies (anti-chromatin-, -histone, -Sm, -dsDNA), as well as for clinical features and histopathology of joints, lungs and kidneys. Joint pathology was quantified by image analysis and tissue cytometry. Ten C57BL/6 mice (Bl/6-PIL) and historical groups of two different RA models were analyzed accordingly.

RESULTS

In BALB/c PIL, clinical arthritis started at three months, occurred finally in 79% of PIL (but not in controls, p<0.001) and correlated with areas of inflammation, erosion, cartilage damage, osteoclast numbers and total severity score (for all: r>0.7, p<0.001). After eight months, 58% of PIL (but no controls, p<0.001) had mild-erosive arthritis. In contrast to RA, the most frequent inflammatory cell type of the pannus was granulocytes (17.7%), PIL had lower numbers of osteoclasts, erosions rarely affected both layers of the cortical bone and there was no progression to complete joint destruction (even after one year of observation). Serum autoantibodies (auto-abs) preceded arthritis and became significantly elevated in all PIL; affected joints showed increased deposits of IgG (and IgM) within the inflammatory tissue, indicative of an ab-mediated process. PIL mice with arthritis also showed signs of pulmonary (100%) and renal (46%) lupus. In contrast to BALB/c, Bl/6-PIL mice did not develop any signs of arthritis.

CONCLUSION

PIL in BALB/c mice is characterized by severe organ involvement, typical autoabs and by a mild-erosive arthritis with similarities to, but also with distinct differences from, RA. PIL may help to study arthritis along with other key features of systemic lupus erythematosus after therapeutic interventions or in knock-out models based on a BALB/c but not on a C57BL/6 background.

Abnormal cerebral microstructure in premature neonates with congenital heart disease

BACKGROUND AND PURPOSE

Abnormal cerebral microstructure has been documented in term neonates with congenital heart disease, portending risk for injury and poor neurodevelopmental outcome. Our hypothesis was that preterm neonates with congenital heart disease would demonstrate diffuse cerebral microstructural abnormalities when compared with critically ill neonates without congenital heart disease. A secondary aim was to identify any association between microstructural abnormalities, white matter injury (eg, punctate white matter lesions), and other clinical variables, including heart lesions.

MATERIALS AND METHODS

With the use of tract-based spatial statistics, an unbiased, voxelwise method for analyzing diffusion tensor imaging data, we compared 21 preterm neonates with congenital heart disease with 2 cohorts of neonates without congenital heart disease: 28 term and 27 preterm neonates, identified from the same neonatal intensive care unit.

RESULTS

Compared with term neonates without congenital heart disease, preterm neonates with congenital heart disease had microstructural abnormalities in widespread regions of the central white matter. However, 42% of the preterm neonates with congenital heart disease had punctate white matter lesions. When neonates with punctate white matter lesions were excluded, microstructural abnormalities remained only in the splenium. Preterm neonates with congenital heart disease had similar microstructure to preterm neonates without congenital heart disease.

CONCLUSIONS

Diffuse microstructural abnormalities were observed in preterm neonates with congenital heart disease, strongly associated with punctate white matter lesions. Independently, regional vulnerability of the splenium, a structure associated with visual spatial function, was observed in all preterm neonates with congenital heart disease.

Abatacept (CTLA-4IG) treatment reduces the migratory capacity of monocytes in patients with rheumatoid arthritis

OBJECTIVE

The binding of abatacept (CTLA-4Ig) to the B7 ligands CD80 and CD86 prevents the engagement of CD28 on T cells and thereby prevents effector T cell activation. In addition, a direct effect of CTLA-4Ig on antigen-presenting cells (APCs) could contribute to the therapeutic effect. To further elucidate the mechanism of CTLA-4Ig, we performed phenotype and functional analyses of APCs in patients with rheumatoid arthritis (RA) before and after the initiation of CTLA-4Ig therapy.

METHODS

Peripheral blood mononuclear cells were analyzed before and at 2 and 4 weeks after the initiation of CTLA-4Ig therapy. Proportions of APCs were determined by flow cytometry. CD14+ monocytes were further analyzed for the expression of costimulatory and adhesion molecules and for their transendothelial migratory capacity in vitro. In addition, CD14+ monocytes from healthy controls were analyzed for their migratory and spreading capacity.

RESULTS

Proportions and absolute numbers of monocytes were significantly increased in RA patients treated with CTLA-4Ig. The expression of several adhesion molecules was significantly diminished. In addition, monocytes displayed a significant reduction in their endothelial adhesion and transendothelial migratory capacity upon treatment with CTLA-4Ig. Likewise, isolated monocytes from healthy controls revealed a significant reduction in their migratory and spreading activity after preincubation with CTLA-4Ig or anti-CD80 and anti-CD86 antibodies.

CONCLUSION

We describe direct effects of CTLA-4Ig therapy on phenotype and functional characteristics of monocytes in RA patients that might interfere with the migration of monocytes to the synovial tissue. This additional mechanism of CTLA-4Ig might contribute to the beneficial effects of CTLA-4Ig treatment in RA patients.

Abnormal microstructure of the atrophic thalamus in preterm survivors with periventricular leukomalacia

BACKGROUND AND PURPOSE

The neuroanatomic substrate of cognitive deficits in long-term survivors of prematurity with PVL is poorly understood. The thalamus is critically involved in cognition via extensive interconnections with the cerebral cortex. We hypothesized that the thalamus is atrophic (reduced in volume) in childhood survivors of prematurity with neuroimaging evidence of PVL and that the atrophy is associated with selective microstructural abnormalities within its subdivisions.

MATERIALS AND METHODS

We performed quantitative volumetric and DTI measurements of the thalamus in 17 children with neuroimaging evidence of PVL (mean postconceptional age, 5.6 ± 4.0 years) who were born prematurely and compared these with 74 term control children (5.7 ± 3.4 years).

RESULTS

The major findings were the following: 1) a significant reduction in the overall volume of the thalamus in patients with PVL compared with controls (P < .0001), which also correlated with the severity of PVL (P = .001); 2) significantly decreased FA (P = .003) and increased λ(⊥) (P = .02) in the thalamus overall and increased axial, radial, and mean diffusivities in the pulvinar (P < .03), suggesting injury to afferent and efferent myelinated axons; and 3) a positive correlation of pulvinar abnormalities with those of the parieto-occipital white matter in periventricular leukomalacia, suggesting that the pulvinar abnormalities reflect secondary effects of damaged interconnections between the pulvinar and parieto-occipital cortices in the cognitive visual network.

CONCLUSIONS

There are volumetric and microstructural abnormalities of the thalamus in preterm children with PVL, very likely reflecting neuronal loss and myelinated axonal injury. The selective microstructural damage in the pulvinar very likely contributes to abnormal cognitive visual processing known to occur in such survivors.

Apparent diffusion and fractional anisotropy of diffuse intrinsic brain stem gliomas

BACKGROUND AND PURPOSE

DIBSGs have the worst prognosis among pediatric brain tumors with no improvement of outcome for several decades. In this study, we determined whether diffusion imaging could improve patient stratification and our understanding of the impact of therapies.

MATERIALS AND METHODS

Nine baseline and 24 follow-up DTI studies performed in 9 patients on a 1.5T clinical MR imaging scanner were reviewed. ADC and FA were measured for the whole lesion and at 5 anatomic levels: the rostral medulla, caudal pons, midpons, rostral pons, and caudal midbrain. Reference data were obtained from 8 controls with normal brain stem, 6 patients with medulloblastoma, and 7 patients with pilocytic astrocytoma.

RESULTS

ADC was higher in untreated DIBSG than in normal brain stem and medulloblastoma (1.14 ± 0.18 [×10⁻³ mm²/s] versus 0.75 ± 0.06 and 0.56 ± 0.05, both P < .001). FA was lower in DIBSG than in normal brain stem (0.24 ± 0.04 versus 0.43 ± 0.02, P < .001) but was higher than that in pilocytic astrocytoma (0.17 ± 0.05, P < .05). Lower baseline ADC and higher FA correlated with a worse clinical course. Correlations were more significant at the caudal midbrain than in other regions. ADC decreased and FA increased after RT. Changes of FA after RT at the caudal midbrain correlated with event-free survival.

CONCLUSIONS

Baseline ADC and FA of DIBSG revealed hypocellular tumors with extensive edema. Diffusion changes after therapy implied reduced edema but did not support a significant response to therapy. The significance of diffusion properties varied with anatomic locations, the caudal midbrain being particularly important.

Citrate in pediatric CNS tumors?

BACKGROUND AND PURPOSE

In a subset of in vivo MR spectra acquired from pediatric brain tumors, we have observed an unassigned peak. The goal of this study was to determine the molecule of origin, and the prevalence and concentration of this chemical in various pediatric brain tumors.

MATERIALS AND METHODS

Single-voxel point-resolved spectroscopy (PRESS) spectra from 85 patients with brain tumors and 469 control subjects were analyzed. Citrate seemed to be a likely candidate, and model spectra of citrate were added to the basis set of metabolites for automated processing with use of LCModel software. Absolute "apparent" concentrations of citrate and the Cramer-Rao lower bounds (CRLB), indicators for the reliability of detection, were determined.

RESULTS

"Apparent" citrate was detected in 26 of 85 patients with CRLB of less than 25%. Diffuse intrinsic brain stem glioma (DIBSG) had the highest mean concentration (4.0 +/- 1.1 mmol/kg in all subjects), and 8 of 12 patients had CRLB less than 25%. A significant reduction of citrate (P < .01) was observed in 6 DIBSGs that had follow-up MR spectroscopy studies after radiation therapy. "Apparent" citrate with CRLB less than 25% was detected in 5 of 22 medulloblastomas (mean citrate, 2.9 +/- 2.2 mmol/kg), in 5 of 14 ependymomas (2.6 +/- 1.8 mmol/kg), 5 of 14 astrocytomas (1.9 +/- 1.2 mmol/kg), and 3 of 23 pilocytic astrocytomas (1.4 +/- 1.1 mmol/kg). In control subjects older than 6 months, CRLB less than 25% was not observed, whereas CRLB less than 25% was observed in 39 of 194 subjects younger than 6 months,.

CONCLUSION

MR signal consistent with citrate was observed in pediatric brain tumors and in the developing brain of infants younger than 6 months.

Quantitative short echo time 1H-MR spectroscopy of untreated pediatric brain tumors: preoperative diagnosis and characterization

PURPOSE

Our aims were to evaluate the metabolic profiles of pediatric brain tumors with short echo time (TE) MR spectroscopy and absolute quantitation of metabolite concentrations (in mmol/kg of tissue) and to describe metabolic features that distinguish individual tumor types and that may help to improve preoperative diagnosis of specific tumors.

METHODS

MR imaging examinations of 60 patients with untreated brain tumors (14 medulloblastomas, 5 anaplastic astrocytomas, 3 low-grade astrocytomas, 17 pilocytic astrocytomas, 4 anaplastic ependymomas, 5 ependymomas, 3 choroid plexus papillomas, 3 choroid plexus carcinomas, and 6 pineal germinomas) were reviewed. Single-voxel proton MR spectroscopy with a TE of 35 ms was performed and absolute metabolite concentrations were determined by using fully automated quantitation.

RESULTS

Taurine (Tau) was significantly elevated in medulloblastomas (P < .00001) compared with all other tumors pooled (All Other). Tau was also observed consistently, at lower concentration, in pineal germinomas. Creatine (Cr) was significantly reduced in pilocytic astrocytomas, distinguishing them from All Other (P < .000001). The MR spectra of choroid plexus papillomas exhibited low Cr (P < .01) concentrations; however, myoinositol was elevated (P < .01) and total choline (tCho) (P < .0001) was reduced relative to All Other. Choroid plexus carcinomas had low Cr (P < .01 versus All Other) and the lowest Cr/tCho ratio (P < .0001 versus All Other) among all tumors studied. Guanidinoacetate was reduced in low-grade astrocytomas and anaplastic astrocytomas (P < .00001) versus All Other, whereas ependymoma and anaplastic ependymomas exhibited particularly low N-acetylaspartate (P < .00001 versus All Other).

CONCLUSION

Quantitative proton MR spectroscopy reveals features of pediatric brain tumors that are likely to improve preoperative diagnoses.

Oligotide, a defibrotide derivative, protects human microvascular endothelial cells against fludarabine-induced activation, damage and allogenicity

Fludarabine is a nonmyeloablative immunosuppressant increasingly used as a component of alternative reduced-intensity conditioning regimens prior to allogeneic stem cell transplantation (SCT). However, we have previously shown that 2-fluoroadenine 9-beta-D-arabinofuranoside (F-Ara) as the active metabolized form of fludarabine induces damage, activation and allogenicity in human microvascular endothelial cells (HMEC). We had also identified the pharmaceutic compound Defibrotide (DF), originally used in the treatment of veno-occlusive disease and thrombotic microangiopathy, as being protective against F-Ara-induced dysfunction of HMEC, importantly, without affecting the antileukemic effect of F-Ara. In the present report, we show that a recently developed derivative of DF, Oligotide, similarly downregulates F-Ara-induced activation and damage of HMEC as well as their antigenicity for allogeneic CD8+ T cells. In addition, Oligotide could also block F-Ara-mediated transendothelial migration of peripheral blood cells across the HMEC barrier. Taken together, these observations argue for a potential clinical use of both DF and Oligotide in pre transplant conditioning.

Membrane phospholipids and high-energy metabolites in childhood ataxia with CNS hypomyelination

BACKGROUND

Childhood ataxia with CNS hypomyelination (CACH) is a leukodystrophy with extreme rarefaction of white matter caused by mutations in one of the five subunits of the translation initiation factor 2B (eIF2B).

METHODS

Seven children with this disease and nine age-matched control subjects were studied with proton-decoupled phosphorus magnetic resonance (MR) spectroscopy.

RESULTS

In patients with CACH, cerebral concentrations of high-energy phosphate metabolites were abnormal. Of the metabolites involved in biosynthesis and catabolism of membrane phospholipids, glycerophosphorylethanolamine was reduced (0.24 +/- 0.18 mmol/kg brain vs 0.44 +/- 0.14; p < 0.02), and phosphorylethanolamine was increased (2.32 +/- 0.53 vs 1.53 +/- 0.22; p < 0.01), whereas the choline-containing phosphorylated metabolites were unchanged. Nucleoside triphosphate (NTP) was reduced (2.44 +/- 0.34 mmol/kg brain tissue vs 3.09 +/- 0.58; p < 0.01), phosphocreatine was elevated (4.11 +/- 0.63 vs 3.27 +/- 0.33; p < 0.01), and inorganic phosphate was reduced (0.77 +/- 0.32 vs 1.06 +/- 0.26; p < 0.05). Intracellular pH was elevated in patients (7.03 +/- 0.04 vs 6.99 +/- 0.02; p < 0.02).

CONCLUSIONS

The authors found an altered energy state of the residual cell population investigated. Together with previously identified replacement of white matter by CSF, the present findings raise the possibility that the genetic defect in eIF2B may result in impairment of myelin membrane synthesis or myelin membrane transport in the in vivo CACH brain. Ethanolamine metabolites constitute the plasmalogens, and the present findings may include a defect in plasmalogen metabolism.

Tricarboxylic acid cycle of glia in the in vivo human brain

In the brain, acetate is exclusively oxidized by glia. To determine the contribution of glial metabolism to the tricarboxylic acid cycle (TCA), 1-(13)C-acetate was infused in six studies in three normal adult subjects and -one epileptic receiving valproic acid for seizure control. Ten grams of 99% 1-(13)C labeled acetate were infused intravenously as a 3.3% w/v solution over 60 min, during which in vivo 13C MR spectra of the brain were acquired. As expected, 13C label rapidly enriched cerebral bicarbonate, glutamate and glutamine C5. The mean rate of acetate oxidation calculated from steady-state 13C enrichment of bicarbonate in fasted normal subjects was 0.13 +/- 0.03 micromol/g/min (n=4), approximately 20% of the total cerebral TCA cycle rate.

Alternative 1-(13)C glucose infusion protocols for clinical (13)C MRS examinations of the brain

Clinical utility of (13)C MRS is limited by cost and long examination times. Three 1-(13)C glucose infusion protocols-a high-dose i.v., low-dose i.v., and oral administration of 1-(13)C glucose-were compared on a GE 1.5T MR scanner. Resolution and sensitivity were sufficient to identify (13)C glucose (1alpha and 1beta), glutamate (C1-C4), glutamine (C1-C4), aspartate (C2 and C3), lactate, alanine, and bicarbonate in brain spectra. The three protocols were efficacious, as measured by cerebral enrichment of 1-(13)C glucose (62%, 42%, and 38%) and its principal metabolite, 4-(13)C glutamate (13%, 11%, and 16%), respectively. Intravenous infusion of 1-(13)C glucose 0.23 g/kg body weight (low dose) provides equivalent information at one third the cost of previous regimes. Magn Reson Med 46:39-48, 2001.

[1-13C]glucose MRS in chronic hepatic encephalopathy in man

[1-13C]-labeled glucose was infused intravenously in a single dose of 0.2 g/kg body weight over 15 min in six patients with chronic hepatic encephalopathy, and three controls. Serial 13C MR spectra of the brain were acquired. Patients exhibited the following characteristics relative to normal controls: 1) Cerebral glutamine concentration was increased (12.6 +/- 3.8 vs. 6.5 +/- 1.9 mmol/kg, P < 0.006) and glutamate was reduced (8.2 +/- 1.0 vs. 9.9 +/- 0.6 mmol/kg, P < 0.02). 2) 13C incorporation into glutamate C4 and C2 positions was reduced in patients (80 min after start of infusion C4: 0.43 +/- 0.09 vs. 0.84 +/- 0.15 mmol/kg, P < 0.001; C2: 0.20 +/- 0.03 vs. 0.45 +/- 0.07 mmol/kg, P < 0.0001). 3) 13C incorporation into bicarbonate was delayed (90 +/- 21 vs. 40 +/- 10 min, P < 0.003), and the time interval between detection of glutamate C4 and C2 labeling was longer in patients (22 +/- 8 vs. 12 +/- 3 min, P < 0.03). 4) Glutamate C2 turnover time was reduced in chronic hepatic encephalopathy (17.1 +/- 6.8 vs. 49.6 +/- 8.7 min, P < 0.0002). 5) 13C accumulation into glutamine C2 relative to its substrate glutamate C2 increased progressively with the severity of clinical symptoms (r = 0.96, P < 0.01). These data indicate disturbed neurotransmitter glutamate/glutamine cycling and reduced glucose oxidation in chronic hepatic encephalopathy. [1-13C] glucose MRS provides novel insights into disease progression and the pathophysiology of chronic hepatic encephalopathy.

Direct determination of the N-acetyl-L-aspartate synthesis rate in the human brain by (13)C MRS and [1-(13)C]glucose infusion

A non-invasive (13)C magnetic resonance spectroscopy (MRS) technique is described for the determination of the N-acetyl-L-aspartate (NAA) synthesis rate, V(NAA), in the human brain in vivo. In controls, the mean V(NAA) was 9.2 +/- 3.9 nmol/min/g. In Canavan disease, where [NAA] is increased (p < 0.001) and [aspartate] is deceased (p < 0.001), V(NAA) was significantly reduced to 3.6 +/- 0.1 nmol/min/g (p < 0.001). These rates are in close agreement with the activity of the biosynthetic enzyme measured in vitro in animals, and with the rate of urinary excretion of NAA in human subjects with Canavan disease. The present result is consistent with the regulation of NAA synthesis by the activity of a single enzyme, L-aspartate-N-acetyltransferase, in vivo, and with its control in Canavan disease by limited substrate supply and/or product inhibition. The (13)C MRS technique provides the means for further determination of abnormal rates of neuronal NAA synthesis among neurological disorders in which low cerebral [NAA] has been identified.