RESUMEN
Haemophagocytic lymphohistiocytosis (HLH) is a clinico-pathologic entity caused by increased proliferation and activation of benign macrophages with haemophagocytosis throughout the reticulo-endothelial system. Virus-associated HLH is a well-recognised entity. Although majority of parvovirus B19 associated HLH does not require any specific treatment and carries good prognosis, outcome of children is worse than adults. We report here a case of HLH associated with acute parvovirus B19 infection in a young healthy patient with underlying hereditary spherocytosis, with bone marrow findings typical of parvovirus infection. Although this patient had spontaneous recovery of cell counts, he succumbed due to complication from prolonged ventilation. Unexpectedly, his immunoglobulin levels were inappropriately normal despite on-going ventilator associated pneumonia, which reflects inadequate humoral immune response towards infection.