ABSTRACT
Introduction: Coronavirus disease 2019 is caused by severe acute respiratory syndrome. Primarily an infection of the lower respiratory tract, it is now well known to cause multisystem abnormalities. Hematologic manifestations constitute a significant area of concern. Coronavirus disease 2019 causes lymphopenia, neutrophilia, and thrombocytopenia. Method(s): We explored the hemocytometric characteristics of Covid-19 pazients, using the Sysmex XN-1000 (Sysmex Corporation - Japan) hematology analyser and EDTA-anticoagulated peripheral blood sample. The analyzer utilizes fluorescence flow cytometry for the leukocyte differential count, allowing for enhanced subset differentiation based on size (forward scatter;FSC), internal structure/granularity (side scatter;SSC) and DNA/RNA content (fluorescence expression;SFL). Result(s): Despite a decrease in lymphocyte count, an increase in certain subpopulations of lymphocytes was observed in COVID-19. Indeed, reactive lymphocytes antibody-synthesizing and high fluorescence lymphocyte cells were higher as compared with controls. The so-called high fluorescence cells represent lymphoplasmacytoid B cells and plasma cells. These lymphocytes are responsible for the adaptive humoral immune response. In the present study, we observed that in addition to lower absolute count, lynfocytes of patients with COVID-19 were slightly larger in size. The fraction of reactive lynfocytes within the whole population were significantly increase in patiens with COVID-19 and showed a tipical pattern in hemocytometric plot where the reactive lynfocytes appare as isolated population, different from those observed in patients with mononucleosis. A perifheral blood film assesment on light microscope showed a distint population with the caracteristic morphology of plasma cells with abundant basophilic cytoplasm and an eccentric nucleus. Cytoplasmic and nuclear morphological anomalies, from hyposegmented nuclei to apopto-sis, have been observed in circulating granulocytes, associated with an increase in relative counts of immature cells. Conclusion(s): Patients withCOVID-19 showed both quantitative and qualitative differences in leucocyte populations. This study is an analysis of a typical pattern observed in Covid-19 patients using the Sysmex XN -1000 (Sysmex Corporation - Japan) hematology analyzer. The on going study will be the correlation with immunophenotipic and clinical characteristic of these patients to understand the morphological changes observed.
ABSTRACT
Background: Antiviral antibody responses to SARS-CoV-2 vaccines are reduced in kidney transplant recipients (KTRs) on belatacept compared to those not on belatacept. However, factors associated with lower odds of developing antibody responses in KTRs on belatacept are not known. Method(s): We conducted a retrospective multicenter cohort study of all KTRs on belatacept who received three mRNA vaccine doses at our institutions, where all KTRs on belatacept had anti-SARS-CoV-2 receptor-binding domain (RBD) antibodies measured by the Roche Elecsys immunoassay. The primary outcome was development of anti-RBD antibodies after the third vaccination. Result(s): 58 KTRs on belatacept were included. Median age was 62 and 69% were female. 78% were on prednisone, 60% on mycophenolate, 11% on mTOR inhibitors and 9% on azathioprine. After the third vaccine, 32/58 KTRs (55%) developed anti-RBD antibodies (Fig. 1A) with a median level of 3.3U/mL (Fig. 1B). Using univariate logistic regression, we found that age>=60, eGFR<45ml/min/1.73m2, prednisone use, and no prior SARS-CoV-2 infection were associated with significantly lower odds of developing anti-RBD responses after vaccination (Fig. 1C). These associations remained significant in the adjusted multivariable model (Fig. 1D). We also evaluated correlation between anti-RBD antibody levels and the number of days between vaccination and the most recent belatacept infusion for each vaccination but did not find an association between the two (Fig. 1E-G). Conclusion(s): Prednisone use, age>=60, eGFR<45ml/min/1.73m2, and no history of SARS-CoV-2 infection are associated with lower odds of anti-RBD antibody responses after vaccination in KTRs on belatacept.
ABSTRACT
Purpose: Emerging SARS-CoV-2 variants may be associated with a higher risk of breakthrough infections compared to wild-type (WT) virus in kidney transplant recipients (KTRs). The purpose of this study was to evaluate antiviral immune responses against WT and Delta (B.1.617.2) variant of SARS-CoV-2 after 3 doses of SARS-CoV-2 mRNA vaccines in KTRs. Method(s): We conducted a multicenter prospective cohort study of adult KTRs who received 3 doses of BNT162b2 or mRNA-1273. Blood samples were collected from KTRs before and 4 weeks after the 3rd vaccine dose. Sera from pre-pandemic healthy controls (HCs) and pre-pandemic kidney transplant control patients (KCs) were used for comparison. A Luminex-based multiplex assay was used to measure anti-spike antibodies for the WT, Alpha, Beta, Gamma and Delta variants of SARSCoV- 2. A surrogate virus neutralization test was used to assess neutralization against the WT and Delta variant. Patients were also monitored for rejection using several non-invasive biomarkers. Result(s): 54 KTRs were enrolled in the study. The median age was 63, 44% were female and the median time post-transplantation was 42 months. 94% received BNT162b2 vaccine. After the 3rd vaccine dose, there was a significant increase in anti-spike antibody MFIs against the WT, Alpha, Beta, Gamma and Delta variants (Fig. 1A, p<0.0001 for all). For comparison, all pre-pandemic HCs and KCs had a negative result for anti-spike antibody levels (Fig. 1B). Prior to the 3rd vaccine dose, 29% of KTRs had anti-spike antibodies against the WT compared to only 2% against the Delta variant (Fig. 1C, p=0.0001). After the 3rd vaccine dose, 67% of KTRs had anti-spike antibodies against the WT compared to 25% against the Delta variant (p<0.0001, Fig. 1D). Differences between WT and other variants are shown in Figure 1C-D. After the 3rd vaccine dose, there was a 2.1-fold and 2.5-fold increase in the percentage of KTRs with neutralizing responses against the WT and Delta variant respectively (p<0.0001 for both). There was no significant change in serum creatinine, proteinuria, or donor-derived cell-free DNA levels after vaccination. No episodes of rejection occurred during follow-up. Conclusion(s): Two doses of SARS-CoV-2 mRNA vaccines in KTRs are associated with minimal anti-spike antibody response directed against the Delta variant of SARS-CoV-2. After the third dose, a quarter of KTRs developed anti-spike antibodies directed against the Delta variant of SARS-CoV-2.