Background: M-HLH is a type of HLH that most often occurs in children in the course of hematological malignancies. The diagnosis is based on meeting the criteria of the HLH-2004 Protocol. The disease has a rapid course, and the lack of proper diagnosis and treatment threatens the patient’s life. Methods: The paper presents the thorough clinical characteristics, course of treatment, and treatment results in 23 patients treated in pediatric hemato-oncology centers in Poland and reported to Polish HLH registry. HLH diagnostic criteria, CNS involvement, coexisting viral infections, genetic test results, treatment modalities, therapeutic responses, relapse incidence, and final outcomes were analyzed. Clinical and laboratory factors were subjected to statistical analysis. Overall survival was estimated using the Kaplan–Meier method for the entire cohort and separately for subgroups defined by type of malignancy and treatment strategy. Separate univariable Cox proportional hazards models were used to explore the association between selected clinical factors and survival. Results: The median age at diagnosis was 11.7 years, in 8 patients HLH symptoms preceded the cancer diagnosis. Acute leukemia was the factor causing M-HLH in 12 patients, in the remaining patients it was lymphoma. The treatment included tumor-directed therapy with or without HLH-directed therapy. The probability of survival in the study group was 0.539 (95% CI 0.364– 0.798). Remission of HLH was statistically significant (p-value = 0.0007) and reduced the risk of death by 90% (HR=0.10). Conclusion: Quick and precise diagnosis and implementation of appropriate treatment bringing the patient into HLH remission is extremely important for survival. Keywords: hemophagocytic lymphohistiocytosis, HLH, malignancy, leukemia, lymphoma, HLH-directed therapy
Wolowiec et al. (Fri,) studied this question.