Efficacy of Bortezomib for Treating Anti-Interferon-Gamma Autoantibody-Associated Adult-Onset Immunodeficiency Syndrome.

BACKGROUND: Currently, there is no effective treatment for adult-onset immunodeficiency (AOID) syndrome with anti-interferon-gamma autoantibodies (anti-IFN-γ-auto-Abs). This study aimed to investigate the effectiveness of bortezomib (BTZ) for decreasing anti-IFN-γ-auto-Abs. METHODS: A pre- and post-intervention study was conducted from February 2017 through June 2019 at Siriraj Hospital (Bangkok, Thailand). Five patients were invited to receive once-weekly BTZ (1.3 mg/m2 body surface area) subcutaneously for 8 weeks followed by oral cyclophosphamide (1 mg/kg/d) for 4 months. The primary outcomes were the difference in antibody level at 8 and 48 weeks compared with baseline and the incidence of serious adverse events (AEs). The secondary outcome was the occurrence of opportunistic infections (OIs) during the 72 weeks after starting BTZ. RESULTS: The median patient age was 46 years (range, 34-53). All patients had 3-5 OIs prior to enrollment. All patients were receiving antimycobacterial agents for treatment of nontuberculous mycobacterial infection at enrollment. There was no significant difference in the mean optical density of auto-Abs at 8 weeks (3.73 ± 0.72) or 48 weeks (3.74 ± 0.53) compared with baseline (3.84 ± 0.49; P = .336 and P = .555, respectively). However, after serum dilution, the antibody titer nonsignificantly decreased 8-16 weeks after BTZ initiation (P = .345). Ten OIs were observed 24-72 weeks after BTZ initiation. CONCLUSIONS: Treatment with BTZ followed by cyclophosphamide yielded no significant decrease in antibody titer levels, and 10 OIs were observed during 24-72 weeks of BTZ treatment. No serious AEs were observed. Combining rituximab with BTZ is likely necessary to prevent generation of new autoantibody-producing plasma cells. Clinical Trials Registration. NCT03103555.

Extrapulmonary Pneumocystis jirovecii infection in an advanced HIV-infected patient: A case report and literature review.

BACKGROUND: Pneumocystis jirovecii infection is the most common opportunistic infection that causes pneumonia in human immunodeficiency virus (HIV)-infected patients; however, extrapulmonary P. jirovecii infection is extremely rare after the use of antiretroviral therapy. Here, we present the second reported case of paraspinal mass caused by P. jirovecii infection in an advanced HIV-infected patient. CASE PRESENTATION: A 45-year-old woman presented with dyspnea on exertion, and significant weight loss within the preceding 4 months. Initial complete blood count (CBC) findings revealed pancytopenia with a hemoglobin (Hb) level of 8.9 g/dL, a white blood cell (WBC) count of 2180 cells/mm3 with 68% neutrophils, and a platelet count of 106,000 cells/mm3. Anti-HIV was positive with an absolute cluster of differentiation 4 (CD4) count of 16 cells/ mm3. A computed tomography scan of the chest revealed an enhancing soft tissue mass-like lesion at the right paravertebral region (T5-T10 level) and a thick-walled cavity lesion at the left lower lung. A CT-guided biopsy of the paravertebral mass was performed and histopathology revealed granulomatous inflammation consisting of dense aggregates of epithelioid cells and macrophages, and scattered foci of pink foamy to granular materials amidst the granulomatous inflammation. Gomori methenamine silver (GMS) staining revealed thin cystic-like structures (ascus) that were observed to be morphologically consistent with P. jirovecii. Molecular identification and DNA sequencing from the paraspinal mass was 100% identical to P. Jirovecii. The patient was successfully treated with oral trimethoprim-sulfamethoxazole for 3 weeks and antiretroviral therapy (ART) with tenofovir (TDF), lamivudine (3TC), and dolutegravir (DTG). A follow-up CT scan of the chest at 2 months after treatment showed a decrease in sizes of both the paravertebral mass and the cavitary lung lesion. CONCLUSIONS: Extrapulmonary pneumocystosis (EPCP) has become an extremely rare condition in HIV-infected patients after the widespread use of ART. EPCP should be considered in ART-naive HIV-infected patients suspected of having or diagnosed with Pneumocystis jirovecii pneumonia who present with atypical symptoms and/or signs. Histopathologic examination with GMS staining of affected tissue is necessary for the diagnosis of EPCP.

The immunogenicity and reactogenicity of four COVID-19 booster vaccinations against SARS-CoV-2 variants following CoronaVac or ChAdOx1 nCoV-19 primary series.

BACKGROUND: The appropriate COVID-19 booster vaccine following inactivated or adenoviral vector COVID-19 vaccination is unclear. OBJECTIVE: To investigate the immunogenicity of four COVID-19 booster vaccines. METHODS: We prospectively enrolled healthy adults who received a two-dose CoronaVac or ChAdOx1 8-12 weeks earlier and allocated them to receive one of the following booster vaccine: inactivated (BBIBP-CorV), ChAdOx1 or mRNA (BNT162b2 at full [30 µg] and half [15 µg] dose) vaccines. We determined the reactogenicity and the humoral (anti-receptor binding domain IgG (anti-RBD-IgG), neutralizing antibodies (nAb) against Delta, Beta and Omicron variants) and cellular immunity measuring by interferon gamma (IFN-γ) responses post-booster. AR patients. RESULTS: Among the 352 participants (179 CoronaVac and 173 ChAdOx1 participants), 285 (81%) were female, and median age was 39 (IQR: 31-47) years. Two weeks post-booster, both 30 µg- and 15 µg- BNT162b2 induced the highest anti-RBD IgG concentration (BAU/mL); Coronavac-prime: 30 µg-BNT162b2, 5152.2 (95%CI 4491.7-5909.8); 15 µg-BNT162b2, 3981.1 (3397.2-4665.4); ChAdOx1, 1358.0 (1141.8-1615.1); BBIBP-CorV, 154.6 (92.11-259.47); ChAdOx1-prime: 30 µg-BNT162b2, 2363.8 (2005.6-2786.1; 15 µg-BNT162b2, 1961.9 (1624.6-2369.1); ChAdOx1, 246.4 (199.6-304.2); BBIBP-CorV, 128.1 (93.5-175.4). Similarly, both 30 µg- and 15 µg- BNT162b2 boosting induced the highest nAb titers against Beta, Delta and Omicron BA.1 variants and highest T-cell response at 2 weeks after boosting. While all BNT162b2 or heterologous ChAdOx1-boosted participants had nAb against Omicron, these were < 50% for BBIBP-CorV and 75% for homologous ChAdOx1-boosted participants. There was significant decrease in nAb ( > 4-fold) at 16-20 weeks post booster for all groups. CONCLUSIONS: Heterologous boosting with BNT162b2 following CoronaVac or ChAdOx1 primary series is most immunogenic. Additional studies are needed to verify the clinical efficacy and persistence of immunity following half-dose BNT162b2.

Understanding the Potential Impact of Different Drug Properties on Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission and Disease Burden: A Modelling Analysis.

BACKGROUND: The public health impact of the coronavirus disease 2019 (COVID-19) pandemic has motivated a rapid search for potential therapeutics, with some key successes. However, the potential impact of different treatments, and consequently research and procurement priorities, have not been clear. METHODS: Using a mathematical model of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission, COVID-19 disease and clinical care, we explore the public-health impact of different potential therapeutics, under a range of scenarios varying healthcare capacity, epidemic trajectories; and drug efficacy in the absence of supportive care. RESULTS: The impact of drugs like dexamethasone (delivered to the most critically-ill in hospital and whose therapeutic benefit is expected to depend on the availability of supportive care such as oxygen and mechanical ventilation) is likely to be limited in settings where healthcare capacity is lowest or where uncontrolled epidemics result in hospitals being overwhelmed. As such, it may avert 22% of deaths in high-income countries but only 8% in low-income countries (assuming R = 1.35). Therapeutics for different patient populations (those not in hospital, early in the course of infection) and types of benefit (reducing disease severity or infectiousness, preventing hospitalization) could have much greater benefits, particularly in resource-poor settings facing large epidemics. CONCLUSIONS: Advances in the treatment of COVID-19 to date have been focused on hospitalized-patients and predicated on an assumption of adequate access to supportive care. Therapeutics delivered earlier in the course of infection that reduce the need for healthcare or reduce infectiousness could have significant impact, and research into their efficacy and means of delivery should be a priority.

Binding and neutralizing antibody levels and vaccine efficacy/effectiveness compared between heterologous and homologous primary series COVID-19 vaccination: A systematic review and meta-analysis.

BACKGROUND: The data on the immunogenicity and efficacy of heterologous primary series COVID-19 vaccination are still limited. OBJECTIVE: To investigate the immunogenicity and vaccine efficacy/effectiveness compared between heterologous and homologous primary series COVID-19 vaccination. METHODS: We conducted a multi-source search for randomized controlled trials, prospective cohort, and case-control studies that investigated the immunogenicity or vaccine efficacy/effectiveness (VE) of heterologous primary series vaccination. Six online databases were searched from inception to June 2022. The primary outcome was the levels of binding antibodies and neutralizing antibodies (NAbs), and the secondary outcomes were VE against COVID-19 infection, hospitalization, and death. RESULTS: Among the 28 included studies, 21 and 7 were included to investigate immunogenicity and VE outcome, respectively. Heterologous CoronaVac (CV)/ChAdOx1 (ChAd) induced higher anti-RBD IgG and NAbs against wild type and delta variants compared to homologous CV or ChAd. However, risk of documented infection of CV/ChAd was similar to homologous CV, but higher than homologous ChAd (odds ratio: 2.56, 95% CI: 1.02-6.37). Heterologous ChAd/BNT162b2 (BNT) elicited a higher anti-spike level than homologous ChAd or BNT, and induced a higher NAbs level against delta variants compared to homologous ChAd. The VE of ChAd/BNT and homologous ChAd or BNT against hospitalization were similar. CONCLUSIONS: Heterologous CV/ChAd induced higher binding and neutralizing antibody levels than homologous CV or ChAd; and, ChAd/BNT induced higher binding and neutralizing antibody levels than homologous ChAd. However, CV/ChAd demonstrated increased risk of infection compared to homologous ChAd. Therefore, immunogenicity findings and real-world vaccine efficacy/effectiveness should be integrated in clinical practice.

Ivermectin Accelerates Circulating Nonstructural Protein 1 (NS1) Clearance in Adult Dengue Patients: A Combined Phase 2/3 Randomized Double-blinded Placebo Controlled Trial.

BACKGROUND: Dengue is the most significant mosquito-borne viral disease; there are no specific therapeutics. The antiparasitic drug ivermectin efficiently inhibits the replication of all 4 dengue virus serotypes in vitro. METHODS: We conducted 2 consecutive randomized, double-blind, placebo-controlled trials in adult dengue patients to evaluate safety and virological and clinical efficacies of ivermectin. After a phase 2 trial with 2 or 3 days of 1 daily dose of 400 µg/kg ivermectin, we continued with a phase 3, placebo-controlled trial with 3 days of 400 µg/kg ivermectin. RESULTS: The phase 2 trial showed a trend in reduction of plasma nonstructural protein 1 (NS1) clearance time in the 3-day ivermectin group compared with placebo. Combining phase 2 and 3 trials, 203 patients were included in the intention to treat analysis (100 and 103 patients receiving ivermectin and placebo, respectively). Dengue hemorrhagic fever occurred in 24 (24.0%) of ivermectin-treated patients and 32 (31.1%) patients receiving placebo (P = .260). The median (95% confidence interval [CI]) clearance time of NS1 antigenemia was shorter in the ivermectin group (71.5 [95% CI 59.9-84.0] hours vs 95.8 [95% CI 83.9-120.0] hours, P = .014). At discharge, 72.0% and 47.6% of patients in the ivermectin and placebo groups, respectively had undetectable plasma NS1 (P = .001). There were no differences in the viremia clearance time and incidence of adverse events between the 2 groups. CONCLUSIONS: A 3-day 1 daily dose of 400 µg/kg oral ivermectin was safe and accelerated NS1 antigenemia clearance in dengue patients. However, clinical efficacy of ivermectin was not observed at this dosage regimen.

Epidemiology, clinical characteristics, and treatment outcomes of patients with COVID-19 at Thailand's university-based referral hospital.

BACKGROUND: The epidemiology and outcomes of COVID-19 patients in Thailand are scarce. METHODS: This retrospective cohort study included adult hospitalized patients who were diagnosed with COVID-19 at Siriraj Hospital during February 2020 to April 2020. RESULTS: The prevalence of COVID-19 was 7.5% (107 COVID-19 patients) among 1409 patients who underwent RT-PCR for SARS-CoV-2 detection at our hospital during the outbreak period. Patients with COVID-19 presented with symptoms in 94.4%. Among the 104 patients who were treated with antiviral medications, 78 (75%) received 2-drug regimen (lopinavir/ritonavir or darunavir/ritonavir plus chloroquine or hydroxychloroquine), and 26 (25%) received a 3-drug regimen with favipiravir added to the 2-drug regimen. Disease progression was observed in 18 patients (16.8%). All patients with COVID-19 were discharged alive. CONCLUSIONS: The prevalence of COVID-19 was 7.5% among patients who underwent RT-PCR testing, and 10% among those having risk factors for COVID-19 acquisition. Combination antiviral therapies for COVID-19 patients were well-tolerated and produced a favorable outcome.

Rapid SARS-CoV-2 antigen detection assay in comparison with real-time RT-PCR assay for laboratory diagnosis of COVID-19 in Thailand.

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic continues to spread across the world. Hence, there is an urgent need for rapid, simple, and accurate tests to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Performance characteristics of the rapid SARS-CoV-2 antigen detection test should be evaluated and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. METHODS: The rapid SARS-CoV-2 antigen detection test, Standard™ Q COVID-19 Ag kit (SD Biosensor®, Republic of Korea), was compared with the real-time RT-PCR test, Allplex™ 2019-nCoV Assay (Seegene®, Korea) for detection of SARS-CoV-2 in respiratory specimens. Four hundred fifty-four respiratory samples (mainly nasopharyngeal and throat swabs) were obtained from COVID-19 suspected cases and contact individuals, including pre-operative patients at Siriraj Hospital, Bangkok, Thailand during March-May 2020. RESULTS: Of 454 respiratory samples, 60 (13.2%) were positive, and 394 (86.8%) were negative for SARS-CoV-2 RNA by real-time RT-PCR assay. The duration from onset to laboratory test in COVID-19 suspected cases and contact individuals ranged from 0 to 14 days with a median of 3 days. The rapid SARS-CoV-2 antigen detection test's sensitivity and specificity were 98.33% (95% CI, 91.06-99.96%) and 98.73% (95% CI, 97.06-99.59%), respectively. One false negative test result was from a sample with a high real-time RT-PCR cycle threshold (Ct), while five false positive test results were from specimens of pre-operative patients. CONCLUSIONS: The rapid assay for SARS-CoV-2 antigen detection showed comparable sensitivity and specificity with the real-time RT-PCR assay. Thus, there is a potential use of this rapid and simple SARS-CoV-2 antigen detection test as a screening assay.

Continuous ambulatory peritoneal dialysis-associated Histoplasma capsulatum peritonitis: a case report and literature review.

BACKGROUND: Fungal peritonitis (FP) is a rare complication of peritoneal dialysis. We herein describe the second case in Asia of Histoplasma capsulatum peritonitis associated with continuous ambulatory peritoneal dialysis (CAPD). CASE PRESENTATION: An 85-year-old woman with end-stage renal disease (ESRD) who had been on CAPD for 3 years and who had a history of 3 prior episodes of peritonitis presented with intermittent abdominal pain for 2 weeks and high-grade fever for 3 days. Elevated white blood cell (WBC) count and rare small oval budding yeasts were found in her peritoneal dialysis (PD) fluid. From this fluid, a white mold colony was observed macroscopically after 7 days of incubation, and numerous large, round with rough-walled tuberculate macroconidia along with small smooth-walled microconidia were observed microscopically upon tease slide preparation, which is consistent with H. capsulatum. The peritoneal dialysis (PD) catheter was then removed, and it also grew H. capsulatum after 20 days of incubation. The patient was switched from CAPD to hemodialysis. The patient was successfully treated with intravenous amphotericin B deoxycholate (AmBD) for 2 weeks, followed by oral itraconazole for 6 months with satisfactory result. The patient remains on hemodialysis and continues to be clinically stable. CONCLUSION: H. capsulatum peritonitis is an extremely rare condition that is associated with high morbidity and mortality. Demonstration of small yeasts upon staining of PD fluid, and isolation of slow growing mold in the culture of clinical specimen should provide important clues for diagnosis of H. capsulatum peritonitis. Prompt removal of the PD catheter and empirical treatment with amphotericin B or itraconazole is recommended until the culture results are known.

Gastrointestinal mucormycosis due to Rhizopus microsporus following Streptococcus pyogenes toxic shock syndrome in an HIV patient: a case report.

BACKGROUND: Gastrointestinal (GI) mucormycosis is a rare and often deadly form of mucormycosis. Delayed diagnosis can lead to an increased risk of death. Here, we report a case of GI mucormycosis following streptococcal toxic shock syndrome in a virologically suppressed HIV-infected patient. CASE PRESENTATION: A 25-year-old Thai woman with a well-controlled HIV infection and Grave's disease was admitted to a private hospital with a high-grade fever, vomiting, abdominal pain, and multiple episodes of mucous diarrhea for 3 days. On day 3 of that admission, the patient developed multiorgan failure and multiple hemorrhagic blebs were observed on all extremities. A diagnosis of streptococcal toxic shock was made before referral to Siriraj Hospital - Thailand's largest national tertiary referral center. On day 10 of her admission at our center, she developed feeding intolerance and bloody diarrhea due to bowel ischemia and perforation. Bowel resection was performed, and histopathologic analysis of the resected bowel revealed acute suppurative transmural necrosis and vascular invasion with numerous broad irregular branching non-septate hyphae, both of which are consistent with GI mucormycosis. Peritoneal fluid fungal culture grew a grayish cottony colony of large non-septate hyphae and spherical sporangia containing ovoidal sporangiospores. A complete ITS1-5.8S-ITS2 region DNA sequence analysis revealed 100% homology with Rhizopus microsporus strains in GenBank (GenBank accession numbers KU729104 and AY803934). As a result, she was treated with liposomal amphotericin B. However and in spite of receiving appropriate treatment, our patient developed recurrent massive upper GI bleeding from Dieulafoy's lesion and succumbed to her disease on day 33 of her admission. CONCLUSION: Diagnosis of gastrointestinal mucormycosis can be delayed due to a lack of well-established predisposing factors and non-specific presenting symptoms. Further studies in risk factors for abdominal mucormycosis are needed.

Clinical Characteristics and Treatment Outcomes for Patients Infected with Mycobacterium haemophilum.

Mycobacterium haemophilum is a nontuberculous mycobacterium that can infect immunocompromised patients. Because of special conditions required for its culture, this bacterium is rarely reported and there are scarce data for long-term outcomes. We conducted a retrospective study at Siriraj Hospital, Bangkok, Thailand, during January 2012-September 2017. We studied 21 patients for which HIV infection was the most common concurrent condition. The most common organ involvement was skin and soft tissue (60%). Combination therapy with macrolides and fluoroquinolones resulted in a 60% cure rate for cutaneous infection; adding rifampin as a third drug for more severe cases resulted in modest (66%) cure rate. Efficacy of medical therapy in cutaneous, musculoskeletal, and ocular diseases was 80%, 50%, and 50%, respectively. All patients with central nervous system involvement showed treatment failures. Infections with M. haemophilum in HIV-infected patients were more likely to have central nervous system involvement and tended to have disseminated infections and less favorable outcomes.

Cumulative incidence and mortality of infective endocarditis in Siriraj hospital-Thailand: a 10-year retrospective study.

BACKGROUND: To investigate the cumulative incidence of and factors associated with mortality among patients with infective endocarditis (IE) at Thailand's largest national tertiary referral center. METHODS: Medical charts of adult patients diagnosed with IE by Duke criteria at Siriraj Hospital during January 2005 to May 2015 were retrospectively reviewed. RESULTS: Of 380 patients, 66.3% had definite IE, and 81.3% had native valve IE (NVE). Cumulative IE incidence was 5.67/1000 admissions. The most common pathogens were viridans group streptococci (VGS) (39.7%), methicillin-sensitive Staphylococcus aureus (MSSA) (13.1%), and beta-hemolytic streptococci (11.5%) in NVE; and, MSSA (20.3%), VGS (20.3%), and Enterococcus spp. (16.9%) in prosthetic valve (PVE) or device-related IE (DRIE). Overall in-hospital mortality was 18.4%. Mortality was significantly higher in PVE/DRIE than in NVE (26.8% vs. 16.5%, p = 0.047). End-stage renal disease (ESRD) (aOR: 9.43, 95% CI: 2.36-37.70), diabetes mellitus (DM) (aOR: 2.81, 95% CI: 1.06-7.49), neurological complication (aOR: 14.16, 95% CI: 5.11-39.22), congestive heart failure (aOR: 4.32, 95% CI: 1.91-9.75), hospital-acquired infection (aOR: 3.78, 95% CI: 1.66-8.57), renal complication (aOR: 3.12, 95%CI: 1.32-7.37), and other complication during admission (aOR: 3.28, 95% CI: 1.41-7.61) were independently associated with mortality. CONCLUSIONS: The incidence of IE, and the mortality rate among those diagnosed with IE are both increasing in Thailand - particularly among those with PVE or DRIE. End-stage renal disease, diabetes mellitus, and development of IE-related complications during admission were found to be independent predictors of mortality.

Case of Microcephaly after Congenital Infection with Asian Lineage Zika Virus, Thailand.

We sequenced the virus genomes from 3 pregnant women in Thailand with Zika virus diagnoses. All had infections with the Asian lineage. The woman infected at gestational week 9, and not those infected at weeks 20 and 24, had a fetus with microcephaly. Asian lineage Zika viruses can cause microcephaly.

Disseminated cryptococcosis in Crohn's disease: a case report.

BACKGROUND: Gastrointestinal (GI) cryptococcosis is rarely reported. Most cases were diagnosed during evaluation of comorbid conditions, incidental findings, or postmortem. Here, we present a case of Crohn's disease with gastrointestinal cryptococcosis that resembled exacerbation of Crohn's disease. CASE PRESENTATION: A 64-year-old woman with Crohn's disease (CD) was referred to Siriraj Hospital due to worsening of abdominal pain and watery diarrhea for 2 weeks. The dose of immunosuppressive agents was increased for presumed exacerbation of CD. Pathologic examination of tissue obtained from polypoid mass at ileocecal valve and multiple clean-based ulcers at cecum revealed active ileitis and colitis with multiple round shape organisms with capsule, which was compatible with Cryptococcus species. Disseminated cryptococcosis was diagnosed due to gastrointestinal involvement and presumed pulmonary involvement regarding the presence of an oval-shaped cavitary lesion on chest X-ray and computed tomography of the lung. Patient was successfully treated with amphotericin B followed by fluconazole with satisfactory result. CONCLUSION: Early diagnosis of gastrointestinal cryptococcosis in Crohn's disease is difficult due to the lack of specific symptoms and sign or mimicking an exacerbation of Crohn's disease. Seeking for other site of involvement in disseminated cryptococcosis including lung or central nervous system as well as detection of serum cryptococcal antigen would be helpful for early diagnosis and management.

B Cell Responses during Secondary Dengue Virus Infection Are Dominated by Highly Cross-Reactive, Memory-Derived Plasmablasts.

UNLABELLED: Dengue virus (DENV) infection results in the production of both type-specific and cross-neutralizing antibodies. While immunity to the infecting serotype is long-lived, heterotypic immunity wanes a few months after infection. Epidemiological studies link secondary heterotypic infections with more severe symptoms, and cross-reactive, poorly neutralizing antibodies have been implicated in this increased disease severity. To understand the cellular and functional properties of the acute dengue virus B cell response and its role in protection and immunopathology, we characterized the plasmablast response in four secondary DENV type 2 (DENV2) patients. Dengue plasmablasts had high degrees of somatic hypermutation, with a clear preference for replacement mutations. Clonal expansions were also present in each donor, strongly supporting a memory origin for these acutely induced cells. We generated 53 monoclonal antibodies (MAbs) from sorted patient plasmablasts and found that DENV-reactive MAbs were largely envelope specific and cross neutralizing. Many more MAbs neutralized DENV than reacted to envelope protein, emphasizing the significance of virion-dependent B cell epitopes and the limitations of envelope protein-based antibody screening. A majority of DENV-reactive MAbs, irrespective of neutralization potency, enhanced infection by antibody-dependent enhancement (ADE). Interestingly, even though DENV2 was the infecting serotype in all four patients, several MAbs from two patients neutralized DENV1 more potently than DENV2. Further, half of all type-specific neutralizing MAbs were also DENV1 biased in binding. Taken together, these findings are reminiscent of original antigenic sin (OAS), given that the patients had prior dengue virus exposures. These data describe the ongoing B cell response in secondary patients and may further our understanding of the impact of antibodies in dengue virus pathogenesis. IMPORTANCE: In addition to their role in protection, antibody responses have been hypothesized to contribute to the pathology of dengue. Recent studies characterizing memory B cell (MBC)-derived MAbs have provided valuable insight into the targets and functions of B cell responses generated after DENV exposure. However, in the case of secondary infections, such MBC-based approaches fail to distinguish acutely induced cells from the preexisting MBC pool. Our characterization of plasmablasts and plasmablast-derived MAbs provides a focused analysis of B cell responses activated during ongoing infection. Additionally, our studies provide evidence of OAS in the acute-phase dengue virus immune response, providing a basis for future work examining the impact of OAS phenotype antibodies on protective immunity and disease severity in secondary infections.

Characterization of Human CD8 T Cell Responses in Dengue Virus-Infected Patients from India.

Epidemiological studies suggest that India has the largest number of dengue virus infection cases worldwide. However, there is minimal information about the immunological responses in these patients. CD8 T cells are important in dengue, because they have been implicated in both protection and immunopathology. Here, we provide a detailed analysis of HLA-DR+ CD38+ and HLA-DR- CD38+ effector CD8 T cell subsets in dengue patients from India and Thailand. Both CD8 T cell subsets expanded and expressed markers indicative of antigen-driven proliferation, tissue homing, and cytotoxic effector functions, with the HLA-DR+ CD38+ subset being the most striking in these effector qualities. The breadth of the dengue-specific CD8 T cell response was diverse, with NS3-specific cells being the most dominant. Interestingly, only a small fraction of these activated effector CD8 T cells produced gamma interferon (IFN-γ) when stimulated with dengue virus peptide pools. Transcriptomics revealed downregulation of key molecules involved in T cell receptor (TCR) signaling. Consistent with this, the majority of these CD8 T cells remained IFN-γ unresponsive even after TCR-dependent polyclonal stimulation (anti-CD3 plus anti-CD28) but produced IFN-γ by TCR-independent polyclonal stimulation (phorbol 12-myristate 13-acetate [PMA] plus ionomycin). Thus, the vast majority of these proliferating, highly differentiated effector CD8 T cells probably acquire TCR refractoriness at the time the patient is experiencing febrile illness that leads to IFN-γ unresponsiveness. Our studies open novel avenues for understanding the mechanisms that fine-tune the balance between CD8 T cell-mediated protective versus pathological effects in dengue. IMPORTANCE: Dengue is becoming a global public health concern. Although CD8 T cells have been implicated both in protection and in the cytokine-mediated immunopathology of dengue, how the balance is maintained between these opposing functions remains unknown. We comprehensively characterized CD8 T cell subsets in dengue patients from India and Thailand and show that these cells expand massively and express phenotypes indicative of overwhelming antigenic stimulus and tissue homing/cytotoxic-effector functions but that a vast majority of them fail to produce IFN-γ in vitro Interestingly, the cells were fully capable of producing the cytokine when stimulated in a T cell receptor (TCR)-independent manner but failed to do so in TCR-dependent stimulation. These results, together with transcriptomics, revealed that the vast majority of these CD8 T cells from dengue patients become cytokine unresponsive due to TCR signaling insufficiencies. These observations open novel avenues for understanding the mechanisms that fine-tune the balance between CD8-mediated protective versus pathological effects.

Adult-onset immunodeficiency in Thailand and Taiwan.

BACKGROUND: Autoantibodies against interferon-γ are associated with severe disseminated opportunistic infection, but their importance and prevalence are unknown. METHODS: We enrolled 203 persons from sites in Thailand and Taiwan in five groups: 52 patients with disseminated, rapidly or slowly growing, nontuberculous mycobacterial infection (group 1); 45 patients with another opportunistic infection, with or without nontuberculous mycobacterial infection (group 2); 9 patients with disseminated tuberculosis (group 3); 49 patients with pulmonary tuberculosis (group 4); and 48 healthy controls (group 5). Clinical histories were recorded, and blood specimens were obtained. RESULTS: Patients in groups 1 and 2 had CD4+ T-lymphocyte counts that were similar to those in patients in groups 4 and 5, and they were not infected with the human immunodeficiency virus (HIV). Washed cells obtained from patients in groups 1 and 2 had intact cytokine production and a response to cytokine stimulation. In contrast, plasma obtained from these patients inhibited the activity of interferon-γ in normal cells. High-titer anti-interferon-γ autoantibodies were detected in 81% of patients in group 1, 96% of patients in group 2, 11% of patients in group 3, 2% of patients in group 4, and 2% of controls (group 5). Forty other anticytokine autoantibodies were assayed. One patient with cryptococcal meningitis had autoantibodies only against granulocyte-macrophage colony-stimulating factor. No other anticytokine autoantibodies or genetic defects correlated with infections. There was no familial clustering. CONCLUSIONS: Neutralizing anti-interferon-γ autoantibodies were detected in 88% of Asian adults with multiple opportunistic infections and were associated with an adult-onset immunodeficiency akin to that of advanced HIV infection. (Funded by the National Institute of Allergy and Infectious Diseases and the National Institute of Dental and Craniofacial Research; ClinicalTrials.gov number, NCT00814827.).

Anti-GM-CSF autoantibodies in patients with cryptococcal meningitis.

Cryptococcal meningitis has been described in immunocompromised patients, as well as in those for whom no immune defect has been identified. GM-CSF regulates the function of phagocytes and pulmonary alveolar macrophages, critical elements in cryptococcal control. We performed clinical histories, immunological evaluation, and anticytokine autoantibody screening in four current patients with cryptococcal meningitis and identified and tested 103 archived plasma/cerebrospinal fluid samples from patients with cryptococcal meningitis. We assessed the ability of anti-GM-CSF autoantibody-containing plasmas to inhibit GM-CSF signaling. We recognized anti-GM-CSF autoantibodies in an otherwise healthy female with cryptococcal meningitis who later developed pulmonary alveolar proteinosis (PAP). Her diagnosis prompted screening of patients with cryptococcal meningitis for anticytokine autoantibodies. We identified seven HIV-negative patients with cryptococcal meningitis who tested positive for high-titer anti-GM-CSF autoantibodies. Two of the seven later developed evidence of PAP. Plasma from all patients prevented GM-CSF-induced STAT5 phosphorylation and MIP-1α production in normal PBMCs. This effect was limited to their IgG fraction. Anti-GM-CSF autoantibodies are associated with some cases of cryptococcal meningitis in otherwise immunocompetent patients. These cases need not have associated PAP.

Cryptococcus gattii infection dampens Th1 and Th17 responses by attenuating dendritic cell function and pulmonary chemokine expression in the immunocompetent hosts.

Cryptococcal infections are primarily caused by two related fungal species: Cryptococcus neoformans and Cryptococcus gattii. It is well known that C. neoformans generally affects immunocompromised hosts; however, C. gattii infection can cause diseases in not only immunocompromised hosts but also immunocompetent individuals. While recent studies suggest that C. gattii infection could dampen pulmonary neutrophil recruitment and inflammatory cytokine production in immunocompetent hosts, the impact of C. gattii infection on the development of their adaptive T helper cell immune response has not been addressed. Here, we report that C. neoformans infection with highly virulent and less virulent strains preferentially induced pulmonary Th1 and Th17 immune responses in the host, respectively. However, fewer pulmonary Th1 and Th17 cells could be detected in mice infected with C. gattii strains. Notably, dendritic cells (DC) in mice infected with C. gattii expressed much lower levels of surface MHC-II and Il12 or Il23 transcripts and failed to induce effective Th1 and Th17 differentiation in vitro. Furthermore, the expression levels of Ip10 and Cxcl9 transcripts, encoding Th1-attracting chemokines, were significantly reduced in the lungs of mice infected with the highly virulent C. gattii strain. Thus, our data suggest that C. gattii infection dampens the DC-mediated effective Th1/Th17 immune responses and downregulates the pulmonary chemokine expression, thus resulting in the inability to mount protective immunity in immunocompetent hosts.

Genome sequences of dengue virus serotypes 2, 3, and 4 isolated from adult patients in Thailand.

Here, we present the genome sequences of dengue viruses (DENV) isolated from adult patients in Thailand during 2016-2017: DENV2 (412749), DENV3 (416384), and DENV4 (416709). These sequences provide valuable genetic and evolutionary information for dengue research and antiviral development.