OBJECTIVETo introduce the clinical manifestations and laboratory tests of adult onset of primary hemophagocytic syndrome (HPS), and to investigate the essentials of diagnosis and the genotype characteristics in adult onset patient.

METHODSThe definite diagnosis of HPS was made according to HLH-2004. Exons of PRF1, STX11, UNC13D, SH2D1A and RAB27A genes coding region were amplified using polymerase chain reaction.

RESULTSA 48-year-old man was admitted to our hospital because of recurrent fever, pancytopenia and lymph node enlargement. His laboratory test revealed bone marrow hemophagocytosis, elevated ferritin level (2000 µg/L), reduced level of NK cell activity (20.13%) and elevated soluble CD25 level (12277 U/ml). Based on the HLH-2004 diagnostic criteria, the patient was diagnosed as HPS. The patient had viral infection, and no other primary disease was identified that would cause HPS. The patient responded poorly to anti-viral therapy. DNA sequencing was used to confirm that perforin gene mutations might be one of the causes of the patient suffered from primary HPS.

CONCLUSIONSAlthough primary HPS usually affects infants and young children, it also occurred in teens and adults. It is essential to perform genetic screenings to patient whose illnesses recur with unknown causes. In addition, detection of molecular genetic alterations can be used to distinguish primary HPS from acquired HPS.