Cryptococcal pneumonia and meningitis in a renal transplant recipient with a false negative serum cryptococcal antigen due to postzone phenomenon
Chelsea Ware,
Sherin Meledathu,
Zoon Tariq,
Rebecca Yee,
John P. Lichtenberger, III,
Marc O. Siegel
Affiliations
Chelsea Ware
Department of Medicine, George Washington University Medical Faculty Associates, 2150 Pennsylvania Avenue, NW, Washington, DC, USA; Correspondence to: Division of Infectious Disease, George Washington University Medical Faculty Associates, 2150 Pennsylvania Avenue, NW, Suite 8-436, Washington, DC 20037, USA.
Sherin Meledathu
Department of Medicine, George Washington University Medical Faculty Associates, 2150 Pennsylvania Avenue, NW, Washington, DC, USA
Zoon Tariq
Department of Pathology, The George Washington University Hospital, 900 23rd Street, NW, Washington, DC, USA
Rebecca Yee
Department of Pathology, The George Washington University Hospital, 900 23rd Street, NW, Washington, DC, USA
John P. Lichtenberger, III
Department of Radiology, The George Washington University Medical Faculty Associates, 900 23rd Street NW, Washington, DC, USA
Marc O. Siegel
Department of Medicine, George Washington University Medical Faculty Associates, 2150 Pennsylvania Avenue, NW, Washington, DC, USA
Cryptococcal infection can cause significant morbidity and mortality in immunocompromised patients. We present a patient who was diagnosed with cryptococcal meningitis and pulmonary disease in the setting of a history of renal transplantation. The diagnosis was made based on growth of Cryptococcus neoformans in blood cultures and identification of cryptococcal antigen (CrAg) in cerebral spinal fluid (CSF) using a lateral flow assay (LFA). Our case is unique since the initial serum CrAg was falsely negative due to excess cryptococcal antigen preventing the formation of antigen-antibody complexes, referred to as the postzone phenomenon. This phenomenon has been reported on CSF samples but rarely reported on serum samples in patients without an HIV diagnosis.
