Bone marrow osteoprotegerin (OPG) and interleukin-8 (IL-8) immunostaining in patients with Ph-negative myeloproliferative neoplasms (MPN): Clinical correlations

We evaluated the expression and intensity of IL-8 and OPG immunostaining in BM biopsies of MPN patients at diagnosis and correlated the results with clinical parameters. Seventy-six patients were studied, diagnosed with MPN from 1984 to 2012 with a median follow up period of 55 months. IL-8 and OPG immunostaining was performed on paraffin-embedded sections of formalin fixed BM biopsies, carried out at the time of diagnosis, using the two-step peroxidase conjugated polymer technique. Grade of positivity and intensity of IL-8 and OPG expression was scored according to a 0 to 3 scale. Statistical analysis was performed conventionally, using the SPSS version 22.0 package, and p values <0.05 were considered significant. High intensity of IL-8 expression in megakaryocytes correlated, in the whole cohort, with neutrophilia (p=0.005) and high haemoglobin (p=0.001). High intensity of OPG expression in megakaryocytes correlated high haemoglobin (p=0.017) and a favorable karyotype (p=0.01). Most importantly, low OPG intensity in megakaryocytes correlated with poor survival (p=0.026) in the whole patient series. In conclusion, our most important finding is that high intensity of OPG expression in megakaryocytes correlated with increased survival and a favorable karyotype in patients with MPN, a finding that has not been reported yet.