Intrinsic factors behind long COVID: III. Persistence of SARS-CoV-2 and its components.

Considerable research has been done in investigating SARS-CoV-2 infection, its characteristics, and host immune response. However, debate is still ongoing over the emergence of post-acute sequelae of SARS-CoV-2 infection (PASC). A multitude of long-lasting symptoms have been reported several weeks after the primary acute SARS-CoV-2 infection that resemble several other viral infections. Thousands of research articles have described various post-COVID-19 conditions. Yet, the evidence around these ongoing health problems, the reasons behind them, and their molecular underpinnings are scarce. These persistent symptoms are also known as long COVID-19. The persistence of SARS-CoV-2 and/or its components in host tissues can lead to long COVID. For example, the presence of viral nucleocapsid protein and RNA was detected in the skin, appendix, and breast tissues of some long COVID patients. The persistence of viral RNA was reported in multiple anatomic sites, including non-respiratory tissues such as the adrenal gland, ocular tissue, small intestine, lymph nodes, myocardium, and sciatic nerve. Distinctive viral spike sequence variants were also found in non-respiratory tissues. Interestingly, prolonged detection of viral subgenomic RNA was observed across all tissues, sometimes in multiple tissues of the same patient, which likely reflects recent but defective viral replication. Moreover, the persistence of SARS-CoV-2 RNA was noticed throughout the brain at autopsy, as late as 230 days following symptom onset among unvaccinated patients who died of severe infection. Here, we review the persistence of SARS-CoV-2 and its components as an intrinsic factor behind long COVID. We also highlight the immunological consequences of this viral persistence.

SARS-CoV-2 nucleocapsid antigen in plasma of children hospitalized for COVID-19 or with incidental detection of SARS-CoV-2 infection.

In hospitalized children, SARS-CoV-2 infection can present as either a primary reason for admission (patients admitted for COVID-19) or an incidental finding during follow-up (patients admitted with COVID-19). We conducted a nested case-control study within a cohort of pediatric patients with confirmed SARS-CoV-2 infection, to investigate the concentration of plasma nucleocapsid antigen (N-Ag) in children admitted for COVID-19 or with COVID-19. While reverse transcriptase polymerase chain reaction Ct values in nasopharyngeal swab were similar between the two groups, children admitted for COVID-19 had a higher rate of detectable N-Ag (12/18 (60.7%) versus 6/18 (33.3%), p = 0.0455) and a higher concentration of N-Ag (medians: 19.51 g/mL vs. 1.08 pg/mL, p = 0.0105). In children hospitalized for COVID-19, the youngest had higher concentration of N-Ag (r = -0.74, p = 0.0004). We also observed a lower prevalence of detectable spike antibodies in children hospitalized for COVID-19 compared to those hospitalized for other medical reasons (3/15 [20%] vs. 13/16 [81.25%], respectively, p = < 0.0011), but similar rates of IgG nucleocapsid antibodies (5/14 [35.7%] vs. 6/17 [35.3%], respectively, p = 0.99). Our findings indicate that N-Ag is associated with COVID-19-related hospitalizations in pediatric patients, and less frequently detected in children tested positive for SARS-CoV-2 but hospitalized for another medical reason. Further studies are needed to confirm the value of N-Ag in identifying COVID-19 disease infections in which SARS-CoV-2 is the main pathogen responsible for symptoms.

Outpatient Cryptococcal Antigen Screening Is Associated With Favorable Baseline Characteristics and Improved Survival in Persons With Cryptococcal Meningitis in Uganda.

BACKGROUND: It is unknown whether persons with symptomatic cryptococcal meningitis detected during routine blood cryptococcal antigen (CrAg) screening have better survival than persons presenting with overt meningitis. METHODS: We prospectively enrolled Ugandans with HIV and cryptocococcal meningitis from December 2018 to December 2021. Participants were treated with amphotericin-based combination therapy. We compared outcomes between persons who were CrAg screened then referred to hospital with those presenting directly to the hospital with symptomatic meningitis. RESULTS: Among 489 participants with cryptococcal meningitis, 40% (194/489) received blood CrAg screening and were referred to hospital (median time to referral 2 days; interquartile range [IQR], 1-6). CrAg-screened persons referred to hospital had lower 14-day mortality than non-CrAg-screened persons who presented directly to hospital with symptomatic meningitis (12% vs 21%; hazard ratio, .51; 95% confidence interval, .32-.83; P = .006). Fewer CrAg-screened participants had altered mental status versus non-CrAg-screened participants (29% vs 41%; P = .03). CrAg-screened persons had lower quantitative cerebrospinal fluid (CSF) culture burden (median [IQR], 4570 [11-100 000] vs 26 900 [182-324 000] CFU/mL; P = .01) and lower CSF opening pressures (median [IQR], 190 [120-270] vs 225 [140-340] mmH2O; P = .004) compared with non-CrAg-screened persons. CONCLUSIONS: Survival from cryptococcal meningitis was higher in persons with prior CrAg screening than those without CrAg screening. Altered mental status was the most potent predictor for mortality in a multivariate model. We suggest that CrAg screening detects cryptococcal meningitis at an earlier stage, as evidenced by a favorable baseline risk profile and notably fewer persons with altered mental status.

Association of Antibody Immunity With Cryptococcal Antigenemia and Mortality in a South African Cohort With Advanced Human Immunodeficiency Virus Disease.

BACKGROUND: Asymptomatic cryptococcal antigenemia (positive blood cryptococcal antigen [CrAg]) is associated with increased mortality in individuals with human immunodeficiency virus (HIV) even after adjusting for CD4 count and despite receiving antifungal treatment. The association of antibody immunity with mortality in adults with HIV with cryptococcal antigenemia is unknown. METHODS: Cryptococcal capsular glucuronoxylomannan (GXM)- and naturally occurring ß-glucans (laminarin, curdlan)-binding antibodies were measured in blood samples of 197 South Africans with HIV who underwent CrAg screening and were followed up to 6 months. Associations between antibody titers, CrAg status, and all-cause mortality were sought using logistic and Cox regression, respectively. RESULTS: Compared with CrAg-negative individuals (n = 130), CrAg-positive individuals (n = 67) had significantly higher IgG1 (median, 6672; interquartile range [IQR], 4696-10 414 vs 5343, 3808-7722 µg/mL; P = .007), IgG2 (1467, 813-2607 vs 1036, 519-2012 µg/mL; P = .01), and GXM-IgG (1:170, 61-412 vs 1:117, 47-176; P = .0009) and lower curdlan-IgG (1:47, 11-133 vs 1:93, 40-206; P = .01) titers. GXM-IgG was associated directly with cryptococcal antigenemia adjusted for CD4 count and antiretroviral therapy use (odds ratio, 1.64; 95% confidence interval [CI], 1.21 to 2.22). Among CrAg-positive individuals, GXM-IgG was inversely associated with mortality at 6 months adjusted for CD4 count and tuberculosis (hazard ratio, 0.50; 95% CI, .33 to .77). CONCLUSIONS: The inverse association of GXM-IgG with mortality in CrAg-positive individuals suggests that GXM-IgG titer may have prognostic value in those individuals. Prospective longitudinal studies to investigate this hypothesis and identify mechanisms by which antibody may protect against mortality are warranted.

High sera levels of SARS-CoV-2 N antigen are associated with death in hospitalized COVID-19 patients.

The presence of free severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid-antigen in sera (N-antigenemia) has been shown in COVID-19 patients. However, the link between the quantitative levels of N-antigenemia and COVID-19 disease severity is not entirely understood. To assess the dynamics and clinical association of N-antigen sera levels with disease severity in COVID-19 patients, we analyzed data from patients included in the French COVID cohort, with at least one sera sample between January and September 2020. We assessed N-antigenemia levels and anti-N IgG titers, and patient outcomes was classified in two groups, survival or death. In samples collected within 8 days since symptom onset, we observed that deceased patients had a higher positivity rate (93% vs. 81%; p < 0.001) and higher median levels of predicted N-antigenemia (2500 vs. 1200 pg/mL; p < 0.001) than surviving patients. Predicted time to N-antigen clearance in sera was prolonged in deceased patients compared to survivors (23.3 vs 19.3 days; p < 0.0001). In a subset of patients with both sera and nasopharyngeal (NP) swabs, predicted time to N-antigen clearance in sera was prolonged in deceased patients (p < 0.001), whereas NP viral load clearance did not differ between the groups (p = 0.07). Our results demonstrate a strong relationship between N-antigenemia levels and COVID-19 severity on a prospective cohort.

High prevalence of central nervous system cryptococcosis using a fingerprick whole-blood lateral flow assay in individuals with neurological symptoms and advanced HIV disease in a Brazilian emergency department.

Timely diagnosis is key in managing central nervous system (CNS) cryptococcosis in people living with HIV/AIDS (PLWHA). There are few data on implementing fingerprick whole-blood cryptococcal antigen (CrAg) lateral flow assay (LFA) as the first test for diagnosing CNS cryptococcosis. We evaluated the prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood in a referral emergency department (ED) in São Paulo, Brazil. This was a prospective cohort study of consecutive adult PLWHA with advanced HIV disease and neurological symptoms. Fingerprick whole-blood CrAg LFA was performed at bedside. Seventy-four individuals were enrolled (median age = 40 years; males = 62%). Prevalence of CNS cryptococcosis was 17.6% (13/74); 95% confidence interval (CI), 9.4-30.0%, and prevalence of positive fingerprick whole-blood CrAg LFA was 25.7% (19/74); 95% CI, 15.5-40.1%. Among the six (8.1%) patients with positive fingerprick whole-blood CrAg LFA and negative CSF CrAg LFA, four (5.4%) had isolated asymptomatic cryptococcal antigenemia, one (1.3%) had symptomatic cryptococcal antigenemia, and one (1.3%) had cryptococcemia. Prevalence of CNS cryptococcosis and cryptococcal antigenemia using fingerprick whole-blood CrAg LFA was high. Point-of-care testing was important for diagnosing CNS cryptococcosis in an ED from a middle-income country.

Successful Treatment with Letermovir in a Heart Transplant Recipient with UL97 Mutation Ganciclovir-Resistant Cytomegalovirus Colitis and Viremia.

Currently available anti-cytomegalovirus (CMV) agents are sometimes poorly tolerated, owing to their side effects. Letermovir is a novel anti-CMV drug that is only approved for CMV prophylaxis in hematopoietic stem cell transplant recipients, with fewer side effects. We report the case of a heart transplant recipient with UL97 mutation (L595F) ganciclovir-resistant cytomegalovirus colitis who was successfully treated with off-label use of letermovir. In treating CMV infection or disease with letermovir, a transient rise or lag in the clearance of CMV-DNA polymerase chain reaction levels has been observed. Our case suggests that CMV-pp65 antigenemia can be an additional marker of treatment efficacy.

Nucleocapsid Antigenemia Is a Marker of Acute SARS-CoV-2 Infection.

Detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is essential for diagnosis, treatment, and infection control. Polymerase chain reaction (PCR) fails to distinguish acute from resolved infections, as RNA is frequently detected after infectiousness. We hypothesized that nucleocapsid in blood marks acute infection with the potential to enhance isolation and treatment strategies. In a retrospective serosurvey of inpatient and outpatient encounters, we categorized samples along an infection timeline using timing of SARS-CoV-2 testing and symptomatology. Among 1860 specimens from 1607 patients, the highest levels and frequency of antigenemia were observed in samples from acute SARS-CoV-2 infection. Antigenemia was higher in seronegative individuals and in those with severe disease. In our analysis, antigenemia exhibited 85.8% sensitivity and 98.6% specificity as a biomarker for acute coronavirus disease 2019 (COVID-19). Thus, antigenemia sensitively and specifically marks acute SARS-CoV-2 infection. Further study is warranted to determine whether antigenemia may aid individualized assessment of active COVID-19.

Measurement of Severe Acute Respiratory Syndrome Coronavirus 2 Antigens in Plasma of Pediatric Patients With Acute Coronavirus Disease 2019 or Multisystem Inflammatory Syndrome in Children Using an Ultrasensitive and Quantitative Immunoassay.

BACKGROUND: Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens in blood has high sensitivity in adults with acute coronavirus disease 2019 (COVID-19), but sensitivity in pediatric patients is unclear. Recent data suggest that persistent SARS-CoV-2 spike antigenemia may contribute to multisystem inflammatory syndrome in children (MIS-C). We quantified SARS-CoV-2 nucleocapsid (N) and spike (S) antigens in blood of pediatric patients with either acute COVID-19 or MIS-C using ultrasensitive immunoassays (Meso Scale Discovery). METHODS: Plasma was collected from inpatients (<21 years) enrolled across 15 hospitals in 15 US states. Acute COVID-19 patients (n = 36) had a range of disease severity and positive nasopharyngeal SARS-CoV-2 RT-PCR within 24 hours of blood collection. Patients with MIS-C (n = 53) met CDC criteria and tested positive for SARS-CoV-2 (RT-PCR or serology). Controls were patients pre-COVID-19 (n = 67) or within 24 hours of negative RT-PCR (n = 43). RESULTS: Specificities of N and S assays were 95-97% and 100%, respectively. In acute COVID-19 patients, N/S plasma assays had 89%/64% sensitivity; sensitivities in patients with concurrent nasopharyngeal swab cycle threshold (Ct) ≤35 were 93%/63%. Antigen concentrations ranged from 1.28-3844 pg/mL (N) and 1.65-1071 pg/mL (S) and correlated with disease severity. In MIS-C, antigens were detected in 3/53 (5.7%) samples (3 N-positive: 1.7, 1.9, 121.1 pg/mL; 1 S-positive: 2.3 pg/mL); the patient with highest N had positive nasopharyngeal RT-PCR (Ct 22.3) concurrent with blood draw. CONCLUSIONS: Ultrasensitive blood SARS-CoV-2 antigen measurement has high diagnostic yield in children with acute COVID-19. Antigens were undetectable in most MIS-C patients, suggesting that persistent antigenemia is not a common contributor to MIS-C pathogenesis.

SARS-CoV-2 N-antigenemia in critically ill adult COVID-19 patients: Frequency and association with inflammatory and tissue-damage biomarkers.

The current study aimed at characterizing the dynamics of SARS-CoV-2 nucleocapsid (N) antigenemia in a cohort of critically ill adult COVID-19 patients and assessing its potential association with plasma levels of biomarkers of clinical severity and mortality. Seventy-three consecutive critically ill COVID-19 patients (median age, 65 years) were recruited. Serial plasma (n = 340) specimens were collected. A lateral flow immunochromatography assay and reverse-transcription polymerase chain reaction (RT-PCR) were used for SARS-CoV-2 N protein detection and RNA quantitation and in plasma, respectively. Serum levels of inflammatory and tissue-damage biomarkers in paired specimens were measured. SARS-CoV-RNA N-antigenemia and viral RNAemia were documented in 40.1% and 35.6% of patients, respectively at a median of 9 days since symptoms onset. The level of agreement between the qualitative results returned by the N-antigenemia assay and plasma RT-PCR was moderate (k = 0.57; p < 0.0001). A trend towards higher SARS-CoV-2 RNA loads was seen in plasma specimens testing positive for N-antigenemia assay than in those yielding negative results (p = 0.083). SARS-CoV-2 RNA load in tracheal aspirates was significantly higher (p < 0.001) in the presence of concomitant N-antigenemia than in its absence. Significantly higher serum levels of ferritin, lactose dehydrogenase, C-reactive protein, and D-dimer were quantified in paired plasma SARS-CoV-2 N-positive specimens than in those testing negative. Occurrence of SARS-CoV-2 N-antigenemia was not associated with increased mortality in univariate logistic regression analysis (odds ratio, 1.29; 95% confidence interval, 0.49-3.34; p = 0.59). In conclusion, SARS-CoV-2 N-antigenemia detection is relatively common in ICU patients and appears to associate with increased serum levels of inflammation and tissue-damage markers. Whether this virological parameter may behave as a biomarker of poor clinical outcome awaits further investigations.

Receptor binding domain-IgG levels correlate with protection in residents facing SARS-CoV-2 B.1.1.7 outbreaks.

BACKGROUND: Limited information exists on nursing home (NH) residents regarding BNT162b2 vaccine efficacy in preventing SARS-CoV-2 and severe COVID-19, and its association with post-vaccine humoral response. METHODS: 396 residents from seven NHs suffering a SARS-CoV-2 B.1.1.7 (VOC-α) outbreak at least 14 days after a vaccine campaign were repeatedly tested using SARS-CoV-2 real-time reverse-transcriptase polymerase chain reaction on nasopharyngeal swab test (RT-qPCR). SARS-CoV-2 receptor-binding domain (RBD) of the S1 subunit (RBD-IgG) was measured in all residents. Nucleocapsid antigenemia (N-Ag) was measured in RT-qPCR-positive residents and serum neutralizing antibodies in vaccinated residents from one NH. RESULTS: The incidence of positive RT-qPCR was lower in residents vaccinated by two doses (72/317; 22.7%) vs one dose (10/31; 32.3%) or non-vaccinated residents (21/48; 43.7%; p < .01). COVID-19-induced deaths were observed in 5 of the 48 non-vaccinated residents (10.4%), in 2 of the 31 who had received one dose (6.4%), and in 3 of the 317 (0.9%) who had received two doses (p = .0007). Severe symptoms were more common in infected non-vaccinated residents (10/21; 47.6%) than in infected vaccinated residents (15/72; 21.0%; p = .002). Higher levels of RBD-IgG (n = 325) were associated with a lower SARS-CoV-2 incidence. No in vitro serum neutralization activity was found for RBD-IgG levels below 1050 AU/ml. RBD-IgG levels were inversely associated with N-Ag levels, found as a risk factor of severe COVID-19. CONCLUSIONS: Two BNT162b2 doses are associated with a 48% reduction of SARS-CoV-2 incidence and a 91.3% reduction of death risk in residents from NHs facing a VOC-α outbreak. Post-vaccine RBD-IgG levels correlate with BNT162b2 protection against SARS-CoV-2 B.1.1.7.

Investigation of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions and performance of a rapid diagnostic test for identifying asymptomatic malaria infection in northern Ethiopia, 2015.

BACKGROUND: Rapid diagnostic tests (RDTs) are widely used for malaria diagnosis of both symptomatic and asymptomatic infections. Although RDTs are a reliable and practical diagnostic tool, the sensitivity of histidine-rich protein 2 (HRP2)-based RDTs can be reduced if pfhrp2 or pfhrp3 (pfhrp2/3) gene deletions exist in the Plasmodium falciparum parasite population. This study evaluated dried blood spot (DBS) samples collected from a national household survey to investigate the presence of pfhrp2/3 deletions and the performance of the RDT used in the cross-sectional survey in a low transmission setting. METHODS: The 2015 Ethiopia Malaria Indicator Survey tested household members by RDT and collected DBS samples. DBS (n = 2648) from three regions in northern Ethiopia were tested by multiplex bead-based antigen detection assay after completion of the survey. The multiplex assay detected pan-Plasmodium lactate dehydrogenase (LDH), pAldolase, and HRP2 antigens in samples. Samples suspected for pfhrp2/3 gene deletions (pLDH and/or pAldolase positive but low or absent HRP2) were further investigated by molecular assays for gene deletions. Antigen results were also compared to each individual's RDT results. Dose-response logistic regression models were fit to estimate RDT level of detection (LOD) antigen concentrations at which 50, 75, 90, and 95% of the RDTs returned a positive result during this survey. RESULTS: Out of 2,648 samples assayed, 29 were positive for pLDH or pAldolase antigens but low or absent for HRP2 signal, and 15 of these samples (51.7%) were successfully genotyped for pfhrp2/3. Of these 15 P. falciparum infections, eight showed single deletions in pfhrp3, one showed a single pfhrp2 deletion, and six were pfhrp2/3 double-deletions. Six pfhrp2 deletions were observed in Tigray and one in Amhara. Twenty-five were positive for HRP2 by the survey RDT while the more sensitive bead assay detected 30 HRP2-positive samples. A lower concentration of HRP2 antigen generated a positive test result by RDT compared to pLDH (95% LOD: 16.9 ng/mL vs. 319.2 ng/mL, respectively). CONCLUSIONS: There is evidence of dual pfhrp2/3 gene deletions in the Tigray and Amhara regions of Ethiopia in 2015. As the prevalence of malaria was very low (< 2%), it is difficult to make strong conclusions on RDT performance, but these results challenge the utility of biomarkers in household surveys in very low transmission settings.

Risk factors for cytomegalovirus reactivation in patients with kidney disease under immunosuppressive therapy.

BACKGROUND: Cytomegalovirus (CMV) is a herpes virus that causes latent infections, and its reactivation due to immunosuppression can cause fatal complications. CMV reactivation is a complication frequently occurring in patients with kidney disease who require immunosuppressive therapy, and, therefore, this study retrospectively examined its risk factors. METHODS: Patients who received immunosuppressive therapy and underwent the CMV antigenemia test (CMV antigenemia: C7-HRP) for the treatment of primary nephritis (minimal change disease, membranous nephropathy, membranoproliferative glomerulonephritis, focal glomerulosclerosis, and IgA nephropathy) and anti-neutrophil cytoplasmic autoantibody (ANCA)-associated nephritis diagnosed at Saiseikai Kurihashi Hospital from January 2014 to December 2019 were recruited as study participants. Risk factors of CMV reactivation were examined using univariable and multivariable analyses. RESULTS: Among the 64 patients (36 men and 28 women; median age, 72 years) included, 34 had primary nephritis (20 minimal disease changes, 10 membranous nephropathy, 1 membranoproliferative glomerulonephritis, 1 focal glomerulosclerosis, and 2 IgA nephropathy) and 30 had ANCA-associated nephritis. Regarding glucocorticoid (GC), 43 patients received oral GC therapy, whereas 21 received GC pulse therapy. CMV reactivation participants showed significant differences in age, ANCA-associated nephritis, hemoglobin level, lymphocyte count, maximum GC dosage, and hemodialysis in univariable analysis. Multivariate analysis showed significantly lower lymphocyte counts in CMV-reactivated patients, but no significant difference in other factors. CONCLUSION: In patients with kidney disease, who require immunosuppressive therapy, CMV reactivation risk is high in patients with low lymphocyte count, and monitoring CMV during the treatment course could lead to early diagnosis and treatment of CMV disease.

Factors associated with cytomegalovirus antigenemia in patients with rheumatic disease: A retrospective study.

INTRODUCTION: This study aimed to examine the factors associated with cytomegalovirus (CMV) antigenemia and the time of onset of CMV antigenemia among patients with rheumatic diseases. METHODS: A single-center, retrospective, observational study was conducted in our institution from January 2009 to December 2017. This study included patients with rheumatic diseases who had at least one CMV antigen measurement. Multivariate analysis and receiver operating characteristic analysis was performed. RESULTS: A total of 249 patients underwent CMV antigenemia assay, and 84 (33.7%) patients tested positive. When the association between CMV antigenemia and possible associated factors was investigated, multivariate analysis showed that daily steroid dose increased the odds of having CMV [odds ratio 16.25, 95% confidence interval (CI), 5.360-49.253]. In this study, the cutoff value of daily steroid dose found in this study (0.45 mg/kg/day) was reasonable in clinical practice, and the area under the curve of the steroid dose was 0.838 [95% CI 0.781-0.882], which was the largest of the known indicators. Moreover, the median time from the start of immunosuppressive therapy to the onset of CMV antigenemia was 30 (interquartile range, 21-44) days, and most of the daily steroid users (85.7%) developed CMV antigenemia within 60 days. CONCLUSIONS: The daily steroid dose is the most important factor associated with CMV antigenemia. Therefore, monitoring and treatment strategies based on the steroid dose, especially in the initial 2 months, are important.

Antibody and Antigen Prevalence as Indicators of Ongoing Transmission or Elimination of Visceral Leishmaniasis: A Modeling Study.

BACKGROUND: Control of visceral leishmaniasis (VL) on the Indian subcontinent has been highly successful. Control efforts such as indoor residual spraying and active case detection will be scaled down or even halted over the coming years. We explored how after scale-down, potential recurrence of VL cases may be predicted based on population-based surveys of antibody or antigenemia prevalence. METHODS: Using a stochastic age-structured transmission model of VL, we predicted trends in case incidence and biomarker prevalence over time after scaling down control efforts when the target of 3 successive years without VL cases has been achieved. Next, we correlated biomarker prevalence with the occurrence of new VL cases within 10 years of scale-down. RESULTS: Occurrence of at least 1 new VL case in a population of 10 000 was highly correlated with the seroprevalence and antigenemia prevalence at the moment of scale-down, or 1 or 2 years afterward. Receiver operating characteristic curves indicated that biomarker prevalence in adults provided the most predictive information, and seroprevalence was a more informative predictor of new VL cases than antigenemia prevalence. Thresholds for biomarker prevalence to predict occurrence of new VL cases with high certainty were robust to variation in precontrol endemicity. CONCLUSIONS: The risk of recrudescence of VL after scaling down control efforts can be monitored and mitigated by means of population-based surveys. Our findings highlight that rapid point-of-care diagnostic tools to assess (preferably) seroprevalence or (otherwise) antigenemia in the general population could be a key ingredient of sustainable VL control.

Association of semi-quantitative cryptococcal antigen results in plasma with subclinical cryptococcal meningitis and mortality among patients with advanced HIV disease.

Blood cryptococcal antigen (CrAg) titers >160 are associated with concurrent subclinical cryptococcal meningitis (CM). When lumbar puncture (LP) is not immediately available in a CrAg screening program, semi-quantitative CrAg assays may provide risk stratification for CM. Two semi-quantitative assays (SQ [Immuno-Mycologics, Norman, OK, USA] and CryptoPS [Biosynex, Strasbourg, France]) were evaluated against a qualitative lateral flow assay (LFA) using 194 plasma samples from a cohort of HIV-seropositive individuals with CD4 counts <100 cells/µl. We compared SQ and CryptoPS results to titers for LFA-positive samples. Among patients with LP, we examined the association between semi-quantitative CrAg results and CM. We used a Cox proportional hazards model to determine the association between SQ score and mortality. Of 194 participants, 60 (31%) had positive LFA results, of whom 41 (68%) had a titer of ≤160 and 19 (32%) a titer >160. Fifty individuals with antigenemia had an LP; a clinically useful SQ score that identified all ten cases of subclinical CM was ≥3 (100% sensitivity, 55% specificity). Patients with an SQ score of 3 or 4 also had a 2.2-fold increased adjusted hazards of 6-month mortality (95% CI: 0.79-6.34; p = 0.13) versus those with score of <3. Nine of ten patients with subclinical CM had a strong-positive CryptoPS result versus 10/40 without subclinical CM (p < 0.001). Semi-quantitative assays offered a sensitive though not specific means of gauging the risk of concurrent CM in this patient population. LAY SUMMARY: We evaluated two single-step laboratory tests that can quantify the amount of cryptococcal antigen in plasma of patients with advanced HIV disease and could thus gauge the risk of concurrent cryptococcal meningitis and subsequent mortality. These tests are not a substitute for a lumbar puncture.

Association between the kinetics of cytomegalovirus reactivation in terms of the area under the curve of cytomegalovirus antigenemia and non-relapse mortality after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: We assessed the kinetics of cytomegalovirus (CMV) reactivation using the area under the curve (AUC), which simultaneously reflects both the viral load at each time point and the duration of CMV antigenemia (CMV-AG). METHODS: We performed a single-institute retrospective analysis in patients who received allogeneic hematopoietic stem cell transplantation (HSCT) between 2007 and 2017 and survived more than 100 days after HSCT. The AUC of CMV-AG (CMV-AUC) was calculated by a trapezoidal method using the number of CMV-AG tested by the C10/C11 method after logarithmic transformation, and plotted weekly up to day 100. RESULTS: CMV reactivation was observed in 195 cases and the median CMV-AUC for CMV-reactivated patients was 8.7 (range 0.5-30.7). Older age, corticosteroid administration, CMV-seropositive transplant recipients, HSCT from an unrelated donor, and underlying diseases were independent predictive factors for higher CMV-AUC. Higher CMV-AUC was associated with poor overall survival (OS) with borderline significance in a univariate analysis (p = .07), but was not significant in a multivariate analysis. Older age, high-risk disease status, and female gender were identified as significant factors associated with poor OS in this study. On the other hand, CMV-AUC (hazard ratio: no reactivation reference, low 0.98, high 2.49, p < .01), older age, HCT-CI ≥3, and corticosteroid administration were identified as significant factors associated with increased incidence of non-relapse mortality (NRM). CONCLUSIONS: The kinetics of CMV reactivation in terms of CMV-AUC reflect both the severity and duration of CMV reactivation. High CMV-AUC was associated with an increased incidence of NRM in survivors over 100 days.

Development of cytomegalovirus retinitis after negative conversion of cytomegalovirus antigenemia due to systemic antiviral therapy.

PURPOSE: Cytomegalovirus (CMV) antigenemia assays have been widely used as adjunct tests to diagnose tissue invasive CMV diseases, including cytomegalovirus retinitis (CMVR). In this study, we examined CMVR cases to assess the presence of CMV in sera and aqueous humor and antiviral therapy received prior to the onset of CMVR. METHODS: A total of 37 eyes from 26 different cases of CMVR in patients who visited Hokkaido University Hospital between 2007 and 2015 were enrolled. The diagnosis of CMVR was established based on characteristic ophthalmoscopic findings and the presence of local and/or systemic CMV infection. Among the 26 cases, 3 cases (12%) were HIV-positive, while the other 23 cases (88%) were HIV-negative. The records of clinical and laboratory results were reviewed from clinical charts retrospectively. RESULTS: CMV antigenemia was positive at the onset of CMVR in 14 cases (53.8%) and negative in the other 12 cases. In 9 cases among the antigenemia-negative cases (75.0%), the antigenemia had been previously positive and had turned negative before the onset of CMVR. In 12 of the 14 antigenemia-positive cases (85.7%) and in 8 of the 9 antigenemia-negative cases (88.9%) that were previously positive, systemic antiviral therapies had never been used or had been used before but had been discontinued prior to the onset of CMVR. CONCLUSION: Even if viremia turns negative, the risk of developing CMVR exists for more than several weeks after the completion of systemic therapy.

Cryptococcal Antigenemia in Human Immunodeficiency Virus Antiretroviral Therapy-Experienced Ugandans With Virologic Failure.

BACKGROUND: Detectable serum or plasma cryptococcal antigen (CrAg) precedes symptomatic cryptococcal meningitis. The World Health Organization recommends CrAg screening for human immunodeficiency virus-positive persons with CD4 count <100 cells/µL initiating antiretroviral therapy (ART). However, an increasing proportion of patients with cryptococcosis are now ART experienced. Whether CrAg screening is cost-effective in those with virologic failure is unknown. METHODS: We retrospectively performed nationwide plasma CrAg testing among ART-experienced Ugandan adults with virologic failure (≥1000 copies/mL) using leftover plasma after viral load testing during September 2017-January 2018. For those who were CrAg positive, we obtained ART history, meningitis occurrence, and 6-month survival via medical records review. RESULTS: Among 1186 subjects with virologic failure, 35 (3.0%) were CrAg positive with median ART duration of 41 months (interquartile range, 10-84 months). Among 25 subjects with 6-month outcomes, 16 (64%) survived, 7 (28%) died, and 2 (8%) were lost. One survivor had suffered cryptococcal meningitis 2 years prior. Two others developed cryptococcal meningitis and survived. Five survivors were known to have received fluconazole. Thus, meningitis-free survival at 6 months was 61% (14/23). Overall, 91% (32/35) of CrAg-positive persons had viral load ≥5000 copies/mL compared with 64% (735/1151) of CrAg-negative persons (odds ratio, 6.0 [95% confidence interval, 1.8-19.8]; P = .001). CrAg prevalence was 4.2% (32/768) among those with viral loads ≥5000 copies/mL and 0.7% (3/419) among those with viral loads <5000 copies/mL. CONCLUSIONS: In addition to the CD4 threshold of <100 cells/µL, reflexive CrAg screening should be considered in persons failing ART in Uganda with viral loads ≥5000 copies/mL.

Evaluation of Serum Cryptococcal Antigen Testing Using Two Novel Semiquantitative Lateral Flow Assays in Persons with Cryptococcal Antigenemia.

Early cryptococcal disease can be detected via circulating antigen in blood before fulminant meningitis develops, when early antifungal therapy improves survival. Two semiquantitative cryptococcal antigen (CrAg) lateral flow assays (LFAs) have been developed, but their diagnostic performance has not been defined. Cryopreserved serum samples from HIV-infected Ugandans obtained as part of a prospective CrAg-screening cohort were tested in duplicate for CrAg by the CrAgSQ (IMMY) and CryptoPS (Biosynex) lateral flow assays. Case-controlled diagnostic performance was measured using the FDA-approved CrAg LFA (IMMY) as a reference standard via McNemar's test. Of 99 serum samples tested, 57 were CrAg positive (CrAg+) by the CrAg LFA reference standard. By CrAgSQ, 57 were read as positive, with 98% sensitivity (56/57; 95% confidence interval [CI], 0.91 to 0.99) and 98% specificity (41/42; 95% CI, 0.88 to 0.99) (McNemar's, P = 0.99). The sample with a false-negative result by CrAgSQ (n = 1) had a titer of <1:5, while the sample with a false-positive result (n = 1) yielded a 1+ result. By CryptoPS, 52 samples were read as positive, with 88% sensitivity (50/57; 95% CI, 0.76 to 0.95) and 95% specificity (40/42; 95% CI, 0.84 to 0.99) (McNemar's, P = 0.18). The CryptoPS false-negative results included samples with titers of <1:5 (n = 1), 1:5 (n = 5), and 1:20 (n = 1), while samples with false-positive results by CryptoPS (n = 2) yielded Positive results. The CryptoPS assay missed 35% (7/20) of samples with CrAg LFA titers of ≤1:20. The new semiquantitative CrAg LFAs allow rapid estimation of titer levels in easy-to-perform platforms. The CrAgSQ demonstrated better qualitative sensitivity and specificity than the CryptoPS compared to the reference standard. The exact grading of the CrAgSQ results has some subjectivity, with interreader variability; however, qualitative reads were generally concordant for both assays.