Modified treatment for pediatric Multisystemic Histiocytosis during SARS-CoV2 lockdown. Serie of cases.

MARIANA NANA; EZEQUIEL RECONDO; STELLA BALLESTRINI; MARTIN HORNOS; MERCEDES MORICI; GUIDO LUIS DALLA VECHIA; CINTHIA M OLEXEN; ANDREA E ERRASTI; E. ANTONIO CARRERA SILVA; DIEGO A. ROSSO

Estocolmo

Congreso; 38th Annual Meeting of the Histiocyte Society; 2022

Histiocyte Society

PURPOSE: Backbone treatment of multisystemic histiocytosis (MS-LCH) is steroids with vinblastine and/or cytarabine. This approach requires a central venous access (CVA) placement because of the possibility of cytostatic extravasation and length of treatment. SARS-CoV2 lockdown forced us to adapt standard treatment in order to skip CVA placement, use of available cytostatic, reduce toxicity and hospital visits. We report here our experience using a modified treatment (MT). METHODS: Series of 4 patients (p) of MS-LCH treated in 3 public institutions during 2020 with a MT. Induction: Oral Methyl prednisone 40 mg/m2 daily for 4 weeks, tapering for 2 weeks, and subcutaneous/intravenous cytarabine 100 mg/m2/day for 4 days, day 1-14. Evaluation at 6th week. If NAD or ADB, continuation treatment: Methyl prednisone 40 mg/m2/day for 5 days every 15 days and subcutaneous/intravenous cytarabine 100 mg/m2/day for 4 days every 3 weeks. Clinical and hematologic evaluation every 3 weeks. Additionally, we studied the presence of circulating CD207+/CD1a+ cells (cc) by flow cytometry. RESULTS: Female 3p. Identical twins (p#1,2). Age at diagnosis: 7, 7, 11 and 29 months. Involvement: skin, lymph nodes and hematopoietic (p#1,2,3,4), ear (p#2,3,4), bone (p#3), hepatosplenomegaly (p#4). All p achieved ADB after 6 weeks of treatment. Reactivation: 1p because of non-adherence to treatment. No grade 3/4 toxicity. COVID infection with mild symptoms (p#1,2). Status: all alive at 2 years (p#1,2) and 1 year (p#3,4) of treatment. Interestingly, all p started with a low score for cc and increased them with the treatment in negative trend to their clinical status, indicating that medication could be restraining cc migration to the lesions.CONCLUSION: This MT was feasible to treat patients with MS-LCH during the SAR-Cov2 lockdown, even those with risk organ involvement. We were able to skip CVA and reduce toxicity.