Incongruity between T cell receptor recognition of breast cancer hotspot mutations ESR1 Y537S and D538G following exogenous peptide loading versus endogenous antigen processing.

T cell receptor engineered T cell (TCR T) therapies have shown recent efficacy against certain types of solid metastatic cancers. However, to extend TCR T therapies to treat more patients across additional cancer types, new TCRs recognizing cancer-specific antigen targets are needed. Driver mutations in AKT1, ESR1, PIK3CA, and TP53 are common in patients with metastatic breast cancer (MBC) and if immunogenic could serve as ideal tumor-specific targets for TCR T therapy to treat this disease. Through IFN-γ ELISpot screening of in vitro expanded neopeptide-stimulated T cell lines from healthy donors and MBC patients, we identified reactivity towards 11 of 13 of the mutations. To identify neopeptide-specific TCRs, we then performed single-cell RNA sequencing of one of the T cell lines following neopeptide stimulation. Here, we identified an ESR1 Y537S specific T cell clone, clonotype 16, and an ESR1 Y537S/D538G dual-specific T cell clone, clonotype 21, which were HLA-B*40:02 and HLA-C*01:02 restricted, respectively. TCR Ts expressing these TCRs recognized and killed target cells pulsed with ESR1 neopeptides with minimal activity against ESR1 WT peptide. However, these TCRs failed to recognize target cells expressing endogenous mutant ESR1. To investigate the basis of this lack of recognition we performed immunopeptidomics analysis of a mutant-overexpressing lymphoblastoid cell line and found that the ESR1 Y537S neopeptide was not endogenously processed, despite binding to HLA-B*40:02 when exogenously pulsed onto the target cell. These results indicate that stimulation of T cells that likely derive from the naïve repertoire with pulsed minimal peptides may lead to the expansion of clones that recognize non-processed peptides, and highlights the importance of using methods that selectively expand T cells with specificity for antigens that are efficiently processed and presented.

Cognitive impairment in a Colombian cohort of patients with systemic lupus erythematosus: A cross-sectional study.

CONTEXT: Cognitive deficits are neuropsychiatric syndromes associated with systemic lupus erythematosus. In our context, there are no data on the frequency of cognitive deficit as a manifestation of neuropsychiatric SLE or the associated conditions. OBJECTIVE: To define determinants of cognitive deficit in a cohort of Colombian patients with SLE attending a third-level hospital. METHODS AND PATIENTS: This descriptive cross-sectional study included patients with SLE, explored the presence of cognitive impairment through screening testing using the Montreal Cognitive Assessment (MoCA test), and diagnostic confirmation with a specific neuropsychological test battery recommended by the American College of Rheumatology. Quality of life was assessed using the LupusCol questionnaire and depression using the Beck Depression Inventory. RESULTS: Most patients were women, with a median age of 37 years (IQR, 28.0 - 46.7). Most patients had a level of higher education or technical education. Fifty-nine (62.9%) patients presented with a normal MoCA test result ≥26 points, and 35 (37.1%) patients with a score <26 points that were considered abnormal. The comprehensive neuropsychological test battery was applied to 31 patients (33.0%) with an abnormal MoCA test. Forty-one patients (48.8%) had some degree of depression. The median loss of quality of life was 21.03% (IQR 10.2 - 40.3). 19 patients (20%) presented some degree of cognitive deficit, 15 (15.95% of the total sample) had cognitive impairment, and 4 (4.25%) had cognitive decline. In a logistic regression analysis using data from patients undergoing specific tests, variables related to cognitive deterioration were found to be associated with a lower quality of life, showing an adjusted odds ratio of 1.05 (CI 1.01-0.09). No association was demonstrated with SLEDAI, prednisolone use, cyclophosphamide use, and the presence of depression. CONCLUSION: In this study, it was found in 16% of patients evaluated with the complete neuropsychological test battery and in 37% with the MoCA screening test. Our results suggest that it is crucial to implement strategies to assess cognitive deficit, depression, and quality of life in the consultation of patients with SLE and to raise awareness among health providers who care for patients with lupus about their presence and impact.