Search

Blood phagocytes, such as neutrophils and monocytes, generate reactive oxygen species (ROS) as a part of host defense response against infections. We investigated the mechanism of Fcγ-Receptor (FcγR) mediated ROS production in these cells to understand how they contribute to anti-malarial immunity. Plasmodium falciparum merozoites opsonized with naturally occurring IgG triggered both intracellular and extracellular ROS generation in blood phagocytes, with neutrophils being the main contributors. Using specific inhibitors, we show that both FcγRIIIB and FcγRIIA acted synergistically to induce ROS production in neutrophils, and that NADPH oxidase 2 and the PI3K intracellular signal transduction pathway were involved in this process. High levels of neutrophil ROS were also associated with protection against febrile malaria in two geographically diverse malaria endemic regions from Ghana and India, stressing the importance of the cooperation between anti-malarial IgG and neutrophils in triggering ROS-mediated parasite killing as a mechanism for naturally acquired immunity against malaria. FcγR-mediated signaling by cytophilic IgG against Plasmodium falciparum merozoites triggers ROS generation predominantly in neutrophils as a mechanism contributing to naturally acquired immunity against malaria in endemic regions in Ghana and India. [ABSTRACT FROM AUTHOR]

Background: Risk stratification of patients with febrile neutropenia (FN) into those at "High Risk" and "Low Risk" of developing complications helps in making decisions regarding optimal treatment, such as whether to treat with oral or intravenous antibiotics, whether to treat as inpatient or outpatient and how long to treat. Risk predictors obtained from Western studies on pediatric FN are unlikely to be relevant to low middle-income country (LMICs). Our study aimed to identify clinical and laboratory parameters predictive of poor outcomes in children with chemotherapy-induced FN in a LMIC.Procedure: Two hundred and fifty consecutive episodes of chemotherapy-induced FN in pediatric (<15 years) patients were analyzed prospectively. Adverse outcomes were defined as per SPOG 2003 FN study as serious medical complications (SMC) due to infection, microbiologically defined infection, and radiologically defined pneumonia (RDP). Variables found to be significant for adverse outcome (P < 0.05) on univariate analysis were selected for multivariate analysis.Results: Five factors that were found to independently predict adverse outcome were (a) previously documented infection in the past 6 months, (b) presence of significant focus of infection, (c) absolute phagocyte count <100/mm3, (d) peak temperature more than 39°C in this episode of FN, and (e) fever lasting more than 5 days during this episode of FN.Conclusions: Identifying the risk factors for adverse outcome in pediatric FN, which are objective and applicable across LMICs would contribute in developing guidelines for the management of FN in a resource-limited setting. [ABSTRACT FROM AUTHOR]

Primary immunodeficiency disorders (PID) are under-reported from the developing world. We present data regarding diagnosis and outcome from a hospital-based registry in India. Forty-seven patients fulfilled diagnostic criteria. Majority were males. Subgroups were disorders of immune dysregulation-29%, B&T-cell abnormalities-28%, predominant antibody deficiencies-23%, other well-defined immunodeficiencies-15%, and phagocyte disorders-4%. Molecular diagnosis was attempted in 12 and was positive in seven. Overall 24 children died. Only three out of 28 children needing stem cell transplant (SCT) underwent the same. Registry data highlights that molecular diagnosis and SCT are a rarity for children with PIDs in the developing world and mortality is high. [ABSTRACT FROM AUTHOR]

Objectives: There is paucity of data on Primary immunodeficiency disorders (PID) from India. Here we describe the frequency of different primary immunodeficiency disorders, their clinical features and disease complications of 159 patients with PID diagnosed in a tertiary care center from India over the last 3 years. Methods: We retrospectively reviewed the records of all the patients identified to have specific PID from 2008 to 2011. The diagnosed patients were classified according to guidelines of International Union of Immunological Society (IUIS) into eight different sub groups. Results: The distribution pattern was as follows: diseases of immune dysregulation (29 %), phagocytic defects (29 %), predominant antibody deficiency (13 %), combined T and B cell deficiency (19 %) and other well defined diseases (10 %). Conclusion: The distribution pattern of PID varied significantly from those reported by western studies. This study highlights the need for development of more advanced facilities for diagnosis and management of PID in India and also the need for establishing population and hospital based registries. [ABSTRACT FROM AUTHOR]