Reasons for multiple biologic and targeted synthetic DMARD switching and characteristics of treatment refractory rheumatoid arthritis.

OBJECTIVE: Switching biologic and targeted synthetic DMARD (b/tsDMARD) medications occurs commonly in RA patients, however data are limited on the reasons for these changes. The objective of the study was to identify and categorize reasons for b/tsDMARD switching and investigate characteristics associated with treatment refractory RA. METHODS: In a multi-hospital RA electronic health record (EHR) cohort, we identified RA patients prescribed ≥1 b/tsDMARD between 2001 and 2017. Consistent with the EULAR "difficult to treat" (D2T) RA definition, we further identified patients who discontinued ≥2 b/tsDMARDs with different mechanisms of action. We performed manual chart review to determine reasons for medication discontinuation. We defined "treatment refractory" RA as not achieving low disease activity (<3 tender or swollen joints on <7.5 mg of daily prednisone equivalent) despite treatment with two different b/tsDMARD mechanisms of action. We compared demographic, lifestyle, and clinical factors between treatment refractory RA and b/tsDMARD initiators not meeting D2T criteria. RESULTS: We identified 6040 RA patients prescribed ≥1 b/tsDMARD including 404 meeting D2T criteria. The most common reasons for medication discontinuation were inadequate response (43.3 %), loss of efficacy (25.8 %), and non-allergic adverse events (13.7 %). Of patients with D2T RA, 15 % had treatment refractory RA. Treatment refractory RA patients were younger at b/tsDMARD initiation (mean 47.2 vs. 55.2 years, p < 0.001), more commonly female (91.8% vs. 76.1 %, p = 0.006), and ever smokers (68.9% vs. 49.9 %, p = 0.005). No RA clinical factors differentiated treatment refractory RA patients from b/tsDMARD initiators. CONCLUSIONS: In a large EHR-based RA cohort, the most common reasons for b/tsDMARD switching were inadequate response, loss of efficacy, and nonallergic adverse events (e.g. infections, leukopenia, psoriasis). Clinical RA factors were insufficient for differentiating b/tsDMARD responders from nonresponders.

Assessing the Severity of COVID-19 Lung Injury in Rheumatic Diseases Versus the General Population Using Deep Learning-Derived Chest Radiograph Scores.

OBJECTIVE: COVID-19 patients with rheumatic disease have a higher risk of mechanical ventilation than the general population. The present study was undertaken to assess lung involvement using a validated deep learning algorithm that extracts a quantitative measure of radiographic lung disease severity. METHODS: We performed a comparative cohort study of rheumatic disease patients with COVID-19 and ≥1 chest radiograph within ±2 weeks of COVID-19 diagnosis and matched comparators. We used unadjusted and adjusted (for age, Charlson comorbidity index, and interstitial lung disease) quantile regression to compare the maximum pulmonary x-ray severity (PXS) score at the 10th to 90th percentiles between groups. We evaluated the association of severe PXS score (>9) with mechanical ventilation and death using Cox regression. RESULTS: We identified 70 patients with rheumatic disease and 463 general population comparators. Maximum PXS scores were similar in the rheumatic disease patients and comparators at the 10th to 60th percentiles but significantly higher among rheumatic disease patients at the 70th to 90th percentiles (90th percentile score of 10.2 versus 9.2; adjusted P = 0.03). Rheumatic disease patients were more likely to have a PXS score of >9 (20% versus 11%; P = 0.02), indicating severe pulmonary disease. Rheumatic disease patients with PXS scores >9 versus ≤9 had higher risk of mechanical ventilation (hazard ratio [HR] 24.1 [95% confidence interval (95% CI) 6.7, 86.9]) and death (HR 8.2 [95% CI 0.7, 90.4]). CONCLUSION: Rheumatic disease patients with COVID-19 had more severe radiographic lung involvement than comparators. Higher PXS scores were associated with mechanical ventilation and will be important for future studies leveraging big data to assess COVID-19 outcomes in rheumatic disease patients.

Prolonged COVID-19 symptom duration in people with systemic autoimmune rheumatic diseases: results from the COVID-19 Global Rheumatology Alliance Vaccine Survey.

OBJECTIVE: We investigated prolonged COVID-19 symptom duration, defined as lasting 28 days or longer, among people with systemic autoimmune rheumatic diseases (SARDs). METHODS: We analysed data from the COVID-19 Global Rheumatology Alliance Vaccine Survey (2 April 2021-15 October 2021) to identify people with SARDs reporting test-confirmed COVID-19. Participants reported COVID-19 severity and symptom duration, sociodemographics and clinical characteristics. We reported the proportion experiencing prolonged symptom duration and investigated associations with baseline characteristics using logistic regression. RESULTS: We identified 441 respondents with SARDs and COVID-19 (mean age 48.2 years, 83.7% female, 39.5% rheumatoid arthritis). The median COVID-19 symptom duration was 15 days (IQR 7, 25). Overall, 107 (24.2%) respondents had prolonged symptom duration (≥28 days); 42/429 (9.8%) reported symptoms lasting ≥90 days. Factors associated with higher odds of prolonged symptom duration included: hospitalisation for COVID-19 vs not hospitalised and mild acute symptoms (age-adjusted OR (aOR) 6.49, 95% CI 3.03 to 14.1), comorbidity count (aOR 1.11 per comorbidity, 95% CI 1.02 to 1.21) and osteoarthritis (aOR 2.11, 95% CI 1.01 to 4.27). COVID-19 onset in 2021 vs June 2020 or earlier was associated with lower odds of prolonged symptom duration (aOR 0.42, 95% CI 0.21 to 0.81). CONCLUSION: Most people with SARDs had complete symptom resolution by day 15 after COVID-19 onset. However, about 1 in 4 experienced COVID-19 symptom duration 28 days or longer; 1 in 10 experienced symptoms 90 days or longer. Future studies are needed to investigate the possible relationships between immunomodulating medications, SARD type/flare, vaccine doses and novel viral variants with prolonged COVID-19 symptoms and other postacute sequelae of COVID-19 among people with SARDs.

Temporal trends in COVID-19 outcomes among patients with systemic autoimmune rheumatic diseases: from the first wave through the initial Omicron wave.

OBJECTIVES: To investigate temporal trends in incidence and severity of COVID-19 among patients with systemic autoimmune rheumatic diseases (SARDs) from the first wave through the initial Omicron wave. METHODS: We conducted a retrospective cohort study investigating COVID-19 outcomes among patientswith SARD systematically identified to have confirmed COVID-19 from 1 March 2020 to 31 January 2022 at Mass General Brigham. We tabulated COVID-19 counts of total and severe cases (hospitalisations or deaths) and compared the proportion with severe COVID-19 by calendar period and by vaccination status. We used logistic regression to estimate the ORs for severe COVID-19 for each period compared with the early COVID-19 period (reference group). RESULTS: We identified 1449 patients with SARD with COVID-19 (mean age 58.4 years, 75.2% female, 33.9% rheumatoid arthritis). There were 399 (28%) cases of severe COVID-19. The proportion of severe COVID-19 outcomes declined over calendar time (p for trend <0.001); 46% of cases were severe in the early COVID-19 period (1 March 2020-30 June 2020) vs 15% in the initial Omicron wave (17 December 2021-31 January 2022; adjusted OR 0.29, 95% CI 0.19 to 0.43). A higher proportion of those unvaccinated were severe compared with not severe cases (78% vs 60%). CONCLUSIONS: The proportion of patients with SARD with severe COVID-19 has diminished since early in the pandemic, particularly during the most recent time periods, including the initial Omicron wave. Advances in prevention, diagnosis and treatment of COVID-19 may have improved outcomes among patients with SARD.

Temporal trends in COVID-19 outcomes among patients with systemic autoimmune rheumatic diseases: From the first wave to Omicron.

Objectives: To investigate temporal trends in incidence and severity of COVID-19 among patients with systemic autoimmune rheumatic diseases (SARDs) from the first wave through the Omicron wave. Methods: We conducted a retrospective cohort study investigating COVID-19 outcomes among SARD patients systematically identified to have confirmed COVID-19 from March 1, 2020 to January 31, 2022 at a large healthcare system in Massachusetts. We tabulated COVID-19 counts of total and severe cases (hospitalizations or deaths) and compared the proportion with severe COVID-19 by calendar period and by vaccination status. We used logistic regression to estimate the ORs for severe COVID-19 for each period compared to the early COVID-19 period (reference group). Results: We identified 1449 SARD patients with COVID-19 (mean age 58.4 years, 75.2% female, 33.9% rheumatoid arthritis). There were 399 (27.5%) cases of severe COVID-19. The proportion of severe COVID-19 outcomes declined over calendar time (p for trend <0.001); 45.6% of cases were severe in the early COVID-19 period (March 1-June 30, 2020) vs. 14.7% in the Omicron wave (December 17, 2021-January 31, 2022; adjusted odds ratio 0.29, 95%CI 0.19-0.43). A higher proportion of those unvaccinated were severe compared to not severe cases (78.4% vs. 59.5%). Conclusions: The proportion of SARD patients with severe COVID-19 has diminished since early in the pandemic, particularly during the most recent time periods, including the Omicron wave. Advances in prevention, diagnosis, and treatment of COVID-19 may have improved outcomes among SARD patients. KEY MESSAGES: What is already known about this subject?: Patients with systemic autoimmune rheumatic diseases (SARDs) may be at increased risk for severe COVID-19, defined as hospitalization or death.Previous studies of SARD patients suggested improving COVID-19 outcomes over calendar time, but most were performed prior to the wide availability of COVID-19 vaccines or the Omicron wave that was characterized by high infectivity.What does this study add?: The proportion of SARD patients with severe COVID-19 outcomes was lower over calendar timeThe adjusted odds ratio of severe COVID-19 in the Omicron wave was 0.29 (95%CI 0.19-0.43) compared to early COVID-19 period.The absolute number of severe COVID-19 cases during the peak of the Omicron variant wave was similar to the peaks of other waves.SARD patients with severe vs. not severe COVID-19 were more likely to be unvaccinated.How might this impact on clinical practice or future developments?: These findings suggest that advances in COVID-19 prevention, diagnosis, and treatment have contributed to improved outcomes among SARD patients over calendar time.Future studies should extend findings into future viral variants and consider the roles of waning immunity after vaccination or natural infection among SARD patients who may still be vulnerable to severe COVID-19.

Batf-mediated epigenetic control of effector CD8+ T cell differentiation.

The response of naive CD8+ T cells to their cognate antigen involves rapid and broad changes to gene expression that are coupled with extensive chromatin remodeling, but the mechanisms governing these changes are not fully understood. Here, we investigated how these changes depend on the basic leucine zipper ATF-like transcription factor Batf, which is essential for the early phases of the process. Through genome scale profiling, we characterized the role of Batf in chromatin organization at several levels, including the accessibility of key regulatory regions, the expression of their nearby genes, and the interactions that these regions form with each other and with key transcription factors. We identified a core network of transcription factors that cooperated with Batf, including Irf4, Runx3, and T-bet, as indicated by their colocalization with Batf and their binding in regions whose accessibility, interactions, and expression of nearby genes depend on Batf. We demonstrated the synergistic activity of this network by overexpressing the different combinations of these genes in fibroblasts. Batf and Irf4, but not Batf alone, were sufficient to increase accessibility and transcription of key loci, normally associated with T cell function. Addition of Runx3 and T-bet further contributed to fine-tuning of these changes and was essential for establishing chromatin loops characteristic of T cells. These data provide a resource for studying the epigenomic and transcriptomic landscape of effector differentiation of cytotoxic T cells and for investigating the interdependency between transcription factors and its effects on the epigenome and transcriptome of primary cells.

Coronavirus Disease 2019 Outcomes Among Recipients of Anti-CD20 Monoclonal Antibodies for Immune-Mediated Diseases: A Comparative Cohort Study.

OBJECTIVE: Patients with immune-mediated diseases treated with anti-CD20 monoclonal antibodies may have worse coronavirus disease 2019 (COVID-19) outcomes due to impaired humoral immunity, but differences compared with the general population are unknown. METHODS: We identified patients with immune-mediated diseases who received anti-CD20 monoclonal antibodies within 1 year prior to the index date of polymerase chain reaction-confirmed COVID-19 between January 31, 2020, and January 31, 2021. General population comparators with COVID-19 were matched up 5:1 by age, sex, and polymerase chain reaction date. Unadjusted and multivariable adjusted (for age, race, body mass index, and Charlson Comorbidity Index) hazard ratios (HRs) and 95% confidence intervals (CIs) for hospitalization, mechanical ventilation, and death in recipients of anti-CD20 monoclonal antibodies versus comparators were estimated by using Cox regression. RESULTS: We identified 114 cases patients COVID-19 who had received anti-CD20 monoclonal antibodies for immune-mediated diseases (mean age 55 years, 70% female) and 559 matched comparators with COVID-19 (mean age 54 years, 70% female). Patients treated with anti-CD20 monoclonal antibodies had higher mortality (adjusted HR 2.16; 95% CI: 1.03-4.54) than matched comparators. Risks of hospitalization (adjusted HR 0.88; 95% CI: 0.62-1.26) and mechanical ventilation use (adjusted HR 0.82; 95% CI: 0.36-1.87) were similar. Similar trends were seen in analyses according to type of indication (eg, rheumatic or neurologic disease) and duration of anti-CD20 monoclonal antibody use (<1 or ≥1 year) and after patients with interstitial lung disease, those with cancer, and those on glucocorticoids prior to COVID-19 diagnosis were excluded. CONCLUSION: Patients who received anti-CD20 monoclonal antibodies for immune-mediated diseases prior to COVID-19 had higher mortality following COVID-19 than matched comparators, highlighting the urgent need to mitigate excess risks in recipients of anti-CD20 monoclonal antibodies during the ongoing pandemic.

COVID-19 Outcomes Among Users of CD20 Inhibitors for Immune-Mediated Diseases: A Comparative Cohort Study.

OBJECTIVE: Patients with immune-mediated diseases treated with CD20 inhibitors may have worse COVID-19 outcomes due to impaired humoral immunity, but differences versus the general population are unknown. METHODS: We identified patients with immune-mediated diseases who received CD20 inhibitors within one year prior to the index date of PCR-confirmed COVID-19 between January 31, 2020, and January 31, 2021. Comparators with COVID-19 were matched up to 5:1 by age, sex, and PCR date. Hazard ratios (HRs) and 95% confidence intervals (CIs) for hospitalization, mechanical ventilation, and death in CD20 inhibitor users versus comparators were estimated using Cox regression. RESULTS: We identified 114 cases with COVID-19 who had received CD20 inhibitors for immune-mediated diseases (mean age 55 years, 70% female) and 559 matched comparators with COVID-19 (mean age 54 years, 70% female). CD20 inhibitor-treated cases had higher mortality (aHR 2.16; 95% CI: 1.03 to 4.54) than matched comparators. Risks of hospitalization (aHR 0.88; 95% CI: 0.62 to 1.26) and mechanical ventilation (aHR 0.82; 95% CI: 0.36 to 1.87) were similar. Similar trends were seen in analyses according to type of indication (e.g., rheumatic or neurologic disease) and duration of CD20 inhibitor use (<1 or ≥1 year), and after excluding patients with interstitial lung disease, cancer, and those on glucocorticoids prior to COVID-19 diagnosis. CONCLUSIONS: Patients who received CD20 inhibitors for immune-mediated diseases prior to COVID-19 had higher mortality following COVID-19 than matched comparators, highlighting the urgent need to mitigate excess risks in CD20 inhibitor users during the ongoing pandemic. KEY MESSAGES: What is already known about this subject?: Patients with immune-mediated diseases treated with CD20 inhibitors may have worse COVID-19 outcomes than those treated with other immunomodulatory medications, but differences compared to the general population are unknown.What does this study add?: CD20 inhibitor-treated cases had over two-fold higher risk of mortality than matched general population comparators, although risks of hospitalization and mechanical ventilation were similar.How might this impact on clinical practice or future developments?: There is an urgent need for risk mitigation strategies, such as SARS-CoV-2 monoclonal antibodies or booster vaccinations, for patients with immune-mediated diseases treated with CD20 inhibitors during the ongoing COVID-19 pandemic.

Circulating blood metabolite trajectories and risk of rheumatoid arthritis among military personnel in the Department of Defense Biorepository.

OBJECTIVES: We sought to identify metabolic changes potentially related to rheumatoid arthritis (RA) pathogenesis occurring in the blood prior to its diagnosis. METHODS: In a US military biorepository, serum samples collected at two timepoints prior to a diagnosis of RA were identified. These were matched to controls who did not develop RA by subject age, race and time between sample collections and RA diagnosis time to stored serum samples. Relative abundances of 380 metabolites were measured using liquid chromatography-tandem mass spectrometry. We determined whether pre-RA case versus control status predicted metabolite concentration differences and differences over time (trajectories) using linear mixed models, assessing for interactions between time, pre-RA status and metabolite concentrations. We separately examined pre-RA and pre-seropositive RA cases versus matched controls and adjusted for smoking. Multiple comparison adjustment set the false discovery rate to 0.05. RESULTS: 291 pre-RA cases (80.8% pre seropositive RA) were matched to 292 controls, all with two serum samples (2.7±1.6 years; 1.0±0.9 years before RA/matched date). 52.0% were women; 52.8% were White, 26.8% Black and 20.4% other race. Mean age was 31.2 (±8.1) years at earliest blood draw. Fourteen metabolites had statistically significant trajectory differences among pre-RA subjects versus controls, including sex steroids, amino acid/lipid metabolism and xenobiotics. Results were similar when limited to pre seropositive RA and after adjusting for smoking. CONCLUSIONS: In this military case-control study, metabolite concentration trajectory differences in pre-RA cases versus controls implicated steroidogenesis, lipid/amino acid metabolism and xenobiotics in RA pathogenesis. Metabolites may have potential as biomarkers and/or therapeutic targets preceding RA diagnosis.

Clinical Experience With a Multidisciplinary Model of Vascular Ultrasound for the Evaluation for Giant Cell Arteritis.

OBJECTIVE: Vascular ultrasound (VUS) is a first-line test for giant cell arteritis (GCA) in Europe but has been of limited use in the United States. We report clinical experience with a multidisciplinary model of VUS for the evaluation of GCA at a large US medical center. METHODS: Patients who underwent VUS for evaluation of GCA between 2013 and 2017 were reviewed. Trained vascular technologists followed a standardized protocol to visualize bilateral temporal, carotid, subclavian, and axillary arteries. Vascular medicine physicians interpreted VUS as no arteritis, hyperechoic wall thickening, or acute arteritis. Characteristics of patients with versus without acute arteritis (no arteritis or hyperechoic wall thickening) were compared. Among patients with suspected new-onset GCA, the treating physician's pretest and posttest suspicion for GCA were compared. RESULTS: Of 530 patients, 10.6% had prior-onset GCA, 31.7% had polymyalgia rheumatica, and 57.6% were taking glucocorticoids. Most patients had no arteritis on VUS (84.3%); 10.6% had acute arteritis, and 5.1% had hyperechoic wall thickening. Typical GCA symptoms, such as jaw claudication and scalp tenderness, were significantly more frequent in patients with acute arteritis. For all 42 patients with suspected new-onset GCA and acute arteritis, posttest suspicion was unchanged or increased. Of 415 patients with suspected new-onset GCA and VUS without acute arteritis, suspicion decreased (76.4%) or was unchanged (20.2%). CONCLUSION: We describe a multidisciplinary model for incorporating VUS into GCA care. When pretest suspicion was low and VUS did not reveal acute arteritis, posttest suspicion typically decreased, whereas when pretest suspicion was high and VUS revealed acute arteritis, posttest suspicion was reinforced.

Follow-up vascular ultrasounds in patients with giant cell arteritis.

OBJECTIVES: Literature describing follow-up vascular ultrasound (VUS) in giant cell arteritis (GCA) is limited. We report our experience with follow-up VUS obtained in clinical care of patients with GCA. METHODS: We retrospectively identified GCA patients with an abnormal initial VUS, defined as circumferential hypoechoic wall thickening ("halo sign"), or circumferential hyperechoic wall thickening without evidence of arteriosclerosis or arteritis, who subsequently underwent follow-up VUS during 2013-2018. Studies were interpreted as active arteritis, hyperechoic wall thickening without active arteritis, or no arteritis. We compared clinical and laboratory characteristics at time of initial VUS among patients with active arteritis vs. hyperechoic wall thickening without active arteritis. We described whether and how VUS interpretation changed from initial to follow-up VUS. Among individual vessels, we tested whether abnormal findings (e.g. halo sign) persisted at follow-up VUS using McNemar's test. RESULTS: 42 patients fulfilled study criteria. Median time between initial and follow-up VUS was 5.1 (IQR 2.6-7.9) months. Characteristics at initial VUS did not differ according to VUS interpretation. Among 36 patients with active arteritis on initial VUS, follow-up VUS showed active arteritis in 25.0%, hyperechoic wall thickening in 33.3% and no arteritis in 41.7%. Among 6 patients with hyperechoic wall thickening on initial VUS, half had no arteritis on follow-up VUS. Sonographic findings tended to persist in axillary arteries and were more likely to change in the superficial temporal arteries. CONCLUSIONS: Among 42 GCA patients, the majority had a change in VUS interpretation between initial and follow-up VUS. Sonographic findings in the temporal circulation more frequently changed than findings in axillary arteries.

LIN-12/Notch Regulates GABA Signaling at the Caenorhabditis elegans Neuromuscular Junction.

The role of Notch signaling in cell-fate decisions has been studied extensively; however, this pathway is also active in adult tissues, including the nervous system. Notch signaling modulates a wide range of behaviors and processes of the nervous system in the nematode Caenorhabditis elegans, but there is no evidence for Notch signaling directly altering synaptic strength. Here, we demonstrate Notch-mediated regulation of synaptic activity at the C. elegans neuromuscular junction (NMJ). For this, we used aldicarb, an inhibitor of the enzyme acetylcholinesterase, and assessed paralysis rates of animals with altered Notch signaling. Notch receptors LIN-12 and GLP-1 are required for normal NMJ function; they regulate NMJ activity in an opposing fashion. Complete loss of LIN-12 skews the excitation/inhibition balance at the NMJ toward increased activity, whereas partial loss of GLP-1 has the opposite effect. Specific Notch ligands and co-ligands are also required for proper NMJ function. The role of LIN-12 is independent of cell-fate decisions; manipulation of LIN-12 signaling through RNAi knockdown or overexpression of the co-ligand OSM-11 after development alters NMJ activity. We demonstrate that LIN-12 modulates GABA signaling in this paradigm, as loss of GABA signaling suppresses LIN-12 gain-of-function defects. Further analysis, in vivo and in silico, suggests that LIN-12 may modulate transcription of the GABAB receptor GBB-2 Our findings confirm a non-developmental role for the LIN-12/Notch receptor in regulating synaptic signaling and identify the GABAB receptor GBB-2 as a potential Notch transcriptional target in the C. elegans nervous system.

Deep conservation of genes required for both Drosphila melanogaster and Caenorhabditis elegans sleep includes a role for dopaminergic signaling.

OBJECTIVES: Cross-species conservation of sleep-like behaviors predicts the presence of conserved molecular mechanisms underlying sleep. However, limited experimental evidence of conservation exists. Here, this prediction is tested directly. MEASUREMENTS AND RESULTS: During lethargus, Caenorhabditis elegans spontaneously sleep in short bouts that are interspersed with bouts of spontaneous locomotion. We identified 26 genes required for Drosophila melanogaster sleep. Twenty orthologous C. elegans genes were selected based on similarity. Their effect on C. elegans sleep and arousal during the last larval lethargus was assessed. The 20 most similar genes altered both the quantity of sleep and arousal thresholds. In 18 cases, the direction of change was concordant with Drosophila studies published previously. Additionally, we delineated a conserved genetic pathway by which dopamine regulates sleep and arousal. In C. elegans neurons, G-alpha S, adenylyl cyclase, and protein kinase A act downstream of D1 dopamine receptors to regulate these behaviors. Finally, a quantitative analysis of genes examined herein revealed that C. elegans arousal thresholds were directly correlated with amount of sleep during lethargus. However, bout duration varies little and was not correlated with arousal thresholds. CONCLUSIONS: The comprehensive analysis presented here suggests that conserved genes and pathways are required for sleep in invertebrates and, likely, across the entire animal kingdom. The genetic pathway delineated in this study implicates G-alpha S and previously known genes downstream of dopamine signaling in sleep. Quantitative analysis of various components of quiescence suggests that interdependent or identical cellular and molecular mechanisms are likely to regulate both arousal and sleep entry.

The transcription factor BATF operates as an essential differentiation checkpoint in early effector CD8+ T cells.

The transcription factor BATF is required for the differentiation of interleukin 17 (IL-17)-producing helper T cells (TH17 cells) and follicular helper T cells (TFH cells). Here we identified a fundamental role for BATF in regulating the differentiation of effector of CD8(+) T cells. BATF-deficient CD8(+) T cells showed profound defects in effector population expansion and underwent proliferative and metabolic catastrophe early after encountering antigen. BATF, together with the transcription factors IRF4 and Jun proteins, bound to and promoted early expression of genes encoding lineage-specific transcription-factors (T-bet and Blimp-1) and cytokine receptors while paradoxically repressing genes encoding effector molecules (IFN-γ and granzyme B). Thus, BATF amplifies T cell antigen receptor (TCR)-dependent expression of transcription factors and augments the propagation of inflammatory signals but restrains the expression of genes encoding effector molecules. This checkpoint prevents irreversible commitment to an effector fate until a critical threshold of downstream transcriptional activity has been achieved.