Hemophagocytic lymphohistiocytosis in acute African swine fever clinic.

INTRODUCTION: Hemophagocytic lymphohistiocytosis (HLH) usually has been defined as the combination of a proliferation of cytologically benign, actively phagocytic macrophages in bone marrow, spleen, lymph nodes, etc. in association with fever, cytopenia, splenomegaly, and hypertriglyceridemia. HLH is often triggered by viral infection. The aim of this study was to ascertain the features of HLH involvement in African swine fever virus (ASFV) (genotype II) pathogenesis.

METHODS: The serum levels of macrophage colony-stimulating factor (MCSF) and granulocyte-macrophage colony-stimulating factor (GMCSF), as well as the histological constitution (for hemophagocytic macrophages detection) of various organs of pigs infected with ASFV genotype II were investigated. The diagnosis of HLH was made according to universally accepted human criteria.

RESULTS: The association of fever, cytopenias, splenomegaly, and hemophagocytosis was present in 87.5% of the infected pigs (absence of hyperthermia in one of eight pigs). Marked hypertriglyceridemia was observed at 3-4days post infection. Previously it was shown that ASFV induced a significant decrease in the level of fibrinogen from day 5 till the end of experiment. Progression of the HLH coincided with a temporary increase in the serum levels of MCSF levels (early stage of disease) and GMCSF levels (2-3 pays post infection).

CONCLUSIONS: Hemophagocytic syndrome should be suspected in ASFV (genotypeII) infected pigs.