Thrombocytopenia and the risk for MDS in patients with VEXAS. (A) PB counts (from the same timepoint) are compared between patients with MDS diagnosis on BM biopsy and those without MDS diagnosis (at either the last BM biopsy performed or the biopsy before treatment for patients with MM). Median platelet counts at the time of MDS diagnosis were significantly lower (P value 0.0030) compared with those of patients whose BM was not diagnostic of MDS (this included 2 patients with MM). The 2 groups were compared using nonparametric Student t test. The error bars represent the range and middle horizontal bars mark the median. (B) Serial blood counts and BM evaluations for UPN-14 are used as an example to show disease progression. Macrocytic anemia was seen at the onset of inflammatory disease, which progressed over the next 5 years to RBC transfusion dependence. After 5 years, there was steady decline in platelet counts to <50 × 10³/µL 1 year later, when the BM biopsy revealed diagnosis of MDS-SLD. Previous BM evaluations did not reveal a diagnosis. ALC, absolute lymphocyte count; AMC, absolute monocyte count; ARC, absolute reticulocyte count.