ABSTRACT
BACKGROUND AND AIMS The poor humoral response after vaccination against SARS-CoV-2 in kidney transplant (KT) patients led to the approval of a third dose. Recent data show an increase in the antibody titer, although lower than in the general population. Our aim is to analyze the humoral immune response after the third dose a mRNA vaccine against SARS-CoV-2 and the evolution of the antispike antibody (antiS) titers in KT recipients. METHOD We performed a prospective cohort study of stable KT patients from our center who received three doses of a mRNA vaccine from March to November 2021. KT recipients with less than 6 months after transplantation and with active oncological or hematologic disease were excluded. We determined antiS titers (Abbott SARS‐CoV‐2 IgG chemiluminescent microparticle immunoassay) at baseline, one month after the second dose and one month after the third one. We compared those KT patients who seroconverted with 2 and with 3 doses of vaccine and those who did not seroconvert. To identify risk factors for no seroconversion, a logistic regression analysis was carried out. RESULTS We included 83 KT. Mean age was 59.3 years and 62.7% were male. The median time from KT to the first vaccine dose was 94 months and between the second and third dose median time was 4 months. Seroconversion rate was 63.8% after 2 doses and 85.5% after the third one (P < 0.001). Twelve KT did not develop antibodies (Table 1). Patients who did not seroconvert were older (P = 0.047), had a worse renal function (P = 0.009) and had fewer lymphocytes than those that developed antibodies (0.013). Besides, they almost half of them received a KT from a non-heart-beating donor (P = 0.026) and were treated with thymoglobulin in the 2 years prior to the vaccine more frequently (P = 0.007). In patients who seroconverted after 2 doses, we observed a 10-fold increase in the antiS titer after the third vaccine (82 [34–350] UI/mL versus 814 [205–2415] UI/mL;P < 0.001). No patients had neither acute rejection nor serious adverse effects. In the multivariable analysis advanced age, a worse kidney function and recent treatment with thymoglobulin were risk factors for no seroconversion (Table 1). CONCLUSION The third dose of a mRNA vaccine against SARS-CoV-2 significantly increased the seroconversion rate and the antiS titers in stable KT patients. Advanced age, poorer kidney function and immunosuppressive treatment are risk factors for no seroconversion.
ABSTRACT
Despite the extraordinary advances achieved to beat COVID-19 disease, many questions remain unsolved, including the mechanisms of action of SARS-CoV-2 and which factors determine why individuals respond so differently to the viral infection. Herein, we performed an in silico analysis to identify host microRNA targeting ACE2, TMPRSS2, and/or RAB14, all genes known to participate in viral entry and replication. Next, the levels of six microRNA candidates previously linked to viral and respiratory-related pathologies were measured in the serum of COVID-19-negative controls (n = 16), IgG-positive COVID-19 asymptomatic individuals (n = 16), and critical COVID-19 patients (n = 17). Four of the peripheral microRNAs analyzed (hsa-miR-32-5p, hsa-miR-98-3p, hsa-miR-423-3p, and hsa-miR-1246) were upregulated in COVID-19 critical patients compared with COVID-19-negative controls. Moreover, hsa-miR-32-5p and hsa-miR-1246 levels were also altered in critical versus asymptomatic individuals. Furthermore, these microRNA target genes were related to viral infection, inflammatory response, and coagulation-related processes. In conclusion, SARS-CoV-2 promotes the alteration of microRNAs targeting the expression of key proteins for viral entry and replication, and these changes are associated with disease severity. The microRNAs identified could be taken as potential biomarkers of COVID-19 progression as well as candidates for future therapeutic approaches against this disease.