Clearance Of Antigenemia Research Articles

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

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. 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. 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. 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.

Use of Valacyclovir for the treatment of cytomegalovirus antigenemia after hematopoietic stem cell transplantation.

BackgroundValacyclovir has been used for prophylaxis against cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT). We investigated the efficacy and safety of high-dose Valacyclovir as pre-emptive therapy in patients with CMV antigenemia after HSCT.MethodsIn a retrospective single center study of 61 patients, we compared the rates of viral clearance, recurrent antigenemia and adverse events in patients with pp65 CMV antigenemia who received high dose Valacyclovir (n = 15), Valganciclovir (n = 16), and Foscarnet (n = 30).ResultsOverall, 60/61 (98 %) of cases achieved CMV antigenemia clearance by day 28, and no patient developed CMV disease. After adjusting for age, sex, diagnosis, CMV serological status, donor type, CMV antigen level, graft-versus-host disease (GVHD) therapy, and conditioning regimen, there were no significant differences in the rates of viral clearance at day 14 in patients who received Valganciclovir (0.18, 95 % confidence interval (CI) 0.01 to 2.15, p = 0.17) and Foscarnet (OR 0.22, 95 % CI 0.03 to 2.40, p = 0.22), compared with Valacyclovir (assigned OR = 1.00). Recurrent antigenemia by day 180 after clearance of the initial CMV episode occurred in 34/61 (56 %) of patients. Using the multivariate model adjusting for the same covariates, there were also no significant differences in secondary episodes of CMV between treatment groups. With regards to adverse effect monitoring, Foscarnet led to significantly increased creatinine levels (P = 0.009), while Valganciclovir led to significant decrease in neutrophil counts (P = 0.012).ConclusionHigh dose Valacyclovir is a potential alternative to Valganciclovir and Foscarnet in the stable post-HSCT patient who has cytopenia and is not keen for inpatient treatment of CMV antigenemia.

Use of Valacyclovir for the Treatment of Cytomegalovirus Antigenemia after Hematopoietic Stem Cell Transplantation

Background: Cytomegalovirus (CMV) infection remains a cause of morbidity and mortality in patients who have undergone allogeneic hematopoietic cell transplantation (HSCT) despite pre-emptive antiviral therapy. Available treatments have clinically significant toxic effects. Valacyclovir is well tolerated, and limited evidence suggests that Valacyclovir is effective in preventing CMV disease when given as prophylactic treatment. We investigated the efficacy and safety of high dose Valacyclovir compared with Valganciclovir or Foscarnet in the pre-emptive therapy of CMV antigenemia.Methods: In a retrospective single-center study, 61 allogeneic HSCT recipients with an initial episode of CMV antigenemia received pre-emptive therapy with either Valacyclovir (n=15), Valganciclovir (n=16), or Foscarnet (n=30). Patients were treated with either Valacyclovir at 2 g twice-daily, Valganciclovir at 900 mg twice-daily, or Foscarnet at 90 mg/kg twice-daily, with appropriate renal dose adjustments for each drug. Patients were assessed weekly using the pp65 antigenemia assay. Endpoints analyzed include viremia clearance at day 14 and 28, and rates of recurrent antigenemia. Neutrophil counts and creatinine levels were monitored during treatment.Results: Overall, 60/61 (98%) of cases achieved CMV antigenemia clearance by day 28, and no patient developed CMV disease. Valacyclovir achieved similar clearance of CMV viremia compared to Valganciclovir and Foscarnet, at rates of 93.3%, 77.5%, and 79.5% respectively at 14 days (p=0.054; log rank test). After adjusting for age, sex, CMV serological status, donor type, CMV antigen level, GVHD therapy, and conditioning regimen, there were no significant differences in the odds of viral clearance at day 14 in patients who received Valganciclovir (odds ratio (OR) 0.16, 95% confidence interval (CI) 0.01 to 2.14, p=0.17) and Foscarnet (OR 0.21, 95% CI 0.02 to 2.39, p=0.21), compared to Valacyclovir (assigned OR 1.00). Recurrent CMV antigenemia by day 180 after clearance of the initial episode occurred in 34/61 (56%) of patients. Use of Acyclovir was not associated with an increased odds of CMV recurrence, compared to Valganciclovir or Foscarnet, after adjusting for the same covariates in logistic regression models. Foscarnet significantly increased creatinine levels (p=0.009), while Valganciclovir significantly reduced neutrophil counts (p=0.012). Laboratory evaluation revealed no hematopoietic or renal toxicity in patients on Valacyclovir treatment.Conclusion: Pre-emptive treatment with Valganciclovir, Foscarnet and Valacyclovir led to similar clearance of CMV antigenemia and rates of recurrence. High dose Valacyclovir is a potential alternative for pre-emptive CMV treatment in allogeneic HSCT recipients, with an acceptable safety profile. Table 1Response to preemptive cytomegalovirus therapyAll(n=61)Valacyclovir(n=15)Valganciclovir(n=16)Foscarnet(n=30)PMedian viral load (No. of CMV positive cells per million leukocytes, range)3 (1-750)3 (1-140)3 (2-181)3.5 (1-750)0.772Clearance, N (%)0.054Cleared by day 735 (58.3)12 (80.0)11 (68.8)12 (41.4)Cleared by day 1414 (23.3)2 (13.3)2 (12.5)10 (34.5)Cleared by day 218 (13.3)1 (6.7)3 (18.8)4 (13.3)Cleared by day 283 (5.0)0 (0)0 (0)3 (10.3)Recurrent antigenemia, N (%)34 (55.8)7 (46.7)11 (68.8)16 (53.3)0.434Median days to recurrence43.5 (11-173)59 (27-173)42 (14-94)38 (11-163)0.081 DisclosuresOff Label Use: Valacyclovir use for CMV pre-emptive therapy in allogeneic HSCT recipients. Goh:Novartis Pte Ltd: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Jannsen Pharmaceuticals Inc: Research Funding; Bristol-Myres Squibb: Membership on an entity’s Board of Directors or advisory committees; Gilead Sciences: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Hospira Inc: Honoraria, Membership on an entity’s Board of Directors or advisory committees.

Immune Mediators of Rotavirus Antigenemia Clearance in Mice

The immunological mediators that clear rotavirus antigenemia or viremia remain undefined. Immunodeficient mice and antibody transfer were used to test whether lymphocytes or rotavirus-specific serum antibodies are essential for resolving antigenemia. Clearance of antigenemia required lymphocytes, but neither T nor B lymphocytes were absolutely required. Transfer of convalescent-phase or nonneutralizing rotavirus-specific serum antibodies to the systemic compartment of severe-combined-immunodeficient (SCID) mice temporarily suppressed the onset or level of chronic rotavirus antigenemia. Our findings provide the first report demonstrating that clearance of rotavirus antigenemia and possibly viremia are mediated by multiple effector lymphocyte subsets and serum antibodies.

Histoplasma Antigen Clearance during Treatment of Histoplasmosis in Patients with AIDS Determined by a Quantitative Antigen Enzyme Immunoassay

Clearance of Histoplasma antigen has been used as a marker for response to treatment of progressive disseminated histoplasmosis (PDH) in patients with AIDS. Advancements in Histoplasma antigen detection permit accurate quantification of antigen concentration. We compared the clearance of antigenemia and antigenuria during effective treatment of PDH. Urine and serum specimens were serially collected from patients with AIDS who were successfully treated for PDH as part of two prospective clinical trials. Samples were stored frozen until they were tested in the quantitative Histoplasma antigen enzyme immunoassay. The kinetics of antigen clearance during the first 12 weeks of therapy were assessed in urine and serum during treatment with liposomal or deoxycholate amphotericin B followed by itraconazole and, in a separate analysis, in patients receiving only itraconazole. Latent class growth analysis was performed to define patterns of antigen clearance over time. In patients receiving amphotericin B, antigen levels declined the most during the first 2 weeks of treatment and antigenemia decreased more rapidly than antigenuria (5.90 ng/ml per week versus 4.21 ng/ml per week, respectively; P = 0.09). Mean reductions of antigen levels from baseline at weeks 2 and 12 were greater in sera than in urine: 11.26 ng/ml versus 7.65 ng/ml (P = 0.0948) and 18.52 ng/ml versus 14.64 ng/ml (P = 0.0440), respectively. In patients who received itraconazole alone, most of the decline in antigenuria occurred later during treatment and was overall slower than that seen with amphotericin B (P < 0.0001). Results of latent class growth modeling showed two distinct trajectories for each parameter. With effective therapy, Histoplasma antigenemia decreases more rapidly than antigenuria, providing a more sensitive early laboratory marker for response to treatment. Antigenuria declines earlier with amphotericin B than with itraconazole.

New Approach for Diagnosis of Candidemia Based on Detection of a 65-Kilodalton Antigen

Nosocomial candidiasis is a major concern in tertiary care hospitals worldwide. This infection generally occurs in patients with degenerative and neoplastic diseases and is considered the fourth most frequent cause of bloodstream infections. Diagnosis of candidemia or hematogenous candidiasis has been problematic because clinical signs and symptoms are nonspecific, leading to delays in diagnosis and, consequently, delays in appropriate antifungal therapy. We developed an inhibition enzyme-linked immunosorbent assay (ELISA) for detection of a 65-kDa antigen in an experimental model of candidemia and for diagnosis of patients in intensive care units (ICUs) with suspected candidemia. An anti-65-kDa monoclonal antibody was tested for detection of the 65-kDa antigen produced by Candida albicans, Candida tropicalis, and Candida parapsilosis in murine candidemia models. The 65-kDa antigen was detected in sera at concentrations ranging from 0.012 to 3.25 microg/ml. A total of 20 human patients with candidemia were then evaluated with the inhibition ELISA using sequential sera. Sixteen (80%) patients had the 65-kDa antigen in concentrations ranging from 0.07 to 5.0 microg/ml. Sequential sera from patients with candidemia presented three different patterns of antigenemia of the 65-kDa molecule: (i) total clearance of antigenemia, (ii) initial clearance and relapse of antigenemia, and (iii) partial clearance of antigenemia. Our results indicate detection of the 65-kDa protein may be a valuable tool for the diagnosis of candidemia by C. albicans, C. tropicalis, and C. parapsilosis.

Preemptive valganciclovir for cytomegalovirus infection in hematological patients

To the Editor We read with interest the ¢ndings by Busca et al. (1) published in the Journal, adding to similar recent ¢ndings supporting the e⁄cacy of preemptive valganciclovir in allogeneic hematopoietic stem cell transplant (HSCT) recipients (2, 3). We add here our single-center preliminary experience in hematological patients. Before November 2005 we usually treated cytomegalovirus (CMV) reactivation (higher than 1500 copies/mL) with intravenous ganciclovir. During a 24 -month period starting in November 2005, all our patients undergoing HSCTor aggressive chemotherapy were monitored with weekly real-time quantitative polymerase chain reaction (PCR) assay (Cobas Amplicor CMV Monitor test, Roche Diagnostics, Mannheim, Germany; sensitivity5 600 CMV DNAcopies/mL) on peripheral blood during treatment and in the ¢rst 3 months after discharge. Thirty-seven patients with CMV viremia higher than 1500 copies/mL (at a median of 45 from end of chemotherapy or HSCT) were identi¢ed and treated for 3 weeks with preemptive oral valganciclovir 450 mg b.i.d. (n5 5) or 900 mg b.i.d. (n5 32) according to renal function. No patient had concurrent infections or was receiving steroids at the time of reactivation. No reduction in immunosuppression was performed in allogeneic HSCT recipients at the time of CMVreactivation. All but 2 patientswho reactivated CMVafter aggressive chemotherapy (n513: 7 myeloablative and 6 nonmyelobalative), or autologous (n5 5: 4 high-dose melphalan and 1 BEAM) or allogeneic (n519) HSCTshowed weekly drops in CMV levels and ¢nally cleared viremia at the ¢nal control on day 21 day since beginning of treatment. Both patients who failed the endpoint were allogeneic HSCT recipients with initial loads lower than 5000 copies/mL who had been treated with valganciclovir 900mgb.i.d.; they had persistent low-level viremia (4000 copies/mL) for at least 2 months despite salvage treatment with intravenous foscarnet. Only 3 patients, all allogeneic HSCTrecipients, developed neutropenia (absolute neutrophil counto500/mL) while on valganciclovir, which could be explained by concurrent immunosuppressive drugs. The median initial viral load in our cohort was 3900 copies/mL, which is a relatively low level and could have contributed to the high e⁄cacy of valganciclovir.W|th the use of such a low threshold, we did not observe any case of symptomatic CMVdisease. Recent data support that the e⁄cacy of valganciclovir 450mg b.i.d. is identical to 900mg b.i.d. in allogeneic HSCT recipients (90% clearance of antigenemia on day 121) (4), and this is likely truewhenever initial CMV load remains quite low, allowing proper treatment of patients with renal failure. In reduced-intensity conditioning HSCT recipients without gastrointestinal graft-versus-host disease (GvHD), the r 2008 Wiley Periodicals, Inc.

A Randomized Trial of Short-Course Preemptive Ganciclovir Compared with Conventional Ganciclovir Therapy To Prevent Cytomegalovirus Infection after Allogeneic Stem Cell Transplantation.

We studied the efficacy and safety of a short course of ganciclovir to prevent cytomegalovirus (CMV) infection in allogeneic hematopoietic stem cell transplantation (HSCT) recipients. In general, preemptive ganciclovir is administered twice daily for 1–2 weeks (induction phase) and then once daily until 6 days after cessation of viremia and antigenemia (maintenance phase). We randomly assigned allogeneic HSCT recipients who had positive shell vial culture for CMV or CMV antigenemia to receive preemptive ganciclovir therapy with or without induction phase (5 mg/kg body weight, twice a day for one week). 32 and 34 patients were randomized to the standard treatment arm and the short course arm, respectively. There were no statistically significant differences in patient characteristics such as age, sex, type of disease, type of transplantation, seropositivity of CMV antibody in donor, seropositivity of CMV antibody in recipient, type of conditioning regimen or GVHD prophylaxis regimen between two groups. The median time to clearance of CMV viremia and antigenemia was 7 d and 9 day, respectively (P = 0.333). Seven patients in the short course arm failed for viral clearance after preemptive therapy and were cross-overed to the standard preemptive therapy, which resulted in clearance of antigenemia and viremia in all patients. The toxicity profile was higher in the standard treatment arm with 5 neutropenia and 1 drug-induced hepatitis whereas there was only 1 neutropenia in the short-course arm. Of 5 patients who experienced neutropenia, 2 died of sepsis. This study shows that the preemptive ganciclovir therapy with maintenance phase alone may be equally effective to the standard treatment arm with less toxicity profile in prevention of CMV disease in allogeneic HSCT recipients. The omission of induction phase in CMV preemptive therapy may allow patients to avoid unnecessary hospital admissions.

Successful preemptive cidofovir treatment for CMV antigenemia after dose-reduced conditioning and allogeneic blood stem cell transplantation.

Cidofovir (CDV) is a nucleotide analogue with proven in vitro effects against cytomegalovirus (CMV) and adenovirus and has been successfully used in the treatment of CMV retinitis in AIDS patients. We performed a prospective study to evaluate the efficacy of CDV in 17 patients with hematological malignancies after allogeneic blood stem cell transplantation from related (n=3) and unrelated (n=14) donors. Dose-reduced conditioning (DRC) regimen consisted of busulfan (Bu)/fludarabine (Flu) (n=9) and idarubicin/cytosine arabinoside/Flu (n=1). Myeloablative conditioning (MC) was performed with Bu/cyclophosphamide (Cy)/etoposide (Eto) (n=4), Bu/Cy (n=2), and total body irradiation (TBI)/Cy/Eto (n=1). Antithymocyte globulin (ATG) was used in seven patients with DRC and in six patients with MC. In all patients, either the donor, host, or both were CMV IgG positive pretransplant. Indication for therapy was preemptive treatment of primary CMV antigenemia defined as two consecutive positive tests of pp65 antigenemia assay after transplant. In case of response with a decreasing number of pp65-positive leukocytes, CDV was scheduled in a dosage of 5 mg/kg body weight once a week for 2 weeks followed by maintenance therapy every 2 weeks in an outpatient setting. All patients received probenecid and prehydration as recommended. Patients were monitored using an immunostaining assay for pp65 antigen and a qualitative and quantitative CMV polymerase chain reaction (PCR). Success of treatment was defined as negativity for the pp65 antigen. After DRC, nine of ten patients (90%) showed a response with seven of nine revealing a complete clearance of the virus (pp65 negative, qualitative PCR negative). In the remaining two responders, treatment was changed to ganciclovir because of either renal impairment or slow clearance of antigenemia. Only one of seven patients in the MC group experienced a temporary clearance of pp65 antigen. After MC, two patients experienced CMV disease. Treatment-related toxicity rate was moderate with four patients developing reversible renal impairment (creatinine 133-180 micromol/L); one patient with proteinuria and three patients with complaints of nausea and vomiting. Our data suggest the feasibility of CDV administration in patients after allogeneic transplantation. In the recommended dose, it might be used successfully for low-risk patients, e.g., after DRC or organ transplantation, in an outpatient setting.

Cytomegalovirus Antigenemia Surveillance in the Treatment of Cytomegalovirus Disease in AIDS Patients

Objective: Surveillance of quantitative cytomegalovirus (CMV) antigenemia among AIDS patients with CMV treated complications in order to determine its value in assessing the response to treatment and survival.Methods: A longitudinal follow-up of antigenemia measurement at diagnosis, after induction therapy with ganciclovir or foscarnet, and every 3 months during maintenance therapy was carried out in 25 patients with CMV retinitis and in 8 with extraocular CMV disease. Positive antigenemia was defined as the presence of any amount of immunofluorescent pp65-positive leukocytes /105 cells.Results: Mean antigenemia values were: 77±148 /105 leukocytes at retinitis diagnosis; 45±114 after induction therapy; and 7±18 and 1.5±4 after 6 months and one year of therapy, respectively. Patients achieving undetectable antigenemia increased from 44% at baseline to 68% at postinduction and 80% during follow-up. Seven patients (28%) who remained free of relapses presented significant minor baseline antigenemias and became negative after induction therapy. Patients with extraocular disease showed erratic antigenemia values and absent therapeutic response. CMV blood cultures before and after induction therapy were positive in 39% and 21% of patients, respectively. Kaplan-Meier analysis revealed a significantly longer survival for patients with retinitis when compared to those with extraocular complications, and for patients with negative antigenemia after induction in comparison with those who failed to achieve it.Conclusions: Low basal antigenemia and antigenemia clearance after induction therapy are variables directly related to good response to treatment and survival. Continuous surveillance of antigenemia during treatment could permit designing of individual strategies to obtain a better response.

Limited Viral Spread and Rapid Immune Response in Lymph Nodes of Macaques Inoculated with Attenuated Simian Immunodeficiency Virus

A comparative study was undertaken to characterize the very early events that distinguish attenuated and pathogenic simian immunodeficiency virus (SIV) infections. Three rhesus macaques were inoculated with the attenuated SIVmac 251 Δnef virus, and three others with a virus of intermediate phenotype, SIVmac 239 nef stop. They were compared to four macaques inoculated with the pathogenic SIVmac 251 isolate. Lymph nodes (LN) taken between 7 days and 2 months postinoculation were analyzed for SIV expression byin situhybridization. During acute infection, SIV 251 Δnef infected 1 to 1.5 log10fewer cells in LN tissue than the pathogenic SIV 251 isolate. The reduction was more marked in the blood, as SIV 251 Δnef infected 2 to 3 log10fewer PBMC than the isolate and did not yield detectable antigenemia. Morphometric measurements showed that the development of germinal centers (GC) was more rapid in the Δnef infection, which led to a more efficient trapping of viral particles, and could account for antigenemia clearance. The SIV 239 nef stop clone reverted to a nef+genotype at Week 2, but induced a lower viral burden than a directly pathogenic virus. The kinetics of GC development was rapid, indicating that SIV 239 nef stop induced an immune response similar to that seen in attenuated infection. This study provides evidence that attenuated SIV elicits a more rapid immune response than pathogenic SIV and suggests that an early immunosuppressive episode may facilitate the dissemination of pathogenic SIV.

Immunopathogenic events in acute infection of rhesus monkeys with simian immunodeficiency virus of macaques.

Infection of the rhesus monkey with simian immunodeficiency virus of macaques (SIVmax) was employed to explore the early immune events associated with the initial containment of an acute AIDS virus infection. In nine rhesus monkeys infected intravenously with uncloned SIVmac strain 251, high-level p27 plasma antigenemia was usually detected transiently from approximately day 7 through day 21 following virus inoculation. SIVmac replication in lymph nodes measured by in situ RNA hybridization closely paralleled the time course and magnitude of viremia. The containment of SIVmac spread by 3 to 4 weeks following infection suggests an efficient, early immune control of this virus infection. Anti-SIVmac antibodies were first detected in the blood at approximately day 14. At the time antigenemia was decreased or cleared, SIVmac neutralizing antibodies were present. A rise in circulating and lymph node CD8+ T cells also occurred coincident with the clearance of antigenemia and persisted thereafter. These CD8+ lymphocytes in lymph nodes had increased expression of both major histocompatibility complex class II and the adhesion molecule LFA-1; they also demonstrated decreased expression of the naive T-cell-associated CD45RA molecule. SIVmac-specific cytotoxic T-lymphocyte precursors were detected in both blood and lymph node by 7 days post-virus inoculation. These studies indicate that both virus-specific humoral and cellular immune mechanisms in blood and lymph node are associated with the clearance of viremia that occurs within the first month of infection of rhesus monkeys with SIVmac.