ABSTRACT
Backgroung: COVID-19 pandemic (SARS-CoV-2) has affected an increasing number of people worldwide, with death rates higher than previous viral epidemics. It is possible that NK cells, known to have great cytokine secreting potential are competent at the onset of the condition and that in some individuals, the viral load is able to exhaust them. Balance between tolerant (CD27- CD11b-), secretory (CD27+ CD11b-/ CD27+ CD11b+) and cytotoxic (CD27- CD11b+) NK cells involved in the inflammatory response and their anti-SARS-CoV-2 activity are still not well established. Strategies that can restore function of NK cells against the virus are worth investigating. Here, we aimed to characterize NK cells frequency, functional subtypes and maturation in early phase of COVID-19 patients, by Multiparametric Flow Cytometry (MFC). Methods: Peripheral blood from 15 COVID-19 patients in early stage of infection (day 1-14, confirmed by RT-PCR), categorized according comorbidities in: G1 (not oncologic;n = 6), G2 (oncologic;n = 3), G3 (hematologic neoplasms;n = 3) and G4 (without comorbidities;n = 3), and 10 healthy samples enrolled the study. Clinical and laboratorial data were collected from electronic medical records. Samples were stained with CD45, CD19, CD3, CD56, CD11b, CD27, acquired on a FACS Canto II (BD Biosciences) and data analyzed with FlowJo V10 software. Results: A lower frequency of lymphocytes was observed in the disease when compared to controls (P < 0.0001) and frequency of NK cells were similar in both groups (P = 0.6605). Although frequency of CD27- CD11b- NK cells was lower in the disease (P = 0.0109), there was a significantly higher frequency of CD27+ CD11b- NK cells in COVID-19 samples when compared to controls (P < 0.0001), featuring a mostly immature profile in the disease. On the other hand, no statistical significance was observed regarding the frequencies of CD27+ CD11b+ (P = 0.1370) and CD27- CD11b+ NK cells with a more mature profile (P = 0.3094). Amongst disease groups, no statistical significance was found regarding frequency of NK cells and G1 showed lower frequency of CD27- CD11b- NK cells (P = 0.0226), while G3 group had an increased frequency of CD27+ CD11b- NK cells (P = 0.0238) when compared to the other groups and controls. Finally, no statistical significance was found in the frequency of CD27+ CD11b+ (P = 0.6691) and CD27- CD11b+ (P = 0.6270) NK cells between disease groups and controls. Conclusion: Although the frequency of NK cells did not show a significant difference between COVID-19 patients and healthy controls, our findings showed a possible change in their maturation profile, which seems to be inversely proportional to normal, with the frequency of CD27+ CD11b- NK cells considerably higher in the disease. This phenotype is directly associated with secretory function of a more immature NK cell and is responsible for triggering inflammatory responses that could lead to severe respiratory failure, what seems to be consistent with COVID-19 profile. A high frequency of cytotoxic cells was observed, which seemed to be similar to what we found in normal heathy samples. Even though unregulated maturation might be associated to a dysfunctional mature NK cell, additional studies of cytotoxicity and activation of NK cells in COVID-19 are required to affirm whether there is functional exhaustion or hyperactivation of the cytotoxic subtypes of these cells.
ABSTRACT
Introdução: A COVID-19 é uma infecção causada pelo vírus SARS-CoV-2, descrita no final de 2019, que ocasionou uma pandemia devido à sua alta transmissibilidade. Em geral, cursa sem alterações clínicas ou com sintomas leves, porém em 5-10% dos casos pode causar quadros graves, inclusive com óbito. Manifestações críticas parecem mais comuns em indivíduos com comorbidades como hipertensão arterial sistêmica e obesidade. Entretanto, como a descrição da doença é recente, há poucos estudos que esclareçam sua história natural e o grande espectro de manifestações clínicas. Considerando que indivíduos com neoplasia maligna apresentam deficiência imunológica e maior risco de doenças infeciosas oportunistas, é possível que haja uma maior incidência da COVID-19 nesse grupo. As recomendações atuais orientam adiar tratamentos e utilizar drogas menos tóxicas quando possível. Entretanto não sabemos o quanto tais medidas terão implicações na mortalidade por câncer. Além disso a incidência de COVID-19 nessa população ainda não é conhecida. Não se sabe se os sintomas infecciosos são um bom parâmetro para motivar mudanças terapêuticas ou se há benefício em testar indivíduos assintomáticos. Objetivos: Determinar a incidência de infecção por SARS-CoV-2 por meio de RT-PCR em pacientes com neoplasias malignas em quimioterapia. Em paralelo, verificar a evolução do quadro clínico dos pacientes infectados e determinar o impacto do screening no tratamento destes pacientes. Métodos: Realizou-se o RT-PCR para o SARS-COV-2 em uma coorte prospectiva de 100 pacientes adultos portadores de câncer em tratamento quimioterápico no serviço de Hematologia e no serviço de Oncologia do Hospital das Clínicas da FMRP-USP e assintomáticos para COVID-19. Além disso, foram coletados dados clínicos de seus prontuários eletrônicos através de questionários no REDCap. A análise estatística foi realizada com o software Graphpad Prism versão 9. Resultados: Apenas dois pacientes foram diagnosticados com COVID-19. Um deles desenvolveu sintomas, mas nenhum apresentou manifestações graves. Os dois apresentavam diagnóstico de neoplasia maligna gastrointestinal. Nenhum fazia uso de profilaxias infecciosas. Ambos tiveram seus tratamentos postergados inicialmente e reiniciados após o período apropriado de isolamento. Discussão: O presente estudo encontrou uma incidência de COVID-19 de 2% (IC 95% 0,5-7%) em pacientes assintomáticos com câncer em quimioterapia, que pode ser considerada como baixa. A incidência nessa população relatada na literatura varia de 0,72% a 8%, o que pode se justificar pelas diferentes incidências locais e pela adoção de medidas preventivas. Conclusão: Diante do número reduzido de casos positivos detectados, acreditamos que seja razoável não testar todos os pacientes em um contexto de saúde pública, priorizando aqueles com sintomas, aqueles com contato recente com casos suspeitos e aqueles com maior chance de desfecho grave, como os portadores de neoplasias hematológicas, desde que as medidas preventivas sejam corretamente adotadas.
ABSTRACT
COVID-19 is an infectious disease caused by the virus SARS-CoV-2, which was first described at the end of 2019. Since then, it has affected a growing portion of the world's population because of its high transmissibility. Most patients are asymptomatic or present with mild symptoms, but approximately 5-10% of cases can develop more serious manifestations, such as severe acute respiratory syndrome, acute kidney injury, shock, myocardial injury and even death. These features seem to occur more commonly in patients with essential hypertension, diabetes mellitus, obesity and chronic pulmonary disease. However, there are few studies that clarify the natural history of the disease and its broad clinical spectrum owing to the fact that it is a new entity. Since individuals with malignancies tend to present some degree of immunological deficiency and are more prone to opportunistic infections, especially those being treated with immunosuppressive drugs, it is possible that this group has a higher incidence of COVID-19. The current recommendations of oncology specialists advise to postpone treatments and to use less toxic drugs when possible. However, we still do not know how much these measures will affect in cancer mortality. Also, the incidence of COVID-19 in this population remains undetermined. We do not know if infectious symptoms are a good parameter to motivate these therapeutic changes or if there is benefit to test asymptomatic patients. In this context, this research submitted 100 patients with hematological malignancies or solid tumors on chemotherapy at the Ribeirão Preto Medical School of the University of São Paulo's Hospital, asymptomatic for COVID-19, to RT PCR to determine the SARS-CoV-2 infection incidence in this population. Only two patients were diagnosed with COVID-19. Both had gastrointestinal cancer. One of them developed symptoms, but none presented severe manifestations. Both had their treatment postponed initially and reinitiated after the appropriate period of isolation. Hence, we believe that it's reasonable not to test every asymptomatic patient when the resource for that is scarce, prioritizing those at greater risk of infection and those more prone to severe outcomes as long as the appropriate preventive measures are being taken. Disclosures: Calado: Team Telomere, Inc.: Membership on an entity's Board of Directors or advisory committees;Agios: Membership on an entity's Board of Directors or advisory committees;Instituto Butantan: Consultancy;Alexion Brasil: Consultancy;AA&MDS International Foundation: Research Funding;Novartis Brasil: Honoraria.