Low ratio of IL-10 to IFN-γ and Low IL-10 level indicate good prognosis in Salmonella enterica serovar Typhimurium triggered secondary hemophagocytic lymphohistiocytosis: a case report and literature review

Abstract

Background: Secondary hemophagocytic lymphohistiocytosis triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients. There is a specific cytokine pattern to differentiate HLH subtypes, including IFN-γ, IL-10, and IL-6, and the ratio of IL-10 to IFN-γ, which can guide HLH treatments choice. Case presentation: We present a pediatric 9-year old patient who presented with fever and pancytopenia for three days into our hospital, who showed positive results of Salmonella enterica serovar Typhimurium, Human Rhino Virus and Mycoplasma Pneumoniae infections. At the time of admission to our institution, the patient’s Th1/Th2 cytokine results showed that IL-6 was 326 pg/ml, IL-10 was 9.1 pg/ml, and IFN-γ was 246.7 pg/ml, with a ratio of IL-10 to IFN-γ was 0.04. In this study, this patient received meropenem, linezolid, and cefoperazone/sulbactam for anti-infection therapy, combined with high dose methylprednisolone therapy and anti-shock supportive treatments for twice. After careful evaluation, this patient did not receive HLH chemotherapy during the whole disease course, and he recovered well. Conclusions: Early antimicrobial and supportive treatment would be enough for Salmonellatriggered sHLH with a ratio of IL-10 to IFN-γ ≤ 1.33, and IL-10 ≤ 10.0 pg/ml, and/or IFN-γ ≤ 225 pg/ml on admission, and HLH-94/2004 protocol was not necessary in such condition.