Measurable Residual Disease by Mass Spectrometry and Next-Generation Flow to Assess Treatment Response in Myeloma.

Quantitative immuneprecipitation mass-spectrometry (QIP-MS) allows the identification of the M-protein in patients with multiple myeloma (MM) otherwise in complete response, and could be considered suitable for measurable residual disease (MRD) evaluation in peripheral blood. In the context of the GEM2012MENOS65 and GEM2014MAIN trials, we compared the performance of QIP-MS in serum with next-generation flow (NGF) cytometry in bone marrow to assess MRD in paired samples obtained post-induction, transplant, consolidation and after 24 cycles of maintenance. At each time point, both NGF and QIP-MS were able to segregate two groups of patients with significantly different progression-free survival (PFS); when the evolution of the results obtained with either method was considered, maintaining or converting to MRD negativity was associated with longer survival, significantly better when compared to sustaining or converting to MRD positivity. Of note, reemergence of MRD by QIP-MS was associated with high risk of imminent clinical progression. In conclusion, MRD evaluation by NGF and MS achieve similar prognostic value based in single time point assessments and kinetics. Thus, the minimally-invasive nature of MRD monitoring by MS represents a breakthrough in high-sensitive response assessment in MM. GEM2012MENOS65: #NCT01916252 and EudraCT as #2012-005683-10. GEM2014MAIN: #NCT02406144 and at EudraCT as 2014-00055410.

T-cell immune profile in blood of systemic mastocytosis: Association with disease features.

BACKGROUND: Systemic mastocytosis (SM) is a heterogeneous disease characterized by an expansion of KIT-mutated mast cells (MC). KIT-mutated MC display activated features and release MC mediators that might act on the tumour microenvironment and other immune cells. Here, we investigated the distribution of lymphocyte subsets in blood of patients with distinct subtypes of SM and determined its association with other disease features. METHODS: We studied the distribution of TCD4+ and TCD4- cytotoxic cells and their subsets, as well as total NK- and B cells, in blood of 115 SM patients-38 bone marrow mastocytosis (BMM), 67 indolent SM (ISM), 10 aggressive SM (ASM)- and 83 age-matched healthy donors (HD), using spectral flow cytometry and the EuroFlow Immunomonitoring panel, and correlated it with multilineage KITD816V, the alpha-tryptasemia genotype (HαT) and the clinical manifestations of the disease. RESULTS: SM patients showed decreased counts (vs. HD) of TCD4- cytotoxic cells, NK cells and several functional subsets of TCD4+ cells (total Th1, Th2-effector memory, Th22-terminal effector and Th1-like Tregs), together with increased T-follicular-helper and Th1/Th17-like Treg counts, associated with different immune profiles per diagnostic subtype of SM, in multilineal versus MC-restricted KITD816V and in cases with a HαT+ versus HαT- genotype. Unique immune profiles were found among BMM and ISM patients with MC-restricted KITD816V who displayed HαT, anaphylaxis, hymenoptera venom allergy, bone disease, pruritus, flushing and GI symptoms. CONCLUSION: Our results reveal altered T- and NK-cell immune profiles in blood of SM, which vary per disease subtype, the pattern of involvement of haematopoiesis by KITD816V, the HαT genotype and specific clinical manifestations of the disease.