Establishing the prevalence of common tissue-specific autoantibodies following severe acute respiratory syndrome coronavirus 2 infection.

Coronavirus 19 (COVID-19) has been associated with both transient and persistent systemic symptoms that do not appear to be a direct consequence of viral infection. The generation of autoantibodies has been proposed as a mechanism to explain these symptoms. To understand the prevalence of autoantibodies associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, we investigated the frequency and specificity of clinically relevant autoantibodies in 84 individuals previously infected with SARS-CoV-2, suffering from COVID-19 of varying severity in both the acute and convalescent setting. These were compared with results from 32 individuals who were on the intensive therapy unit (ITU) for non-COVID reasons. We demonstrate a higher frequency of autoantibodies in the COVID-19 ITU group compared with non-COVID-19 ITU disease control patients and that autoantibodies were also found in the serum 3-5 months post-COVID-19 infection. Non-COVID patients displayed a diverse pattern of autoantibodies; in contrast, the COVID-19 groups had a more restricted panel of autoantibodies including skin, skeletal muscle and cardiac antibodies. Our results demonstrate that respiratory viral infection with SARS-CoV-2 is associated with the detection of a limited profile of tissue-specific autoantibodies, detectable using routine clinical immunology assays. Further studies are required to determine whether these autoantibodies are specific to SARS-CoV-2 or a phenomenon arising from severe viral infections and to determine the clinical significance of these autoantibodies.

Proteinuric kidney disease in children at Queen Elizabeth Central Hospital, Malawi.

BACKGROUND: There is a paucity of data on paediatric kidney disease in developing countries such as Malawi. Descriptive research on kidney disease is essential to improving patient outcomes. METHODS: We conducted a cross-sectional study at a tertiary hospital in Malawi from 2012 to 2013. Children under 14 years with proteinuric kidney disease were enrolled from paediatric wards and outpatient clinics at Queen Elizabeth Central Hospital (QECH). Demographic, clinical and laboratory data were collected from patients at enrolment and at 3 months review at which point clinical status and disease outcome were ascertained. RESULTS: Thirty-four (22 male) patients were studied, mean age 8.54 (SD = 3.62 years). Glomerular disease (n = 25, 68%) was the most common presumed renal lesion at presentation. Nephritic syndrome (10) was characterised by a lower baseline complement C3 than nephrotic syndrome (p = 0.0027). Seven (47%) cases of nephrotic syndrome achieved complete remission. Eight (80%) cases of nephritic syndrome improved with supportive therapy. Nineteen (56%) patients presented with clinically significant renal damage with eGFR< 60 ml/min/1.73m2. Six patients presented in chronic kidney disease (CKD) stage 5 of unclear aetiology, five (83%) died. Three (9%) patients had impaired kidney function and obstructive uropathy demonstrated on ultrasound, two recovered after surgery and one died. Eight (24%) patients had acute kidney injury (AKI) due to primary kidney disease, three of these patients progressed to CKD stage G3a. Seven (21%) patients were lost to follow up. CONCLUSION: Kidney disease is a significant cause of mortality and morbidity in children at QECH. Less than half of Nephrotic syndrome cases achieved complete remission. Mortality is highest in children with CKD of unclear cause. Some patients with AKI secondary to primary renal disease progressed to CKD. Understanding the aetiology of paediatric kidney disease and improving patient outcomes by developing enhanced diagnostic and clinical services are priorities at QECH and within Malawi.

Saliva antiviral antibody levels are detectable but correlate poorly with serum antibody levels following SARS-CoV-2 infection and/or vaccination.

The importance of salivary SARS-CoV-2 antibodies, following infection and vaccination, has not been fully established. 875 healthcare workers were sampled during the first wave in 2020 and 66 longitudinally in response to Pfizer BioNTech 162b2 vaccination. We measured SARS-CoV-2 total IgGAM and individual IgG, IgA and IgM antibodies. IgGAM seroprevalence was 39.9%; however, only 34.1% of seropositive individuals also had salivary antibodies. Infection generated serum IgG antibodies in 51.4% and IgA antibodies in 34.1% of individuals. In contrast, the salivary antibody responses were dominated by IgA (30.9% and 12% generating IgA and IgG antibodies, respectively). Post 2nd vaccination dose, in serum, 100% of infection naïve individuals had IgG and 82.8% had IgA responses; in saliva, 65.5% exhibited IgG and 55.2% IgA antibodies. Prior infection enhanced the vaccine antibody response in serum but no such difference was observed in saliva. Strong neutralisation responses were seen for serum 6 months post 2nd-vaccination dose (median 87.1%) compared to low neutralisation responses in saliva (median 1%). Intramuscular vaccination induces significant serum antibodies and to a lesser extent, salivary antibodies; however, salivary antibodies are typically non-neutralising. This study provides further evidence for the need of mucosal vaccines to elicit nasopharyngeal/oral protection. Although saliva is an attractive non-invasive sero-surveillance tool, due to distinct differences between systemic and oral antibody responses, it cannot be used as a proxy for serum antibody measurement.

Non-cirrhotic intrahepatic portal hypertension: associated gut diseases and prognostic factors.

BACKGROUND/AIMS: Non-cirrhotic intrahepatic portal hypertension (NCIPH) is generally regarded to have a benign prognosis. We have studied a cohort followed-up at a tertiary referral center and postulate that gut-derived prothrombotic factors may contribute to the pathogenesis and prognosis of NCIPH. METHODS: We retrospectively analyzed prognostic indicators in 34 NCIPH patients. We also searched for associated gut diseases. RESULTS: Transplant-free survival in NCIPH patients from first presentation with NCIPH at 1, 5, and 10 years was 94% (SE: 4.2%), 84% (6.6%), and 69% (9.8%), respectively. Decompensated liver disease occurred in 53% of patients. Three (9%) patients had ulcerative colitis while five of 31 (16%) tested had celiac disease and on Kaplan-Meier analysis, celiac disease predicted reduced transplant-free survival (p=0.018). On multivariable Cox regression analysis, independent predictors of reduced transplant-free survival were older age at first presentation with NCIPH, hepatic encephalopathy, and portal vein thrombosis. Prevalence of elevated initial serum IgA anticardiolipin antibody (CLPA) was significantly higher in NCIPH (36% of patients tested), compared to Budd-Chiari syndrome (6%) (p=0.032, Fisher's exact test) and celiac disease without concomitant liver disease (0%) (p=0.007). CONCLUSIONS: We have identified prognostic factors and report progression to liver failure in 53% of NCIPH patients followed-up at our center. Our data supports a role for intestinal disease in the pathogenesis of intrahepatic portal vein occlusion leading to NCIPH.

Humoral immunity in late-onset Pre-eclampsia and linkage with angiogenic and inflammatory markers.

PROBLEM: Pre-eclampsia (PE) is a leading cause of maternal and foetal morbidity worldwide. Given the implication of immune mechanisms, we compared markers of humoral immunity in PE and their relationship to circulating markers of inflammation, angiogenic factors, and renal function. METHOD OF STUDY: Serum samples from 88 previously healthy women admitted to hospital with PE and 107 healthy pregnant controls at term were analysed for serum immunoglobulins (Ig), including IgG subclasses and free light chain (sFLC) levels, beta-2 microglobulin (B2-M), high-sensitivity C-reactive protein (HS-CRP), albumin, complement proteins (C3 & C4), creatinine, cystatin-C and the ratio of soluble fms-like tyrosine kinase-1 (sFLT-1) and placental growth factor (PlGF). RESULTS: Compared to the controls, women with PE had significantly reduced renal function, serum IgG (subclass 1 & 3), albumin, and C4 levels, whilst concentrations of total sFLC, HS-CRP, B2-M, and sFLT-1:PlGF were raised. On multivariable analysis, sFLT-1:PlGF ratio (P < 0.001), sFLC (P < 0.001) and IgG1 (P < 0.024) were found to be independently associated with PE, after accounting for renal function, patient age, BMI, ethnicity, and parity. B2-M and sFLT-1:PlGF had comparable diagnostic association with PE (P = 0.184), and correlated strongly with each other (ρ = 0.588, P < 0.001) as well as with renal function and adverse clinical outcome. CONCLUSION: We describe for the first time that PE is independently associated with activation of the humoral immune system independent of deranged kidney function and angiogenic markers. The role of B2-M as a potential predictive marker of PE remains to be determined.

Development of a highly-sensitive multi-plex assay using monoclonal antibodies for the simultaneous measurement of kappa and lambda immunoglobulin free light chains in serum and urine.

Monoclonal κ and λ immunoglobulin free light chain (FLC) paraproteins in serum and urine are important markers in the diagnosis and monitoring of B cell dyscrasias. Current nephelometric and turbidimetric methods that use sheep polyclonal antisera to quantify serum FLC have a number of well-observed limitations. In this report, we describe an improved method using specific mouse anti-human FLC monoclonal antibodies (mAbs). Anti-κ and anti-λ FLC mAbs were, separately, covalently coupled to polystyrene Xmap® beads and assayed, simultaneously, in a multi-plex format by Luminex® (mAb assay). The mAbs displayed no cross-reactivity to bound LC, the alternate LC type, or other human proteins and had improved sensitivity and specificity over immunofixation electrophoresis (IFE) and Freelite™. The assay gives good linearity and sensitivity (<1 mg/L), and the competitive inhibition format gave a broad calibration curve up to 437.5 mg/L and prevented anomalous results for samples in antigen excess i.e. high FLC levels. The mAbs displayed good concordance with Freelite™ for the quantitation of normal polyclonal FLC in plasma from healthy donors (n=249). The mAb assay identified all monoclonal FLC in serum from consecutive patient samples (n=1000; 50.1% with monoclonal paraprotein by serum IFE), and all FLC in a large cohort of urine samples tested for Bence Jones proteins (n=13090; 22.8% with monoclonal κ, 9.0% with monoclonal λ, and 0.8% with poly LC detected by urine IFE). Importantly this shows that the mAbs are at least close to the ideal of detecting FLC from all patients and neoplastic plasma cell clones. Given the overall effectiveness of the anti-FLC mAbs, further clinical validation is now warranted on serial samples from a range of patients with B cell disorders. Use of these mAbs on other assay platforms should also be investigated.