Baseline Titers Research Articles

The “Baseline Widal Titre” Amongst Apparently Healthy Adults Working at a Tertiary Care Medical Institution, a Pilot Study, Uttarakhand, India

Introduction: As typhoid fever is known for its endemicity all over the India, healthy people may contain antibodies against salmonella typhi and paratyphi. These antibodies may react up-to a variable titre either due to past exposure, vaccination or/and cross -reacting antigen. Therefore, antibody titre in widal test varies widely from place to place and is referred as baseline titre of that particular area. Two properly staged tests (2-4 weeks interval) show about a four -fold rise in antibody levels leads to a reliable widal test. Single widal test values are not considered significant for diagnosis but many places still use this as diagnostic marker which further depends upon baseline titre prevalent in that particular area. Aims: This study was undertaken in jhajra, Uttarakhand to determine the baseline titre in this geographical region for calculating significant widal titres. Material and Methods: Blood samples were collected from apparently healthy individuals which included medical students, nursing staff, doctors, and other health care workers (aged 19-45) with proper consent. All the samples after being screened by slide agglutination test were further confirmed by Quantitative tube agglutination test, to find out the baseline titre. The tube agglutination test was carried out by taking 0.5 ml of two-fold serially diluted sera (dilutions from 1:20 to 1:320) in 0.9% normal saline with an equal amount of antigen. Results: Out of total 110 serum samples,36 (32.7%) sera were positive (titre ≥ 1:20) and 74 (67.3%) were negative(titre<1:20). A total of 36 samples were positive for agglutinins of “O” antigen,32 for agglutinins of “H” antigen,16 for paratyphi A and 10 for paratyphi B. 23 out of 36 (63.8 %) sera were positive for agglutinins of 'O' antigen of Salmonella typhi (TO) at a titre of 1:40 followed by 6 sera positive at 1:20 (16.6%) and 1:80 (16.6%) and 1 serum sample positive at 1:160 (2.77%) 59.3 % (19) sera were positive for 'H' antigen of Salmonella typhi (TH) at a titre of 1:80 and 10 % sera (11) were positive for 'H' antigen at a titre of 1:40 and 2(1.8%) were positive at 1:20.16(44.4%) sera samples were positive for of Salmonella paratyphi A (AH) and Salmonella paratyphi B (BH) respectively, both at a titre of 1:20 and 8.3% sera were positive at 1:40 respectively. Conclusion: The most frequently recorded titre of the reactive sera was 1:40 and 1:80 for anti-O antibodies and anti-H antibodies and 1:20 for AH and BH. Thus, the significant cut-off level for TO and TH was ≥ 1:80 and ≥ 1:160 that for AH and BH was ≥ 1:40.

SEROLOGICAL RESPONSE TO CANINE DISTEMPER VACCINATION IN WILD CAUGHT RACCOONS (PROCYON LOTOR).

Canine distemper virus (CDV) is a well-known RNA virus that affects domestic dogs and all families of wild terrestrial carnivores. Spillover infections from wildlife to domestic animals are mitigated by preventive vaccination, but there is limited information on the off-label use of veterinary vaccines for wildlife like raccoons (Procyon lotor). Twenty wild-caught raccoons were inoculated with a commercial recombinant DNA canarypox-vectored CDV vaccine, applying a regimen of two serial doses by SC route with an interval of 25-28 days between doses. The CDV serum virus neutralizing antibody (VNA) baseline titers and the postvaccination titers were measured at fixed time points. Forty percent (8/20) of the wild-caught raccoons had CDV VNA titers of 1:8 or greater upon intake, and all but a single individual were juvenile animals. Approximately one month following the first vaccine dose, 8% (1/12) of raccoons seronegative at baseline had serum CDV VNA titers of 1:24 or greater. Approximately one month following the booster vaccine dose, 67% (8/12) of raccoons seronegative at baseline had serum CDV VNA titers of 1:24 or greater. Among raccoons with CDV VNA titers greater than or equal to 1:8 at baseline, 13% (1/8) demonstrated a fourfold or greater rise in titer one month after the first vaccine dose, whereas 38% (3/8) reached the same threshold one month after the booster dose. The presence of naturally acquired CDV VNA in juvenile raccoons at the time of vaccination may have interfered with the humoral VNA response. A regimen of at least two serially administered SC vaccine doses may be immunogenic for raccoons, but further investigation of alternative routes, regimens, and CDV vaccine products is also warranted for this species.

Baseline value and longitudinal kinetics of circulating nucleosomes during neo-adjuvant chemotherapy in newly diagnosed ovarian cancer: Results from the randomized phase II trial CHIVA (GINECO).

e15029 Background: Nucleosomes (DNA wound around histone proteins) were reported as potential cancer biomarkers (1). The links between circulating nucleosomes and clinical endpoints in advanced ovarian cancer (OC) patients treated with neo-adjuvant chemotherapy (NACT) +/- interval debulking surgery (IDS) were retrospectively assessed in the randomized phase II CHIVA trial (2). Methods: The diagnostic concentration and the longitudinal kinetics of 2 nucleosomes (H3K27 and H3K36, log-scale) were investigated at baseline, during NACT, after IDS, and at progression. The baseline titer measured with Nu.Q prototype immunoassays (H3K27Me3, H3K36Me3 (Belgian Volition SRL, Belgium)) was compared to those of a cohort of 201 cancer-free subjects. Their prognostic values regarding the probability of obtaining a complete IDS and progression-free survival (PFS) were assessed with respect to the modeled CA-125 KELIM (3), classical clinical covariates and treatment arms. The maximum selected rank statistics was used to determine the optimal cut-off at different disease management times. Results: H3K27 and H3K36 nucleosome concentrations were available for 148/188 patients. H3K36 and H3K27 baseline concentrations were correlated and significantly higher in OC patients compared to cancer-free subjects (H3K36, 2.8 vs 2.4 ng/mL, P<0.0001; H3K27, 3.2 vs 2.1, P<0.0001), without difference according to BRCA status. The baseline titer of H3K36 was an independent predictor of the completeness of IDS (OR=0.33; 95% CI=0.13-0.71, p=0.009). The baseline concentration of H3K27 was independently associated with PFS (< or ≥3.8 ng/mL, HR=1.84, 95%CI=1.11-3.02, p=0.016), complementary to the CA-125 KELIM. Both nucleosome longitudinal kinetics showed a decrease during NACT, but there was no significant statistical association between their kinetics and radiological response rate, completeness of IDS or PFS. Conclusions: Baseline values of H3K36 and H3K27 could represent a non-invasive method for detecting OC, with potential relevant prognostic value of initial titers in newly diagnosed OC patients. 1. McAnena, Cancers 2017. 2. Ferron, Gynecol Oncol 2023. 3. You, CCR 2020.

Empirical sample-specific approaches to define HPV16 and HPV18 seropositivity in unvaccinated, young, sexually active women.

Given low seroconversion rates following human papillomavirus (HPV) infection, fixed external cutoffs may lead to errors in estimating HPV seroprevalence. We evaluated finite mixture modeling (FMM) and group-based trajectory modeling (GBTM) among unvaccinated, sexually active, HPV-exposed women to determine study-specific HPV16 and HPV18 seropositivity thresholds. We included 399 women (aged 18-24 years) enrolled in the HPV Infection and Transmission Among Couples Through Heterosexual Activity (HITCH) cohort study between 2005 and 2011 in Montreal, Canada. Participants' blood samples from up to six visits spanning 2 years were tested by multiplex serology for antibodies [median fluorescence intensity (MFI)] specific to bacterially expressed HPV16 and HPV18 L1 glutathione S-transferase fusion proteins. We applied FMM and GBTM to baseline and longitudinal antibody titer measurements, respectively, to define HPV type-specific seronegative and seropositive distributions. Study-specific thresholds were generated as five standard deviations above the mean seronegative antibody titers, mimicking cutoffs (HPV16: 422 MFI; HPV18: 394 MFI) derived from an external population of sexually inactive, HPV DNA-negative Korean women (aged 15-29 years). Agreement (kappa) of study-specific thresholds was evaluated against external cutoffs. Seroprevalence estimates using FMM (HPV16: 27.5%-43.2%; HPV18: 21.7%-49.5%) and GBTM (HPV16: 11.8%-11.8%; HPV18: 9.9%-13.4%) thresholds exceeded those of external cutoffs (HPV: 10.2%; HPV18: 9.7%). FMM thresholds showed slight-to-moderate agreement with external cutoffs (HPV16: 0.26%-0.46%; HPV18: 0.20%-0.56%), while GBTM thresholds exhibited high agreement (HPV16: 0.92%-0.92%; HPV18: 0.82%-0.99%). Kappa values suggest that GBTM, used for longitudinal serological data, and otherwise FMM, for cross-sectional data, are robust methods for determining the HPV serostatus without prior classification rules.IMPORTANCEWhile human papillomavirus (HPV) seropositivity has been employed as an epidemiologic determinant of the natural history of genital HPV infections, only a fraction of women incidentally infected with HPV respond by developing significant antibody levels. HPV seropositivity is often determined by a dichotomous fixed cutoff based on the seroreactivity of an external population of women presumed as seronegative, given the lack of evidence of HPV exposure. However, considering the variable nature of seroreactivity upon HPV infection, which arguably varies across populations, such externally defined cutoffs may lack specificity to the population of interest, causing inappropriate assessment of HPV seroprevalence and related epidemiologic uses of that information. This study demonstrates that finite mixture modeling (FMM) and group-based trajectory modeling (GBTM) can be used to independently estimate seroprevalence or serve as the basis for defining study-specific seropositivity thresholds without requiring prior subjective assumptions, consequently providing a more apt internally valid discrimination of seropositive from seronegative individuals.

Chlamydia psittaci Screening of Animal Workers from Argentina Exposed to Carrier Birds.

Different syndromes are involved in human psittacosis (flu-like syndrome, atypical pneumonia up to lacrimal gland lymphoma). Diagnostic methods include serology, culture, and PCR. The rate of Chlamydia psittaci (Cp) positive tests among exposed workers is still unknown. Our study aimed to assess the rate of positive tests among workers who have contact with carrier birds in natural reserves from Buenos Aires, Argentina. Secondary aims were to analyze risk factors linked to these outcomes and the occurrence of signs that suggest psittacosis. Nasopharyngeal swabs and serum pairs were collected from employees who had interacted with confirmed carrier birds. Those with detectable DNA of Cp and/or anti-Chlamydia spp. antibody baseline titer ≥ 160mUI/ml, or at least quadruplicating, were considered positive. Activities performed with or near birds, personal protective equipment use, and previous chronic conditions were assessed. Possible Cp-related pathologies were evaluated during follow-up. A total of 63 exposed workers (71.4% men) with a median age of 35.7years (IQR 26-39) were evaluated to detect 28.6% positives. Respiratory chronic conditions were the unique factor associated with positive tests (OR 5.2 [1.5-18.5] p < .05). Surprisingly, about a third of the workers resulted positive and all responded to medical treatment, none developing an acute atypical pneumonia syndrome associated with classical presentation of psittacosis. Active testing for early diagnosis and proper treatment in zoological workers exposed to carrier or potentially carrier birds is strongly suggested as part of zoonotic diseases preventive measures.

Anti–Phospholipase A2 Receptor 1 and Anti–Cysteine Rich Antibodies, Domain Recognition and Rituximab Efficacy in Membranous Nephropathy: A Prospective Cohort Study

Rationale & ObjectiveProteinuria and anti-phospholipase A2 receptor 1 (anti-PLA2R1) antibody titers are associated with primary membranous nephropathy (MN) outcomes. We evaluated the association of antibodies against the cysteine-rich (CysR) and C-type lectin 1, 7, and 8 (CTLD1, CTLD7, and CTLD8) domains of PLA2R1 with MN outcomes. Study DesignProspective cohort study. Setting & ParticipantsOne-hundred-thirteen consecutive, consenting patients referred to the Nephology Unit of the Azienda-Socio-Sanitaria-Territoriale (ASST) Papa Giovanni XXIII (Bergamo, Italy) with PLA2R1-related, biopsy-proven MN whose persistent nephrotic syndrome (NS) was managed conservatively for >6 months and were monitored with serial evaluations of proteinuria, autoantibodies (by ELISA), and clinical outcomes. ExposureRituximab. OutcomesComplete (proteinuria <0.3 g/24h) or partial (proteinuria >0.3 g/24h and <3.0 g/24h with >50% reduction vs. basal) NS remission. Analytical ApproachUnivariable and multivariable Cox regression analyses. ResultsAll patients had anti-CysR antibodies; 62 (54.9%) were multi-domain recognizers. Anti-PLA2R1 and anti-CysR antibody titers were strongly correlated at baseline (p<0.001, r=0.934), 6 months (p<0.001, r=0.964), and 12 months (p<0.001, r=0.944). During a median (IQR) follow-up of 37.1 (20.3-56.9) months, 71 patients (62.8%) achieved either complete or partial remission of their NS. Lower baseline anti-PLA2R1 [HR (95% CI): 0.997 (0.996-0.999), p=0.002) and anti-CysR [HR (95% CI): 0.996 (0.993-0.998), p=0.001) titers were associated with a higher probability of remission, along with female sex, lower proteinuria, and lower serum creatinine levels (p<0.05 for all comparisons). Anti-CTLD antibodies were not associated with outcomes. At 6 and 12 months, compared to baseline, anti-PLA2R1 and anti-CysR antibody titers decreased more in patients progressing to partial or complete remission than in those without remission (p<0.05 for all comparisons). LimitationsObservational design. ConclusionsIn PLA2R1-related MN, anti-PLA2R1 and anti-CysR antibodies similarly predict rituximab efficacy, independent of PLA2R1 domain recognition. The choice between these tests should be dictated by feasibility and costs. Evaluating anti-CTLD antibodies appears unnecessary.

I-JAMM-(I): A survey providing an insight into the practices of isoagglutinin titration in ABO incompatible kidney and liver transplantation

Background and objectivesABO-incompatible transplantations allow patients to receive timely transplants. Isoagglutinin titration to ascertain levels of incompatible antibodies in the recipient is important in determining patient selection and transplant survivability. To find out the prevalent trends in India, the largest, first of its kind survey was carried out among the transplant centers regarding their practices in isoagglutinin titration. MethodsThe survey was drafted by a working group of Transfusion and Transplant Immunology specialists from six different centers. Data was obtained via the use of an online questionnaire. ResultsResults were categorized into four categories, Hospital information, Titration methodology, Role of transfusion specialists and cut-off titers. Most centers had a well-established solid-organ transplant program with considerable number of ABO-incompatible transplantations. Most centers performed isoagglutinin titration in Transfusion Medicine department. Column Agglutination Technique (CAT) was the most common method, using EDTA blood samples and freshly-prepared in-house pooled cells. Most centers had a turn-around time of less than 12 h. While the policy for ascertaining baseline and threshold titers is well-defined in ABO-incompatible renal transplants, variations from center to center still exist for ABO-incompatible liver transplants. Most centers required a Transfusion Medicine consultation for the patients before such transplants. ConclusionWith increasing ABO-incompatible kidney and liver transplants across the country, the role of Transfusion medicine specialists has become vital in pre-conditioning regimes enabling the viability and success of such transplants. This was a unique survey that provided a snapshot of current trends and practices of isoagglutinin titration for ABO-incompatible transplants in India.

Immunogenicity and Safety of Alternative Influenza Vaccination Strategies in Repeated Seasons in Pediatric Hematopoietic-Cell Transplant Recipients

Abstract Background Pediatric hematopoietic cell transplant (HCT) recipients are at increased risk for morbidity and mortality from influenza infection. Annual influenza vaccination is recommended; however, HCT recipients have diminished immune responses to vaccination. Our recent trial demonstrated that two doses of high-dose trivalent influenza vaccine (HD-TIV) given four weeks apart post-HCT were more immunogenic than two doses of standard dose quadrivalent influenza vaccine (SD-QIV). We assessed the impact of this strategy in a consecutive season post-HCT. Methods The initial trial was a multi-center double-blinded phase II randomized controlled trial comparing two doses of HD-TIV to two doses of SD-QIV in children 3-17 years old given 3-35 months post-allogeneic HCT. Participants completing the initial trial could re-enroll the subsequent influenza season to receive the same two-dose vaccine formulation. Hemagglutinin inhibition (HAI) titers were measured at baseline and 28-42 days following each dose. Injection-site and systemic adverse events were assessed. The immunogenicity endpoints were the post-dose 1 and post-dose 2 geometric mean HAI titers (GMTs) in the second year of participation. Results A total of 170 participants were enrolled in the initial trial, with 65 re-enrolling for a second year (n=33 SD-QIV and n=32 HD-TIV). Post-dose 1 and 2 GMTs were higher for both the SD-QIV and HD-TIV groups in the second year compared the first year (Table 1). In year two, the adjusted geometric mean ratio (aGMR) comparing HD-TIV to SD-QIV was higher post-dose 1 for A/H1N1 (aGMR=1.99, 95% CI:[1.07, 3.68]). The HD-TIV group demonstrated a higher frequency of four-fold titer rise after a single dose compared to two doses of SD-QIV for A/H3N2 (61% vs. 48%) and B/Victoria (77% vs. 65%). Frequency of injection site and systemic reactions were similar between the HD-TIV and SD-QIV groups in year two. Conclusions The post-dose 1 and 2 GMTs were consistently higher for HD-TIV compared to SD-QIV in year two, and aGMR reached statistical significance after a single dose of HD-TIV for A/H1N1. Year two reactogenicity was comparable for both vaccination strategies. Further studies with larger numbers of participants are needed to demonstrate if one or two doses of HD-TIV are needed in subsequent influenza seasons post-HCT when a two-dose vaccination series is given in the first post-HCT season. Table 1. Point estimates and 95% CIs for geometric mean HAI titer, titer ≥1:40, and proportion with ≥4-fold rise from baseline for each vaccine regimen, stratified for each antigen. Also included is the ratio of the observed values (n) to the number of evaluable subjects (N) at each visit. Baseline titers are measured prior to first vaccine dose, post-dose 1 titers are measured 28-42 days following first dose (prior to the second dose), post-dose 2 titers are measured 28-42 days following second dose. Table 1 Note: If 100% achieved seroprotection or seroconversion, “n/a” was entered as a two-sided 95% CI could not be calculated.

Immunogenicity and safety of heterologous boost immunization with PastoCovac Plus against COVID-19 in ChAdOx1-S or BBIBP-CorV primed individuals.

This study aimed at evaluation and comparison of PastoCovac Plus protein-subunit vaccine in parallel with ChAdOx1-S (AstraZeneca) and BBIBP-CorV (Sinopharm) in primarily vaccinated volunteers with two doses of ChAdOx1-S or BBIBP-CorV. 194 volunteers enrolled the study who were previously primed with 2 doses of ChAdOx1-S or BBIBP-CorV vaccines. They were divided into two heterologous regimens receiving a third dose of PastoCovac Plus, and two parallel homologous groups receiving the third dose of BBIBP-CorV or ChAdOx1-S. Serum samples were obtained just before and 4 weeks after booster dose. Anti-spike IgG and neutralizing antibodies were quantified and the conventional live-virus neutralization titer, (cVNT50) assay was done against Omicron BA.5 variant. Moreover, the adverse events data were recorded after receiving booster doses. ChAdOx1-S/PastoCovac Plus group reached 73.0 units increase in anti-Spike IgG rise compared to the ChAdOx1-S/ ChAdOx1-S (P: 0.016). No significant difference was observed between the two groups regarding neutralizing antibody rise (P: 0.256), indicating equivalency of both booster types. Adjusting for baseline titers, the BBIBP-CorV/PastoCovac Plus group showed 135.2 units increase (P<0.0001) in anti-Spike IgG, and 3.1 (P: 0.008) unit increase in mean rise of neutralizing antibodies compared to the homologous group. Adjustment for COVID-19 history, age, underlying diseases, and baseline antibody titers increased the odds of anti-Spike IgG fourfold rise both in the ChAdOx1-S (OR: 1.9; P: 0.199) and BBIBP CorV (OR: 37.3; P< 0.0001) heterologous groups compared to their corresponding homologous arms. The odds of neutralizing antibody fourfold rise, after adjustment for the same variables, was 2.4 (P: 0.610) for the ChAdOx1-S heterologous group and 5.4 (P: 0.286) for the BBIBP CorV heterologous groups compared to their corresponding homologous groups. All the booster types had the potency to neutralize BA.5 variant with no significant difference. The highest rate of adverse event incidence was recorded for ChAdOx1-S homologous group. PastoCovac Plus booster application in primed individuals with BBIBP-CorV or ChAdOx1-S successfully increased specific antibodies' levels without any serious adverse events. This vaccine could be administrated in the heterologous regimen to effectively boost humoral immune responses.

Relationship of Heterologous Virus Responses and Outcomes in Hospitalized COVID-19 Patients.

The clinical trajectory of COVID-19 may be influenced by previous responses to heterologous viruses. We examined the relationship of Abs against different viruses to clinical trajectory groups from the National Institutes of Health IMPACC (Immunophenotyping Assessment in a COVID-19 Cohort) study of hospitalized COVID-19 patients. Whereas initial Ab titers to SARS-CoV-2 tended to be higher with increasing severity (excluding fatal disease), those to seasonal coronaviruses trended in the opposite direction. Initial Ab titers to influenza and parainfluenza viruses also tended to be lower with increasing severity. However, no significant relationship was observed for Abs to other viruses, including measles, CMV, EBV, and respiratory syncytial virus. We hypothesize that some individuals may produce lower or less durable Ab responses to respiratory viruses generally (reflected in lower baseline titers in our study), and that this may carry over into poorer outcomes for COVID-19 (despite high initial SARS-CoV-2 titers). We further looked at longitudinal changes in Ab responses to heterologous viruses, but found little change during the course of acute COVID-19 infection. We saw significant trends with age for Ab levels to many of these viruses, but no difference in longitudinal SARS-CoV-2 titers for those with high versus low seasonal coronavirus titers. We detected no difference in longitudinal SARS-CoV-2 titers for CMV seropositive versus seronegative patients, although there was an overrepresentation of CMV seropositives among the IMPACC cohort, compared with expected frequencies in the United States population. Our results both reinforce findings from other studies and suggest (to our knowledge) new relationships between the response to SARS-CoV-2 and Abs to heterologous viruses.

Correlates of protection for booster doses of the SARS-CoV-2 vaccine BNT162b2

Vaccination, especially with multiple doses, provides substantial population-level protection against COVID-19, but emerging variants of concern (VOC) and waning immunity represent significant risks at the individual level. Here we identify correlates of protection (COP) in a multicenter prospective study following 607 healthy individuals who received three doses of the Pfizer-BNT162b2 vaccine approximately six months prior to enrollment. We compared 242 individuals who received a fourth dose to 365 who did not. Within 90 days of enrollment, 239 individuals contracted COVID-19, 45% of the 3-dose group and 30% of the four-dose group. The fourth dose elicited a significant rise in antibody binding and neutralizing titers against multiple VOCs reducing the risk of symptomatic infection by 37% [95%CI, 15%-54%]. However, a group of individuals, characterized by low baseline titers of binding antibodies, remained susceptible to infection despite significantly increased neutralizing antibody titers upon boosting. A combination of reduced IgG levels to RBD mutants and reduced VOC-recognizing IgA antibodies represented the strongest COP in both the 3-dose group (HR = 6.34, p = 0.008) and four-dose group (HR = 8.14, p = 0.018). We validated our findings in an independent second cohort. In summary combination IgA and IgG baseline binding antibody levels may identify individuals most at risk from future infections.

Diagnostic value of hPG80, as a new multi-cancer blood biomarker, in 16 different cancers: Results of the ONCOPRO prospective study.

3033 Background: hPG80 (also called circulating progastrin) has been described as a promising multi-cancer blood biomarker. Indeed, hPG80 is released from cancer cells to blood at the early steps of tumorigenesis due to WNT pathway activation (You et al eBioMedicine 2020). ONCOPRO study was designed to prospectively assess the hPG80 diagnostic &amp; clinical utility in patients with 16 types of cancers. Methods: ONCOPRO study (NCT03787056) was a large prospective case-control study led in Lyon University Hospital (France), designed to assess the diagnostic, and monitoring value of hPG80 blood titers in 420 patients with 16 newly diagnosed cancers. hPG80 was measured using kit DxPG80.Lab (Biodena care) at diagnosis, and then at each cycle/visit until recurrence for the curative cohorts, or for 3 treatment lines for the non-curative cohorts. The diagnostic value of hPG80 (primary endpoint) was assessed by comparing the hPG80 baseline titers measured in cancer patients to those of 330 healthy volunteers recruited in parallel (age &amp; sex ratios matched with the cancer group), with a sample size calculated for precision of ±0.23 for ROC AUC. Results: Out of 499 cancer patients enrolled between December 2018 and June 2022, 419 were assessable in 16 cancer cohorts (NSCLC &amp; SCLC: n=70; Breast: n=50; Renal: n=50; Prostate: n=50; Liver: n=50; Head&amp;Neck: n=49; Hepatocellular carcinoma (HCC): n=50; Colorectal: n=10; Thyroid: n=10; Pancreas: n=14; Ovarian: n=10; Glioblastoma: n=10; Endometrial: n=10; Bladder: n=10; Superficial oesophago-gastric: n=10; Lymphoma: n=10; Gastric: n=10). The median age of cancer patients was 66 [IQR: 58-73], with 60% men. hPG80 concentration was significantly higher in cancer patients than in healthy subjects (median, 3.8 vs 2.0 pM, P &lt; 0.001). It was not impacted by renal/liver, or CRP level, but slightly linked to age. hPG80 titer was found stable on a 24h-hour period. The global diagnostic accuracy in cancer patients / control was ROC AUC, 0.63 [0.59-0.67] in the whole population. The highest diagnostic accuracy was seen in patients with lung cancer (AUC, 0.75 [0.68-0.82]; Sensitivity (Se)/Specificity (Sp) 0.49/0.90 for hPG80 &gt;7.73 pM) and HCC (AUC, 0.75, 95% CI 0.66-083; Se/Sp 0.48/0.90 for hPG80 &gt; 7.73 pM). Conclusions: This large prospective study confirms that cancer patients have significantly higher blood concentration of hPG80 than healthy subjects. The data about the different cohorts will guide the future development of hPG80. Strong diagnostic accuracy was seen for lung cancers and HCC, with specificity &gt; 90%. The screening programs of these cancers could be enriched by this simple blood hPG80 ELISA assay, for complementing imaging limited specificity. Clinical trial information: NCT03787056 .

Large volume plasmapheresis using a single-use immunoadsorption column: A cost-effective approach for desensitization in ABO-incompatible liver transplant.

Liver transplant is a life-saving treatment, but due to the limited availability of suitable liver donors, ABO-incompatible liver transplants (ABOi-LT) are conducted to increase the availability of liver donors. Perioperative desensitization for ABOi-LT is an established strategy to circumvent the risk of graft rejection. A single prolonged session can be performed to achieve the desired titers to avoid using multiple immunoadsorption (IA) columns or off-label reuse of single-use columns. This study retrospectively assessed the effectiveness of a single prolonged plasmapheresis session using IA as a desensitization strategy in live donor liver transplant (LDLT). This retrospective observational study conducted at a center for liver diseases in North India on six ABOi-LDLT patients who underwent single prolonged IA sessions in the perioperative period from January 2018 to June 2021. Median baseline titer in patients was 320 (64, 1024). The median plasma volume adsorbed was 7.5 volumes (4, 8) per procedure, with a mean procedure time of 600 min (310-753). The reduction in titer ranged from 4 log to 7 log reduction per procedure. Two patients developed transient hypotension during the procedure, which was managed successfully. The median duration of pre-transplant hospital stay was 1.5 days (1, 3). Desensitization therapy helps overcome the ABO barrier and decreases the waiting period before a transplant when ABO identical donors are unavailable. A single prolonged IA session reduces the cost of additional IA columns and hospital stay, thus making it a cost-effective approach to desensitization.

Immunogenicity of quadrivalent meningococcal conjugate vaccine in frequent platelet donors

AbstractFrequent plateletpheresis is associated with severe lymphopenia of uncertain clinical significance. We assessed the functional impact of frequent platelet donations and associated lymphopenia on the response to neoantigens. We conducted a prospective study of 102 platelet donors (HIV uninfected) who were naive to meningococcal vaccination recruited at Brigham and Women’s Hospital. One dose of quadrivalent meningococcal conjugate vaccine was administered. Seroresponse was defined as a fourfold increase of serum bactericidal antibody titers and seroprotection was defined as postvaccination titers of ≥1:8, for each of the 4 vaccine antigens (A, C, W, and Y). Mean age of participants was 61 years, 69% were male, and medial number of platelet donations in prior year was 14 (interquartile range, 4-20). Frequent platelet donors had a low CD4 count (14% with ≤200/μL and 34% with ≤350/μL). Seroresponse rates varied from 68% for serogroup Y to 86% for serogroup A and were higher for participants with baseline titers of <1:8. Postvaccination seroprotection rates varied from 76% for serogroup Y to 96% for serogroup A. After adjustments for age, sex, and frequent donations, lower total lymphocyte or lower CD4 counts were not associated with lower responses. These data suggest no impairment by plateletpheresis-associated lymphopenia on response to these neoantigens. This trial was registered at www.clinicaltrials.gov as #NCT04224311.

Successful restoration of protective immunity against measles, mumps, and rubella following MMR vaccination in adult hematopoietic cell transplant recipients.

The optimal number of doses as well as the role for measurement of postvaccination titers after measles, mumps, rubella (MMR) vaccination in adult hematopoietic cell transplantation (HCT) recipients remains unknown. In the present study, we assessed humoral immunity against measles, mumps and rubella before and after MMR vaccination in 187 adults who received at least one dose of the MMR vaccine after HCT. Among those with baseline titers, posttransplant prevaccination seroprotection rates were 56%, 30%, and 54% for measles, mumps, and rubella, respectively; and significantly lower in allogeneic versus autologous HCT recipients for measles (39%vs. 80%, p = .0001), mumps (22%vs. 41%; p = .02) and rubella (48%vs. 62%, p = .12). Among those who were seronegative at baseline, seroconversion rates after one dose of MMR were 69%, 56%, and 97% for measles, mumps, and rubella, respectively. Seronegative patients after one dose of MMR (i.e., nonresponders) seroconverted for measles and mumps after a second MMR vaccine dose. Our findings demonstrate successful restoration of protective immunity against measles, mumps, and rubella after vaccination in adult HCT recipients; one dose of MMR elicited protective titers in the majority of patients, and a second vaccine dose was immunogenic in nonresponders.

A Multi-Center, Controlled Human Infection Study of Influenza A (H1N1)pdm09 in Healthy Adults.

We evaluated the associations between baseline influenza virus-specific hemagglutination inhibition (HAI) and microneutralization (MN) titers and subsequent symptomatic influenza virus infection in a controlled human infection study. We inoculated unvaccinated healthy adults aged 18 through 49 years with an influenza A/California/04/2009/H1N1pdm-like virus (NCT04044352). We collected serial safety labs, serum for HAI and MN, and nasopharyngeal swabs for RT-PCR testing. Analyses used the putative seroprotective titer of ≥40 for HAI and MN. The primary clinical outcome was mild-to-moderate influenza disease (MMID), defined as ≥1 post-challenge positive qualitative RT-PCR test with a qualifying symptom/clinical finding. Of 76 participants given influenza virus challenge, 54 (71.1%) experienced MMID. Clinical illness was generally very mild. MMID attack rates among participants with baseline titers ≥40 by HAI and MN were 64.9% and 67.9%, respectively, while MMID attack rates among participants with baseline titers <40 by HAI and MN were 76.9% and 78.3%, respectively. The estimated odds of developing MMID decreased by 19% (odds ratio=0.81; 95% CI: 0.62, 1.06; p=0.126) for every two-fold increase in baseline HAI. There were no significant adverse events. We achieved a 71.1% attack rate of MMID. High baseline HAI and MN were associated with protection from illness.

Immunogenicity and safety of a quadrivalent meningococcal conjugate vaccine (MenACYW-TT) administered as a booster to adults aged ≥59 years: A phase III randomized study

ABSTRACT This 2-stage Phase III study (NCT04142242) of a recently licensed quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) assessed the safety and immunogenicity of a booster dose in older adults (≥59 years) primed with either MenACYW-TT or a quadrivalent meningococcal polysaccharide vaccine (MPSV4). Immune persistence of MenACYW-TT and MPSV4 after primary vaccination was also evaluated. During Stage I, the participants administered MPSV4 (n = 165) or MenACYW-TT (n = 236) 3 years previously were randomized 9:2 to receive either a MenACYW-TT booster or to have blood drawn for persistence only. Participants primed with MPSV4 or MenACYW-TT 6–7 years previously had blood drawn for antibody persistence only. A serum bactericidal assay using human complement was used to measure functional antibodies against each serogroup at baseline and, for those receiving a booster, 30 days post-vaccination (D30). Proportions of participants with seroresponse (post-vaccination titers ≥1:16 when baseline titers <1:8 or ≥ 4-fold increase when baseline titers ≥1:8) were determined. Safety data were collected up to D30. Seroresponse rates for all serogroups at D30 ranged from 49.2% to 60.8% in the MPSV4-primed group, and 79.3–93.1% in the MenACYW-TT-primed group. MenACYW-TT induced sufficient seroresponses in each primed group. Geometric mean titers (GMTs) for serogroups C, W, and Y remained or trended higher than pre-vaccination levels at both 3 and 6–7 years after primary vaccination, indicating immune persistence. Safety outcomes were comparable between groups. A MenACYW-TT booster was immunogenic and well tolerated in participants aged ≥59 years regardless of previous quadrivalent meningococcal vaccine received. The greatest immune responses occurred in those primed with MenACYW-TT.

Safety, tolerability, and immunogenicity of the chimpanzee adenovirus type 3-vectored Marburg virus (cAd3-Marburg) vaccine in healthy adults in the USA: a first-in-human, phase 1, open-label, dose-escalation trial

WHO has identified Marburg virus as an emerging virus requiring urgent vaccine research and development, particularly due to its recent emergence in Ghana. We report results from a first-in-human clinical trial evaluating a replication-deficient recombinant chimpanzee adenovirus type 3 (cAd3)-vectored vaccine encoding a wild-type Marburg virus Angola glycoprotein (cAd3-Marburg) in healthy adults. We did a first-in-human, phase 1, open-label, dose-escalation trial of the cAd3-Marburg vaccine at the Walter Reed Army Institute of Research Clinical Trials Center in the USA. Healthy adults aged 18-50 years were assigned to receive a single intramuscular dose of cAd3-Marburg vaccine at either 1 × 1010 or 1 × 1011 particle units (pu). Primary safety endpoints included reactogenicity assessed for the first 7 days and all adverse events assessed for 28 days after vaccination. Secondary immunogenicity endpoints were assessment of binding antibody responses and T-cell responses against the Marburg virus glycoprotein insert, and assessment of neutralising antibody responses against the cAd3 vector 4 weeks after vaccination. This study is registered with ClinicalTrials.gov, NCT03475056. Between Oct 9, 2018, and Jan 31, 2019, 40 healthy adults were enrolled and assigned to receive a single intramuscular dose of cAd3-Marburg vaccine at either 1 × 1010 pu (n=20) or 1 × 1011 pu (n=20). The cAd3-Marburg vaccine was safe, well tolerated, and immunogenic. All enrolled participants received cAd3-Marburg vaccine, with 37 (93%) participants completing follow-up visits; two (5%) participants moved from the area and one (3%) was lost to follow-up. No serious adverse events related to vaccination occurred. Mild to moderate reactogenicity was observed after vaccination, with symptoms of injection site pain and tenderness (27 [68%] of 40 participants), malaise (18 [45%] of 40 participants), headache (17 [43%] of 40 participants), and myalgia (14 [35%] of 40 participants) most commonly reported. Glycoprotein-specific antibodies were induced in 38 (95%) of 40 participants 4 weeks after vaccination, with geometric mean titres of 421 [95% CI 209-846] in the 1 × 1010 pu group and 545 [276-1078] in the 1 × 1011 pu group, and remained significantly elevated at 48 weeks compared with baseline titres (39 [95% CI 13-119] in the 1 ×1010 pu group and 27 [95-156] in the 1 ×1011 pu group; both p<0·0001). T-cell responses to the glycoprotein insert and neutralising responses against the cAd3 vector were also increased at 4 weeks after vaccination. This first-in-human trial of this cAd3-Marburg vaccine showed the agent is safe and immunogenic, with a safety profile similar to previously tested cAd3-vectored filovirus vaccines. 95% of participants produced a glycoprotein-specific antibody response at 4 weeks after a single vaccination, which remained in 70% of participants at 48 weeks. These findings represent a crucial step in the development of a vaccine for emergency deployment against a re-emerging pathogen that has recently expanded its reach to new regions. National Institutes of Health.

Cardiolipin Antibody: A Potential Biomarker for Depression.

Background: Inflammation plays a pivotal role in the etiopathology of Major Depressive Disorder (MDD), at least in a subset of patients. It is crucial to first establish which specific inflammatory biomarkers are of clinical utility. Anti-cardiolipin antibody (aCL IgM) is an inflammatory marker that has the potential to be such a candidate but there are insufficient studies to confirm this potential. Objective: To investigate the baseline titer level and the longitudinal progression of plasma titers of aCL IgM in MDD subjects receiving antidepressant therapy in comparison to healthy control (HC) subjects; to determine if changes in aCL IgM plasma titers correlate to changes in depressive symptoms; and, to ascertain if baseline aCL IgM plasma titers could predict treatment response. Methods: Forty-eight medically healthy outpatients diagnosed with MDD were enrolled in one of two groups in two sequentially conducted clinical trials. In Group-E, patients received a 12-week regimen of escitalopram (n = 20). Those in Group-Q received a 12-week regimen of quetiapine (n = 28). The main outcome measure was plasma aCL IgM titers, the Hamilton Rating Scale for Depression (HAM-D17) and the Hamilton Rating Scale for Anxiety (HAM-A). There were 16 HC subjects. Results: When Group-Q and Group-E participants were grouped together (n = 48), MDD subjects had an elevated baseline aCL IgM (19.9 μg/mL) compared to HC subjects (8.32 μg/mL) (p = 0.006). aCL IgM correlated significantly with HAM-D17 scores at baseline in MDD subjects (p = 0.0185, r = 0.296). Examining the individual groups, Group-Q MDD patients had a significantly elevated baseline aCL IgM (p = 0.008) while Group-E's MDD patients did not. On the other hand, only Group-E MDD patients showed a significant correlation at baseline between aCL IgM and HAM-A score (p = 0.0392, r = 0.4327); they also showed a significant inverse correlation between week 12 HAMD-17 Item #10 (Anxiety, Psychic) and week 12 aCL IgM titer (p = 0.0268, r = -0.5516). Conclusions: MDD patients had significantly higher plasma titers of aCL IgM when compared to HC subjects. Moreover, at baseline, the higher the aCL IgM titer, the higher the depression severity, as measured by HAMD-17 score. However, this study did not demonstrate that aCL IgM titers changed significantly throughout a 12-week course of antidepressant treatment and revealed no correlation between changes in depressive symptoms and changes in aCL IgM titers. Baseline aCL IgM could not predict treatment response. We conclude that, despite lacking predictive ability as regards treatment response, plasma titers of aCL IgM have a diagnostic potential in MDD that necessitates further exploration.

316.7: ABO – Incompatible Kidney Transplantation in COVID 19 Era: A Single Centre Experience

Introduction: Though there are multiple studies on outcome of ABO incompatible kidney transplants, we herein present the short term outcome of ABO-incompatible kidney transplantations done in the Covid-19 era. Methods: We analysed 40 consecutive ABO incompatible kidney transplant recipients undergone transplant from October 2020 till February 2022, followed up till March 2022.Included patients received rituximab 100 mg/200 mg depending on baseline anti ABO titre, plasma exchange and IVIG for desensitization. Target pre transplant anti ABO titre was ≤ 1:64.Patients received induction therapy with anti thymocyte globulin and IV methylprednisolone. Results: The median duration of follow up was 294 days. The highest baseline and pre transplant titre were 2048 and 64 respectively. The mean serum creatinine at discharge was 1.35±0.39 mg/dl and at follow up was 1.48 ± 0.59 mg/dl.The patient and death censored graft survival were 97.5% each. The single graft and patient loss was due to fungal pyelonephritis. 5 patients (12.5%) experienced episodes of biopsy proven rejection.3 patients (7.5%) had acute antibody mediated rejection and 2 patients (5%) suffered T Cell Mediated rejection. The post-transplant hospital stay was 12.79 ± 4.61 days. 5 patients needed hospitalisation for infection in the post transplant follow up period. 10 covid-19 recovered patients were transplanted after a mean duration of 88.4 days with mild to moderate severity. 3 patients (7.5%) acquired covid-19 post-transplantation, 2 in early post transplant (<3 months) and 1 patient at 5 months post-transplant period. Conclusion: There were no significant differences in the patient and graft survival in covid-19 era as compared to our pre covid studies. Rather, they had lower infection rates due to covid-19 related precautions. There was no increase in mortality or infection in a shorter term of follow up of our study period. Keywords: Short term outcome, ABO incompatible kidney transplantation, Covid19 Era.