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1.
Am J Kidney Dis ; 83(2): 173-182.e1, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37726050

RESUMEN

RATIONALE & OBJECTIVE: Kidney transplant patients with failing allografts have a physical and psychological symptom burden as well as high morbidity and mortality. Palliative care is underutilized in this vulnerable population. We described kidney transplant clinicians' perceptions of palliative care to delineate their perceived barriers to and facilitators of providing palliative care to this population. STUDY DESIGN: National explanatory sequential mixed methods study including an online survey and semistructured interviews. SETTING & PARTICIPANTS: Kidney transplant clinicians in the United States surveyed and interviewed from October 2021 to March 2022. ANALYTICAL APPROACH: Descriptive summary of survey responses, thematic analysis of qualitative interviews, and mixed methods integration of data. RESULTS: A total of 149 clinicians completed the survey, and 19 completed the subsequent interviews. Over 90% of respondents agreed that palliative care can be helpful for patients with a failing kidney allograft. However, 46% of respondents disagreed that all patients with failing allografts benefit from palliative care, and two-thirds thought that patients would not want serious illness conversations. More than 90% of clinicians expressed concern that transplant patients and caregivers would feel scared or anxious if offered palliative care. The interviews identified three main themes: (1) transplant clinicians' unique sense of personal and professional responsibility was a barrier to palliative care engagement, (2) clinicians' uncertainty regarding the timing of palliative care collaboration would lead to delayed referral, and (3) clinicians felt challenged by factors related to patients' cultural backgrounds and identities, such as language differences. Many comments reflected an unfamiliarity with the broad scope of palliative care beyond end-of-life care. LIMITATIONS: Potential selection bias. CONCLUSIONS: Our study suggests that multiple barriers related to patients, clinicians, health systems, and health policies may pose challenges to the delivery of palliative care for patients with failing kidney transplants. This study illustrates the urgent need for ongoing efforts to optimize palliative care delivery models dedicated to kidney transplant patients, their families, and the clinicians who serve them. PLAIN-LANGUAGE SUMMARY: Kidney transplant patients experience physical and psychological suffering in the context of their illnesses that may be amenable to palliative care. However, palliative care is often underutilized in this population. In this mixed-methods study, we surveyed 149 clinicians across the United States, and 19 of them completed semistructured interviews. Our study results demonstrate that several patient, clinician, system, and policy factors need to be addressed to improve palliative care delivery to this vulnerable population.


Asunto(s)
Cuidados Paliativos al Final de la Vida , Trasplante de Riñón , Cuidado Terminal , Humanos , Estados Unidos , Cuidados Paliativos/métodos , Cuidado Terminal/métodos , Aloinjertos
2.
Am J Transplant ; 23(4): 549-558, 2023 04.
Artículo en Inglés | MEDLINE | ID: mdl-36740193

RESUMEN

Face transplantation is a life-changing procedure for patients with severe composite facial defects. However, it is hampered by high acute rejection rates due to the immunogenicity of skin allograft and toxicity linked to high doses of immunosuppression. To reduce immunosuppression-associated complications, we, for the first time in face transplant recipients, used low-dose interleukin 2 (IL-2) therapy to expand regulatory T cells (Tregs) in vivo and to enhance immune modulation, under close immunological monitoring of peripheral blood and skin allograft. Low-dose IL-2 achieved a sustained expansion (∼4-fold to 5-fold) of circulating Tregs and a reduction (∼3.5-fold) of B cells. Post-IL-2 Tregs exhibited greater suppressive function, characterized by higher expression of TIM-3 and LAG3co-inhibitory molecules. In the skin allograft, Tregs increased after low-dose IL-2 therapy. IL-2 induced a distinct molecular signature in the allograft with reduced cytotoxicity-associated genes (granzyme B and perforin). Two complications were observed during the trial: one rejection event and an episode of autoimmune hemolytic anemia. In summary, this initial experience demonstrated that low-dose IL-2 therapy was not only able to promote immune regulation in face transplant recipients but also highlighted challenges related to its narrow therapeutic window. More specific targeted Treg expansion strategies are needed to translate this approach to the clinic.


Asunto(s)
Trasplante Facial , Interleucina-2 , Humanos , Rechazo de Injerto , Interleucina-2/administración & dosificación , Interleucina-2/inmunología , Proyectos Piloto , Linfocitos T Reguladores
3.
Am J Transplant ; 23(9): 1388-1400, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37257653

RESUMEN

Technological advances in the field of histocompatibility have allowed us to define anti-human leukocyte antigen (HLA) antibody specificity at the allelic level. However, how allele-specific antibodies affect organ allocation is poorly studied. We examined allelic specificities of class I HLA antibodies in 6726 consecutive serum samples from 2953 transplant candidates and evaluated their impact on the corresponding crossmatch and organ allocation. Out of 17 class I HLA antigens represented by >1 allele in the LABScreen single antigen bead assay, 12 had potential allele-specific reactivity. Taking advantage of our unbiased cohort of deceased donor-candidate testing (123,135 complement-dependent cytotoxicity crossmatches between 2014 and 2017), we estimated that the presence of allele-specific antibody detected using a single antigen bead assay (median fluorescence intensity, >3000) against only the rare allele was a poor predictor of a positive complement-dependent cytotoxicity crossmatch, with a positive predictive value of 0% to 7%, compared with 52.5% in allele-concordant class I HLA antibodies against A or B locus antigens. Further, we confirmed allele-specific reactivity using flow crossmatch in 3 scenarios: A11:01/A11:02, A68:01/A68:02, and B44:02/B44:03. Our results suggest that allele-specific antibodies may unnecessarily exclude transplant candidates (up to 10%) from organ offers by overcalling unacceptable antigens; incorporation of selective reactivity pattern in allocation may promote precision matching and more equitable allocation.


Asunto(s)
Antígenos de Histocompatibilidad Clase I , Isoanticuerpos , Humanos , Alelos , Prueba de Histocompatibilidad/métodos , Antígenos de Histocompatibilidad Clase I/genética , Antígenos HLA/genética , Antígenos
4.
Transpl Int ; 36: 11172, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37456682

RESUMEN

The management of failing kidney allograft and transition of care to general nephrologists (GN) remain a complex process. The Kidney Pancreas Community of Practice (KPCOP) Failing Allograft Workgroup designed and distributed a survey to GN between May and September 2021. Participants were invited via mail and email invitations. There were 103 respondents with primarily adult nephrology practices, of whom 41% had an academic affiliation. More than 60% reported listing for a second kidney as the most important concern in caring for patients with a failing allograft, followed by immunosuppression management (46%) and risk of mortality (38%), while resistant anemia was considered less of a concern. For the initial approach to immunosuppression reduction, 60% stop antimetabolites first, and 26% defer to the transplant nephrologist. Communicating with transplant centers about immunosuppression cessation was reported to occur always by 60%, and sometimes by 29%, while 12% reported making the decision independently. Nephrologists with academic appointments communicate with transplant providers more than private nephrologists (74% vs. 49%, p = 0.015). There are heterogeneous approaches to the care of patients with a failing allograft. Efforts to strengthen transitions of care and to develop practical practice guidelines are needed to improve the outcomes of this vulnerable population.


Asunto(s)
Trasplante de Riñón , Nefrología , Adulto , Humanos , Nefrólogos , Terapia de Inmunosupresión , Encuestas y Cuestionarios
5.
Am J Transplant ; 22(7): 1766-1778, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35320600

RESUMEN

Antibody-mediated rejection is a major cause of long-term graft loss in kidney transplant patients. T follicular helper (Tfh) cells are crucial for assisting B cell differentiation and are required for an efficient antibody response. Anti-thymocyte globulin (ATG) is a widely used lymphocyte-depleting induction therapy. However, less is known about how ATG affects Tfh cell development and donor-specific antibody (DSA) formation. We observed an increase in circulating Tfh cells at 6 months after kidney transplant in patients who received ATG. Using an NP-OVA immunization model, we found that ATG-treated mice had a higher percentage of Tfh cells, germinal center B cells, and higher titers of antigen-specific antibodies compared to controls. ATG-treated animals had lower levels of IL-2, a known Bcl-6 repressor, but higher levels of IL-21, pSTAT3 and Bcl-6, favoring Tfh differentiation. In a mouse kidney transplant model, ATG-treated recipients showed an increase in Tfh cells, DSA and C4d staining in the allograft. Although ATG was effective in depleting T cells, it favored the expansion of Tfh cells following depletion. Concomitant use of IL-2, tacrolimus, or rapamycin with ATG was essential to control Tfh cell expansion. In summary, ATG depletion favors Tfh expansion, enhancing antibody-mediated response.


Asunto(s)
Inmunidad Humoral , Trasplante de Riñón , Células T Auxiliares Foliculares , Animales , Suero Antilinfocítico , Centro Germinal , Rechazo de Injerto/prevención & control , Interleucina-2 , Ratones , Células T Auxiliares Foliculares/citología , Linfocitos T Colaboradores-Inductores
6.
Nephrol Dial Transplant ; 37(12): 2569-2580, 2022 11 23.
Artículo en Inglés | MEDLINE | ID: mdl-35687020

RESUMEN

BACKGROUND: Recent improvement in treatment and patient survival has opened the eligibility of kidney transplantation to patients who developed end-stage kidney disease (ESKD) from plasma cell dyscrasias (PCDs). Data on clinical outcomes in this population are lacking. METHODS: We conducted a retrospective study of United Network for Organ Sharing/Organ Procurement and Transplantation Network dataset (2006-2018) to compare patient and graft outcomes of kidney transplant recipients with ESKD due to PCD versus other causes. RESULTS: Among 168 369 adult first kidney transplant recipients, 0.22-0.43% per year had PCD as the cause of ESKD. The PCD group had worse survival than the non-PCD group for both living and deceased donor types {adjusted hazard ratio [aHR] 2.24 [95% confidence interval (CI) 1.67-2.99] and aHR 1.40 [95% CI 1.08-1.83], respectively}. The PCD group had worse survival than the diabetes group, but only among living donors [aHR 1.87 (95% CI 1.37-2.53) versus aHR 1.16 (95% CI 0.89-1.2)]. Graft survival in patients with PCD were worse than non-PCD in both living and deceased donors [aHR 1.72 (95% CI 1.91-2.56) and aHR 1.30 (95% CI 1.03-1.66)]. Patient and graft survival were worse in amyloidosis but not statistically different in multiple myeloma compared with the non-PCD group. CONCLUSION: The study data are crucial when determining kidney transplant eligibility and when discussing transplant risks in patients with PCD.


Asunto(s)
Amiloidosis , Fallo Renal Crónico , Trasplante de Riñón , Mieloma Múltiple , Adulto , Humanos , Estados Unidos/epidemiología , Trasplante de Riñón/efectos adversos , Mieloma Múltiple/complicaciones , Estudios Retrospectivos , Supervivencia de Injerto , Donadores Vivos , Fallo Renal Crónico/etiología , Fallo Renal Crónico/cirugía , Amiloidosis/complicaciones , Amiloidosis/cirugía , Resultado del Tratamiento , Rechazo de Injerto/epidemiología
7.
Br J Clin Pharmacol ; 88(9): 3950-3961, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35593302

RESUMEN

AIMS: Calcineurin inhibitors (CNIs) are often used for solid organ transplantation recipients or patients with immune-mediated diseases. This systematic review and meta-analysis aims to understand how CNIs affect pregnancy and neonatal outcomes. METHODS: Electronic databases were searched for observational studies assessing pregnancy and neonatal outcomes in CNI-treated patients. The pooled rate of each outcome was determined. Metaregression was conducted to identify contributing factors to the outcomes. RESULTS: We analysed 98 studies with a total of 5355 pregnancies in 4450 CNI-treated patients. The pooled rates of live birth and spontaneous abortion were 82.1% (95% confidence interval [CI] 76.7-86.4%) and 11.7% (95% CI 8.7-15.5%), respectively. The rates of preterm delivery (33.2%, 95% CI 29.2-37.5%), low birth weight (35.8%, 95% CI 27.7-44.8%) and preeclampsia (13.5%, 95% CI 9.4-19.2%) were 3-4 times higher than the rates of general population. Nearly half of the CNI-treated patients required caesarean delivery (43.5%, 95% CI 36.9-50.3%). The rates of stillbirth, neonatal and maternal death were 4.2% (95% CI 2.8-6.2%), 2.9% (95% CI 1.8-4.8%) and 2.3% (95% CI 1.3-4.1%), respectively. Metaregression showed that preeclampsia was significantly associated with the risks of preterm delivery and low birth weight. Older maternal age, prepregnancy hypertension and cyclosporine use increased the risk of preeclampsia. CONCLUSION: Given the higher mortalities in CNI-treated patients and their children than the general averages, their pregnancy is considered high risk. The risks of preterm delivery and low birth weight were primarily attributed to preeclampsia. Since prepregnancy hypertension increased its risk, an appropriate preconception blood pressure management may improve their outcomes.


Asunto(s)
Hipertensión , Preeclampsia , Nacimiento Prematuro , Inhibidores de la Calcineurina/efectos adversos , Niño , Femenino , Humanos , Recién Nacido , Preeclampsia/inducido químicamente , Preeclampsia/epidemiología , Embarazo , Resultado del Embarazo/epidemiología , Nacimiento Prematuro/epidemiología
8.
Kidney Int ; 100(1): 196-205, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33359528

RESUMEN

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.


Asunto(s)
Carcinoma de Células Escamosas , Trasplante de Riñón , Neoplasias Cutáneas , Carcinoma de Células Escamosas/tratamiento farmacológico , Humanos , Inhibidores de Puntos de Control Inmunológico , Trasplante de Riñón/efectos adversos , Estudios Prospectivos , Estudios Retrospectivos , Neoplasias Cutáneas/tratamiento farmacológico
9.
J Am Soc Nephrol ; 31(2): 435-446, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31896554

RESUMEN

BACKGROUND: Despite increasing recognition of the importance of immune checkpoint inhibitor-associated AKI, data on this complication of immunotherapy are sparse. METHODS: We conducted a multicenter study of 138 patients with immune checkpoint inhibitor-associated AKI, defined as a ≥2-fold increase in serum creatinine or new dialysis requirement directly attributed to an immune checkpoint inhibitor. We also collected data on 276 control patients who received these drugs but did not develop AKI. RESULTS: Lower baseline eGFR, proton pump inhibitor use, and combination immune checkpoint inhibitor therapy were each independently associated with an increased risk of immune checkpoint inhibitor-associated AKI. Median (interquartile range) time from immune checkpoint inhibitor initiation to AKI was 14 (6-37) weeks. Most patients had subnephrotic proteinuria, and approximately half had pyuria. Extrarenal immune-related adverse events occurred in 43% of patients; 69% were concurrently receiving a potential tubulointerstitial nephritis-causing medication. Tubulointerstitial nephritis was the dominant lesion in 93% of the 60 patients biopsied. Most patients (86%) were treated with steroids. Complete, partial, or no kidney recovery occurred in 40%, 45%, and 15% of patients, respectively. Concomitant extrarenal immune-related adverse events were associated with worse renal prognosis, whereas concomitant tubulointerstitial nephritis-causing medications and treatment with steroids were each associated with improved renal prognosis. Failure to achieve kidney recovery after immune checkpoint inhibitor-associated AKI was independently associated with higher mortality. Immune checkpoint inhibitor rechallenge occurred in 22% of patients, of whom 23% developed recurrent associated AKI. CONCLUSIONS: This multicenter study identifies insights into the risk factors, clinical features, histopathologic findings, and renal and overall outcomes in patients with immune checkpoint inhibitor-associated AKI.


Asunto(s)
Lesión Renal Aguda/inducido químicamente , Antígeno B7-H1/antagonistas & inhibidores , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Lesión Renal Aguda/mortalidad , Lesión Renal Aguda/terapia , Anciano , Femenino , Humanos , Riñón/patología , Masculino , Persona de Mediana Edad , Nefritis Intersticial/inducido químicamente , Estudios Retrospectivos , Factores de Riesgo
10.
Circulation ; 140(10): 846-863, 2019 09 09.
Artículo en Inglés | MEDLINE | ID: mdl-31266349

RESUMEN

BACKGROUND: Transplantation is the treatment of choice for many patients with end-stage organ disease. Despite advances in immunosuppression, long-term outcomes remain suboptimal, hampered by drug toxicity and immune-mediated injury, the leading cause of late graft loss. The development of therapies that promote regulation while suppressing effector immunity is imperative to improve graft survival and minimize conventional immunosuppression. Notch signaling is a highly conserved pathway pivotal to T-cell differentiation and function, rendering it a target of interest in efforts to manipulate T cell-mediated immunity. METHODS: We investigated the pattern of Notch-1 expression in effector and regulatory T cells (Tregs) in both murine and human recipients of a solid-organ transplant. Using a selective human anti-Notch-1 antibody (aNotch-1), we examined the effect of Notch-1 receptor inhibition in full major histocompatibility complex-mismatch murine cardiac and lung transplant models, and in a humanized skin transplant model. On the basis of our findings, we further used a genetic approach to investigate the effect of selective Notch-1 inhibition in Tregs. RESULTS: We observed an increased proportion of Tregs expressing surface and intracellular (activated) Notch-1 in comparison with conventional T cells, both in mice with transplants and in the peripheral blood of patients with transplants. In the murine cardiac transplant model, peritransplant administration of aNotch-1 (days 0, 2, 4, 6, 8, and 10) significantly prolonged allograft survival in comparison with immunoglobulin G-treated controls. Similarly, aNotch-1 treatment improved both histological and functional outcomes in the murine lung transplant model. The use of aNotch-1 resulted in a reduced proportion of both splenic and intragraft conventional T cells, while increasing the proportion of Tregs. Furthermore, Tregs isolated from aNotch-1-treated mice showed enhanced suppressive function on a per-cell basis, confirmed with selective Notch-1 deletion in Tregs (Foxp3EGFPCreNotch1fl/fl). Notch-1 blockade inhibited the mammalian target of rapamycin pathway and increased the phosphorylation of STAT5 (signal transducer and activator of transcription 5) in murine Tregs. Notch-1low Tregs isolated from human peripheral blood exhibited more potent suppressive capacity than Notch-1high Tregs. Last, the combination of aNotch-1 with costimulation blockade induced long-term tolerance in a cardiac transplant model, and this tolerance was dependent on CTLA-4 (cytotoxic T-lymphocyte-associated antigen-4) signaling. CONCLUSIONS: Our data reveal a promising, clinically relevant approach for immune modulation in transplantation by selectively targeting Notch-1.


Asunto(s)
Rechazo de Injerto/metabolismo , Receptor Notch1/antagonistas & inhibidores , Subgrupos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Animales , Anticuerpos Bloqueadores/farmacología , Células Cultivadas , Regulación de la Expresión Génica , Rechazo de Injerto/inmunología , Rechazo de Injerto/mortalidad , Humanos , Tolerancia Inmunológica , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Transgénicos , Trasplante de Órganos , Receptor Notch1/genética , Receptor Notch1/metabolismo , Factor de Transcripción STAT5/metabolismo , Transducción de Señal , Análisis de Supervivencia
11.
Transpl Infect Dis ; 20(5): e12959, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29968947

RESUMEN

Direct-acting antiviral agents (DAAs) are very effective therapy for chronic hepatitis C infection, and have revolutionized the treatment of hepatitis C in kidney allograft recipients. Although well tolerated in general, rare renal complications have been reported. We describe a case of recurrent membranous nephropathy and acute cellular rejection in a kidney allograft recipient after DAA (ledipasvir/sofosbuvir) therapy, whose allograft function had been stable for more than 30 years. The patient was presented with nephrotic range proteinuria with stable creatinine. The kidney allograft biopsy revealed recurrent membranous nephropathy with fine granular deposits of IgG1/IgG4 codominance and positive phospholipase A2 receptor (PLA2R) staining. The patient was treated with pulse steroid and rituximab, leading to a decrease in proteinuria. As DAAs are more frequently used, physicians should be aware of immune-related renal complications.


Asunto(s)
Antivirales/efectos adversos , Glomerulonefritis Membranosa/inmunología , Rechazo de Injerto/inmunología , Hepatitis C Crónica/tratamiento farmacológico , Anciano , Aloinjertos/inmunología , Aloinjertos/patología , Antivirales/inmunología , Bencimidazoles/efectos adversos , Bencimidazoles/inmunología , Biopsia , Fluorenos/efectos adversos , Fluorenos/inmunología , Glomerulonefritis Membranosa/patología , Rechazo de Injerto/prevención & control , Hepacivirus/aislamiento & purificación , Hepatitis C Crónica/virología , Humanos , Terapia de Inmunosupresión/métodos , Riñón/inmunología , Riñón/patología , Masculino , Recurrencia , Sofosbuvir , Uridina Monofosfato/efectos adversos , Uridina Monofosfato/análogos & derivados , Uridina Monofosfato/inmunología
13.
Curr Opin Nephrol Hypertens ; 25(6): 556-562, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27584931

RESUMEN

PURPOSE OF REVIEW: The present review aims to highlight the major recent advances in transplantation with regards to basic, translational, and clinical research. RECENT FINDINGS: We describe new concepts in understanding allorecognition and allospecificity of T cells, and discuss current challenges in targeting memory T cells, including the limitation of rodent disease models. From a clinical perspective, we highlight the advances in molecular biopsy characterization, which have expanded our knowledge of potential drivers of injury and may provide better parameters for patient risk stratification. We also highlight the dual role of innate immunity in both stimulating and regulating adaptive immunity, as well as novel insights into environmental exposures that may affect immune regulation, such as high-salt diet. Finally, we discuss advances in understanding humoral response and novel technologies, such as chimeric antigen receptors-engineered T cells, microparticle-based drug delivery, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (Cas9) gene editing, that may provide intriguing and promising approaches to restrain alloimmunity. SUMMARY: Current advances in our understanding of the basic mechanisms of alloimmunity and their potential translation to clinical applications will permit the development of novel diagnostic and therapeutic strategies to improve long-term graft survival.


Asunto(s)
Rechazo de Injerto/inmunología , Inmunidad Celular , Inmunidad Humoral , Inmunidad Innata , Trasplante de Riñón , Sistemas CRISPR-Cas , Edición Génica , Rechazo de Injerto/prevención & control , Humanos , Trasplante Homólogo
15.
FASEB J ; 28(9): 3965-74, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24891524

RESUMEN

G2A (from G2 accumulation) receptor is a member of the proton-sensing G-protein coupled receptor (GPCR) family and induces signal transduction events that regulate the cell cycle, proliferation, oncogenesis, and immunity. The mechanism by which G2A-mediated signal transduction is regulated by the extracellular pH remains unresolved. Here, we first visualize the pH-dependent G2A distribution change in living cells by a sortase A-mediated pulse labeling technology: the short-peptide tag-fused human G2A on human embryo kidney HEK293T cell surfaces was labeled with a small fluorescent dye in the presence of lysophosphatidylcholine, and the labeled G2A was chased at acidic and neutral pHs in real time by microscope time course observations. G2A internalization from cell surfaces into intracellular compartments was observed to be inhibited under acidic pH conditions, and this inhibition was relieved at neutral pH. Additionally, the internalized G2A was redistributed onto cell surfaces by jumping from a neutral to an acidic pH. From quantitative image analysis data, we conclude the amount of G2A on the cell surface was controlled by suppressing the G2A internalization rate by one-tenth in response to the extracellular acidic pH, and this acidic pH-induced G2A accumulation on cell surfaces may be explained by proton-induced dissociation of G2A from endocytic machinery.


Asunto(s)
Membrana Celular/metabolismo , Técnica del Anticuerpo Fluorescente , Colorantes Fluorescentes , Fragmentos de Péptidos/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Aminoaciltransferasas/metabolismo , Proteínas Bacterianas/metabolismo , Cisteína Endopeptidasas/metabolismo , Células HEK293 , Humanos , Concentración de Iones de Hidrógeno , Procesamiento de Imagen Asistido por Computador , Lisofosfatidilcolinas/metabolismo , Microscopía Confocal , Modelos Estadísticos , Fragmentos de Péptidos/química , Fagocitosis , Transporte de Proteínas , Transducción de Señal
16.
Transplantation ; 108(2): 386-398, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-37314442

RESUMEN

We have attempted here to provide an up-to-date review of the collaboration between helper T cells and B cells in response to protein and glycoprotein antigens. This collaboration is essential as it not only protects from many pathogens but also contributes to a litany of autoimmune and immune-mediated diseases.


Asunto(s)
Enfermedades Autoinmunes , Autoinmunidad , Humanos , Linfocitos T Colaboradores-Inductores , Antígenos , Linfocitos B
17.
Clin Kidney J ; 17(4): sfae061, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38606169

RESUMEN

Cancer is a common complication after kidney transplantation. Kidney transplant recipients (KTR) have a 2- to 4-fold higher risk of developing cancer compared to the general population and post-transplant malignancy is the third most common cause of death in KTR. Moreover, it is well known that certain cancer types are overrepresented after transplantation, especially non-melanoma skin cancer. Immune checkpoint inhibitors (ICI) have revolutionized the treatment of cancer, with remarkable survival benefit in a subgroup of patients. ICI are monoclonal antibodies that block the binding of specific co-inhibitory signaling molecules. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), programmed cell death protein 1 (PD-1), and its ligand programmed cell death ligand 1 (PD-L1) are the main targets of ICI. Solid organ transplant recipients (SOTR) have been excluded from clinical trials owing to concerns about tumor response, allo-immunity, and risk of transplant rejection. Indeed, graft rejection has been estimated as high as 48% and represents an emerging problem. The underlying mechanisms of organ rejection in the context of treatment with ICI are poorly understood. The search for restricted antitumoral responses without graft rejection is of paramount importance. This review summarizes the current knowledge of the use of ICI in KTR, the potential mechanisms involved in kidney graft rejection during ICI treatment, potential biomarkers of rejection, and how to deal with rejection in clinical practice.

18.
Transplant Direct ; 10(1): e1543, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38094134

RESUMEN

Despite the continued improvements in pancreas transplant outcomes in recent decades, a subset of recipients experience graft failure and can experience substantial morbidity and mortality. Here, we summarize what is known about the failed pancreas allograft and what factors are important for consideration of retransplantation. The current definition of pancreas allograft failure and its challenges for the transplant community are explored. The impacts of a failed pancreas allograft are presented, including patient survival and resultant morbidities. The signs, symptoms, and medical and surgical management of a failed pancreas allograft are described, whereas the options and consequences of immunosuppression withdrawal are reviewed. Medical and surgical factors necessary for successful retransplant candidacy are detailed with emphasis on how well-selected patients may achieve excellent retransplant outcomes. To achieve substantial medical mitigation and even pancreas retransplantation, patients with a failed pancreas allograft warrant special attention to their residual renal, cardiovascular, and pulmonary function. Future studies of the failed pancreas allograft will require improved reporting of graft failure from transplant centers and continued investigation from experienced centers.

19.
J Clin Oncol ; 42(9): 1021-1030, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38252908

RESUMEN

PURPOSE: Cemiplimab is approved for treating locally advanced or metastatic cutaneous squamous cell carcinoma (CSCC). Solid organ transplant recipients have been excluded from immunotherapy trials, given concern for allograft rejection despite their increased risk of skin cancers. Chronic immunosuppression is necessary to prevent organ rejection but may attenuate antitumor response with PD-1 inhibitors. METHODS: We report a phase I study of cemiplimab for kidney transplant recipients (KTRs) with advanced CSCC. After cross-taper to a mammalian target of rapamycin (mTOR) inhibitor and pulsed dose corticosteroids (prednisone 40 mg once daily, the day before and on days 1-3 of each cycle, followed by 20 mg once daily on days 4-6, then 10 mg once daily until the day before each subsequent cycle), patients received cemiplimab 350 mg intravenously once every 3 weeks for up to 2 years and were assessed for response every 8 weeks. The primary end point was the rate of kidney rejection, with key secondary end points including rate and duration of response, and survival. RESULTS: Twelve patients were treated. No kidney rejection or loss was observed. A response to cemiplimab was observed in five of 11 evaluable patients (46%; 90% CI, 22 to 73), including two with durable responses beyond a year. Median follow-up was 6.8 months (range, 0.7-29.8). Treatment-related grade 3 or greater adverse events occurred in five patients (42%), including diarrhea, infection, and metabolic disturbances. One patient died of angioedema and anaphylaxis attributed to mTOR inhibitor cross-taper. CONCLUSION: mTOR inhibitor and corticosteroids represent a favorable immunosuppressive regimen for KTRs with advanced CSCC receiving immunotherapy. This combination resulted in durable antitumor responses with no kidney rejection events (funded by Regeneron Pharmaceuticals [ClinicalTrials.gov identifier: NCT04339062]).


Asunto(s)
Anticuerpos Monoclonales Humanizados , Carcinoma de Células Escamosas , Trasplante de Riñón , Neoplasias Cutáneas , Humanos , Neoplasias Cutáneas/tratamiento farmacológico , Neoplasias Cutáneas/patología , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/patología , Trasplante de Riñón/efectos adversos , Inhibidores mTOR , Corticoesteroides/uso terapéutico
20.
Curr Transplant Rep ; 10(4): 173-187, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-38152593

RESUMEN

Purpose of Review: Multi-omics approach has advanced our knowledge on transplantation-associated clinical outcomes, such as acute rejection and infection, and emerging omics data are becoming available in kidney transplant and COVID-19. Herein, we discuss updated findings of multi-omics data on kidney transplant outcomes, as well as COVID-19 and kidney transplant. Recent Findings: Transcriptomics, proteomics, and metabolomics revealed various inflammation pathways associated with kidney transplantation-related outcomes and COVID-19. Although multi-omics data on kidney transplant and COVID-19 is limited, activation of innate immune pathways and suppression of adaptive immune pathways were observed in the active phase of COVID-19 in kidney transplant recipients. Summary: Multi-omics analysis has led us to a deeper exploration and a more comprehensive understanding of key biological pathways in complex clinical settings, such as kidney transplantation and COVID-19. Future multi-omics analysis leveraging multi-center biobank collaborative will further advance our knowledge on the precise immunological responses to allograft and emerging pathogens.

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