Real-life impact of immunologic tests to predict relapse after treatment cessation in patients with bullous pemphigoid: A French multicenter retrospective study.

BACKGROUND: A high level of anti-BP180 antibodies on enzyme-linked immunosorbent assay and a persistent positive direct immunofluorescence at the end of treatment (immunologic tests, [ITs]) are predictors of relapse after treatment cessation (TC) in patients with bullous pemphigoid. OBJECTIVE: To evaluate the real-life impact of the immunologic-based decision of TC on the 3- and 6-month relapse rates after TC in bullous pemphigoid. METHODS: Retrospective multicentric study included patients followed almost 6 months after TC. Patients were classified according to whether the TC decision was in accordance with the results of ITs performed during the 3 months before TC, despite the results of ITs or without ITs performed. RESULTS: We included 238 patients. Three months after TC, 36 patients showed relapse: 14 of 95 patients with TC in accordance with IT results (14.7%); 5 of 21 with TC despite ITs (23.8%); and 17 of 122 with TC without ITs (13.9%; P = .5). Six months after TC, the relapse rate was 18.9%, 28.6%, and 18.9% (P = .56), respectively, in the 3 groups. LIMITATIONS: The retrospective design and the limited follow up. CONCLUSION: In real-life practice, in bullous pemphigoid, the 3- and 6-month relapse rates were not significantly reduced with TC decision based on results of ITs as compared with a classic clinical-based decision.

Primary cutaneous large B-cell lymphomas: relevance of the 2017 World Health Organization classification: clinicopathological and molecular analyses of 64 cases.

AIMS: We applied the 2017 World Health Organization (WHO) classification criteria to categorise a series of 64 primary cutaneous large B-cell lymphomas (PCLBCLs), containing a majority (≥80%) of large cells and a proliferative rate of ≥40%, raising the problem of the differential diagnosis between PCLBCL, leg type (PCLBCL-LT) and primary cutaneous follicle centre lymphoma, large cell (PCFCL-LC). The aims were to determine the reproducibility and prognostic relevance of the 2017 WHO criteria. METHODS AND RESULTS: Morphology and phenotype identified 32 PCLBCLs-LT and 25 PCFCLs-LC; seven cases (11%) remained unclassified. Morphology was less reproducible than immunophenotype. Pertinent markers for the differential diagnosis were MUM1, FOXP1, CD10, and IgM. bcl-2 and bcl-6 were expressed by both PCFCLs-LC and PCLBCLs-LT at substantial levels. Neither Ki67 expression nor p63 expression was of diagnostic value. MYD88 was found to be mutated only in PCLBCLs-LT (n = 22, 69%). According to Hans/Hans modified algorithms, 23 of 25 PCFCLs-LC had germinal centre (GC) status, and the 32 PCLBCLs-LT had non-GC status. Overall survival was poorer for PCLBCLs-LT than PCFCLs-LC (P = 0.0002). Non-GC cases had poorer overall survival than GC cases (P = 0.0007). In PCLBCLs-LT, MYC expression was associated with cutaneous relapses (P = 0.014). When GC/non-GC status was applied to unclassified cases, only a single case remained discordant. CONCLUSIONS: Our results support the 2017 WHO classification criteria for PCLBCL diagnosis. The Hans modified algorithm using CD10 and MUM1 distinguished PCFCLs-LC from PCLBCLs-LT with optimal diagnostic value without requiring bcl-6 immunolabelling (poorly reproducible). Rare unclassified cases may constitute a provisionally heterogeneous subgroup for which GC/non-GC status (relevant for prognosis) may guide therapeutic decisions.