Bartonella henselaemasquerading as possible gamma–delta T-cell lymphoma in a paediatric patient with 22q11.2 deletion syndrome

Abstract

A 14-year-old boy with 22q11.2 deletion syndrome and a right ventricular to pulmonary artery xenograft conduit presented to an Australian tertiary children’s hospital with prolonged fevers, weight loss, splenomegaly and a high proportion of gamma–delta T cells in peripheral blood and bone marrow, concerning for possible gamma–delta T-cell lymphoma. However, investigations did not reveal evidence of lymphoma or autoimmune disease. After 5 months of intermittent fever episodes and ongoing symptoms, he was found to have an extremely high Bartonella henselae titre (8192) on serological testing, with the organism also detected on blood PCR. After 6 months of oral azithromycin and rifampicin, with complete resolution of his symptoms 3 months into treatment, his blood PCR was negative and gamma–delta T cells in peripheral blood were decreasing. The B. henselae titre remained unchanged for some time, but decreased to 2048 around 1 year after treatment was started.