Toxoplasma gondii IgG Serointensity Is Positively Associated With Frailty

BACKGROUND

Persistent inflammation related to aging ("inflammaging") is exacerbated by chronic infections and contributes to frailty in older adults. We hypothesized associations between Toxoplasma gondii (T. gondii), a common parasite causing an oligosymptomatic unremitting infection, and frailty, and secondarily between T. gondii and previously reported markers of immune activation in frailty.

METHODS

We analyzed available demographic, social, and clinical data in Spanish and Portuguese older adults [N = 601; age: mean (SD) 77.3 (8.0); 61% women]. Plasma T. gondii immunoglobulin G (IgG) serointensity was measured with an enzyme-linked immunosorbent assay. The Fried criteria were used to define frailty status. Validated translations of Mini-Mental State Examination, Geriatric Depression Scale, and the Charlson Comorbidity Index were used to evaluate confounders. Previously analyzed biomarkers that were significantly associated with frailty in both prior reports and the current study, and also related to T. gondii serointensity, were further accounted for in multivariable logistic models with frailty as outcome.

RESULTS

In T. gondii-seropositives, there was a significant positive association between T. gondii IgG serointensity and frailty, accounting for age (p = .0002), and resisting adjustment for multiple successive confounders. Among biomarkers linked with frailty, kynurenine/tryptophan and soluble tumor necrosis factor receptor II were positively associated with T. gondii serointensity in seropositives (p < .05). Associations with other biomarkers were not significant.

CONCLUSIONS

This first reported association between T. gondii and frailty is limited by a cross-sectional design and warrants replication. While certain biomarkers of inflammaging were associated with both T. gondii IgG serointensity and frailty, they did not fully mediate the T. gondii-frailty association.

Decreasing Tryptophan and Increasing Neopterin Plasma Levels During Pregnancy are Associated with High First Trimester Porphyromonas gingivalis K-Serotype IgG Serointensity in a Cohort of Hispanic Women

BACKGROUND

Immune activation or high levels of stress may lead to increased metabolism of tryptophan during pregnancy. Porphyromonas gingivalis (Pg), the "keystone" periodontal pathogen, induces immune and indoleamine 2,3-dioxygenase (IDO) activation. Thus, we hypothesized that larger gestational decreases in tryptophan and elevations in neopterin and kynurenine would occur in pregnant women with elevated IgG antibodies to Pg capsular (K) serotypes.

METHODS

Venous blood of 52 Hispanic pregnant women with a mean age (SD) of 31.8 (5.9) years was sampled once per trimester of pregnancy (V1, V2, V3), and plasma was obtained and stored. ELISAs were used to measure Pg capsular (K) serotype IgG serointensity (V1 only) and neopterin levels (V1-V3). Tryptophan and kynurenine (V1-V3) were measured with high-performance liquid chromatography. The participants having IgG serointensity for any of the seven Pg K serotypes in the highest quartile were defined as the "High PgK_IgG" group and those having IgG serointensity for all K serotypes in the lowest three quartiles were defined as the "Low PgK_IgG" group. Statistics included multivariable linear and nonparametric methods.

RESULTS

Significant decreases in plasma tryptophan levels and increases in neopterin during gestation were found in "High PgK_IgG" women but not in "Low PgK_IgG" women. Kynurenine changes were not significantly different between the two groups.

CONCLUSION

If replicated in larger studies and further characterized clinically, radiologically, and microbiologically, our results may potentially lead to novel interventional targets, as well as the development of more complete prognostic and predictive interactive biomarkers for adverse obstetrical outcomes and peripartum depression, and their prevention.

136 Sleep and Porphyromonas gingivalis K-Capsular IgG Serotypes: A Study in the Old Order Amish

Introduction

Sleep problems and periodontal disease have a bidirectional relationship and are independently linked with depression, dementia, and metabolic disease. Inadequate sleep can worsen inflammation, a hallmark of periodontal disease, and the activation of the immune system can alter sleep/wake cycles. A key player in periodontal disease is Porphyromonas gingivalis, a bacteria that can translocate to the brain and induce miRNA’s. Antibodies to P. gingivalis capsular virulence factors, K1-7, have been used to estimate P. gingivalis virulence. This study was conducted to explore cross-sectional associations between seropositivity of K serotypes of P. gingivalis and measures of self-reported impairment in sleep. If identified, these links would provide a rationale to initiate causality and mediation studies. We hypothesized that sleep impairment is positively associated with P. gingivalis K IgG serointensity.

Methods

880 Old Order Amish aged 44.8 (SD: 17.2 years); 360 men (40.91%), 520 women (59.09%) responded to an adapted Pittsburgh-Sleep-Quality-Index questionnaire. IgG serointensity to 7 K-capsular P. gingivalis serotypes were measured with ELISAs. We tested for the association of log-transformed serotype IgG intensity and positivity (successively defined as within the top 5% and 25% for each serotype) with sleep parameters (as binary and continuous variables) using linear and logistic regressions, adjusting for age and sex.

Results

We confirmed no hypothesized associations between any of the sleep problems on the PSQI and K serotype serointensity and seropositivity. Exploratory analysis returned a negative association of log-transformed K3 IgG with daytime sleepiness (p=0.01); however, this did not resist adjustment for multiple comparisons and was inconsistent with the direction of the hypothesis.

Conclusion

Strengths of the study include the reduced smoking prevalence in the Amish and the relatively homogenous lifestyle, reducing confounding. The results imply P. gingivalis serotypes are not associated with sleep disturbance. Limitations are self-reporting of sleep, cross-sectional approach and limited generalizability. Results do not support an association between P. gingivalis K serotypes and sleep-problems.

Support (if any)

MVM-CoRE

Performance of nucleocapsid and spike-based SARS-CoV-2 serologic assays

There is an urgent need for an accurate antibody test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have developed 3 ELISA methods, trimer spike IgA, trimer spike IgG, and nucleocapsid IgG, for detecting anti-SARS-CoV-2 antibodies. We evaluated their performance along with four commercial ELISAs, EDI™ Novel Coronavirus COVID-19 ELISA IgG and IgM, Euroimmun Anti-SARS-CoV-2 ELISA IgG and IgA, and one lateral flow assay, DPP® COVID-19 IgM/IgG System (Chembio). Both sensitivity and specificity were evaluated and the probable causes of false-positive reactions were determined. The assays were evaluated using 300 pre-epidemic samples and 100 PCR-confirmed COVID-19 samples. The sensitivities and specificities of the assays were as follows: 90%/100% (in-house trimer spike IgA), 90%/99.3% (in-house trimer spike IgG), 89%/98.3% (in-house nucleocapsid IgG), 73.7%/100% (EDI nucleocapsid IgM), 84.5%/95.1% (EDI nucleocapsid IgG), 95%/93.7% (Euroimmun S1 IgA), 82.8%/99.7% (Euroimmun S1 IgG), 82.0%/91.7% (Chembio nucleocapsid IgM), 92%/93.3% (Chembio nucleocapsid IgG). The presumed causes of false positive results from pre-epidemic samples in commercial and in-house assays were mixed. In some cases, assays lacked reproducibility. In other cases, reactivity was abrogated by competitive inhibition (spiking the sample with the same antigen that was used for coating ELISAs prior to performing the assay), suggesting positive reaction could be attributed to the presence of antibodies against these antigens. In other cases, reactivity was consistently detected but not abrogated by the spiking, suggesting positive reaction was not attributed to the presence of antibodies against these antigens. Overall, there was wide variability in assay performance using our samples, with in-house tests exhibiting the highest combined sensitivity and specificity. The causes of "false positivity" in pre-epidemic samples may be due to plasma antibodies apparently reacting with the corresponding antigen, or spurious reactivity may be directed against non-specific components in the assay system. Identification of these targets will be essential to improving assay performance.

Specificity and Performance of Nucleocapsid and Spike-based SARS-CoV-2 Serologic Assays

There is an urgent need for an accurate antibody test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this paper, we have developed 3 ELISA methods, trimer spike IgA, trimer spike IgG, and nucleocapsid IgG, for detecting anti-SARS-CoV-2 antibodies. We evaluated their performance in comparison with four commercial ELISAs, EDI™ Novel Coronavirus COVID-19 ELISA IgG and IgM, Euroimmun Anti-SARS-CoV-2 ELISA IgG and IgA, and one lateral flow assay, DPP® COVID-19 IgM/IgG System (Chembio). Both sensitivity and specificity were evaluated and the causes of false-positive reactions were determined. The assays were compared using 300 pre-epidemic samples and 100 PCR-confirmed COVID-19 samples. The sensitivities and specificities of the assays were as follows: 90%/100% (in-house trimer spike IgA), 90%/99.3% (in-house trimer spike IgG), 89%/98.3% (in-house nucleocapsid IgG), 73.7%/100% (EDI nucleocapsid IgM), 84.5%/95.1% (EDI nucleocapsid IgG), 95%/93.7% (Euroimmun S1 IgA), 82.8%/99.7% (Euroimmun S1 IgG), 82.0%/91.7% (Chembio nucleocapsid IgM), 92%/93.3% (Chembio nucleocapsid IgG). The presumed causes of positive signals from pre-epidemic samples in commercial and in-house assays were mixed. In some cases, positivity varied with assay repetition. In other cases, reactivity was abrogated by competitive inhibition (spiking the sample with analyte prior to performing the assay). In other cases, reactivity was consistently detected but not abrogated by analyte spiking. Overall, there was wide variability in assay performance using our samples, with in-house tests exhibiting the highest combined sensitivity and specificity. The causes of "false positivity" in pre-epidemic samples may be due to plasma antibodies apparently reacting with the analyte, or spurious reactivity may be directed against non-specific components in the assay system. Identification of these targets will be essential to improving assay performance.

Comparison of HIV oral fluid and plasma antibody results during early infection in a longitudinal Nigerian cohort

BACKGROUND

Oral fluid (OF) testing is a less-invasive alternative to blood-based testing for HIV. The performance of HIV OF tests has not been extensively evaluated in serially collected paired specimens from seroconverters.

OBJECTIVE

To compare paired OF and plasma test performance in a cohort of HIV-1 seroconverters from Nigeria.

STUDY DESIGN

Paired plasma and OF specimens from 14 seroconverters collected during 24 months of longitudinal follow up were included in the study. Plasma and OF were tested using Avioq HIV-1 Microelisa System, and first reactivity in plasma and OF specimens was compared. OF specimens reactive by Avioq were subsequently tested by OraSure HIV-1 Western blot. Genetic Systems HIV-1 Western blot was also performed on the corresponding plasma of the first 2 Avioq-OF positive time-points.

RESULTS

Of the 14 seroconverters, 5 (35.7%) had concordant results between plasma and OF for all time points tested, whereas 9 (64.3%) showed reactivity on plasma before OF specimens early in infection. The median delay between plasma and OF reactivity was 29 days (range: 0 day-20 months) (p<0.0039); the median overall delay for OF compared to RNA testing was 69.5 days. Delayed antibody response with OF was observed in both males and females regardless of viral load or HIV subtypes.

CONCLUSIONS

Results demonstrate decreased sensitivity of OF testing compared to blood-based testing with specimens obtained early after HIV infection. Programs that utilize OF testing in populations with increased risk of incident HIV infection should understand these limitations of OF testing.

Toxoplasma gondii immunoglobulin G antibodies and nonfatal suicidal self-directed violence

OBJECTIVE

The primary aim was to relate Toxoplasma gondii seropositivity and serointensity to scores on the self-rated Suicide Assessment Scale (SUAS-S). Another aim was to reevaluate the previously reported positive association between T gondii serointensity and a history of nonfatal suicidal self-directed violence.

METHOD

This cross-sectional, observational study compared T gondii serointensity and seropositivity in plasma from 54 adult suicide attempters (inpatients at Lund University Hospital, Lund, Sweden) and 30 adult control subjects (randomly selected from the municipal population register in Lund, Sweden) recruited between 2006 and 2010. The potential of patients and controls for self-directed violence was evaluated with the SUAS-S. Psychiatric diagnoses were made according to DSM-IV criteria. Plasma samples were tested for immunoglobulin G antibodies to T gondii, cytomegalovirus, and herpes simplex virus type 1. Data were analyzed using multivariable logistic regression to investigate the association between T gondii serointensity or seropositivity and a history of nonfatal suicidal self-directed violence; multivariable linear regression was used to explore the relationship between T gondii serointensity or seropositivity and the SUAS-S. Both regression models included sex, age, and body mass index as covariates.

RESULTS

Seropositivity of T gondii (adjusted odds ratio [OR] = 7.12; 95% CI, 1.66-30.6; P = .008) and serointensity of T gondii (adjusted OR = 2.01; 95% CI, 1.09-3.71; P = .03) were positively associated with a history of nonfatal suicidal self-directed violence. Seropositivity of T gondii was associated with higher SUAS-S scores, a relationship significant for the whole sample (P = .026), but not for suicide attempters only. No significant associations with other pathogens were identified.

CONCLUSIONS

These results are consistent with previous reports on the association between T gondii infection and nonfatal suicidal self-directed violence. Confirming these results in future large longitudinal studies and including suicide as an outcome may lead to novel individualized approaches in suicide prevention.

HIV counseling and testing and access-to-care needs of populations most-at-risk for HIV in Nigeria

Mobile HIV counseling and testing (mHCT) is an effective tool to access hard-to-reach most-at-risk populations (MARPs), but identifying which populations are not accessing services is often a challenge. We compared correlates of human immunodeficiency virus (HIV) infection and awareness of HIV care services among populations tested through mHCT and at testing facilities in Nigeria. Participants in a cross-sectional study completed a questionnaire and HCT between May 2005 and March 2010. Of 27,586 total participants, 26.7% had been previously tested for HIV; among mHCT clients, 14.7% had previously been tested. HIV prevalence ranged from 6.6% among those tested through a facility to 50.4% among brothel-based sex workers tested by mHCT. Among mHCT participants aged 18-24, women were nine times more likely to be infected than men. Women aged 18-24 were also less likely than their male counterparts to know that there were medicines available to treat HIV (63.2 vs. 68.1%; p=0.03). After controlling for gender, age, and other risk factors, those with current genital ulcer disease were more likely to be HIV-infected (OR(mHCT)=1.65, 1.31-2.09; OR(facility)=1.71, 1.37-2.14), while those previously tested were less likely to be HIV-infected (OR(mHCT)=0.75, 0.64-0.88; OR(facility)=0.27, 0.24-0.31). There is an urgent need to promote strategies to identify those who are HIV-infected within MARPs, particularly young women, and to educate and inform them about availability of HIV testing and care services. mHCT, ideally coupled with sexually transmitted infection management, may help to ensure that MARPs access HIV prevention support, and if infected, access care, and treatment.

Characterization of acute HIV-1 infection in high-risk Nigerian populations

BACKGROUND

Acute phase of human immunodeficiency virus (HIV) infection (AHI) may account for a significant proportion of HIV-1 transmission. We identified and characterized individuals in Nigeria with AHI.

METHODS

Individuals were tested using a combination of rapid HIV testing in mobile units and laboratory-based specimen pooling for nucleic acid amplification testing. Genome sequences were characterized. A linear segmented regression model was fit to serial viral load (VL) measurements to characterize early VL profiles.

RESULTS

Sixteen AHIs were identified from 28 655 persons screened. Specimens were genotyped: 7 (43.8%) were CRF02_AG, 6 (37.5%) were subtype G, 1 (6.3%) was CRF06_cpx, and 2 (12.5%) were unique recombinant forms. No antiretroviral resistance mutations were detected. The mean duration of high VL burden from peak to nadir was 76 days (95% confidence interval [CI], 58-93 days), and the mean rate of viremic control was -0.66 log(10) VL per month. The mean VL at set-point was 4.5 log(10) copies/mL (95% CI, 3.9-5.1 log(10) copies/mL).

CONCLUSIONS

This study is the first to characterize AHI among Nigerians identified as HIV infected before seroconversion who would be otherwise missed by conventional HIV testing. Infections by HIV subtypes in Nigeria exhibit long periods of high viral burden, which can contribute to increased transmissibility.

Determination of mean recency period for estimation of HIV type 1 Incidence with the BED-capture EIA in persons infected with diverse subtypes

The IgG capture BED enzyme immunoassay (BED-CEIA) was developed to detect recent HIV-1 infection for the estimation of HIV-1 incidence from cross-sectional specimens. The mean time interval between seroconversion and reaching a specified assay cutoff value [referred to here as the mean recency period (ω)], an important parameter for incidence estimation, is determined for some HIV-1 subtypes, but testing in more cohorts and new statistical methods suggest the need for a revised estimation of ω in different subtypes. A total of 2927 longitudinal specimens from 756 persons with incident HIV infections who had been enrolled in 17 cohort studies was tested by the BED-CEIA. The ω was determined using two statistical approaches: (1) linear mixed effects regression (ω(1)) and (2) a nonparametric survival method (ω(2)). Recency periods varied among individuals and by population. At an OD-n cutoff of 0.8, ω(1) was 176 days (95% CL 164-188 days) whereas ω(2) was 162 days (95% CL 152-172 days) when using a comparable subset of specimens (13 cohorts). When method 2 was applied to all available data (17 cohorts), ω(2) ranged from 127 days (Thai AE) to 236 days (subtypes AG, AD) with an overall ω(2) of 197 days (95% CL 173-220). About 70% of individuals reached a threshold OD-n of 0.8 by 197 days (mean ω) and 95% of people reached 0.8 OD-n by 480 days. The determination of ω with more data and new methodology suggests that ω of the BED-CEIA varies between different subtypes and/or populations. These estimates for ω may affect incidence estimates in various studies.

Experiences in establishing a PEPFAR-supported laboratory quality system in Nigeria

The need to accurately diagnose HIV-infected persons and monitor their immune status and sequelae from increased access to antiretroviral therapy dictated the establishment of a quality assurance (QA) system supported by dedicated personnel, financial resources, and a close monitoring system. Assessment of laboratories and personnel in Nigeria revealed the need for improved laboratory infrastructure and training, including on-site didactic and wet workshops and the institution of a tiered QA unit of laboratory regional officers, focal persons, and site monitors who provided guidance and continuous monitoring. Quarterly assessments and generated reports guided corrective actions. A sustainable quality laboratory system was developed for the first time in Nigeria with funding from the US President's Emergency Plan for AIDS Relief. With expansion from 7 to 34 comprehensive treatment sites, a tiered laboratory organizational structure with regional and site-based Nigerian quality control officers was developed. Measured improvements included reduction in deficiencies from 13% to 2%.

Molecular-based laboratory testing and monitoring for human immunodeficiency virus infections

Applications of laboratory testing for human immunodeficiency virus type 1 (HIV-1) infection have made significant impact on clinical care of HIV-infected patients globally. As these technologies continue to evolve and new technologies emerge, unique and highly sensitive nucleic acid-based testing methods will offer more and better means for us to guide physicians in anti-retroviral treatment strategies and clinical management of HIV infected patients. In this review we discuss a variety of current molecular-based methods that are available for HIV testing including diagnosis, monitoring disease progression, and detection of drug resistance to anti-retroviral therapy. Newer approaches that could be used in future HIV testing are also introduced.

Evaluation of youth preferences for rapid and innovative human immunodeficiency virus antibody tests

OBJECTIVE

To determine youth preferences for Food and Drug Administration (FDA)-approved and investigational human immunodeficiency virus (HIV) antibody collection and testing methods before and after subjects learned of test result response times; to determine how influential test result response times are on participants' preferences.

DESIGN

After health educators explained and demonstrated 6 different HIV antibody collection and testing strategies (3 saliva, 1 urine, and 2 fingerstick methods), participants completed a confidential survey about test method preference and tried the different testing methods. The participants had an opportunity to re-rank their test method preference after learning about each test's result response time.

SETTING

Health education sessions in both clinical and community settings.

PARTICIPANTS

Youths aged 12 to 24 years.

RESULTS

An oral collection device with a rapid saliva test was the most highly preferred test method. The preference for this method and the rapid response test methods via fingerstick procedures improved significantly after subjects learned of the rapid result response time, while the other methods were given significantly lower preference rankings after subjects learned of the longer result response times. Shifts in preference rankings were not related to sex, age, ethnic group, experience with HIV testing, or practice of risk behaviors.

CONCLUSIONS

Our research supports the use of noninvasive and rapid HIV testing methods with rapid response times for adolescents to assist in the early identification of HIV status, while offering HIV prevention opportunities and immediate linkage to care.

[Infection by the human immunodeficiency virus in the Republic of Djibouti: literature review and regional data]

The first evidence of HIV infection in Djibouti, East Africa, was found in the spring of 1986; the first case of acquired immunodeficiency syndrome (AIDS) was diagnosed in March 1988; and, as of the end of 1991, 104 cases of AIDS had been reported. HIV-1 infection was predominant. Previously published results of four serosurveys carried out in October 87, June 1998, February 1990, and from January 1991 to April 1991 among high risk groups are presented and compared. The subjects included street girls, bar hostesses, and male STD patients. HIV-1 infection was demonstrated in 1991 among 36.0% of street girls, 15.3% of bar hostesses and 10.4% of male STD patients. Three sera were positive for both HIV-1 and HIV-2 antibodies. The prevalence of HIV-1 infection among street girls in Djibouti did not increase between February 1990 and January 1991 while the prevalence of HIV infection among male STD patients rose almost five-fold during the same period. HIV prevalence in bar hostesses showed a steady growth. Epidemiology of HIV infection among prostitutes is complex as theses populations have a rapid turn-over. HIV prevalence data and predominance of Ethiopian nationality among prostitutes suggest importation of HIV from Ethiopia via the prostitutes and their clients. These results are reviewed and compared with data from Ethiopia and Somalia.

EBV strain variation: geographical distribution and relation to disease state

The strains of Epstein-Barr virus (EBV) were characterized in epithelial and lymphoid malignancies from geographic regions with high or low incidence. The predominant strains in nasopharyngeal carcinoma (NPC) from regions with elevated incidence were EBV type 1 in southeast Asia and Mediterranean Africa. In Alaskan Eskimos, a distinct variant of EBV type 2 was found in NPC and carcinoma of the parotid gland. This strain contained polymorphisms characteristic of the Asian EBV type 1. The strains prevalent in southeast Asia and Mediterranean Africa were also found in NPC which developed in caucasian Americans. These variants were not detected in lymphomas which developed in central Africa, Mediterranean Africa, or continental United States. These results suggest that distinct EBV strains predominate in geographic areas with elevated incidence of NPC. The detection of these distinct strains in epithelial tumors from areas of low incidence may reflect an epithelial cell tropism or pathogenicity.