Immunogenicity of a three-dose primary series of mRNA COVID-19 vaccines in patients with lymphoid malignancies

Background

Patients with lymphoid malignancies are at risk for poor COVID-19 related outcomes and have reduced vaccine-induced immune responses. Currently a three-dose primary regimen of mRNA vaccines is recommended in the U.S. for immunocompromised hosts.

Methods

A prospective cohort study of healthy adults (n = 27) and patients with lymphoid malignancies (n = 94) was conducted, with longitudinal follow-up through completion of a two or three-dose primary mRNA COVID vaccine series, respectively. Humoral responses were assessed in all participants, and cellular immunity in a subset of participants.

Results

The rate of seroconversion (68.1% v. 100%) and the magnitude of peak anti-S IgG titer (median anti-S IgG 32.4, IQR 0.48-75.0 v. 72.6, IQR 51.1-100.1; p = 0.0202) were both significantly lower in patients with lymphoid malignancies as compared to the healthy cohort. However, peak titers of patients with lymphoid malignancies who responded to vaccination were similar to healthy cohort titers (median anti-S IgG 64.3, IQR 23.7 - 161.5, p = 0.7424). The third dose seroconverted 7/41 (17.1%) patients who were seronegative after the first two doses. Although most patients with lymphoid malignancies produced vaccine-induced T-cell responses in the subset studied, B-cell frequencies were low with minimal memory cell formation.

Conclusions

A three-dose primary mRNA series enhanced anti-S IgG responses to titers equivalent to healthy adults in patients with lymphoid malignancies who were seropositive after the first two doses and seroconverted 17.1% who were seronegative after the first two doses. T-cell responses were present, raising the possibility that the vaccines may confer some cell-based protection even if not measurable by anti-S IgG.

586. Immunogenicity of COVID-19 mRNA Vaccines in Patients with Lymphoid Malignancies

Background

Patients with lymphoid malignancies are at high risk of severe COVID-19 disease and were not included in the phase 3 mRNA vaccine trials. Many patients with lymphoid malignancies receive immunosuppressive therapies, including B-cell depleting agents, that may negatively impact humoral response to vaccination.

Methods

We recruited patients with lymphoid malignancies and healthy participants who planned to receive two doses of SARS-CoV-2 mRNA vaccine (BNT162b2 or mRNA-1273). Blood was drawn at baseline, prior to second dose of vaccine, and 28 days after last vaccination. Disease characteristics and therapies were extracted from patients’ electronic medical record. An ultrasensitive, single molecule array (Simoa) assay detected anti-Spike (S), anti-S1, anti-receptor binding domain (RBD), and anti-Nucleocapsid (N) IgG from plasma at each timepoint.

Results

23 healthy participants and 37 patients with lymphoid malignancies were enrolled (Table 1). Low titers of anti-N (Fig 1A) demonstrate no prior exposure or acquisition of COVID-19 before vaccination or during the study. 37.8% of the lymphoid malignancy cohort responded to the vaccine, using an internally validated AEB cutoff of 1.07. A significantly higher magnitude of anti-S (p< 0.0001), anti-S1 (p< 0.0001) and anti-RBD (p< 0.0001) are present in the healthy as compared to lymphoid malignancy cohort at the second dose and day 28 post-series (Fig 1B, Fig 1C and Fig 1D). Anti-S IgG titers were compared between the healthy cohort, treatment naïve, and treatment experienced groups (Fig 2). The treatment naïve cohort had high titers by series completion which were not significantly different from the healthy cohort (p=0.2259), although the treatment experienced group had significantly decreased titers (p< 0.0001). Of the 20 patients who had received CD20 therapy, there was no clear correlation of anti-S IgG response with time from CD20 therapy, although most patients who received CD20 therapies within 12 months from the vaccine had no response (Figure 3).

Table 1. Demographics

Figure 1. Anti-N, Anti-S, Anti-S1, Anti-RBD and Anti-N Ig G for healthy v. lymphoid malignancy cohort

The dotted line at 1.07 marks in an internally validated threshold to mark anti-S IgG response. The black bars denote median with 95% CI.

Figure 2: Anti-S IgG for healthy v. treatment naïve v. treatment experienced

The dotted line at 1.07 marks in an internally validated threshold to mark antibody response. The black bars denote median with 95% CI.

Conclusion

The vaccine-induced immune response was poor among treatment-experienced patients with lymphoid malignancies, especially among those who received CD20 therapies within 12 months.

Figure 3. Months from CD20 therapy v. anti-S IgG titers

The dotted line at 1.07 marks in an internally validated threshold to mark antibody response.

Disclosures

Jennifer Crombie, MD, AbbVie (Grant/Research Support)Bauer (Grant/Research Support)Karyopharm (Consultant)MorphoSys (Consultant) Philippe Armand, MD PhD, ADCT, Celgene, Morphosys, Daiichi, Miltenyi, Tessa, C4, Genmab, Enterome, Regeneron, Genentech, Epizyme, Astra Zeneca (Consultant, Sorry to put them all in, hope you can deconvolute for me)Affimed, Adaptive, BMS, Merck, Kite, IGM, Genentech (Research Grant or Support, Institutional research funding) David Walt, PhD, Quanterix Corporation (Board Member, Shareholder) Nicolas C. Issa, MD, AiCuris (Scientific Research Study Investigator)Astellas (Scientific Research Study Investigator)GSK (Scientific Research Study Investigator)Merck (Scientific Research Study Investigator)

A dimensional investigation of error-related negativity (ERN) and self-reported psychiatric symptoms

Alterations in error processing are implicated in a range of DSM-defined psychiatric disorders. For instance, obsessive-compulsive disorder (OCD) and generalised anxiety disorder show enhanced electrophysiological responses to errors-i.e. error-related negativity (ERN)-while others like schizophrenia have an attenuated ERN. However, as diagnostic categories in psychiatry are heterogeneous and also highly intercorrelated, the precise mapping of ERN enhancements/impairments is unclear. To address this, we recorded electroencephalograms (EEG) from 196 participants who performed the Flanker task and collected scores on 9 questionnaires assessing psychiatric symptoms to test if a dimensional framework could reveal specific transdiagnostic clinical manifestations of error processing dysfunctions. Contrary to our hypothesis, we found non-significant associations between ERN amplitude and symptom severity of OCD, trait anxiety, depression, social anxiety, impulsivity, eating disorders, alcohol addiction, schizotypy and apathy. A transdiagnostic approach did nothing to improve signal; there were non-significant associations between all three transdiagnostic dimensions (anxious-depression, compulsive behaviour and intrusive thought, and social withdrawal) and ERN magnitude. In these same individuals, we replicated a previously published transdiagnostic association between goal-directed learning and compulsive behaviour and intrusive thought. Possible explanations discussed are (i) that associations between the ERN and psychopathology might be smaller than previously assumed, (ii) that these associations might depend on a greater level of symptom severity than other transdiagnostic cognitive biomarkers, or (iii) that task parameters, such as the ratio of compatible to incompatible trials, might be crucial for ensuring the sensitivity of the ERN to clinical phenomena.

A phase 1b/2 study of duvelisib in combination with FCR (DFCR) for frontline therapy for younger CLL patients

Fludarabine, cyclophosphamide, and rituximab (FCR) is highly effective initial therapy for younger patients with chronic lymphocytic leukemia (CLL); however, most eventually relapse. Duvelisib is a delta/gamma PI3K inhibitor approved for relapsed/refractory CLL. We conducted an investigator-initiated, phase 1b/2 study of duvelisib + FCR (DFCR) as initial treatment for CLL patients aged ≤65. A standard 3 + 3 design included two dose levels of duvelisib (25 mg qd and 25 mg bid). Duvelisib was given for 1 week, then with standard FCR added for up to six 28-day cycles, then up to 2 years of duvelisib maintenance. Thirty-two patients were enrolled. The phase 2 dose of duvelisib was identified as 25 mg bid. Hematologic toxicity was common, and all-grade non-hematologic toxicities included transaminitis (28%), febrile neutropenia (22%), pneumonia (19%), and colitis (6%). The best overall response rate by ITT was 88% (56% CR/CRi and 32% PR). The best rate of bone marrow undetectable minimal residual disease (BM-uMRD) by ITT was 66%. The rate of CR with BM-uMRD at end of combination treatment (primary endpoint) was 25%. Three-year PFS and OS are 73 and 93%, respectively. DFCR is active as initial therapy of younger CLL patients. Immune-mediated and infectious toxicities occurred and required active management.

Qualitative Evaluation of a Community-Based Physical Activity and Yoga Program for Men Living With Prostate Cancer: Survivor Perspectives

Purpose

Physical activity (PA) programs for prostate cancer survivors have positive effects on many aspects of health-related quality of life. Translating this research into sustainable community-based settings is necessary to ensure access to programs for survivors. This study examines patient perspectives in the community-based TrueNTH Lifestyle Management (TrueNTH LM) program in Calgary, Canada.

Methods

Eleven men from programs at civic wellness centers participated in 2 small semistructured focus groups (n = 5 and 6) at the University of Calgary. Motivation for program initiation and adherence, benefits and barriers to participation, and individual satisfaction and feedback on program improvement were discussed. Audio recordings were transcribed and analyzed using thematic methodology guided by a pragmatic philosophy on the patient experience in the program.

Results

Themes identified included perceived benefits of participating (physical, psychological, and social), facilitators for involvement in the PA program (program design, initial free access, tailored to prostate cancer specific needs, psychosocial environment), and opportunities for improvement and sustainability (exercise as a part of standard care, cost structure, home-based options).

Conclusions

These findings provide valuable insight into patient perspectives on effective characteristics of prostate cancer and exercise programs. TrueNTH LM has implemented findings, and ensuring needs (benefits and barriers) are addressed for prostate cancer survivors when entering community-based PA programs.

Ofatumumab plus high dose methylprednisolone followed by ofatumumab plus alemtuzumab to achieve maximal cytoreduction prior to allogeneic transplantation for 17p deleted or TP53 mutated chronic lymphocytic leukemia

We hypothesized that ofatumumab with sequential methylprednisolone - alemtuzumab would be an effective and tolerable regimen for patients with high-risk chronic lymphocytic leukemia (CLL) with TP53 dysfunction. Thirty CLL patients with TP53 dysfunction (15 treatment naive (TN), 15 relapsed/refractory (R/R)) were enrolled in this phase II study. Therapy included ofatumumab with methylprednisolone for 2-4 monthly cycles, then ofatumumab with alemtuzumab for 4-24 weeks, then allogeneic transplantation or maintenance. The rate of overall response, complete response, marrow minimal residual disease (MRD) negativity, 3-year progression-free survival and overall survival were 80, 13, 80, 53, and 66%, respectively, in TN patients and 68, 0, 54, 25, and 53%, respectively, in R/R patients. Notable grade 3/4 toxicities included neutropenia and infection in 43 and 40% of patients, respectively. At median follow-up of 45 months, 13 patients died, and 10 patients are alive posttransplant. Overall, we observed high rates of MRD-negativity and acceptable tolerability in high-risk CLL.

Abstract P2-04-02: Immunomodulatory effects of entinostat on PD-L1 and MHC class I and II in different subtypes of breast cancer

Background: Targeting immune checkpoint programmed death receptor 1 (PD-1)/PD-L1 pathway has shown promising clinical activity with some preliminary association of clinical benefit with PD-L1 expression on tumors. Recent preclinical and clinical studies highlight the beneficial immunomodulatory potential of epigenetic therapy. Entinostat is a class I specific histone deacetylase inhibitor (HDACi). A promising preclinical study showed that entinostat in combination with immune checkpoint blockade agent can eradicate modestly immunogenic breast tumors in mice via reduction in immunosuppressive myeloid-derived suppressor cells. In this study, we investigated the effects of entinostat on expression of immune-related genes in breast cancer cells to further explore the potential mechanism of its combined activity.

Method: Gene expression was assessed on Nanostring platform using the nCounter GX Human ImmunologyV2 panel comprised of 594 immune-related and 15 reference genes. Gene expression was normalized to the internal positive controls and reference genes using nSolver2.0 software. Hormone receptor-positive (HR+) breast cancer (MCF-7 and T47D) and triple negative breast cancer (TNBC) cell lines (MDA-MB-231 and Hs578T) were used for the analysis. Gene expression analysis was performed on control and after 24-hour treatment of entinostat at clinically relevant 125 and 500 nM concentrations.

Results: Overall, a greater number of immune-related genes were induced &gt; 2 fold with entinostat at 125 and 500 nM in TNBC compared to HR+: 77 and 118 genes in MDA-MB-231, 80 and 147 genes in Hs578T, 20 and 64 genes in MCF-7, and 73 and 72 genes in T47D, respectively. In particular, MHC class I (HLA-A, HLA-B, HLA-C) and II (HLA-DMA, HLA-DMB, HLA-DOA, HLA-DOB, HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQA2, HLA-DQB1, HLA-DQB2, HLA-DRA, and HLA-DRB1) genes were induced by entinostat in a dose dependent manner (range 1.5-22.44 fold). These inductions were observed in both HR+ and TNBC cell lines. Interestingly, we found higher baseline expression and a several fold increase in PD-L1 expression in TNBC. PD-L1 mRNA expression increased by 1.74 and 2.14 fold in MDA-MB-231 and 3 and 9.6 fold in Hs578T with 125 and 500 nM treatment, respectively. Corresponding increase in PD-L1 protein expression after entinostat treatment was also observed. In contrast, there appeared to be no significant changes in PD-L1 expression after entinostat treatment in MCF-7 and T47D. Furthermore, we also identified 21 genes that were differentially induced by entinostat in TNBC but not in HR+. These genes include PTPN22, ARG2, CISH, IL17A, ICAM2, KIR3DL1, CXCR3, TLR2, CFD, CCR5, IL13, LILRA3, IL8, TNFRSF9, DPP4, MR1, SELPLG, PTGS2, IL1B, CD3D, and MBL2. No significant change in PDL2 expression was observed in any of the cell lines.

Conclusion: Our data suggest that entinostat induces immune-related genes involved in antigen presentation in both ER+ and TNBC cells, potentially increasing the immunogenicity of these tumors. Given the significant induction of PD-L1 expression with entinostat in TNBC, our preclinical data provides support for further investigation of entinostat in combination with anti-PD1 or anti-PD-L1 in this subtype of breast cancer.

Citation Format: Chumsri S, Necela BM, Ordentlich P, Advani P, Moreno-Aspitia A, McLaughlin SA, Geiger X, McDonough M, Vallow LA, Perez EA, Thompson EA. Immunomodulatory effects of entinostat on PD-L1 and MHC class I and II in different subtypes of breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-04-02.

Abstract P4-01-11: Limits of [18F]-FLT PET as a clinical biomarker of proliferation in breast cancer

Background:

Imaging biomarkers of cellular division offer promise as non-invasive measures of tumor response. 3’-deoxy-3’[18F]-fluorothymidine ([18F]-FLT) positron emission tomography (PET) imaging generally correlates with pathology-based measurements of cancer proliferation, especially the Ki67 score. Though clinical studies have associated changes in [18F]-FLT uptake with therapeutic response, clinical studies validating its ability to assess cell proliferation are comparatively lacking. The goal of this study was to determine quantitative relationships between [18F]-FLT compared with molecular and cellular metrics of proliferation during treatment for locally advanced breast cancer (LABC).

Methods:

Baseline [18F]−FLT-PET scans were obtained prior to the initiation of chemotherapy for LABC from patients enrolled at several academic oncology study sites. MRI scans, and transmission CT scans were obtained. Core needle biopsies were obtained to determine Ki-67 indices using immuno-histochemistry and to assess an mRNA signature based measurement of proliferation. Prospectively specified quantitative relationships between PET, Ki67 immunohistochemistry and the mRNA signature were evaluated using image-matched tumor specimens. Correlations between volumetric MRI changes and pathologic responses were evaluated in a post-hoc exploratory analysis.

Results:

Motivated by the hypothesis that effective chemotherapies should decrease tumor cell proliferation, FLT-PET was compared with biomarkers of proliferation including Ki67 and the mRNA signature during neoadjuvant treatment for LABC. [18F]-FLT correlated both with the Ki67 labeling index (SUVmean r = 0.53) and with the proliferation signature (SUVmean r = 0.7), validating the principle of thymidine analogue imaging. However, variability in the [18F]-FLT PET and tumor cell proliferation measures likely contributed to correlations less than pre-specified target values considered appropriate for clinical use (r &gt; 0.78). Moreover, none of the proliferation biomarkers predicted pathologic complete responses at the end of neoadjuvant therapy ∼16 weeks after the 3 week response scan. In contrast, an evaluation of change in tumor volume measured by MRI after 3 weeks of therapy confirmed its superior ability to predict pCR and tumor re-staging.

Conclusion:

With large numbers of cancer drugs entering therapeutic pipelines, early efficacy measures remain critical for drug development. The 3-4 month neoadjuvant treatment paradigm for LABC offers unique opportunities for drug evaluation. Functional imaging using [18F]-FLT has been advanced as an assessor of cellular proliferation, potentially offering a non-invasive approach to response evaluation. While [18F]-FLT generally correlated with proliferation, its lack of association with patient responses likely limit its clinical utility. On the other hand, the predictive value of MRI offers unique opportunities for future trial designs and confirms previous reports (1).

1. N. M. Hylton et al., Locally advanced breast cancer: MR imaging for prediction of response to neoadjuvant chemotherapy. Radiology 263, 663 (2012).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-01-11.

Substance abuse in young patients with type 1 diabetes: easily neglected in complex medical management

The use of recreational drugs has become increasingly popular among young people. As a centre caring for a large group of young patients with type 1 diabetes, we have become concerned about the number of patients presenting with drug-related metabolic problems. We present a case series highlighting the issues of substance abuse in young patients with type 1 diabetes.

Saving clinicians' time by delegating routine aspects of therapy to a computer: a randomized controlled trial in phobia/panic disorder

BACKGROUND

The demand for time-consuming psychotherapy of phobia/panic exceeds the supply of trained therapists. Delegating routine therapy aspects to a computer might ease this problem.

METHOD

Ninety-three out-patients with phobia or panic disorder were randomized in a 2: 2 : 1 ratio to have self-exposure therapy guided either mainly by a stand-alone computer system (FearFighter) or entirely face-to-face by a clinician, or to have mainly computer-guided self-relaxation as a placebo. Both computer groups (FearFighter and relaxation) had brief back-up advice from a clinician. Primary outcome measures were self- and blind-assessor ratings of Main Problem and Goals, and Global Phobia.

RESULTS

Drop-outs occurred significantly more often in the two self-exposure groups (43% if mainly computer-guided, 24% if entirely clinician-guided) than with self-relaxation (6%); the difference between the two self-exposure groups was not significant. Even with all drop-outs included, the mainly computer-guided exposure group and the relaxation group had 73% less clinician time per patient than did the entirely clinician-guided exposure group. The two self-exposure groups had comparable improvement and satisfaction at post-treatment and at 1-month follow-up, while relaxation was ineffective. Mean improvement on the primary outcome measures (self- and assessor-rated) was 46% computer, 49% clinician, 9% relaxation at post-treatment (week 10) and 58% computer, 53% clinician and -4% relaxation at 1-month follow-up (week 14). Mean effect sizes on the primary outcome measures were 2.9 computer, 3.5 clinician and 0.5 relaxation at post-treatment; and 3.7 computer, 3.5 clinician and 0.5 relaxation at 1-month follow-up. The assessor did not rate patients at follow-up.

CONCLUSIONS

Despite its (non-significantly) higher dropout rate, self-exposure therapy for panic/ phobia cut clinician time per patient by 73% without losing efficacy when guided mainly by a computer rather than entirely by a clinician. The finding needs confirmation at a follow-up that is longer and includes a blind assessor. Self-relaxation had the highest rate of completers but was ineffective.

Pharmacological management of obsessive-compulsive disorder: a review for clinicians

Obsessive-compulsive disorder (OCD) has been treated pharmacologically with drugs that enhance availability of the neurotransmitter serotonin. This review summarizes the available literature on the pharmacological treatments of OCD. Numerous randomized controlled trials have attested to the efficacy of serotonin-reuptake inhibitors (SRIs) in treating this disorder, although a coherent model of serotonin dysfunction in OCD has not been established. Meta-analyses of randomized controlled trials have found better results with clomipramine than with other SRIs, but comparative studies have so far not replicated this finding. Aspects of the methodology in these studies that might explain this discrepancy are considered. Tolerability, side effects, dosing, and safety during pregnancy of the SRIs are discussed. Treatment of OCD with poor insight and of OCD comorbid with a tic disorder, augmentation strategies, and management of partial response to SRIs are reviewed. Finally, the available interventions for refractory OCD are considered.

Erotomania revisited: clinical course and treatment

Erotomania is a rare disorder in which an individual has a delusional belief that a person of higher social status falls in love and makes amorous advances towards him/her. Little is known about the background, classification, treatment, or outcome of individuals with this disorder. The purpose of this study was to evaluate current criteria for diagnosing and classifying primary and secondary erotomania in addition to examining course, outcome, and impact on victims of erotomania. Semistructured interviews covering personal and family details in addition to treatment and outcome to date were performed on a series of erotomanic patients identified in a defined area. Evaluation of diagnosis used DSM-IV and other criteria. Fifteen erotomanic subjects (11 female, four male) were identified. Most were isolated, without a partner or full-time occupation. Forty percent had a first-degree relative with a psychiatric history and of those half had a first-degree relative with a mono-delusional disorder. Less than half of the objects of their affection, mainly noncelebrities, were subject to harassment. Subjects with primary erotomania and erotomania secondary to other psychiatric diagnoses were identified using DSM-IV criteria. Ellis and Mellsop's criteria were found to be useful in assessing erotomania but we could not replicate Seeman's fixed and recurrent groups. Treatment and outcome was better than expected particularly for those with primary erotomania and erotomanics with a diagnosis of bipolar affective disorder. In this series, erotomanic symptoms largely occurred in the context of other psychiatric disorders, although subjects with pure erotomanic symptoms were seen. Subjects were less dangerous and engaged in less harassment of victims than the literature suggests. Subjects were often isolated, unemployed, and with few social contacts. Strong family psychiatric histories were seen particularly with regard to mono-delusional disorders raising the possibility of genetic inheritance. An adaptation of Ellis and Mellsop's criteria was suggested for the diagnosis of primary and secondary erotomania. Response to treatment and prognosis was good, particularly for primary erotomania and erotomania secondary to bipolar affective disorder.

Olanzapine for chronic, stereotypic self-injurious behaviour: a pilot study in seven adults with intellectual disability

Dopamine one (D1) receptor supersensitvity in the corpus striatum is said to be the primary mechanism within the dopamine model proposed for chronic, refractory self-injurious behaviour (SIB), which may explain why conventional neuroleptics have proven largely ineffective. In common with other atypical antipsychotic agents, olanzapine has more affinity for the D1 receptor. The present study explored whether olanzapine could reduce rates of the stereotypic form of chronic SIB, a subtype where dopamine dysfunction is the most likely underlying mechanism. A clinical sample of seven patients with various levels of learning disability who displayed features of stereotypic SIB were assessed over a 6-week period of baseline measurement and a 15-week treatment phase during which olanzapine was added to existing medication. Both SIB and other aberrant behaviours were measured by daily nurse rating and the Self-Injury Trauma Scale (SITS). All measurements were unblind. Doses ranged from 5 to 15 mg. Out of the seven subjects, three showed a clear improvement, one showed a marginal improvement, one deteriorated, and the data was equivocal for the remaining two individuals. The means of the SITS Number and Severity Indices (NI and SI, respectively) reduced significantly from baseline during both the 5- and 10-mg treatment phases, and taking treatment as a whole, by 53% and 48%, respectively (NI: mean = 0.7 units reduction, P = 0.02; SI: mean = 0.9 units reduction, P = 0.04). The risk index also reduced, but did not reach significance. A modest reduction in mean nurse-rated SIB was not significant for either phase or for treatment as a whole. At doses above 5mg, mean scores deteriorated on balance, although two responders showed a marginal additional improvement. Olanzapine was well tolerated with one adverse event reported (somnolence) which was mild and transient. The present pilot study suggests that olanzapine can reduce stereotypic SIB. A larger trial is indicated.

A role for POR1, a Rac1-interacting protein, in ARF6-mediated cytoskeletal rearrangements

The ARF6 GTPase, the least conserved member of the ADP ribosylation factor (ARF) family, associates with the plasma membrane and intracellular endosome vesicles. Mutants of ARF6 defective in GTP binding and hydrolysis have a marked effect on endocytic trafficking and the gross morphology of the peripheral membrane system. Here we report that expression of the GTPase-defective mutant of ARF6, ARF6(Q67L), remodels the actin cytoskeleton by inducing actin polymerization at the cell periphery. This cytoskeletal rearrangement was inhibited by co-expression of ARF6(Q67L) with deletion mutants of POR1, a Rac1-interacting protein involved in membrane ruffling, but not with the dominant-negative mutant of Rac1, Rac1(S17N). A synergistic effect between POR1 and ARF6 for the induction of actin polymerization was detected. Furthermore, we observed that ARF6 interacts directly with POR1 and that this interaction was GTP dependent. These findings indicate that ARF6 and Rac1 function on distinct signaling pathways to mediate cytoskeletal reorganization, and suggest a role for POR1 as an important regulatory element in orchestrating cytoskeletal rearrangements at the cell periphery induced by ARF6 and Rac1.

RAC regulation of actin polymerization and proliferation by a pathway distinct from Jun kinase

The RAC guanine nucleotide binding proteins regulate multiple biological activities, including actin polymerization, activation of the Jun kinase (JNK) cascade, and cell proliferation. RAC effector loop mutants were identified that separate the ability of RAC to interact with different downstream effectors. One mutant of activated human RAC protein, RACV12H40 (with valine and histidine substituted at position 12 and 40, respectively), was defective in binding to PAK3, a Ste20-related p21-activated kinase (PAK), but bound to POR1, a RAC-binding protein. This mutant failed to stimulate PAK and JNK activity but still induced membrane ruffling and mediated transformation. A second mutant, RACV12L37 (with leucine substituted at position 37), which bound PAK but not POR1, induced JNK activation but was defective in inducing membrane ruffling and transformation. These results indicate that the effects of RAC on the JNK cascade and on actin polymerization and cell proliferation are mediated by distinct effector pathways that diverge at the level of RAC itself.

Exercise and resting pulmonary function in sarcoidosis

Patients with sarcoidosis frequently complain of exercise intolerance but reports of the value of static tests of pulmonary function in predicting disability have been contradictory. We studied 32 patients with sarcoidosis and dyspnea, correlating x-ray stages, spirometry and lung volume measurements with graded exercise testing. Patients demonstrated a reduction in maximum workload (Wmax) when compared to an age matched group of 7 normal subjects (p < 0.05). While ventilation (VEmax) at Wmax was lower in patients, when adjusted for workload (V/E/watt) there was relative hyperventilation (p < 0.05). Exercise induced arterial desaturation (PaO2 decrease) was significantly related to resting DLCO% predicted (r = 0.74, p < 0.05). When patients were separated into subgroups of > < DLCO 55% predicted, the lower diffusing capacity group had a lower Wmax and greater fall in exercise PaO2. Chest radiograph staging and the vital capacity proved to be poor predictors of exercise capacity though maximum impairment was associated with advanced x-ray changes and greater decreases in vital capacity. In conclusion, the magnitude of functional impairment may vary widely from apparent histopathologic involvement as reflected by chest x-ray and lung volumes. Actual exercise testing is necessary to accurately characterize and quantitate the impairment in patients with sarcoidosis complaining of dyspnea.

Novel CDC34 (UBC3) ubiquitin-conjugating enzyme mutants obtained by charge-to-alanine scanning mutagenesis

CDC34 (UBC3) encodes a ubiquitin-conjugating (E2) enzyme required for transition from the G1 phase to the S phase of the budding yeast cell cycle. CDC34 consists of a 170-residue catalytic N-terminal domain onto which is appended an acidic C-terminal domain. A portable determinant of cell cycle function resides in the C-terminal domain, but determinants for specific function must reside in the N-terminal domain as well. We have explored the utility of "charge-to-alanine" scanning mutagenesis to identify novel N-terminal domain mutants of CDC34 that are enzymatically competent with respect to unfacilitated (E3-independent) ubiquitination but that nevertheless are defective with respect to its cell cycle function. Such mutants may reveal determinants of specific in vivo function, such as those required for interaction with substrates or trans-acting regulators of activity and substrate selectivity. Three of 18 "single-scan" mutants (in which small clusters of charged residues were mutated to alanine) were compromised with respect to in vivo function. One mutant (cdc34-109, 111, 113A) targeted a 12-residue segment of the Cdc34 protein not found in most other E2s and was unable to complement a cdc34 null mutant at low copy numbers but could complement a null mutant when overexpressed from an induced GAL1 promoter. Combining adjacent pairs of single-scan mutants to produce "double-scan" mutants yielded four additional mutants, two of which showed heat and cold sensitivity conditional defects. Most of the mutant proteins expressed in Escheria coli displayed unfacilitated (E3-independent) ubiquitin-conjugating activity, but two mutants differed from wild-type and other mutant Cdc34 proteins in the extent of multiubiquitination they catalyzed during an autoubiquitination reation-conjugating enzyme function and have identified additional mutant alleles of CDC34 that will be valuable in further genetic and biochemical studies of Cdc34-dependent ubiquitination.

Characterization of novel yeast RAD6 (UBC2) ubiquitin-conjugating enzyme mutants constructed by charge-to-alanine scanning mutagenesis

Ubiquitination of intracellular proteins by the yeast RAD6 (UBC2) ubiquitin-conjugating (E2) enzyme is required for cellular processes as diverse as DNA repair, selective proteolysis, and normal growth. For most RAD6-dependent functions, the relevant in vivo targets, as well as the mechanisms and cofactors that govern RAD6 substrate selectivity, are unknown. We have explored the utility of "charge-to-alanine" scanning mutagenesis to generate novel RAD6 mutants that are enzymatically competent with respect to unfacilitated (E3-independent) ubiquitination but that are nevertheless severely handicapped with respect to several in vivo functions. Five of the nine mutants we generated show defects in their in vivo functions, but almost all of the most severely affected mutants displayed unfacilitated ubiquitin-conjugating activity in vitro. We suggest that E2 mutants obtained by this approach are likely to be defective with respect to interaction with other, trans-acting factors required for their intracellular activity or substrate selectivity and therefore will be useful for further genetic and biochemical studies of ubiquitin-conjugating enzyme function.

Construction and initial characterization of a mouse-human chimeric anti-TNF antibody

Tumor necrosis factor-alpha (TNF) has been implicated in the pathogenesis of a variety of human diseases including septic shock, cachexia, graft-versus-host disease and several autoimmune diseases. Monoclonal antibodies directed against TNF provide an attractive mode of therapeutic intervention in these diseases. We have generated a murine monoclonal antibody (A2) with high affinity and specificity for recombinant and natural human TNF. To increase its therapeutic usefulness, we used genetic engineering techniques to replace the murine constant regions with human counterparts while retaining the murine antigen binding regions. The resulting mouse-human chimeric antibody should have reduced immunogenicity and improved pharmacokinetics in humans. Molecular analysis of light chain genomic clones derived from the murine hybridoma suggests that two different alleles of the same variable region gene have rearranged independently and coexist in the same hybridoma cell. The chimeric A2 antibody (cA2) exhibits better binding and neutralizing characteristics than the murine A2 which was shown to contain a mixture of two kappa light chains. The properties of cA2 suggest that it will have advantages over existing murine anti-TNF antibodies for clinical use.

Lung transplantation in New Jersey

Single- or bilateral-lung transplantation is an effective treatment for end-stage pulmonary diseases. Refinements in the surgical technique and postoperative management of recipients have resulted in a return to normal function in most cases and a one-year survival in 70 percent of patients.

Stable expression of cloned human antibody genes in murine myeloma cells

Human monoclonal antibodies (MAbs) offer potential advantages over murine MAbs for therapy because they are not likely to elicit immune responses and are expected to interact more efficiently with the human immune system to activate therapeutically useful functions. Traditional methods for obtaining human MAbs (i.e., immortalization of B cells by cell fusion or transformation) can result in low and unstable antibody secretion. Recently, methods have been devised for direct cloning of human variable region genes via polymerase chain reaction and phage combinatorial libraries. Both types of human MAb production can benefit from expression systems that support the stable, high-level antibody secretion required for therapeutic use. Using an existing human-derived hybridoma that secretes a human IgM antibody as a convenient source of antibody genes, we have demonstrated that cloned human antibody genes can be efficiently expressed in murine myeloma cells and that cell lines with properties suitable for large-scale economical production can be obtained. We were unable to detect any differences between the antibodies produced by the original hybridoma and the engineered cell line. In addition, we were able to express an IgG form of the antibody, showing that expression of a recombinant human antibody need not be limited to the original antibody class.

Late auditory evoked potentials in alcoholics. Identifying those with a history of epileptic seizures during withdrawal

The N1-P2 wave of the auditory evoked potential was studied in 19 alcoholics, six of whom had withdrawal seizures on previous admissions. The recordings were made at 1 and 5 days after cessation of drinking. Eight nonalcoholic volunteers were used as controls. The latencies of N1 and P2 were slightly prolonged in alcoholics, but during the detoxification period they frequently shortened (p less than 0.05), occasionally attaining the values of the controls. One day after withdrawal, the amplitude of N1-P2 was consistently reduced in the alcoholics compared to the controls (p less than 0.05 and p less than 0.01), but higher in alcoholics with a seizure history compared to alcoholics without seizures (p less than 0.05 and p less than 0.001). Five days after cessation of drinking, the amplitude in the alcoholic groups always increased from the admission values (p less than 0.05 and p less than 0.01). By that time, the alcoholics with a history of withdrawal seizures had significantly (p less than 0.05 and p less than 0.01) higher amplitudes than those of the controls or the alcoholics without seizures. Large N1-P2 amplitude during alcohol withdrawal may reflect increased cerebral excitability and contribute to the identification of alcoholics with high risk for withdrawal seizures.

Cardiac sarcoidosis. A case with unusual manifestation

A 26-year-old woman was hospitalized with new-onset congestive heart failure. M-mode and two-dimensional echocardiography revealed abnormal motion involving the apex and posterolateral wall of the left ventricle. Cardiac catheterization was performed. The left ventriculogram demonstrated apical akinesis and an apical filling defect. The diagnosis of cardiac sarcoidosis was made from an open myocardial biopsy.

Inhibition of platelet phospholipid methylation during platelet secretion

A pathway for the synthesis of membrane phosphatidylcholine involving the N-methylation of phosphatidylethanolamine has been detected in several types of mammalian cells. Furthermore, it has been implicated in the coupling of agonist binding to cell response. We examined whether human platelets exhibit this synthetic pathway and whether platelet agonists influence its activity. When washed platelets were incubated with 0.15 microM L-[methyl-3H]methionine at 37 degrees C, they incorporated methyl-3H into their phospholipids linearly at the rate of 1 pmole/10(9) platelets/hr. When incubated with 20 microM radiolabeled methionine, they incorporated about 15 pmole/10(9) platelets/hr. The radioactivity was found predominantly in phosphatidyl-N-monomethylethanolamine, phosphatidyl-N,N-dimethylethanolamine, and phosphatidylcholine. Thrombin caused an immediate (within 15 sec) and sustained (up to 30 min) decrease in the rate and extent of N-methylation of platelet phospholipids. This was accounted for by a decrease in synthesis of methylated phospholipids rather than an increase in their degradation. This thrombin effect correlated with serotonin release and could be dissociated from platelet aggregation and prostaglandin synthesis. Thrombin also decreased the synthesis of phosphatidylcholine when choline was used as the radiolabeled substrate. Other agonists such as epinephrine, adenosine diphosphate (ADP), or A23187 also decreased phospholipid methylation under conditions in which they stimulated serotonin release. These data demonstrate that platelets are capable of synthesizing phosphatidylcholine from phosphatidylethanolamine by N-methylation and that agonists perturb this pathway as they induce platelet secretion. The precise role of phospholipid methylation in either resting or stimulated platelets remains to be established.

Carbenicillin and penicillin G inhibit platelet function in vitro by impairing the interaction of agonists with the platelet surface

Carbenicillin or penicillin G administered in large doses can cause a bleeding diathesis as a result of platelet dysfunction. These antibiotics also inhibit platelet aggregation in vitro, although several-fold larger concentrations of drug are required to demonstrate this effect. We wondered whether these antibiotics might impair platelet function by interfering with the initial step of platelet activation: the binding of agonists to their specific receptors on the platelet surface.Platelet aggregation and [(14)C]serotonin release induced by epinephrine were competitively inhibited by carbenicillin and penicillin G in vitro. At antibiotic concentrations that inhibited platelet function by more than 80%, the affinity of platelet alpha-adrenergic receptors for the alpha-adrenergic antagonist, [(3)H]dihydroergocryptine, and for epinephrine was reduced twofold by carbenicillin and sixfold by penicillin G (P < 0.01). Platelet aggregation and [(14)C]serotonin release stimulated by ADP were also competitively inhibited by these antibiotics. In addition, carbenicillin reduced the incorporation of an ADP affinity label, 5'-p-fluorosulfonylbenzoyl [(3)H]adenosine, into its binding protein in platelet membranes. Moreover, both carbenicillin and penicillin G impaired the interaction of von Willebrand factor with platelets as evidenced by their inhibition of the agglutination of formalin-fixed platelets by ristocetin, snake venom, or bovine factor VIII. These studies demonstrate that carbenicillin and penicillin G inhibit platelet function in vitro by impairing the interaction of several agonists with their specific receptors on the platelet surface membrane. If this were mechanism operative in vivo, it could account for the hemorrhagic as well as the potential antithrombotic effects of these antibiotics.

Carbenicillin and Penicillin G Impair Platelet Function by Inhibiting the Binding of Agonists to the Platelet Surface

Carbenicillin (carb) and penicillin G (pen) inhibit human platelet function in vivo and can cause a bleeding diathesis. Since the mechanism by which these drugs inhibit platelets is unknown, we investigated whether they might interfere with the binding of epinephrine, ADP, or ristocetin (von Willebrand factor) to the platelet surface in vitro. Pen (10 mM) or carb (20 mM) produced a 6-fold decrease in the affinity of receptors on intact platelets for both epinephrine and for the α-adrenergic antagonist, 3U-dihydroer-gocryptine (p < 0.001). Neither antibiotic changed the maximum number of α-adrenergic binding sites per platelet. Pen and carb at these concentrations completely inhibited 14C-serotonin release induced by 1 μM epinephrine and inhibited primary platelet aggregation by 1 μM. Similarly, these antibiotics inhibited aggregation and serotonin release induced by 1 μM ADP and inhibited the covalent binding of an ADP analogue (5'FSO2BZAdo) to its specific binding protein in platelet membranes. Moreover, pen and carb inhibited competitively the agglutination of platelets by ristocetin. Thus, carbenicillin and penicillin G decrease the affinity of a number of distinct platelet receptors for their specific agonists, and this correlates with inhibition of platelet function induced by these agonists. Interaction of these antibiotics with the platelet surface membrane may account for their hemorrhagic as well as their anti-thrombotic activity.

Platelet function in essential thrombocythemia. Decreased epinephrine responsiveness associated with a deficiency of platelet alpha-adrenergic receptors

Platelets from two patients with essential thrombocythemia failed to aggregate or release serotonin in response to concentrations of epinephrine that aggregated platelets from normal controls. Therefore, we studied their alpha-adrenergic receptors, using 3H-dihydroergocryptine (3H-DHE), an alpha-adrenergic antagonist. These platelets contained an average (mean +/- S.E.) of 210 +/- 18 and 227 +/- 27 3H-DHE binding sites per platelet--less than half that found on control platelets, 464 +/- 37 (P less than 0.01). In contrast, platelets from two other patients with essential thrombocythemia responded to epinephrine and contained a normal number of 3H-DHE sites. Platelets in essential thrombocythemia demonstrated normal kinetics of 3H-DHE binding and normal affinities for 3H-DHE and for epinephrine. When control platelets were preincubated with a half-saturating concentration of 3H-DHE, there was a diminution of epinephrine-induced platelet function comparable to that seen in essential thrombocythemia. Thus, a deficiency of alpha-adrenergic receptors may account for diminished functional responsiveness of platelets to epinephrine in some patients with essential thrombocythemia.

Elevation of platelet factor four in acute myocardial infarction: measurement by radioimmunoassay

A radioimmunoassay has been developed for the measurement of PF-4--a chemically well-defined heparin-neutralizing molecule. PF-4 was iodinated, repurified by affinity chromatography on heparin-Sepharose, and incubated with rabbit antiserum and a source of unlabeled antigen. Following incubation at 4 degrees C for 24 hr, bound PF-4 was precipitated with 2.2M ammonium sulfate. The assay, which could detect 25 pg of purified PF-4, was unaffected by the presence of plasma containing up to 50 U/ml heparin. The plasma concentration of PF-4 in 30 normal subjects was 16 +/- 4 ng/ml. This level was increased in patients with pulmonary emboli, prosthetic cardiac valves, and severe cardiorespiratory failure. In addition, 21 of 50 patients admitted to the hospital with acute chest pain who had sustained a myocardial infarct had a mean level of 95 ng/ml. In contrast, the mean level in 21 patients with chest pain but without evidence of infarction was 29 ng/ml. PF-4 remained elevated for at least 1 week after infarction in six of the eight patients studied and then returned to within the normal range. The data suggest that radioimmunoassay of PF-4 may be a useful test to measure activation of the coagulation system and an aid to the diagnosis and treatment of patients with thromboembolic disorders.