A vital component of HLH care is its identification, since the disorder is frequently misdiagnosed. “We’ve gotten very good at diagnosing HLH early, and it has changed the course of care for some patients,” explains Prakash Satwani, MD. “Early recognition is key, because by the time many patients are diagnosed, the damage is done.”

For example, some patients whose symptoms are thought to be caused by liver failure and who are referred for liver transplantation are in fact diagnosed with HLH and are properly treated with a bone marrow transplant instead. In another case, an infant referred to us for a bone marrow transplant for HLH diagnosed at another hospital turned out not to have the disorder — a finding made possible by the PIPseq program.

With supportive care, the boy recovered without needing a bone marrow transplant.

While in infants HLH is often driven by an inherited mutation, older children with HLH may develop the disorder after infection with the Epstein-Barr virus (EBV). That was the case for Xavier, who presented to the ER at NYP/Morgan Stanley Children’s with a persistent fever and a swollen abdomen, just three days shy of his third birthday. Dr. Satwani told his mother that her son was in grave condition. After several weeks of ups and downs and an intensive pre-transplant regimen aimed at controlling the EBV, he received a bone marrow transplant, followed by an infusion of his donor’s T cells that were modified to kill any remaining EBV.

Today Xavier is a 4-year-old boy who lives in the Bronx and enjoys basketball, Batman, and “everything iPad,” his mother says. “From the beginning, I felt like the staff at Morgan Stanley Children’s Hospital took care of Xavier like he was their own child,” she adds. “I am so grateful to have gone there for his care and to find the doctors we needed.”