Application of immunomodulatory therapy in a human brucellosis patient with pancytopenia: A case report

Brucellosis is a common zoonotic infectious disease with diverse and non-specific clinical manifestations caused by Brucella. Although Brucella can cause damage to multiple systems in the human body, hematological complications are relatively rare. We present a case of a 47-year-old male brucellosis patient with pancytopenia. In May 2018, the patient was diagnosed with brucellosis and recovered after receiving antibiotic treatment (rifampicin 600 mg/day and doxycycline 200 mg/day) for six weeks. However, after three years, the patient experienced a recurring high fever. Brucellosis relapse was confirmed based on the patient's clinical history, Rose Bengal plate agglutination test and standard tube agglutination test results. Routine blood examination revealed a decrease in the whole blood cell count, suggesting bone marrow suppression. Bone marrow aspiration and bacterial culture confirmed the diagnosis of brucellosis with pancytopenia. Antibiotic treatment failed to effectively improve the patient's condition. Therefore, a combination of immunomodulatory and antibiotic treatments was used. The antibiotic regimen included oral rifampicin 600 mg/day, intravenous doxycycline hydrochloride 200 mg/day, and subcutaneous injection of human granulocyte-stimulating factor (0.2 mg/day). Immunomodulatory therapy consisted of 20,000 mg/day intravenous human immunoglobulin (pH 4) for five days and 800 mg/day oral pidotimod liquid for 20 days. As the treatment progressed, the count gradually recovered to normal levels, and the symptoms of bone marrow suppression were alleviated. PCR testing revealed the absence of Brucella DNA in both monocyte and serum samples. Furthermore, negative standard tube agglutination test results were obtained. These findings indicate that the immunomodulatory therapy resulted in a complete clearance of Brucella. Therefore, immunomodulatory therapy could be an effective option in cases of brucellosis with pancytopenia that are unresponsive to conventional antibiotic treatment. Further research and clinical evidence are required to confirm and optimize the use of immunomodulatory therapies in patients with brucellosis.