Virus Infection Research Articles

Impact of transport conditions and underlying disease on post-stocking survival of juvenile Lates calcarifer.

Diseases caused by pathogens commonly occurring in the aquatic environment or those that are non-host specific are prevalent and threaten the rapid growth of tropical aquaculture. This study investigates causes of mortality in 12 batches of newly stocked juvenile Lates calcarifer from three different hatcheries. Cytology based on Diff-Quik™-stained tissue and blood smears provides rapid diagnosis of possible causes of mortality, while histopathology and haematology provide a better understanding of how prolonged transport and fish with existing chronic disease are more likely to experience elevated mortality post-stocking. Our findings showed that accumulation of ammonia during prolonged transport causes extensive damage to epithelial barriers in gastrointestinal tracts and depressed immunity due to marked hypoglycaemia, predisposing fish to acute Streptococcosis. Lates calcarifer with chronic bacterial enteritis developed severe hypoglycaemia, had low circulating total plasma protein, and suffered high mortality within 24 hours post-stocking. Hypoglycaemia and low circulating blood proteins disrupt osmoregulation and exacerbate dehydration, which is fatal in fish in sea water. Dying L. calcarifer tested PCR positive for scale drop disease virus (SDDV) at 28 days post-stocking showed a 10-fold elevation of white blood cell counts, severe vasculitis, and obstruction of blood supply to major organs. Destruction of important immune organs such as spleen is a hallmark of SDDV infection that explains high incidences of opportunistic Vibrio harveyi infections in 61% of fish with SDDV. Overall, this study reiterates the importance of stocking disease-free fish and reducing transport stress.

#1718 Infectious complications among early versus late pulse steroid therapy among renal transplant recipients

Abstract Background and Aims Renal transplant recipients are at risk for infectious complications, with opportunistic infections predominating early after transplant and community acquired infections occurring in late transplant period. Pulse steroid is a form of heightened immunosuppression given to a transplant recipient, usually for treatment of rejection. This study aimed to investigate the effects of early and late pulse steroid therapy on the development of infectious complications in renal transplant recipients. Method Study population was drawn from patients undergoing kidney transplantation in the period between 1st January, 2016 and 31st December, 2020 in the study centre. Early and late pulse steroid therapy was defined based on whether pulse steroid was received within or after 90 days from date of transplant respectively. Patients receiving either early or late (but not both) pulse steroids who were more than or equal to 18 years of age and had at least 90 days of follow up were included in the study. Patients were followed up till 31st December, 2021 or till their death (whichever came earlier). Results Total of 516 patients underwent renal transplantation in the study centre in the specified period, out of whom 128 patients (24.8%) fulfilled the inclusion criteria without fulfilling the exclusion criteria. Out of these 128 patients, 83 (64.8%) and 45 (35.2%) patients received early and late pulse steroids respectively. The 2 groups were similar with respect to respect to baseline characteristics and use of other immunosuppressive agents. The mean values (95% confidence interval) for overall infections in early and late pulse steroid categories were 0.46 (0.31-0.61) and 1.16 (0.55-1.78) episodes per year respectively (p = 0.28). Sepsis occurred at higher rate in patients receiving late pulse steroids, with mean values (95% confidence interval) for sepsis in early and late pulse steroid categories being 0.02 (0.00-0.06) and 0.30 (0.04- 0.57) episodes per year respectively (p = 0.01). Viral infections also occurred at higher rate in patients receiving late pulse steroids, with mean values (95% confidence interval) for viral infections in early and late pulse steroid categories being 0.04 (0.02- 0.09) and 0.23 (0.03-0.43) episodes per year respectively (p = 0.01). Rates of other types of infection did not significantly differ between the 2 categories. A greater proportion of patients receiving late pulse steroids died (4.8% and 17.8% in early and late pulse steroid categories respectively, p = 0.02). Conclusion Late pulse steroid therapy is associated with more episodes of sepsis and viral infections compared to early pulse steroid therapy, although rate of overall infections do not significantly differ between the two groups. This study highlights the importance of surveillance for infections after pulse steroid therapy in renal allograft recipients.

Diagnostic value of serum STIP1 in HCC and AFP-negative HCC.

This study aimed to investigate the diagnostic value of stress-induced phosphoprotein 1 (STIP1) in serum for hepatocellular carcinoma (HCC) and alpha-fetoprotein (AFP)-negative HCC (ANHC). In this study, serum samples were collected from 158 HCC patients and 63 non-HCC patients. Logistic regression analysis was performed to identify independent risk factors associated with HCC and ANHC. The diagnostic values of each index for HCC and ANHC were analyzed using receiver operating characteristic (ROC) curve analysis. The STIP1, des-γ-carboxy prothrombin (DCP), and AFP levels were higher in the HCC groups than in the non-HCC groups (P < .05). Age, DCP, STIP1, and hepatitis B virus infection were independent predictors of HCC (P < .05). The diagnostic value of STIP1 for HCC was higher than that of DCP. Additionally, age, STIP1, and hepatitis B virus infection were independent predictors for ANHC patients. The ROC curve exhibited an area under the curve value of 0.919 for STIP1, with a diagnostic cutoff value of 68.5 U/mL. Moreover, 36 ANHC patients and 19 AFP-negative non-HCC patients were included to validate the diagnostic model. A total of 20 patients had STIP1 levels greater than 68.5 U/mL, resulting in diagnostic accuracy of 67.3%, sensitivity of 55.6%, and specificity of 89.5%. STIP1 demonstrates excellent diagnostic value for HCC and ANHC.

Understanding the impact of congenital infections and perinatal viral exposures on the developing brain using white matter magnetic resonance imaging: a scoping review

BackgroundMagnetic Resonance Imaging (MRI)-based imaging techniques are useful for assessing white matter (WM) structural and microstructural integrity in the context of infection and inflammation. The purpose of this scoping review was to assess the range of work on the use of WM neuroimaging approaches to understand the impact of congenital and perinatal viral infections or exposures on the developing brain.MethodsThis scoping review was conducted according to the Arksey and O’ Malley framework. A literature search was performed in Web of Science, Scopus and PubMed for primary research articles published from database conception up to January 2022. Studies evaluating the use of MRI-based WM imaging techniques in congenital and perinatal viral infections or exposures were included. Results were grouped by age and infection.ResultsA total of 826 articles were identified for screening and 28 final articles were included. Congenital and perinatal infections represented in the included studies were cytomegalovirus (CMV) infection (n = 12), human immunodeficiency virus (HIV) infection (n = 11) or exposure (n = 2) or combined (n = 2), and herpes simplex virus (HSV) infection (n = 1). The represented MRI-based WM imaging methods included structural MRI and diffusion-weighted and diffusion tensor MRI (DWI/ DTI). Regions with the most frequently reported diffusion metric group differences included the cerebellar region, corticospinal tract and association fibre WM tracts in both children with HIV infection and children who are HIV-exposed uninfected. In qualitative imaging studies, WM hyperintensities were the most frequently reported brain abnormality in children with CMV infection and children with HSV infection.ConclusionThere was evidence that WM imaging techniques can play a role as diagnostic and evaluation tools assessing the impact of congenital infections and perinatal viral exposures on the developing brain. The high sensitivity for identifying WM hyperintensities suggests structural brain MRI is a useful neurodiagnostic modality in assessing children with congenital CMV infection, while the DTI changes associated with HIV suggest metrics such as fractional anisotropy have the potential to be specific markers of subtle impairment or WM damage in neuroHIV.

Tripartite motif-containing protein 21 is involved in IFN-γ-induced suppression of hepatitis B virus by regulating hepatocyte nuclear factors.

The antiviral role of the tripartite motif-containing (TRIM) protein family , a member of the E3-ubiquitin ligase family, has recently been actively studied. Hepatitis B virus (HBV) infection is a major contributor to liver diseases; however, the host factors regulated by cytokine-inducible TRIM21 to suppress HBV remain unclear. In this study, we showed the antiviral efficacy of TRIM21 against HBV in hepatoma cell lines, primary human hepatocytes isolated from patient liver tissues, and mouse model. Using TRIM21 knock-out cells, we confirmed that the antiviral effects of interferon-gamma, which suppress HBV replication, are diminished when TRIM21 is deficient. Northern blot analysis confirmed a reduction of HBV RNA levels by TRIM21. Using Luciferase reporter assay, we also discovered that TRIM21 decreases the activity of HBV enhancers, which play a crucial role in covalently closed circular DNA transcription. The participation of the RING domain and PRY-SPRY domain in the anti-HBV effect of TRIM21 was demonstrated through experiments using deletion mutants. We identified a novel interaction between TRIM21 and hepatocyte nuclear factor 4α (HNF4α) through co-immunoprecipitation assay. More specifically, ubiquitination assay revealed that TRIM21 promotes ubiquitin-mediated proteasomal degradation of HNF4α. HNF1α transcription is down-regulated as a result of the degradation of HNF4α, an activator for the HNF1α promoter. Therefore, the reduction of key HBV enhancer activators, HNF4α and HNF1α, by TRIM21 resulted in a decline in HBV transcription, ultimately leading to the inhibition of HBV replication.IMPORTANCEDespite extensive research efforts, a definitive cure for chronic hepatitis B remains elusive, emphasizing the persistent importance of this viral infection as a substantial public health concern. Although the risks associated with hepatitis B virus (HBV) infection are well known, host factors capable of suppressing HBV are largely uncharacterized. This study elucidates that tripartite motif-containing protein 21 (TRIM21) suppresses HBV transcription and consequently inhibits HBV replication by downregulating the hepatocyte nuclear factors, which are host factors associated with the HBV enhancers. Our findings demonstrate a novel anti-HBV mechanism of TRIM21 in interferon-gamma-induced anti-HBV activity. These findings may contribute to new strategies to block HBV.

Accurate prediction of antibody function and structure using bio-inspired antibody language model.

In recent decades, antibodies have emerged as indispensable therapeutics for combating diseases, particularly viral infections. However, their development has been hindered by limited structural information and labor-intensive engineering processes. Fortunately, significant advancements in deep learning methods have facilitated the precise prediction of protein structure and function by leveraging co-evolution information from homologous proteins. Despite these advances, predicting the conformation of antibodies remains challenging due to their unique evolution and the high flexibility of their antigen-binding regions. Here, to address this challenge, we present the Bio-inspired Antibody Language Model (BALM). This model is trained on a vast dataset comprising 336 million 40% nonredundant unlabeled antibody sequences, capturing both unique and conserved properties specific to antibodies. Notably, BALM showcases exceptional performance across four antigen-binding prediction tasks. Moreover, we introduce BALMFold, an end-to-end method derived from BALM, capable of swiftly predicting full atomic antibody structures from individual sequences. Remarkably, BALMFold outperforms those well-established methods like AlphaFold2, IgFold, ESMFold and OmegaFold in the antibody benchmark, demonstrating significant potential to advance innovative engineering and streamline therapeutic antibody development by reducing the need for unnecessary trials. The BALMFold structure prediction server is freely available at https://beamlab-sh.com/models/BALMFold.

#2358 Impact of COVID-19 on the clinical course of nephrotic syndrome in children: a single-center study

Abstract Background and Aims Children with nephrotic syndrome may experience disease relapse or aggravation triggered by various viral infections. Limited studies on the clinical implications of the coronavirus disease 2019 (COVID-19) pandemic in children with nephrotic syndrome have been published worldwide. Therefore, this study aimed to investigate the effects of COVID-19 on the clinical course of nephrotic syndrome in children. Method The medical records of pediatric patients with idiopathic nephrotic syndrome who visited our hospital between February and June 2022 were retrospectively analyzed. Patients aged &amp;lt;1 year and &amp;gt;19 years and those with inadequate medical records were excluded. Finally, total 59 patients (20 pediatric patients diagnosed with COVID-19 and 39 pediatric patients who did not have COVID-19) were included in the study. Results Twenty of the total 59 patients with nephrotic syndrome were diagnosed with COVID-19 during the study period. The mean age at the time of the diagnosis of nephrotic syndrome and COVID-19 in all 20 patients was 4.6 ± 3.5 and 8.9 ± 3.9 years, respectively. Three patients (15%) were diagnosed with nephrotic syndrome relapse during COVID-19 and the relapse rate was similar to them without COVID-19 (20.5%, 8/39 patients). At the time of the COVID-19 diagnosis, fever (85%) and cough (40%) were the most common symptoms. After the diagnosis of COVID-19, all patients showed improvement with symptomatic treatment, including antipyretic analgesics and cold medicine. None of the critical patients required hospitalization or oral antiviral medications. Conclusion Despite the use of immunosuppressants, the clinical manifestations of COVID-19 in children with nephrotic syndrome were not severe and are expected to be similar to that in the general population. The relapse rate of nephrotic syndrome in children with COVID-19 was also not different from them without COVID-19.

Computational Discovery of Novel Imidazole Derivatives as Inhibitors of SARS-CoV-2 Main Protease: An Integrated Approach Combining Molecular Dynamics and Binding Affinity Analysis

One of the most pressing challenges associated with SARS treatment is the emergence of new variants that may be transmissible, causing more severe disease or being resistant to the current standard of treatment. This study aimed to identify potential drug candidates from novel imidazole derivatives against SARS-CoV-2 main protease (Mpro), a crucial drug target for treating viral infection, using a computational approach that integrated molecular docking and dynamics simulation. In this study, we utilized AutoDock Vina within the PyRx workspace for molecular docking analysis to explore the inhibitory effects of the compounds on the Mpro, a drug target for SARS-CoV-2. The ADMET properties of these compounds, including absorption, distribution, metabolism, excretion, and toxicity, were evaluated using the SwissADME and ADMETLab servers. Each of the 18 compounds that were tested demonstrated strong binding affinities towards Mpro, with imidazolyl–methanone C10 showing the most significant binding affinity. Moreover, pyridyl–imidazole C5, thiophenyl–imidazole C1, and quinoline–imidazole C14 displayed binding affinities of −8.3, −8.2, and −7.7 Kcal/mol, respectively. These compounds interacted with specific amino acid residues (HIS A:41—CYS A:145) within the Mpro protein. To assess the stability of the ligand with the best binding affinity, molecular dynamics (MD) simulations were conducted using Schrodinger software, which revealed its stability over the simulation period. The study provides valuable insights into the potential of imidazole derivatives as SARS-CoV-2 Mpro inhibitors. All compounds including C10 display promising characteristics and hold potential as drug candidates for SARS-CoV-2. However, further optimization and experimental validation of these compounds are necessary to advance their development as effective therapeutics against viral infections.

A closer look at mammalian antiviral condensates.

Several biomolecular condensates assemble in mammalian cells in response to viral infection. The most studied of these are stress granules (SGs), which have been proposed to promote antiviral innate immune signaling pathways, including the RLR-MAVS, the protein kinase R (PKR), and the OAS-RNase L pathways. However, recent studies have demonstrated that SGs either negatively regulate or do not impact antiviral signaling. Instead, the SG-nucleating protein, G3BP1, may function to perturb viral RNA biology by condensing viral RNA into viral-aggregated RNA condensates, thus explaining why viruses often antagonize G3BP1 or hijack its RNA condensing function. However, a recently identified condensate, termed double-stranded RNA-induced foci, promotes the activation of the PKR and OAS-RNase L antiviral pathways. In addition, SG-like condensates known as an RNase L-induced bodies (RLBs) have been observed during many viral infections, including SARS-CoV-2 and several flaviviruses. RLBs may function in promoting decay of cellular and viral RNA, as well as promoting ribosome-associated signaling pathways. Herein, we review these recent advances in the field of antiviral biomolecular condensates, and we provide perspective on the role of canonical SGs and G3BP1 during the antiviral response.

#2992 Risk and prognostic factors for post-transplantation lymphoproliferative disease in solid organ transplant recipients—a multicenter analysis

Abstract Background and Aims Post-transplantation lymphoproliferative disorder (PTLD), a potentially fatal complication of transplantation, affects solid organ transplant recipients at different rates, depending on organ graft type: the risk greater in lung transplant recipients (LngTRs), lower for liver transplant recipients (LTRs) and lowest for kidney transplant recipients (KTR). In this study we aimed to investigate the factors affecting the development and treatment outcomes of PTLD and compare their effect on KTRs, LTRs and LngTRs. Method In this retrospective cohort study we have included all KTRs, LTRs and LngTRs diagnosed with PTLD at six transplantation centers in Poland. The data collected from medical records included: immunosuppression (IS), viral infections, PTLD type, treatment and outcomes. Chi-squared test was used to assess the differences in group composition. To determine the impact of variables upon PTLD time of onset and patient survival, univariate Cox regression was used. p-values below 0.05 were considered statistically significant. Results We enrolled 50 KTRs, 36 LTRs and 5 LngTRs from 6 transplantation centers in Poland. Based on the data from the most contributing centers in each group, the prevalence of PTLD was 0.82% of KTRs, 2.03% LTRs and 1.51% of LngTRs. Two thirds of the enrolled patients were male, the median age at first transplantation was 40 years for KTRs, 45 for LTRs and 25 for LngTRs (Table 1). The groups significantly differed in IS treatment: steroid (GCS) and cyclosporin (CsA) use was more frequent in KTRs (p&amp;lt;0.001 and p&amp;lt;0.001 and respectively), tacrolimus (TAC) and anti-CD25 induction in LTRs (p ≤ 0.001 and p&amp;lt;0.001 respectively), sirolimus (RAPA) in LngTRs (p&amp;lt;0.001). KTRs were the latest to develop PTLD (126 months after transplantation, p&amp;lt;0.001). In all groups Monomorphic B-cell PTLD was the most frequent. Initial IS treatment reduction was used in 80-86% of patients, R-CHOP chemotherapy was most common in LTRs (p=0.021), other chemotherapy regimens in KTRs (p=0.031). TAC had the opposite effect on PTLD time of onset in KTRs (HR=2.18, p=0.013) and LTRs (HR=0.18, p=0.036). The overall survival at the end of observation period was 26% for KTRs, 58% for LTRs and 80% for LngTRs. Loss to follow up was most frequent in KTRs at 26%. Patient survival was not affected by PTLD treatment. Conclusion KTRs develop PTLD later than LTRs and LngTRs, and time of disease onset is associated with TAC use. Lower survival in KTRs may result from the longer follow-up period compared to other solid organ transplant recipients.

#2867 Is there an interrelationship between the SARS-CoV-2 virus and the BK polyomavirus in kidney transplant recipients?

Abstract Background and Aims Several viral co-infections following SARS-CoV-2 infection have been described. However, there is very limited and inconclusive data on the relationship between COVID-19 and BK polyomavirus (BKV) in kidney transplant (KT) recipients. Method Retrospective analysis of KT recipients with BK infection (BKi) in our centre from March 2020 (first cases of COVID-19) to March 2023. BK viremia is periodically determined prospectively in all KTs performed in our hospital. We carried out a case-control study, choosing two controls without BKi for each case (closest transplant date and similar donor and recipient age). We analyzed clinical characteristics and evolution, as well as previous history of COVID-19 in both groups. A composite outcome including de novo BKi and/or significant increase in BK viremia (increase &amp;gt; 50% in at least 2 consecutive samples) was analyzed. Multivariate analysis was performed using logistic regression for de novo BKi and/or significant increase in BK viremia risk factors. Results During this period 235 KTs were performed in our center, of which 37 were diagnosed with BKi (16.1%). The median time from the date of KT to BKi was 73 days. When comparing cases versus controls, demographic characteristics and donor type were similar in both groups, except for a higher proportion of males in the BKi group (76.3% vs. 55.3%; p = 0.029). The incidence of SARS-CoV-2 infection was significantly higher in patients with de novo/increased viremia BKi than in the control group (44.7% vs. 26.3% p = 0.048). During follow-up, one patient in the BKi group died and one patient in the control group lost the graft due to causes other than viral infections. In multivariate analysis, male gender and SARS-CoV-2 infection were risk factors for the composite outcome. Conclusion As has been described with other viruses, there may be an interrelationship between SARS-CoV-2 and BKV. Our experience suggests that close monitoring for BKV after episodes of COVID-19 may be appropriate.

#2336 Hepatitis-B virus related membranous nephropathy presenting as nephrotic syndrome treated with tenofovir

Abstract Background The prevalence of Hepatitis B virus (HBV) related nephropathy particularly membranous nephropathy follows geographic HBV prevalence patterns. Hepatitis B virus infection occurs throughout the world and is endemic in developing countries such as Africa, Eastern Europe, the Middle East, Central Asia, China, Southeast Asia, the Pacific islands and the Amazon basin of South America. Vertical transmission from mother to child often predominates in endemic areas. Membranous glomerulonephritis is the most common histological renal lesion associated with hepatitis B virus infection. Treatment options for renal patients with chronic HBV infection are complex, being dictated by the overall clinical picture and best conducted by multidisciplinary approach and thorough renal monitoring. Therapeutic guidelines are very limited, mostly case series are available in this setting. Anti-viral treatment is indicated in hepatitis B surface antigen (HBsAg)-positive patients with evidence of active liver disease based on aminotransferases and serum HBV DNA levels of 2000-20 000 IU/ml have been proposed as the threshold to start treatment Aim To present a case of young healthy male with chronic HBV infection with nephrotic syndrome and Membranous Nephropathy who developed reactivation after discontinuation of Tenofovir. Case A 32-year old man presented with generalized edema 5 months ago associated with dipstick proteinuria. The swelling has progressed and now associated with walking difficulty thus sought consult and was then admitted. His mother had been hypertensive for more than a decade and work up revealed that she is positive for anti-HBS and negative for HBsAg. His father is negative for HBsAg. His childhood and past medical history is unremarkable. He is a non-smoker, non alcoholic and no history of illicit drug use. He is monogamous and not promiscuous. He has 6 siblings and two of his brothers are hypertensives and found to have chronic Hepatitis B infection. His complement levels were low, ANA and ASO titers were negative. His creatinine was 1.06 mg/dl, BUN- 11.77 mg/dl, SGPT-161 U/L (NV: &amp;lt; 42 U/L), albumin- 1.50 g/dl (NV: 3.5-5.0 g/dl). Total cholesterol- 443.30 mg/dl, Triglycerides 330.46 mg/dl. Urine PCR-4,369 mg/g. Hepatitis profile revealed reactive for HBsAg and HBeAg. His HBV viral load was 170 000 000 IU/ml (989 400 000 copies/ml). His HIV screening was negative. A kidney biopsy was performed which revealed Membranous Glomerulonephritis. He was given Tenofovir 300 mg daily for 6 months. His repeat HBV viral load was &amp;lt; 20 IU/ml (&amp;lt; 116 copies/ml) and his 24 h urinary protein was 1,891 mg/24H. His albumin was 4.57 g/dl and his creatinine remained stable at 0.96 mg/dl while his SGPT went back to normal at 40 U/L. A repeat HBeAg revealed 0.55 which could be a possible seroconversion. Tenofovir was discontinued for 6 months however patient came back with persistent proteinuria associated with high HBV DNA titer. A repeat 24H-urine protein showed 1,182 mg/24H. Tenofovir was resumed and Enalapril was continued. Follow up check up 3 months after revealed urine PCR was 850 mg/g and his kidney function remained stable. He is advised to continue Tenofovir with frequent follow up until he becomes HBsAg-negative. Recommendation We recommend that antiviral treatment in this subset of population requires prolong treatment until persistent seroconversion of HBeAg and persistent undetectable HBV DNA level or have lost HBsAg even if the patient does not develop hepatitis B surface antibody. This recommendation of prolong treatment are still developing and requires further investigation.

#3090 Parvovirus infection in renal transplant recipients: a systematic review of clinical profile and treatment strategies

Abstract Background and Aims Parvovirus B 19 (PVB-19) virus infection can cause severe, persistent and/or refractory anaemia in kidney transplant recipients (KTR). There is paucity of data on the clinical manifestations, diagnosis and management of this infection and limited to case reports and case series. Method We performed a literature search of kidney transplant recipients infected with PVB-19 in MEDLINE, EMBASE and Cochrane databases and 93 articles were identified as suitable for assessment. The review was conducted in accordance with PRISMA statement. Results A total of two hundred and eighty-two patients were included from the studies assessed in the review. The mean age of the cohort was 37.05 years. The infection was more common in males when compared to females. The median onset of PVB-19 infection post transplantation was at 5 weeks (2, 15 weeks). One fourth of the recipients had at least one episode of rejection prior to PVB-19 infection. Majority of the patients were on Tacrolimus, MMF and corticosteroids maintenance. One third of the patients had co-infections with other organisms (EBV, CMV, etc.). Anemia and fever were the most common manifestations among all the kidney transplant patients infected with PVB-19 while CNS manifestations and rash were least reported. Hemoglobin was low (&amp;lt;10 mg/dl) in ninety eight percent of the patients (n=151). The lowest hemoglobin reported in the due course of illness was 6 mg/dl (5, 7.2 mg/dl) and with corrected reticulocyte count being only 0.2% (0.1%, 0.6%). The most consistent finding on peripheral smear was normocytic, normochromic anemia while a few reported helmet cells too. Pure Erythroid hypoplasia alone (45.3%) combined with giant pronormoblasts and inclusion bodies (49%) were the most common findings on bone marrow aspirate. Majority of PVB-19 diagnosis was made with the help of multiple methods of detection like IgM assay, PCR—qualitative and quantitative (42.2%). The average PCR copies detected were 1.3*107 (4.28*105, 2.53*109). IVIG only (47.2%) and combined IVIG + immunosuppression reduction (41.2%) was the mainstay of the treatment in majority. The median time to recover was 8 weeks (3, 16 weeks). One fourth of the patients had recurrence after recovery. A majority of the patients (96.7%) recovered from reactivation of PVB-19. Conclusion Parvovirus infection is not uncommon in the early post-transplant period. Though data is insufficient, immunosuppression reduction with IVIG remains the treatment of choice for affected patients. Prospective studies to assess the hemoglobin cutoffs and dose of IVIG are needed to frame screening and treatment protocols.

#1976 Non-IgA mesangial proliferative glomerulonephritis in a patient with IgA deficiency, a case report

Abstract Background and Aims IgA deficiency (IgAD) is the most common primary immunoglobulin deficiency in western countries. This entity is associated with increased risk of other autoimmune diseases. Mesangial proliferative glomerulonephritis (MesPGN) is a histological pattern defined by mesangial cell proliferation and expansion of the extracellular matrix within the mesangium. The clinical presentation can vary, from nephrotic syndrome to isolated hematuria. 30-40% of MesPGN cases are associated with IgA nephropathy. Other common diagnostic entities that present with this pattern include IgM nephropathy, C1q nephropathy or lupus nephritis, as well as Hepatitis B or C virus infection; idiopathic MesPGN is poorly described in the literature. To the best of our knowledge, this is the first report of idiopathic MesPGN associated with IgAD. Results A 17-year old woman with a background of IgAD and occasional episodes of bronchitis in her childhood presented in January 2022 with nonspecific abdominal pain and macroscopic hematuria. She had been suffering these symptoms for the last few weeks, usually after physical exercise. She was normotensive and showed no fever, skin rashes or other symptoms. Laboratory tests revealed normal renal function (serum creatinine 0.65 mg/dL), urinary albumin-to-creatinine ratio of 23.9 mg/g, a 24-h protein excretion ranging from 40 to 240 mg and non-dysmorphic hematuria of up to 51-150 erythrocytes/field. Additional laboratory tests repeatedly showed only low IgA serum levels, with normal ANA, ANCA or complement levels. Renal ultrasound showed both kidneys with normal size and cortical thickness. A CT urogram observed multiple, bilateral, non-obstructive small-sized kidney stones and a persistent nephrogram. Genetic tests were negative for Alport syndrome-related mutations. Additional workup included occult blood in the stool, stool culture, rectal biopsy and colonoscopy, which were all negative. Symptoms persisted during the following 12 months. A kidney biopsy was performed, finding 40 glomeruli with normal optical appearance, none of them sclerosed. Discrete mesangial expansion and cell proliferation was observed, with capillary lumens with occasional congestion but without thrombi or fibrinoid necrosis. Tubules and interstitium showed no sign of sclerosis or fibrosis, with conserved basement membranes and brush borders. In vessels, subintimal fibrosis, hyalinosis or concentric arteriolar hyperplasia or endarteritis were ruled out. Immunofluorescence showed low-intensity, discrete granular C3 mesangial deposits and no deposition of IgA, IgG, IgM, fibrinogen, C4, C1q or albumin. A diagnosis of non-IgA MesPGN was reached. The patient stopped performing intense physical exercise on a regular basis. This translated in hematuria and abdominal pain of much lower intensity. The patient is currently receiving only supportive therapy and maintains a normal renal function, with persistence of microscopic non-dysmorphic hematuria and occasional, low-grade proteinuria as described. Conclusion MesPGN is the most diagnosed form of glomerulonephritis worldwide. However, most cases are associated with granular IgA deposition in the mesangium, which was absent in this case. Idiopathic, non-IgA MesPGN is a much rarer condition that has been considered by some authors as a form focal segmental glomerulosclerosis or minimal change disease, although others believe it to be a separate condition. IgAD has been previously associated with Crohn's disease, which could explain this patient's symptoms. Crohn's disease has also been associated with non-IgA MesPGN in a low number of patients. Nevertheless, no findings in the patient workup were suggestive of Crohn's disease. A capsule endoscopy study will be performed to clearly rule out such diagnosis.

Hepatitis B virus DNA and RNA persist in liver after serologic recovery in persons with hepatitis C virus.

After recovery from a hepatitis B virus (HBV) infection, reactivation can occur with immunosuppression; thus, it is assumed that replication competent HBV persists in the liver. We sought to detect persistent HBV from 13 people with spontaneous recovery. We quantified HBV DNA and RNA in core liver biopsies (median 1.72x106 cells) from people who inject drugs (PWID). Among 13 biopsies, 8 (61%) had evidence of HBV DNA or RNA and 5 (38%) had both HBV DNA and RNA. mRNAs derived from cccDNA and integrated HBV DNA. Here, we show prevalent HBV DNA and RNA despite clinical recovery in PWID.

Effects of palivizumab prophylaxis on respiratory syncytial virus (RSV) infections in Montenegro

Background. Respiratory syncytial virus (RSV) is one of the most common pathogens causing severe lower respiratory tract disease in infancy and childhood. In newborns, young infants, and in infants with co-morbidities, the risk of severe infection is increased. Current protection against severe RSV infection is immunoprophylaxis with the monoclonal antibody palivizumab. The study aimed to assess the effects of palivizumab prophylaxis in the Republic of Montenegro in comparison to the pre-prophylaxis period. Methods. The study was conducted in prospective/retrospective single center format in Montenegro in the Clinical Center of Podgorica, for the period 2009-2019. Results. A total of 104 high-risk infants in the palivizumab prophylaxis program (2014-2019 RSV seasons) and 168 high-risk children without palivizumab prophylaxis (2009-2013 RSV seasons) were enrolled. A total of 51 children (49.0%) received prophylaxis for prematurity, 33 (31.7%) for bronchopulmonary dysplasia (BPD), 13 (12.5%) for hemodynamically significant heart disease/defect (HSCHD), and 7 (6.8%) for “miscellaneous” indications. In the control group most children had prematurity (101, 60.1%), followed by BPD (59, 35.1%), HSCHD (3, 1.8%), and “miscellaneous” (5, 3.4%) conditions. Readmission to the pediatric intensive care units (PICU) due to RSV infection was significantly lower in prophylaxis group (0.0 vs 16.1%, p&lt;0.001). No lethal outcomes were observed in high-risk children with palivizumab prophylaxis compared to 2.4% in the control group. Conclusions. The introduction of RSV immunoprophylaxis as well as other new protective treatment strategies for high-risk newborns led to significant improvements in infant and childcare in Montenegro. This is the first report on palivizumab prophylaxis in Montenegro, demonstrating the effectiveness and safety of palivizumab use in clinical settings.

#1888 Association between intrapatient variability of serum tacrolimus levels with the development of diabetes in post-kidney transplantation patients

Abstract Background and Aims Kidney transplantation is the most cost-effective renal replacement therapy compared to dialysis. Diabetes is main cause of increased cardiovascular risk and death. Post-transplant Diabetes Mellitus (PTDM) it refers to presence of diabetes in an environment after kidney transplantation; According to the ADA (American Diabetes Association) criteria, the diagnosis must be made with a tolerance test with 75 grams of oral glucose (Oral glucose tolerance test-OGTT) or the determination of glycosylated hemoglobin 1Ac (Hb1Ac) in a post-transplant period of stability of the immunosuppression dose and without infections. There are various risk factors for the development of PTDM: hypomagnesemia, glucocorticoids, calcineurin inhibitors (tacrolimus and cyclosporine); hepatitis C virus and cytomegalovirus infections. In a Mexican kidney transplant recipients in Guadalajara, Andrade SG demonstrated that the incidence of PTDM was 10.1% at 1 year post-transplant. In the Spanish population, Porrini E demonstrated that tacrolimus represents a risk factor for the development of PTDM, increasing the incidence of prediabetes by 33% at 12 months post-transplant. Several mechanisms have been implicated in the association of calcineurin inhibitor and PTDM: decreased insulin secretion, glucose intolerance, reduced pancreatic beta cell mass, increased islet apoptosis and decreased insulin gene expression. Studies mention that tacrolimus (FK) is more diabetogenic than cyclosporine (CsA) especially at levels above 20 ng/mL. The DIRECT study (Diabetes Incidence after Renal Transplantation) showed the incidence in 73 kidney transplant patients with CsA (26%) and 96 FK patients (33.6%, p = 0.046). By the other side, Malik RF mentions that FK levels aren´t a risk factor for the development of PTDM. To demonstrate that the high intrapatient variability of tacrolimus/cyclosporine serum levels correlates with the development of diabetes (PTDM) in kidney transplant recipients at the central military hospital in Mexico City. Method Observational, analytical, longitudinal and retrospective study. All kidney transplant recipients from living donors and cadaveric donors from January 2002 to December 2020 were included. FK and CsA were used as maintenance immunosuppression. Serum levels of FK/CsA, Hb1Ac and glucose were measured at months 0, 3, 6, 9 and 12 and intra-patient variability (IPV) of FK/CsA levels was calculated for each patient. The patients were separated into 2 groups, IPV low and IPV high according to the mean the coefficient of variability (CV). The IPV of the calcineurin inhibitor was estimated by calculating the CV in each patient according to the following equation: CV(%)= (SD/mean trough concentration of FK/ CsA)×100. The diagnosis of PTDM followed the criteria of the American Diabetes Association. The Mann Whitney U test was used. Results 638 kidney transplant recipients were included. The mean age of the recipients was 36.78 (±12.81) years. At the time of kidney transplant, the BMI was 22.67 (±3.90) and 25.76 (±3.99) kg/m² BS at 1 year post-transplant for whole cohort. At 1 year post-transplant, 72.3% patients were on FK and 27.7% on CsA. Hb1Ac for whole cohort was 4.81 (±0.71)% and 4.84 (±0.77)% at month 0 and 12 post-kidney transplant, respectively. FK and CsA levels were 12.41 (±5.31) and 234.34 (±87.80) ng/mL and 9.13 (±5.3) and 194.38 (±92.44) ng/mL in the PTDM and non-PTDM groups, respectively (p = 0.029). 17.96% of patients developed PTDM. Mean CV of the entire cohort was 33.84 (±20.41)%. When performing the analysis of the IPV coefficient by subgroups of maintenance immunosuppression used at 1 year post-transplant: the IPV of FK was 43.39 (±18.49)% and 29.99 (±17.56)% in the PTDM and non-PTDM groups respectively, p = 0.000, which shows that patients with a high IPV coefficient of tacrolimus developed more PTDM than those with low variability, student's t-test to compare IPV was 0.03. The IPV of CsA was 38.61 (±18.76)% and 37.51 (±25.67)% in the PTDM and non-PTDM groups respectively, p = 0.819. Conclusion High intrapatient variability of tacrolimus was correlated with the development of PTDM in Mexican kidney transplant recipients.

SIV infection and ARV treatment reshape the transcriptional and epigenetic profile of naïve and memory T cells in vivo.

Human and simian immunodeficiency viruses (HIV and SIV) are lentiviruses that reverse transcribe their RNA genome with subsequent integration into the genome of the target cell. How progressive infection and administration of antiretrovirals (ARVs) longitudinally influence the transcriptomic and epigenetic landscape of particular T cell subsets, and how these may influence the genetic location of integration are unclear. Here, we use RNAseq and ATACseq to study the transcriptomics and epigenetic landscape of longitudinally sampled naïve and memory CD4+ and CD8+ T cells in two species of non-human primates prior to SIV infection, during chronic SIV infection, and after administration of ARVs. We find that SIV infection leads to significant alteration to the transcriptomic profile of all T cell subsets that are only partially reversed by administration of ARVs. Epigenetic changes were more apparent in animals with longer periods of untreated SIV infection and correlated well with changes in corresponding gene expression. Known SIV integration sites did not vary due to SIV status but did contain more open chromatin in rhesus macaque memory T cells, and the expression of proteasome-related genes at the pre-SIV timepoint correlated with subsequent viremia.IMPORTANCEChronic inflammation during progressive human and simian immunodeficiency virus (HIV and SIV) infections leads to significant co-morbidities in infected individuals with significant consequences. Antiretroviral (ARV)-treated individuals also manifest increased levels of inflammation which are associated with increased mortalities. These data will help guide rational development of modalities to reduce inflammation observed in people living with HIV and suggest mechanisms underlying lentiviral integration site preferences.

#610 Alterations in frequency and function exhausted memory B cells in lupus nephritis and systemic lupus erythematosus

Abstract Background and Aims Various B cell abnormalities have been implicated in the pathogenesis of LN, and our previous studies have demonstrated that memory B cells assume pathogenic relevance in disease relapse. Memory B cell exhaustion is a B lymphocyte aberration initially reported in chronic human immunodeficiency virus (HIV) infection, and was later also observed in chronic graft versus host disease (cGVHD) and autoimmune disorders. The pathogenic roles of exhausted memory B cells in LN and disease relapse remains unclear. We will validate the significance role of exhausted B cell in the pathogenesis of LN. Method Classical memory (CD19 + CD21 + CD27+) and exhausted B cells (CD19 + CD21 – CD27–) were measured in LN patients with multiple relapses (MR) (n=15) or no relapse (NR) (n=15) during disease remission. B cell-related cytokines, homing and inhibitory receptors, proliferation and calcium mobilization in classical and exhausted memory B cells were also assessed. Using single-cell RNA sequencing data from NIH and GEO, we also performed bioinformatics analysis to identify genes and pathways relevant to memory and exhausted B cells in SLE, LN and healthy controls. Results The MR group exhibited higher proportion of circulating exhausted memory B cells compared to NR. Blood levels of IL-6, BAFF and IL-21 in MR patients were higher than the NR group. The MR had higher blood levels of Siglec-6, CXCR3 and CD62L than the NR group. Expression of inhibitory receptors CD22, CD85j, CD183 and FCRL4 in exhausted B cells were increased in the MR group compared to the NR group. Exhausted B cells from MR patients also showed decreased proliferation compared to NR patients and impaired calcium mobilization in response to B-cell receptor triggering. STAT1, XAF1, MX1, IFI44L, EPSTI1, LCP1, OAS1, NEAT1, IFI16, IFI44 in exhausted B cells and XAF1, MX1, IFI44L in memory B cells play a pathogenic role in LN patients (Figs. 1 and 2). SLE patients also show increased proportion of exhausted B cells compared to healthy control and the expression of STAT1, XAF1, MX1, IFI44L correlate positively with the proportion of exhausted B cells. Conclusion Our results suggested that altered numbers and function of exhausted B cells may have pathogenic significance in SLE and LN.

Pulmonary MicroRNA expression after heterologous challenge with swine influenza A virus (H1N2) in immunized and non-immunized pigs

MicroRNAs (miRNAs) contribute to post-transcriptional modulation of the host response during influenza A virus (IAV) infection and may be involved in shaping disease severity. Differential disease severity was achieved in two groups of pigs by immunization of one group with a commercial swine IAV vaccine prior to heterologous IAV (H1N2) challenge of both groups. Lung tissue was harvested 1, 3, and 14 days after challenge and miRNA expression was quantified. Gene Ontology term enrichment analysis was employed to examine the functional relevance of genes potentially regulated by differentially expressed miRNAs in pigs with varying degrees of disease severity following IAV infection. Results suggested that the miRNA response associated with less severe disease may modulate host mechanisms essential for viral life cycle, e.g. transcription, translation, and protein trafficking. During more severe disease, miRNA-mediated regulation may focus on dampening virus-specific processes e.g. virion assembly and viral protein processing, and controlling host metabolism.