Decline and loss of anti-SARS-CoV-2 antibodies in kidney transplant recipients in the 6 months following SARS-CoV-2 infection

Factors That Predict a Sustained Humoral Response to COVID-19 Vaccines in Kidney Transplant Recipients

INTRODUCTION

Kidney transplant recipients (KTRs) produce a weak humoral response to coronavirus disease 2019 (COVID-19) vaccines. However, the factors associated with the quality of the serological response to three doses of COVID-19 vaccine have not been unambiguously identified.

METHODS

We included KTRs followed in the Nephrology Department at Amiens University Hospital (Amiens, France) between June and December 2021 who had received three doses of a COVID-19 mRNA vaccine (or two doses plus an episode of polymerase chain reaction-confirmed COVID-19). The lack of a humoral response was defined as an antibody titer below 7.1 binding antibody units (BAU)/mL, and an optimal response was defined as an antibody titer above 264 BAU/mL.

RESULTS

Of the 371 patients included, 246 (66.3%) were seropositive, and 97 (26.1%) had an optimal response. In a multivariate analysis, the only factor associated with seropositivity was a history of COVID-19 [odds ratio (OR) 87.2; 95% confidence interval (CI) (7.88-965.0); p < 0.0001], while the main factors associated with non-response were female sex [OR 0.28; 95%CI (0.15-0.51); p < 0.0001], less than 36 months between kidney transplantation and vaccination [OR 0.26; 95%CI (0.13-0.52); p < 0.0001], a higher creatinine level [OR 0.33; 95%CI (0.19-0.56); p < 0.0001], the use of tacrolimus [OR 0.23; 95%CI (0.12-0.45); p < 0.0001], the use of belatacept [OR 0.01; 95%CI (0.001-0.20); p = 0.002] and three-drug immunosuppression [OR 0.39; 95%CI (0.19-0.78); p = 0.015]. A history of COVID-19 was associated with an optimal response [OR 4.03; 95%CI (2.09-7.79); p < 0.0001], while an older age at vaccination [OR 0.97; 95%CI (0.95-0.99); p = 0.002], less than 36 months between kidney transplantation and vaccination [OR 0.35; 95%CI (0.18-0.69); p = 0.002], a higher creatinine level [OR 0.60; 95%CI (0.38-0.93); p = 0.02], three-drug immunosuppression [OR 0.45; 95%CI (0.27-0.76); p = 0.003] were associated with a poorer response.

CONCLUSION

We identified factors associated with a humoral response to a COVID-19 mRNA vaccine in KTRs. These findings might help physicians to optimize vaccination in KTRs.

Evaluation of the Humoral and Cellular Immune Response Post COVID-19 Infection in Kidney Transplant Recipients

Kidney transplantation is a major risk factor for severe forms of coronavirus disease 2019 (COVID-19). The dynamics and the persistence of the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in this immunocompromised population remain largely unknown. This study aimed to evaluate the persistence of humoral and cellular immune response in kidney transplant recipients (KTRs) and to establish whether immunosuppressive therapy influenced long-term immunity in this population. We report here the analysis of anti-SARS-CoV-2 antibodies and T cell-mediated immune responses in 36 KTRs compared to a control group who recovered from mild COVID-19. After a mean time of 5.22 ± 0.96 months post symptom onset for kidney transplant recipients, 97.22% of patients and 100% of the control group displayed anti-S1 immunoglobulin G SARS-CoV-2 antibodies (p > 0.05). No significant difference was reported in the median of neutralizing antibodies between the groups (97.50 [55.25-99] in KTRs vs. 84 [60-98] in control group, p = 0.35). A significant difference in SARS-CoV-2-specific T cell reactivity was found in the KTRs compared to the healthy controls. The levels of IFNγ release after stimulation by Ag1, Ag2 and Ag3 were higher in the control group compared to the kidney transplant group (p = 0.007, p = 0.025 and p = 0.008, respectively). No statistically significant correlation between humoral and cellular immunity was found in the KTRs. Our findings indicated that humoral immunity persisted similarly for up to 4 to 6 months post symptom onset in both the KTRs and the control group; however, T cell response was significantly higher in the healthy population compared to the immunocompromised patients.

Assessing Vulnerability to COVID-19 in High-Risk Populations: The Role of SARS-CoV-2 Spike-Targeted Serology

Individuals at increased risk for severe coronavirus disease-2019 (COVID-19) outcomes, due to compromised immunity or other risk factors, would benefit from objective measures of vulnerability to infection based on vaccination or prior infection. The authors reviewed published data to identify a specific role and interpretation of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) spike-targeted serology testing. Specific recommendations are provided for an evidence-based and clinically-useful interpretation of SARS-CoV-2 spike-targeted serology to identify vulnerability to infection and potential subsequent adverse outcomes. Decreased vaccine effectiveness among immunocompromised individuals is linked to correspondingly high rates of breakthrough infections. Negative results on SARS-CoV-2 antibody tests are associated with increased risk for subsequent infection. "Low-positive" results on semiquantitative SARS-CoV-2 spike-targeted antibody tests may help identify persons at increased risk as well. Standardized SARS-CoV-2 spike-targeted antibody tests may provide objective information on the risk of SARS-CoV-2 infection and associated adverse outcomes. This holds especially for high-risk populations that demonstrate a relatively high rate of seronegativity. The widespread availability of such tests presents an opportunity to refine risk assessment for individuals with suboptimal SARS-CoV-2 antibody levels and to promote effective interventions. Interim federal guidance would support physicians and patients while additional investigations are pursued.

Antibody Response to ChAdOx1 nCoV-19 (AZD1222) Vaccine in Kidney Transplant Recipients

Kidney transplant recipients (KTRs) are at a much higher risk of complications and death following COVID-19 and are poor vaccine responders. The data are limited on the immune response to Covishield® in KTRs. We prospectively recruited a cohort of 67 KTRs aged >18 between April 2021 and December 2021. Each participant was given two intramuscular doses of Covishield®, each of 0.5 mL, at an interval of 12 weeks. A blood specimen of 5.0 mL was collected from each participant at two points within a few days before administering the first dose of the vaccine and at any time between 4−12 weeks after administering the second dose. The sera were tested for anti-RBD antibody (ARAb) titre and neutralising antibody (NAb). An ACE2 competition assay was used as a proxy for virus neutralization. According to the prior COVID-19 infection, participants were grouped as (i) group A: prior symptomatic COVID-19 infection, (ii) group B: prior asymptomatic COVID-19 infection as evidenced by detectable ARAb in the prevaccination specimen, (iii) Group C: no prior infection with COVID-19, (iv) group D: Unclassified, i.e., participants had no symptoms suggestive of COVID-19, but their prevaccination specimen was not available for ARAb testing before vaccination. Fifty of sixty-seven participants (74.6%) provided paired specimens (group A 14, group B 27, and group C 9) and 17 participants (25.4%) provided only postvaccination specimens (group D). In the overall cohort (n = 67), 91% and 77.6% of participants developed ARAb and NAb, respectively. Their ARAb titre and NAb proportion were 2927 (520−7124) U/mL and 87.9 (24.4−93.2) %, respectively. Their median ARAb titre increased 65.6 folds, from 38.2 U/mL to 3137 U/mL. Similarly, the proportion of participants with NAb increased from 56% to 86%, and the NAb proportion raised 2.7 folds, from 23% to 91%. A comparison of vaccine response between the study groups showed that all those with or without prior COVID-19 infection showed a significant rise in ARAb titre (p < 0.05) and NAb proportion (p < 0.05) after the two doses of vaccine administration. The median value of folds rise in anti-RBD and NAb between groups A and B were comparable. Hence, ARAb is present in more than 3/4th of KTRs before the ChAdOx1 vaccine in India. The titer of ARAb and the proportion of NAb significantly increased after the two doses of the ChAdOx1 vaccine in KTRs.

The prospective screening for SARS-CoV-2 S1/S2 antibodies delineates the factual incidence of COVID-19 and shows a sustained serological response post COVID-19 in kidney transplant recipients

BACKGROUND

The impact of immunosuppression on the occurrence of Coronavirus Disease 2019 (COVID-19) remains unclear.

METHODS

We conducted a prospective screening of anti-S1/S2 IgGs against SARS-CoV-2 Spike protein from March, 1 2020 to May, 15 2021 (prior to the vaccination campaign) in a cohort of 713 kidney transplant recipients (KTRs). In a first phase, the factual incidence and seroprevalence of COVID-19 was established in this cohort: cases diagnosed by serology were added to RT-PCR-based diagnoses to obtain the overall incidence of COVID-19 in both symptomatic and asymptomatic KTRs. In the second phase, the kinetics of the post-COVID-19 humoral response were studied, taking into account the severity of the disease defined by the need for oxygen therapy (group S, "severe") or not (group nS, "not severe").

RESULTS

The combined diagnostic approaches identified 138 COVID-19 cases (19.2%), with 37 diagnoses by serology (26.8%). The rate of asymptomatic KTRs reached 20.3% (28/138). Thirteen patients (9.4%) died from COVID-19. The seroconversion rate was 91.7% (99/108). The peak anti-S1/S2 IgG level was 85 [30-150] AU/ml and was similar between the S and nS groups (117 [38; 186] AU/ml versus 73 [23; 140] AU/ml). A high probability of persistence of anti-S1/S2 IgG post-COVID-19 was observed, with only 10.1% (7/69) of the patients having negated their serology during the 9-month follow-up.

CONCLUSION

Our pragmatic serological screening combined with RT-PCR tests provides a better estimation of the real incidence of COVID-19 in KTRs. A significant proportion of KTRs develop humoral immunity post COVID-19, which most often persists beyond 9 months.

Immune responses to SARS-CoV-2 in dialysis and kidney transplantation

Despite progressive improvements in the management of patients with coronavirus disease 2019 (COVID-19), individuals with end-stage kidney disease (ESKD) are still at high risk of infection-related complications. Although the risk of infection in these patients is comparable to that of the general population, their lower rate of response to vaccination is a matter of concern. When prevention strategies fail, infection is often severe. Comorbidities affecting patients on maintenance dialysis and kidney transplant recipients clearly account for the increased risk of severe COVID-19, while the role of uremia and chronic immunosuppression is less clear. Immune monitoring studies have identified differences in the innate and adaptive immune response against the virus that could contribute to the increased disease severity. In particular, individuals on dialysis show signs of T cell exhaustion that may impair antiviral response. Similar to kidney transplant recipients, antibody production in these patients occurs, but with delayed kinetics compared with the general population, leaving them more exposed to viral expansion during the early phases of infection. Overall, unique features of the immune response during COVID-19 in individuals with ESKD may occur with severe comorbidities affecting these individuals in explaining their poor outcomes.

SARS-CoV-2 Specific Antibody Response and T Cell-Immunity in Immunocompromised Patients up to Six Months Post COVID: A Pilot Study

COVID-19 generates SARS-CoV-2-specific antibodies in immunocompetent individuals. However, in immunocompromised patients, the humoral immunity following infection may be impaired or absent. Recently, the assessment of cellular immunity to SARS-CoV-2, both following natural infection and vaccination, has contributed new knowledge regarding patients with low or no antibody responses. As part of a prospective cohort study which included hospitalized patients with COVID-19, we identified immunocompromised patients and compared them with age- and sex-matched immunocompetent patients regarding co-morbidities, biomarkers of COVID-19 and baseline viral load by real-time PCR in nasopharyngeal swabs. Spike and nucleocapsid antibody responses were analyzed at inclusion and after two weeks, six weeks and six months. Plasma immunoglobulin G (IgG) levels were quantified, lymphocyte phenotyping was performed, and SARS-CoV-2 specific CD4 and CD8 T cell responses after in vitro antigen stimulation were assessed at six months post infection. All patients showed IgG levels above or within reference limits. At six months, all patients had detectable SARS-CoV-2 anti-spike antibody levels. SARS-CoV-2 specific T cell responses were detected in 12 of 12 immunocompetent patients and in four of six immunocompromised patients. The magnitude of long-lived SARS-CoV-2 specific T cell responses were significantly correlated with the number of CD4 T cells and NK cells. Determining the durability of the humoral and cellular immune response against SARS-CoV-2 in immunocompromised individuals could be of importance by providing insights into the risk of re-infection and the need for vaccine boosters.

The seroprevalence of COVID-19 in patients living with HIV in metropolitan Detroit

Background

COVID-19, a novel respiratory illness caused by SARS-CoV-2, has become a global pandemic. As of December 2020, 4.8% of the 941 people living with HIV in our Ryan White clinic have tested polymerase chain reaction positive for SARS-CoV-2. The aim of our study was to estimate the seroprevalence of COVID-19 in our Ryan White people living with HIV, irrespective of known past infection.

Methods

We conducted a cross-sectional study that recruited people living with HIV in the Ryan White program at Henry Ford Hospital in Detroit, Michigan, from September 2020 through May 2021. All Ryan White patients were offered participation during clinic visits. After informed consent, patients completed a survey, and had blood sampled for SARS-CoV-2 antibody testing.

Results

Of the 529 individuals who completed the written survey, 504 participants were tested for SARS-CoV-2 antibody and 52 people living with HIV were COVID-19 immunoglobulin (Ig) G positive resulting in a seroprevalence of 10.3%. Among 36 persons with PCR-confirmed COVID-19, 52.8% were IgG negative. Inclusion of PCR positive but IgG-negative people living with HIV yields a COVID-19 infection prevalence of 14.1%.

Conclusions

These findings suggest that passive public health-based antibody surveillance in people living with HIV significantly underestimates past infection.

Potential importance of early treatment of SARS-CoV-2 infection in intestinal transplant patient: A case report

BACKGROUND

Predispositions for severe coronavirus disease 2019 (COVID-19) are age, immunosuppression, and co-morbidity. High levels of maintenance immunosuppression render intestinal transplant (ITx) patients vulnerable for severe COVID-19. COVID-19 also provokes several gastroenterological pathologies which have not been discussed in ITx, so far.

CASE SUMMARY

During the second European COVID-19 wave in November 2020, an ITx recipient was admitted to the hospital because of electrolyte disturbances due to dehydration. Immunosuppression consisted of tacrolimus, azathioprine, and low-dose corticosteroids. During hospitalization, she tested positive on screening COVID-19 nasopharyngeal polymerase chain reaction swab, while her initial test was negative. She was initially asymptomatic and had normal inflammatory markers. Tacrolimus levels were slightly raised, as Azathioprine was temporarily halted. Due to elevated D-dimers at that time, prophylactic low-molecular weight heparin was started. Seven days after the positive test, dyspnea, anosmia, and C-reactive protein increase (25 mg/L) were noted. Remdesivir was administered during 5 d in total. High stomal output was noted in two consecutive days and several days thereafter. To exclude infection or rejection, an ileoscopy and biopsy were performed and excluded these. Four weeks later, she was discharged from the hospital and remains in good health since then.

CONCLUSION

Early eradication of severe acute respiratory syndrome coronavirus 2 in ITx recipients may be warranted to prevent acute rejection provocation by it.

COVID-19 and kidney disease: insights from epidemiology to inform clinical practice

Over the course of the COVID-19 pandemic, numerous studies have aimed to address the challenges faced by patients with kidney disease and their caregivers. These studies addressed areas of concern such as the high infection and mortality risk of patients on in-centre haemodialysis and transplant recipients. However, the ability to draw meaningful conclusions from these studies has in some instances been challenging, owing to barriers in aspects of usual care, data limitations and problematic methodological practices. In many settings, access to SARS-CoV-2 testing differed substantially between patient groups, whereas the incidence of SARS-CoV-2 infection varied over time and place because of differences in viral prevalence, targeted public health policies and vaccination rates. The absence of baseline kidney function data posed problems in the classification of chronic kidney disease and acute kidney injury in some studies, potentially compromising the generalizability of findings. Study findings also require attentive appraisal in terms of the effects of confounding, collider bias and chance. As this pandemic continues and in the future, the implementation of sustainable and integrated research infrastructure is needed in settings across the world to minimize infection transmission and both prevent and plan for the short-term and long-term complications of infectious diseases. Registries can support the real-world evaluation of vaccines and therapies in patients with advanced kidney disease while enabling monitoring of rare complications.

Patients with kidney disease are at particular risk of the adverse outcomes of COVID-19. Throughout the pandemic, epidemiological studies have been performed to inform clinical care; however, these studies have faced a number of methodological challenges. This Review discusses current understanding of the effects of COVID-19 on patients with kidney disease and some of the major obstacles encountered when conducting epidemiological research in a pandemic setting.

Patients who are receiving in-centre dialysis have a higher risk of exposure to SARS-CoV-2 than members of the general population, owing to their limited ability to isolate.

Studies have found a dose–response of increasing risk of mortality from COVID-19 with decreasing kidney function, with particularly high mortality seen in people with kidney failure and those on kidney replacement therapy.

Evidence of how infection risk can be mitigated in patients with chronic kidney disease is often of poor quality due to the many challenges of conducting epidemiological research in fragmented health-care settings.

Observational studies of associations between risk factors, such as chronic kidney disease or transplantation, and outcomes, such as COVID-19-related mortality, can be distorted as a result of collider bias, and thus care must be taken in study design and evaluation.

Recognizing the challenges that affect epidemiological studies in pandemic settings together with information on local health contexts enables rigorous assessment of study quality; adequate reporting of aspects relevant to local care availability enables readers to identify studies that contribute robust findings to the literature.

To confront the challenges wrought by future pandemics, a sustainable and integrated global infrastructure is needed to identify evidence-based approaches to minimize infection transmission and adverse outcomes.

Longevity of anti-spike and anti-nucleocapsid antibodies after COVID-19 in solid organ transplant recipients compared to immunocompetent controls

Solid organ transplant recipients (SOTRs) are on lifelong immunosuppression, which may interfere with adaptive immunity to COVID-19. The data on dynamics and duration of antibody response in SOTRs are limited. This longitudinal study examined the longevity of both anti-spike (S)- and anti-nucleocapsid (N)-specific IgG antibodies after COVID-19 in SOTRs compared to matched immunocompetent persons. SOTRs (n = 65) were matched with controls (n = 65) for COVID-19 disease severity, age, and sex in order of priority. Serum-IgG antibodies against N and S antigens of SARS-CoV-2 were analyzed. At 1 and 9 months after COVID-19, anti-S-IgG detectability decreased from 91% to 82% in SOTRs versus 100% to 95% in controls, whereas the anti-N-IgG decreased from 63% to 29% in SOTRs versus 89% to 46% in controls. A matched paired analysis showed SOTRs having significantly lower levels of anti-N-IgG at all time points (1 month p = .007, 3 months p < .001, 6 months p = .019, and 9 months p = .021) but not anti-S-IgG at any time points. A mixed-model analysis confirmed these findings except for anti-S-IgG at 1 month (p = .005) and identified severity score as the most important predictor of antibody response. SOTRs mount comparable S-specific, but not N-specific, antibody responses to SARS-CoV-2 infection compared to immunocompetent controls.

Post vaccination analysis of anti-spike antibody responses in kidney transplant recipients with and without COVID-19 infection in a tertiary care center, India

Background

To investigate the anti-spike antibody response to vaccination in Kidney transplant recipients (KTRs) previously infected with SARS-CoV-2 as compared to KTRs with no history of COVID-19 from India.

Methods

SARS-CoV-2 spike immunoglobulin (Ig) G antibody response was measured in 105 post COVID-19 KTRs with PCR confirmed SARS-CoV-2 infection who received either no vaccination (cohort 1), single (cohort 2) or two doses (cohort 3) of vaccine and compared to 103 two-dose vaccinated COVID-19 naïve KTRs with no history of COVID-19 (cohort 4).

Results

Out of 103 COVID-19 naïve two-dose vaccinated KTRs, less than 50% became seropositive with anti-spike antibody titres &gt; 50AU/mL subsequent to complete vaccination, the seroconversion rate being comparable in subjects receiving CovishieldTM versus CovaxinTM vaccines. However, the seropositive KTRs vaccinated with CovishieldTM had higher anti-spike antibody titres as compared to those who received CovaxinTM. We observed higher anti-SARS-CoV-2 spike antibody levels in post COVID-19 KTRs after 1 dose of vaccine as compared with COVID-19 naïve two-dose vaccinated KTRs. Importantly, the second dose in post COVID-19 KTRs did not significantly increase anti-spike antibody levels compared with the single dose recipients.

Conclusions

Our data presents that in KTRs with previous SARS-CoV-2 infection a single dose of vaccine (CovishieldTM) may be effective in mounting optimal immune response. In contrast, COVID-19 naïve two-dose vaccinated KTRs respond poorly (&lt;50%) to current recommendation of a two-dose regimen in India.

Anti-CD20 therapies decrease humoral immune response to SARS-CoV-2 in patients with multiple sclerosis or neuromyelitis optica spectrum disorders

BACKGROUND

SARS-CoV-2 seroconversion rate after COVID-19 may be influenced by disease-modifying therapies (DMTs) in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorders (NMO-SD).

OBJECTIVE

To investigate the seroprevalence and the quantity of SARS-CoV-2 antibodies in a cohort of patients with MS or NMO-SD.

METHODS

Blood samples were collected in patients diagnosed with COVID-19 between 19 February 2020 and 26 February 2021. SARS-CoV-2 antibody positivity rates and Ig levels (anti-S IgG titre, anti-S IgA index, anti-N IgG index) were compared between DMTs groups. Multivariate logistic and linear regression models were used to estimate the influence of DMTs and other confounding variables on SARS-CoV-2 serological outcomes.

RESULTS

119 patients (115 MS, 4 NMO, mean age: 43.0 years) were analysed. Overall, seroconversion rate was 80.6% within 5.0 (SD 3.4) months after infection. 20/21 (95.2%) patients without DMT and 66/77 (85.7%) patients on DMTs other than anti-CD20 had at least one SARS-CoV-2 Ig positivity, while this rate decreased to only 10/21 (47.6%) for patients on anti-CD20 (p<0.001). Being on anti-CD20 was associated with a decreased odd of positive serology (OR, 0.07 (95% CI 0.01 to 0.69), p=0.02) independently from time to COVID-19, total IgG level, age, sex and COVID-19 severity. Time between last anti-CD20 infusion and COVID-19 was longer (mean (SD), 3.7 (2.0) months) in seropositive patients compared with seronegative patients (mean (SD), 1.9 (1.5) months, p=0.04).

CONCLUSIONS

SARS-CoV-2 antibody response was decreased in patients with MS or NMO-SD treated with anti-CD20 therapies. Monitoring long-term risk of reinfection and specific vaccination strategies in this population may be warranted.

TRIAL REGISTRATION NUMBER

NCT04568707.

Predictive Factors for Humoral Response After 2-dose SARS-CoV-2 Vaccine in Solid Organ Transplant Patients

Background

A weak immunogenicity has been reported in solid organ transplant (SOT) recipients after 2 doses of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine. The aim of this retrospective study was to identify the predictive factors for humoral response in SOT patients.

Methods

Three hundred and ninety-three SOT patients from our center with at least 4 wk of follow-up after 2 doses of mRNA-based vaccine were included in this study. Anti-SARS-Cov-2 spike protein antibodies were assessed before and after vaccination.

Results

Anti-SARS-CoV-2 antibodies were detected in 34% of the patients: 33.7% of kidney transplant patients, 47.7% of liver transplant patients, and 14.3% of thoracic transplant patients (P = 0.005). Independent predictive factors for humoral response after vaccination were male gender, a longer period between transplantation and vaccination, liver transplant recipients, a higher lymphocyte count at baseline, a higher estimated glomerular filtration rate and receiving the tacrolimus + everolimus ± steroids combination. Conversely, the nondevelopment of anti-SARS-CoV-2 antibodies after vaccination was associated with younger patients, thoracic organ recipients, induction therapy recipients, and tacrolimus + mycophenolic acid ± steroids recipients.

Conclusions

The immunosuppressive regimen is a modifiable predictive factor for humoral response to SARS-CoV-2 vaccine.

Risk Factors Associated With an Impaired Antibody Response in Kidney Transplant Recipients Following 2 Doses of the SARS-CoV-2 mRNA Vaccine

Background.

Data about vaccine efficacy in solid organ transplant patients are limited. We previously reported our initial observation of a 6.2% immunogenicity rate in kidney transplant recipients (KTRs) after administration of 1 dose of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine. We sought to report our observations of anti-SARS-CoV-2 antibody in KTRs after 2 doses of the SARS-CoV-2 mRNA vaccine.

Methods.

We identified 105 KTRs who received 2 doses of the Pfizer-BioNTech or Moderna mRNA-1273 vaccine per availability and had anti-SARS-CoV-2 labs obtained at least 2 wk following administration of the second dose. Antibody testing was performed using 3 clinically validated qualitative and semiquantitative assays.

Results.

KTRs had a 36.2% antibody response rate, whereas an age ≥68 years and a longer time from transplant were factors associated with antibody response.

Conclusions.

The low antibody response in KTRs may be associated with the immunosuppressive state. More data are needed to evaluate if KTRs may require higher vaccine doses or an additional booster dose to increase their ability to mount an immune response to the SARS-CoV-2 vaccine.

Circulating IgG Levels in SARS-CoV-2 Convalescent Individuals in Cyprus

Long-term persistence and the heterogeneity of humoral response to SARS-CoV-2 have not yet been thoroughly investigated. The aim of this work is to study the production of circulating immunoglobulin class G (IgG) antibodies against SARS-CoV-2 in individuals with past infection in Cyprus. Individuals of the general population, with or without previous SARS-CoV-2 infection, were invited to visit the Biobank at the Center of Excellence in Biobanking and Biomedical Research of the University of Cyprus. Serum IgG antibodies were measured using the SARS-CoV-2 IgG and the SARS-CoV-2 IgG II Quant assays of Abbott Laboratories. Antibody responses to SARS-CoV-2 were also evaluated against participants’ demographic and clinical data. All statistical analyses were conducted in Stata 16. The median levels of receptor binding domain (RBD)-specific IgG in 969 unvaccinated individuals, who were reportedly infected between November 2020 and September 2021, were 432.1 arbitrary units (AI)/mL (interquartile range—IQR: 182.4–1147.3). Higher antibody levels were observed in older participants, males, and those who reportedly developed symptoms or were hospitalized. The RBD-specific IgG levels peaked at three months post symptom onset and subsequently decreased up to month six, with a slower decay thereafter. IgG response to the RBD of SARS-CoV-2 is bi-phasic with considerable titer variability. Levels of IgG are significantly associated with several parameters, including age, gender, and severity of symptoms.

Humoral response to SARS-CoV-2 is well preserved and symptom dependent in kidney transplant recipients

Data on the immune response to SARS-CoV-2 in kidney transplant recipients are scarce. Thus, we conducted a single-center observational study to assess the anti-SARS-CoV-2 IgG seroprevalence in outpatient kidney transplant recipients (KTR; n = 1037) and healthcare workers (HCW; n = 512) during the second wave of the COVID-19 pandemic in fall 2020 and evaluated the clinical variables affecting antibody levels. Antibodies against S1 and S2 subunit of SARS-CoV-2 were evaluated using immunochemiluminescent assay (cut off 9.5 AU/ml, sensitivity of 91.2% and specificity of 90.2%). Anti-SARS-CoV-2 IgG seroprevalence was lower in KTR than in HCW (7% vs. 11.9%, p = .001). Kidney transplant recipients with SARS-CoV-2 infection were younger (p = .001) and received CNI-based immunosuppression more frequently (p = .029) than seronegative KTR. Anti-SARS-CoV-2 IgG positive symptomatic KTR had a higher BMI (p = .04) than asymptomatic KTR. Interestingly, anti-SARS-CoV-2 IgG levels were higher in KTR than in HCW (median 31 AU/ml, IQR 17-84 vs. median 15 AU/ml, IQR 11-39, p < .001). The presence of moderate to severe symptoms in KTR was found to be the only independent factor affecting IgG levels (Beta coefficient = 41.99, 95% CI 9.92-74.06, p = .011) in the multivariable model. In conclusion, KTR exhibit a well-preserved symptom-dependent humoral response to SARS-CoV-2 infection.

Delayed Kinetics of IgG, but Not IgA, Antispike Antibodies in Transplant Recipients following SARS-CoV-2 Infection

BACKGROUND

Kidney transplant recipients are at increased risk of severe outcomes during COVID-19. Antibodies against the virus are thought to offer protection, but a thorough characterization of anti-SARS-CoV-2 immune globulin isotypes in kidney transplant recipients following SARS-CoV-2 infection has not been reported.

METHODS

We performed a cross-sectional study of 49 kidney transplant recipients and 42 immunocompetent controls at early (≤14 days) or late (>14 days) time points after documented SARS-CoV-2 infection. Using a validated semiquantitative Luminex-based multiplex assay, we determined the abundances of IgM, IgG, IgG1-4, and IgA antibodies against five distinct viral epitopes.

RESULTS

Kidney transplant recipients showed lower levels of total IgG antitrimeric spike (S), S1, S2, and receptor binding domain (RBD) but not nucleocapsid (NC) at early versus late time points after SARS-CoV-2 infection. Early levels of IgG antispike protein epitopes were also lower than in immunocompetent controls. Anti-SARS-CoV-2 antibodies were predominantly IgG1 and IgG3, with modest class switching to IgG2 or IgG4 in either cohort. Later levels of IgG antispike, S1, S2, RBD, and NC did not significantly differ between cohorts. There was no significant difference in the kinetics of either IgM or IgA antispike, S1, RBD, or S2 on the basis of timing after diagnosis or transplant status.

CONCLUSIONS

Kidney transplant recipients mount early anti-SARS-CoV-2 IgA and IgM responses, whereas IgG responses are delayed compared with immunocompetent individuals. These findings might explain the poor outcomes in transplant recipients with COVID-19.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/JASN/2021_11_23_briggsgriffin112321.mp3.

SARS-CoV-2-specific Humoral and Cellular Immunities in Kidney Transplant Recipients and Dialyzed Patients Recovered From Severe and Nonsevere COVID-19

Kidney transplantation and dialysis are two major risk factors for severe forms of coronavirus disease 2019 (COVID-19). The dynamics of the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in this population remain largely unknown.

Methods

We report here the analysis of anti-SARS-CoV-2 antibody- and T cell-mediated immune responses in 26 kidney transplant recipients (KTRs) and 11 dialyzed patients (DPs) who recovered from COVID-19.

Results

After a mean time of 83 ± 26 d post-symptom onset for KTRs and 97 ± 31 d for DPs, 20 KTRs (76.9%) and 10 DPs (90.9%) displayed anti-S1 immunoglobulin G SARS-CoV-2 antibodies (P = 0.34), at similar titers in both groups. SARS-CoV-2-specific interferon-γ-producing T cells were evidenced in 26 KTRs (100%) and 10 DPs (90.9%). Total numbers of SARS-CoV-2-reactive T cells were high and not statistically different between the 2 groups. No correlation between the severity of the disease and the number of reactive T cells was found in KTRs. In 5 KTRs, also evaluated 10 mo after COVID-19, weak or absent antibody response was observed, whereas specific memory T-cell response was detected in all cases.

Conclusion

T-cell response persisted up to 3 mo post-symptom onset, even in KTRs in whom full immunosuppressive regimen was reinstated at recovery, and seems to be present up to 10 mo after infection. Our findings have implications in the understanding of the natural course of the disease in transplant patients and DPs.

Comparing Humoral and Cellular Adaptive Immunity during Convalescent Phase of COVID-19 in Hemodialysis Patients and Kidney Transplant Recipients

Background. It is still unclear whether COVID-19 convalescent kidney transplant recipients (KTR) and hemodialysis (HD) patients can develop anti-SARS-CoV-2 adaptive immunity. The aim was to characterize and compare the immune response to the virus in HD patients and KTR. Methods. The study included 26 HD patients and 54 KTR—both convalescent (14 HD, 25 KTR) and unexposed. The immune response was assessed by determining the anti-SARS-CoV-2 antibodies in serum and specific T cell response via the interferon-gamma release assay (IGRA). Moreover, blood-morphology-derived parameters, immune cell phenotypes, and acute phase reactants were evaluated. Results. KRT and HD convalescents presented similar serum levels of anti-SARS-CoV-2 IgG and IgA. A negative correlation occurred between IgG and time after the infection was observed. There was a strong relationship between the prevalence of anti-SARS-CoV-2 cellular and humoral responses in both groups. Convalescent IGRA response was significantly higher in HD patients compared to KTR. Conclusions. HD patients and KTR develop humoral and cellular responses after COVID-19. The antibodies levels are similar in both groups of patients. SARS-CoV-2-reactive T cell response is stronger in HD patients compared to KTR. The SARS-CoV-2-specific IgG level decreases with time while IgA and a cellular response are maintained. IGRA proved to be a valuable test for the assessment of specific cellular immunity in immunocompromised HD patients and KTR.

Lack of immune response after mRNA vaccination to SARS-CoV-2 in a solid organ transplant patient

The recent approval and distribution of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) have been a major development in the fight against the current coronavirus disease 2019 (COVID‐19) pandemic. The first two vaccines approved in the United States, mRNA‐1273, and BNT162b2, are both messenger RNA (mRNA) based and highly effective in immunocompetent persons, but efficacy in patients on immunosuppressants has not been established. Additionally, data suggests these patients are less likely than immunocompetent people to develop neutralizing antibodies after COVID‐19 infection. Given the high risk of poor outcomes in organ transplant and immunosuppressed patients, effective vaccination is paramount in this group. We present the first reported case of a solid organ transplant patient who failed to achieve seroconversion after two doses of mRNA vaccine. This case has significant implications about how immunosuppressed patients should be counseled about SARS‐CoV‐2 vaccination and the protection provided. Physicians should remain clinically suspicious for infection with SARS‐CoV‐2 despite vaccination status in solid organ transplant patients.