Building prognostic models for adverse outcomes in a prospective cohort of hospitalised patients with acute leptospirosis infection in the Philippines.

Leptospirosis is endemic to the Philippines. Ten per cent of cases will develop severe or fatal disease. Predicting progression to severity is difficult. Risk factors have been suggested, but few attempts have been made to create predictive models to guide clinical decisions. We present two models to predict the risk of mortality and progression to severe disease. Data was used from a prospective cohort study conducted between 2011 and 2013 in San Lazaro Hospital, Manila. Predictive factors were identified from a literature review. A strategy utilizing backwards stepwise-elimination and multivariate fractional polynomials identified key predictive factors. A total of 203 patients met the inclusion criteria. The overall mortality rate was 6.84%. Multivariable logistic regression revealed that neutrophil counts [OR 1.38, 95% CI 1.15-1.67] and platelet counts [OR 0.99, 95% CI 0.97-0.99] were predictive for risk of mortality. Multivariable logistic regression revealed that male sex (OR 3.29, 95% CI 1.22-12.57) and number of days between symptom onset and antibiotic use (OR 1.28, 95% CI 1.08-1.53) were predictive for risk of progression to severe disease. The multivariable prognostic models for the risks of mortality and progression to severe disease developed could be useful in guiding clinical management by the early identification of patients at risk of adverse outcomes.

Diagnostic Accuracy of Recombinant Immunoglobulin-like Protein A-Based IgM ELISA for the Early Diagnosis of Leptospirosis in the Philippines.

BACKGROUND: Leptospirosis is an important but largely under-recognized public health problem in the tropics. Establishment of highly sensitive and specific laboratory diagnosis is essential to reveal the magnitude of problem and to improve treatment. This study aimed to evaluate the diagnostic accuracy of a recombinant LigA protein based IgM ELISA during outbreaks in the clinical-setting of a highly endemic country. METHODOLOGY/PRINCIPAL FINDINGS: A prospective study was conducted from October 2011 to September 2013 at a national referral hospital for infectious diseases in Manila, Philippines. Patients who were hospitalized with clinically suspected leptospirosis were enrolled. Plasma and urine were collected on admission and/or at discharge and tested using the LigA-IgM ELISA and a whole cell-based IgM ELISA. Sensitivity and specificity of these tests were evaluated with cases diagnosed by microscopic agglutination test (MAT), culture and LAMP as the composite reference standard and blood bank donors as healthy controls: the mean+3 standard deviation optical density value of healthy controls was used as the cut-off limit (0.062 for the LigA-IgM ELISA and 0.691 for the whole cell-based IgM ELISA). Of 304 patients enrolled in the study, 270 (89.1%) were male and the median age was 30.5 years; 167 (54.9%) were laboratory confirmed. The sensitivity and ROC curve AUC for the LigA-IgM ELISA was significantly greater than the whole cell-based IgM ELISA (69.5% vs. 54.3%, p<0.01; 0.90 vs. 0.82, p<0.01) on admission, but not at discharge. The specificity of LigA-IgM ELISA and whole cell-based IgM ELISA were not significantly different (98% vs. 97%). Among 158 MAT negative patients, 53 and 28 were positive by LigA- and whole cell-based IgM ELISA, respectively; if the laboratory confirmation was re-defined by LigA-IgM ELISA and LAMP, the clinical findings were more characteristic of leptospirosis than the diagnosis based on MAT/culture/LAMP. CONCLUSIONS/SIGNIFICANCE: The newly developed LigA-IgM ELISA is more sensitive than the whole cell-based IgM based ELISA. Although the final diagnosis must be validated by more specific tests, LigA-IgM ELISA could be a useful diagnostic test in a real clinical-setting, where diagnosis is needed in the early phase of infection.

Safety and immunogenicity of purified vero cell rabies vaccine versus purified chick embryo cell rabies vaccine using pre-exposure and post exposure regimen among healthy volunteers in San Lazaro Hospital

OBJECTIVE: This is a prospective, randomized open-labeled clinical study to demonstrate the safety and immunogenicity of Purified Vero Cell Rabies Vaccine (PVRV) Freeze-Dried using pre-exposure and post- exposure regimen utilizing Modified Thai Red Cross schedule (Modified TRC) in comparison with Purified Chick Embryo Cell (PCEC) Rabies Vaccine among healthy volunteers in San Lazaro Hospital.METHODOLOGY: A total of 189 healthy Filipino volunteers were randomized into three groups: Group A received PVRV 0.1 ml intradermally (ID) using the pre-exposure regimen (Day 0, 7, 28). Group B and Group C were given PVRV 0.1 ml ID and PCEC 0.1 ml ID, respectively, using the Modified TRC on days 0, 3, 7 and 30. The statistical tables and graphs were generated using Microsoft® Excel® 2010. SPSS® version 13 for Windows™ was used for descriptive statistics (geometric mean, arithmetic mean, standard deviation and percentages) and inferential statistics (?2 test, one-way ANOVA and two-way mixed factorial ANOVA).RESULTS: The results revealed that the percentage seroconversion of both PRVR and PCEC post-exposure groups in this clinical study were 100% on days 14 and 90. The PRVR pre-exposure group achieved 96% seroconversion on Day 28 with Geometric Mean titers (GMT) of 1.96 IU/ml (95% CI: 1.45 - 2.65), which is comparable to other similar studies on pre-exposure rabies vaccination. There was no overall difference in all three groups for the whole duration of the study (p = 1.000). The geometic mean titers (GMT) for post-exposure PRVR and PCEC groups on days 14, 30 and 90 were all above 0.5 IU/ml. There was no significant difference between these two post-exposure groups (p = 0.052). The proportion of the subjects in the three groups who experienced local (pain and tenderness at the injection sites, erythema and itching) or systemic reactions (low grade fever, dizziness and headache) during follow-up period were not significantly different (p = 0.134). There were no serious adverse events (SAEs) reported during the follow-up period.CONCLUSION: The Asian manufactured PVRV is safe, tolerable, immunogenic and comparable with PCEC and therefore, the Asian manufactured PVRV can be an economical alternative for rabies post-exposure treatment using the modified TRC regimen and for pre-exposure prophylaxis.

Platelet apoptosis and apoptotic platelet clearance by macrophages in secondary dengue virus infections.

BACKGROUND: The mechanisms of thrombocytopenia and platelet phagocytosis in dengue illness are not fully understood. METHODS: A prospective hospital-based study was conducted to examine the relationships between platelet counts, serum thrombopoietin (TPO) levels, and platelet apoptosis and phagocytosis in 81 patients with secondary dengue virus (DV) infections and 38 healthy volunteers. The apoptosis and phagocytosis of cultured platelets after exposure to DV were also examined. RESULTS: Platelet apoptosis, platelet phagocytosis, and serum TPO levels were increased significantly in patients during the acute and early convalescence phases compared with levels observed in patients during the convalescence phase and in healthy volunteers. A significant correlation between platelet apoptosis and platelet phagocytosis was also observed in these patients. Platelet phagocytosis was inhibited significantly by the D89E mutant, which carries a point mutation in the RGD motif of milk fat globule-epidermal growth factor 8, a phosphatidylserine-recognizing bridge molecule. DV-induced platelet apoptosis and increased phagocytosis of DV-induced apoptotic platelets was confirmed using in vitro assays. CONCLUSIONS: Our data suggest an increased phagocytosis of DV-induced apoptotic platelets by macrophages via a phosphatidylserine-recognizing pathway in secondary DV infection. Accelerated platelet clearance, however, was overcome by TPO-induced enhanced thrombopoiesis in these patients. CLINICAL TRIALS REGISTRATION: UMIN000004835.