Vancomycin Induced Maturation Arrest with Reactive Promyelocyte Proliferation: A Diagnosticand Therapeutic Challenge

ABSTRACT

Introduction: Drug induced leucopenia complicates any clinicalsituation especially when it's associated with COVID-19 infection.Here we report a case of vancomycin induced myeloid maturationarrest in a patient with COVID-19 infection where his conditionreverted to normal after stopping the drug.Aims &Objectives: It highlights the adverse effects of Vancomycinleading to promyelocyte proliferation posing a diagnostic challenge todifferentiate it from neoplastic promyelocyte proliferation.Materials &Methods: Case report A 47 year old male presentedwith fever, dry cough and difficulty in breathing for 12 days. He wasCOVID-19 positive with CT lung showing bilateral pneumonic consolidations for which Vancomycin was started. Hemogram showedhemoglobin-6.8 gm/dl, total leucocyte count-3200/cumm with a differential count revealing Neutrophil-28% (with left shift and featuresof dyspoiesis), Lymphocyte-66%, Monocyte-4%, Eosinophil-2%(Fig. 1a), and platelets-90,000/cumm. Bone marrow aspiration(BMA) and biopsy was advised. BMA was hypercellular for age withmarked promyelocyte proliferation &maturation arrest with strongMPO positivity (1b, c d). Bone marrow biopsy also reflected similarfindings (Fig-1e). FISH for PML-RARA translocation turned out to benegative, differentiating it from Acute promyeloytic Leukemia(Fig. 1f). A diagnosis of drug induced leucopenia with reactivepromyelocyte proliferation was made. Considering worsening of thesehematological findings, Vancomycin was stopped and patient'shematological findings improved drastically with stabilization ofhematological parameters.Result: Discussion: Drug induced leukopenia occurs in a dosedependent or dose-independent (idiosyncratic) reaction. Vancomycindependent antibodies against neutrophils lead to an autoimmunereaction directly affecting progenitor cell growth especially of myeloid cell lineage leading to maturation arrest. Secondly cytotoxicT-cell mediated response also has damaging effects on hematopoieticcells. Infections like COVID-19 can also lead to suppression ofnormal myeloid maturation due to release of interleukins.Conclusions: Myeloid maturation arrest with marked promyelocyteproliferation poses a diagnostic dilemma especially in patients presenting with cytopenia as they are confused with Acute promyelocytic Leukemia. This case highlights the importance of detailed knowledgerelated to drug induced myeloid maturation arrest which is reversibleafter stoppage of the offending drug.