Original Research Article
Year: 2020 | Month: January | Volume: 10 | Issue: 1 | Pages: 153-160
Galactomannan Enzyme Immunoassay: Diagnosis & Monitoring Invasive Aspergillosis in Patients of Acute Leukemia & Stem Cell Transplant
Jasjit Singh, Sachin Maggo, Jyoti Kotwal, Inderpal, Rajiv Kumar, Ajay Sharma, Rajan Kapoor, Sanjeevan Sharma, S. Das
Department of Medicine & Clinical Hematology, Command Hospital Western Command, Chandimandir, Panchkula, Haryana (India)
Corresponding Author: Sachin Maggo
ABSTRACT
Introduction: Invasive fungal infections (IFI) are one of the major life threatening infections in patients of acute leukemias including those undergoing haematopoietic stem cell transplantation, of which candida and aspergillus are chief fungal pathogens. In most of the cases antifungal treatment is started empirically, due to lack of specific clinical radiological, and laboratory features, which has a mortality benefit but at the cost of overuse of antifungals in more than 50% of high risk patients, though incidence of IFI is only around 10%.
Aim & Objectives: Use of Galactomannan Enzyme Immunoassay for the diagnosis and monitoring of Invasive Aspergillosis in patients of Acute leukemia and Allogenic Hematopoietic Stem Cell Transplantation.
Materials & Methods: Serum Galactomannan levels of 100 patients who have received chemotherapy for acute leukemia or myelodysplastic syndrome or those who have undergone a myeloablative HSCT, were prospectively monitored for 16 weeks. These results were compared with probability of having invasive aspergillosis (IA) at any time during induction chemotherapy or allogenic stem cell transplantation as per EORTC/MSG criteria.
Results: Thirteen patients had proven IA whereas, 45 patients had probable or possible IA and 42 patients had no evidence of IA as per EORTC/MSG criteria. Mycological evidence of aspergillosis was obtained in 32 patients whereas CT chest & PNS at any time point showed evidence of aspergillosis in 34 out of 100 patients. Serum Galactomannan index at any time point was positive in 39 patients by taking cut-off of 0.5. S. Galactomannan was found to be positive earlier than CT positivity for IA (9 vs 14 days). Nineteen patients had persistent positive Galactomannan index. Sensitivity and specificity of S.Galactomannan for diagnosing IA was 75% & 83.3% respectively on day +1 of fever and 78.6% & 84.7% respectively on day +4 of fever. There was significant correlation between absolute neutrophil count and GM index.
Conclusion: Galactomannan index is an early predictor of invasive aspergillosis which was found to be positive earlier than CT positivity. Besides being a diagnostic marker of IA, serum GM can also be used to monitor response to therapy. However further studies are required to validate the hypothesis.
Keywords: Galactomannan Enzyme Immunoassay, Invasive Aspergillosis, Acute leukemia, Stem cell transplant.