Theel, Elitza S.

ABSTRACT Histoplasma and Blastomyces antigen detection assays are commonly used diagnostic tools. However, a high level of cross-reactivity between these antigens prevents definitive pathogen identification by these assays alone. Retrospective analysis of 3,529 patients with Histoplasma and Blastomyces antigen testing performed on the same serum sample yielded an overall percent agreement of 99.3% (3,506 of 3,529; kappa: 0.859) between the two assays, suggesting that use of a single assay to detect both antigens may be an alternative diagnostic approach. We assessed performance of the Gotham BioTech Blastomyces antigen (GBA) enzyme immunoassay (EIA) (Portland, Maine) for detection of Blastomyces and Histoplasma antigens in serum. Comparison to the MiraVista Diagnostics Blastomyces (MVB) EIA showed 100% positive (24 of 24), negative (57 of 57), and overall (81 of 81) percent agreement. Additionally, 171 sera were used to compare the GBA EIA to the MiraVista Diagnostics Histoplasma (MVH) EIA, which showed 91.3% (63 of 69), 98% (100 of 102), and 95.3% (163 of 171) positive, negative, and overall percent agreement, respectively. Among eight patients with discordant GBA/MVH EIA results, seven had additional fungal testing performed, and results suggested that the MVH and GBA results were inaccurate for two and five samples, respectively. Overall, this study suggests that the GBA EIA has a high level of agreement with both of the commonly used, individual Blastomyces and Histoplasma antigen EIAs. By taking advantage of the high level of cross-reactivity between Blastomyces and Histoplasma antigen EIAs, utilization of a single antigen detection assay for these fungi provides an opportunity to optimize test utilization and decrease patient cost while maintaining a high level of diagnostic accuracy.

AbstractIntroductionCytomegalovirus (CMV) causes significant morbidity in solid organ transplant recipients (SOTR). Measuring cell‐mediated immunity (CMI) may inform the risk of CMV infection after antiviral prophylaxis and predict relapse after CMV treatment.MethodsWe serially assessed CMV CMI using the QuantiFERON‐CMV assay (QF‐CMV; Qiagen, Germantown, MD) in two cohorts of SOTRs: during valganciclovir prophylaxis and during treatment of CMV viremia. Results of CMI were correlated with post‐prophylaxis CMV infection and post‐treatment relapse, respectively.ResultsOnly one (4.2%) of 24 CMV D+/R‐ patients demonstrated positive QF‐CMV by the end of valganciclovir prophylaxis. Four (16.6%) patients developed post‐prophylaxis CMV infection; all four had undetectable QF‐CMV at end of prophylaxis. Among 20 patients treated for CMV infection, 18 (90%) developed QF‐CMV levels >.2 IU/mL by end of antiviral treatment and none developed CMV relapse. In contrast, the single patient who relapsed after completing treatment had a CMV CMI <.2 IU/ml (p = .0036).ConclusionSince CMV D+/R‐ SOTRs are unlikely to develop adequate CMV CMI while receiving valganciclovir prophylaxis, the utility of CMV CMI monitoring for risk stratification during time of prophylaxis had limited value. Conversely, CMV CMI testing may be a useful marker of the risk of CMV relapse after antiviral treatment.

Abstract Despite intensive characterization of immune responses after COVID-19 infection and vaccination, research examining protective correlates of vertical transmission in pregnancy are limited. Herein, we profiled humoral and cellular characteristics in pregnant women infected or vaccinated at different trimesters and in their corresponding newborns. We noted a significant correlation between spike S1–specific IgG antibody and its RBD-ACE2 blocking activity (receptor-binding domain–human angiotensin-converting enzyme 2) in maternal and cord plasma (P &lt; .001, R &gt; 0.90). Blocking activity of spike S1–specific IgG was significantly higher in pregnant women infected during the third trimester than the first and second trimesters. Elevated levels of 28 cytokines/chemokines, mainly proinflammatory, were noted in maternal plasma with infection at delivery, while cord plasma with maternal infection 2 weeks before delivery exhibited the emergence of anti-inflammatory cytokines. Our data support vertical transmission of protective SARS-CoV-2–specific antibodies. This vertical antibody transmission and the presence of anti-inflammatory cytokines in cord blood may offset adverse outcomes of inflammation in exposed newborns.

Abstract Background Diagnosis of neurosyphilis (NS) is challenging due to nonspecific clinical symptoms and the lack of a sensitive and specific laboratory test. The non-treponemal Venereal Disease Research Laboratory (VDRL-CSF) assay is a commonly used test in diagnosing NS. An important limitation of the VDRL-CSF is limited specificity, in part due to the inability to differentiate between intrathecally produced antibodies vs passive antibody diffusion into the CSF due to blood-brain barrier (BBB) disruption. Here, we compared the intrathecal synthesis antibody index (AI) of anti-Treponema pallidum IgG antibodies to results from the VDRL-CSF assay in routinely submitted clinical samples for evaluation of suspected NS. Methods Paired serum and CSF residual clinical samples from 98 patients with previous VDRL-CSF results were collected. For each pair, the serum and CSF were drawn within 24 h. No additional clinical information and limited supporting clinical test results were available. Thirty-one positive and 67 negative paired samples were tested by an anti-T. pallidum IgG ELISA (Euroimmun, Lübeck, Germany). The AI was calculated using Reiber’s method, with intrathecal total IgG synthesis corrected using the Reiber recommended albumin quotient calculation. Results were compared for positive, negative and overall agreement between methods. Results The anti-T. pallidum AI showed a positive, negative and overall agreement of 71.0% (22/31), 100% (67/67) and 90.8% (89/98), respectively, compared to VDRL-CSF. Of note, all nine discordant samples showed abnormally elevated albumin levels in CSF (range: 27.4 to 215 mg/dl; median = 41.7 mg/dl; normal value =&lt;27 mg/dl), indicating a compromised BBB which likely resulted in false-positive VDRL-CSF results. The range and median value for CSF albumin in the 22 concordant samples was 12.4 to 168 mg/dl and 37.2 mg/dl, respectively. In total, 83.9% (26/31) of VDRL-CSF positive samples showed elevated CSF albumin levels which suggests a high percentage of BBB impairment in this patient population. This demonstrates the advantage in specificity that is offered by AI testing compared to use of the VDRL-CSF assay, given the ability of AI to differentiate intrathecally produced vs passively diffused syphilis-specific antibodies. No potential increase in sensitivity was observed in AI testing as 100% negative agreement was obtained. Conclusion Our data suggests that establishment of an AI using a treponemal assay to detect intrathecal antibody synthesis provides improved specificity compared to the current commonly performed VDRL-CSF antibody test as an aid in the diagnosis of NS. Further evaluation of sensitivity is warranted using samples from patients with clinically diagnosed NS.

Abstract Background Powassan virus (POWV) is an emerging arthropod-borne flavivirus, transmitted by Ixodes spp. ticks, which has been associated with neuroinvasive disease and poor outcomes. Methods A retrospective study was conducted at Mayo Clinic from 2013 to 2022. We included clinical and epidemiologic data of probable and confirmed neuroinvasive POWV cases. Results Sixteen patients with neuroinvasive POWV were identified; their median age was 63.2 years, and 62.5% were male. Six patients presented with rhombencephalitis, 4 with isolated meningitis, 3 with meningoencephalitis, 2 with meningoencephalomyelitis, and 1 with opsoclonus myoclonus syndrome. A median time of 18 days was observed between symptom onset and diagnosis. Cerebrospinal fluid analysis showed lymphocytic pleocytosis with elevated protein and normal glucose in the majority of patients. Death occurred within 90 days in 3 patients (18.8%), and residual neurologic deficits were seen in 8 survivors (72.7%). Conclusions To our knowledge, this is the largest case series of patients with neuroinvasive POWV infection. We highlight the importance of a high clinical suspicion among patients who live in or travel to high-risk areas during the spring to fall months. Our data show high morbidity and mortality rates among patients with neuroinvasive disease.

AbstractIn a COVID‐19 sero‐surveillance cohort study with predominantly healthy and vaccinated individuals, the objectives were (i) to investigate longitudinally the factors associated with the quantitative dynamics of antispike (anti‐S1) IgG antibody levels, (ii) to evaluate whether the levels were associated with protection from SARS‐CoV‐2 infection, and (iii) to assess whether the association was different in the pre‐Omicron compared with the Omicron period. The QuantiVac Euroimmun ELISA test was used to quantify anti‐S1 IgG levels. The entire study period (16 months), the 11‐month pre‐Omicron period and the cross‐sectional analysis before the Omicron surge included 3219, 2310, and 895 reactive serum samples from 949, 919, and 895 individuals, respectively. Mixed‐effect linear, mixed‐effect time‐to‐event, and logistic regression models were used to achieve the objectives. Age and time since infection or vaccination were the only factors associated with a decline of anti‐S1 IgG levels. Higher antibody levels were significantly associated with protection from SARS‐CoV‐2 infection (0.89, 95% confidence interval [CI] 0.82–0.97), and the association was higher during the time period when Omicron was predominantly circulating compared with the ones when Alpha and Delta variants were predominant (adjusted hazard ratio for interaction 0.66, 95% CI 0.53–0.84). In a prediction model, it was estimated that >8000 BAU/mL anti‐S1 IgG was required to reduce the risk of infection with Omicron variants by approximately 20%–30% for 90 days. Though, such high levels were only found in 1.9% of the samples before the Omicron surge, and they were not durable for 3 months. Anti‐S1 IgG antibody levels are statistically associated with protection from SARS‐CoV‐2 infection. However, the prediction impact of the antibody level findings on infection protection is limited.

TB remains a leading cause of morbidity and mortality worldwide. However, most infected immunocompetent individuals are asymptomatic and only 5–10% of these will eventually develop active TB during their lifetime (typically within 2 years after exposure). Therefore, rapid diagnosis and efficient management of asymptomatic infected individuals who are at the highest risk of progression and transmission remain major clinical and public health challenges. In recent years, there has been important scientific progress in our understanding of the spectrum of asymptomatic Mycobacterium tuberculosis (Mtb) infections that not only includes the dynamic state of latent TB infection (LTBI), but also the preclinical state of incipient and subclinical TB. The latter is possibly as prevalent as symptomatically active TB and potentially contributes to global Mtb transmission in various settings. We summarize the latest developments and current challenges of the existing testing tools for LTBI and describe promising biomarkers and diagnostics for the spectrum of asymptomatic TB. Following the negative results of a recent clinical trial for a biomarker-guided preventive therapy approach, we also suggest some treatment options for incipient TB.

Objectives In a COVID-19 sero-surveillance cohort study with predominantly healthy and vaccinated individuals, the objectives were (i) to investigate longitudinally the factors associated with the quantitative dynamics of anti-spike IgG antibody levels, (ii) to evaluate whether the antibody levels were associated with protection from SARS-CoV-2 infection and (iii) to assess whether the association was different in the pre-Omicron compared with the Omicron period. Methods The QuantiVac Euroimmun ELISA test was used to quantify anti-S1 IgG levels. The entire study period (16 months), the 11-month pre-Omicron period and the cross-sectional analysis prior to the Omicron surge included 3219, 2310 and 895 reactive serum samples from 949, 919 and 895 study participants, respectively. Mixed-effect linear, mixed-effect time-to-event and logistic regression models were used to achieve the objectives. Results Age and time since infection or vaccination were the only factors associated with a decline of anti-S1 IgG levels. Antibody levels were significantly associated with protection from SARS-CoV-2 infection, and the association was higher for the Omicron than for the Alpha and Delta variants. In a prediction model, it was estimated that >8000 BAU/mL anti-S1 IgG was required to reduce the risk of infection with Omicron variants by 20% to 30% for 90 days. Conclusions Anti-S1 IgG antibody levels are associated with protection from infection. The levels in the pre-Omicron periods were less significant than during the Omicron surge, which in turn required very high levels for protection in a statistical model.