Chavan, Rahul N.

BackgroundComplications from graft‐vs.‐host disease (GVHD), a major contributor to morbidity and mortality following hematopoietic cell transplantation, may be mitigated by early diagnosis and intervention. However, differentiation between acute cutaneous GVHD and other common skin eruptions that develop in the post‐transplantation period, such as drug hypersensitivity reaction, can be challenging clinically and microscopically. Because recent evidence indicates that CD123, a marker of plasmacytoid dendritic cells, can help to distinguish gastrointestinal GVHD from the clinicopathologic mimic cytomegalovirus colitis, we aimed to determine whether CD123 could aid in the diagnosis of acute cutaneous GVHD.MethodsWe studied 12 skin specimens of patients with grades I–II cutaneous GVHD and 12 from patients who had drug hypersensitivity reaction with vacuolar interface changes on biopsy.ResultsNo differences were seen between the two groups with regards to density or distribution of CD123 expression. Specimens representing GVHD showed significantly less spongiosis (P < 0.001) and fewer dermal eosinophils (P = 0.03) compared to those representing drug hypersensitivity reaction.ConclusionsWe conclude that CD123 does not appear to be a useful ancillary test in the diagnosis of acute cutaneous GVHD. Careful correlation between clinical findings and features with microscopy remains the cornerstone of accurate diagnosis of acute cutaneous GVHD.

Abstract Monocytes may contribute to tumor progression in part by mediating tumor-induced immunosuppression. Alterations to the monocyte populations and functions in untreated patients with late-stage melanoma are not fully understood. To characterize these alterations, we compared the frequency, phenotype, and functional capacity of peripheral blood monocytes and other myeloid cells in untreated, newly diagnosed stage IV melanoma patients (n = 18) with those in healthy volunteers. Stage IV untreated melanoma patients exhibited a sizeable decrease in the percentage of monocytes (P &lt; 0.0001) that included a drop in the percentage of the CD14+CD16− classical monocyte pool (P = 0.006). Although there was not a significant difference in the CD14+HLA-DRlow/− monocyte population between the patients with melanoma and the healthy volunteers, the HLA-DR levels were considerably lower in the patients' CD14+CD16+ intermediate (P &lt; 0.0001) and CD14lowCD16+ nonclassical monocyte populations (P = 0.001). Decreased surface expression of CD86 (P = 0.0006) and TNFRII (P = 0.0001) and increased expression of tissue factor and PD-L1 (P = 0.003) were identified on monocytes from patients with melanoma. Furthermore, these monocytes had decreased ability to upregulate CD80 expression and cytokine production following stimulation with agonist of Toll-like receptor 3 (TLR3). Peripheral blood dendritic cell subsets were decreased in untreated stage IV melanoma patients. Our study demonstrates that untreated late-stage melanoma patients exhibit monocytopenia in addition to phenotypic and functional deficiencies that may negatively affect their immune function. These findings open new avenues into examining the role of monocyte populations in melanoma development. Cancer Immunol Res; 2(3); 241–8. ©2013 AACR.