Procalcitonin elevation in febrile recipients during pre-transplant conditioning with anti-thymocyte globulin.

Infection is a major contributor to non-relapse mortality in allogeneic hematopoietic stem cell transplantation (allo-HSCT). Detecting infectious diseases in febrile patients during pretransplant conditioning is crucial for subsequent transplant success. Procalcitonin (PCT) is an auxiliary diagnostic marker of severe bacterial infections and has been proposed as a useful predictor of infection in patients undergoing allo-HSCT. Pre-transplant use of anti-thymocyte globulin (ATG) can cause side effects, such as fever and hypotension, which must be distinguished from infectious diseases. Although ATG administration may increase PCT levels, data on PCT levels in febrile patients after ATG administration are limited. Furthermore, no studies have compared PCT levels during allo-HSCT conditioning using ATG or non-ATG regimens. To investigate whether ATG increases PCT levels during febrile episodes in pre-transplant conditioning and whether PCT could be used to discriminate infections during this period, we analyzed 17 ATG and 59 non-ATG patients with fever and who underwent PCT level measurements during pre-transplant conditioning. Our findings revealed that ATG administration was the only significant factor that increased PCT positivity during fever (p = 0.01). In contrast, infectious diseases did not affect PCT positivity in the ATG group (p = 0.24). Furthermore, bloodstream infection was a significant risk factor for PCT positivity in patients who received non-ATG regimens (p < 0.01). Incorporating PCT levels into the diagnostic workup for infectious diseases requires careful consideration, particularly for patients receiving ATG regimens.

Thrombospondin-1 is an endogenous substrate of cereblon responsible for immunomodulatory drug-induced thromboembolism.

ABSTRACT: Immunomodulatory drugs (IMiDs) are key drugs for treating multiple myeloma and myelodysplastic syndrome with chromosome 5q deletion. IMiDs exert their pleiotropic effects through the interaction between cell-specific substrates and cereblon, a substrate receptor of the E3 ubiquitin ligase complex. Thus, identification of cell-specific substrates is important for understanding the effects of IMiDs. IMiDs increase the risk of thromboembolism, which sometimes results in fatal clinical outcomes. In this study, we sought to clarify the molecular mechanisms underlying IMiDs-induced thrombosis. We investigated cereblon substrates in human megakaryocytes using liquid chromatography-mass spectrometry and found that thrombospondin-1 (THBS-1), which is an inhibitor of a disintegrin-like and metalloproteinase with thrombospondin type 1 motifs 13, functions as an endogenous substrate in human megakaryocytes. IMiDs inhibited the proteasomal degradation of THBS-1 by impairing the recruitment of cereblon to THBS-1, leading to aberrant accumulation of THBS-1. We observed a significant increase in THBS-1 in peripheral blood mononuclear cells as well as larger von Willebrand factor multimers in the plasma of patients with myeloma, who were treated with IMiDs. These results collectively suggest that THBS-1 represents an endogenous substrate of cereblon. This pairing is disrupted by IMiDs, and the aberrant accumulation of THBS-1 plays an important role in the pathogenesis of IMiDs-induced thromboembolism.

A case of successful CAR-T cell therapy for early isolated CNS recurrence of DLBCL with persistent CAR-T cells.

Secondary central nervous system (CNS) lymphomas typically require CNS-penetrating drugs; however, the available agents are limited with temporary effects and poor outcomes. Chimeric antigen receptor T (CAR-T) cell therapy (lisocabtagene maraleucel; liso-cel) has been used to treat a few cases of isolated secondary CNS lymphoma. Herein, we report the case of a 66-year-old male diagnosed with diffuse large B-cell lymphoma (Ann Arbor grade IV; R-IPI, good risk; CNS IPI: Intermediate risk) who achieved complete remission (CR) after six courses of R-CHOP therapy. Three months later, he presented with ptosis and eye movement disorder. Systemic CT and bone marrow examination revealed no lymphoma. Although cranial-enhanced MRI showed normal findings, an increased number of B-cells (51/µL) with the original lymphoma phenotype (CD19+CD79a+CD5-CD10-CD20-Igλ+) was detected in cerebrospinal fluid (CSF), indicating an isolated CNS relapse. Seven high-dose methotrexate courses led to partial response. Subsequently, the patient received CAR-T cell therapy with tolerable adverse events - cytokine release syndrome treated with tocilizumab, no immune effector cell-associated neurotoxicity syndrome, and bone marrow failure treated with granulocyte-colony stimulating factor and eltrombopag. Sequential flow cytometry revealed a high peak of CAR-T cells and the presence of residual CAR-T cells in the peripheral blood, indicating immune surveillance of CNS lymphoma by CAR-T cells. This treatment led to a second CR. This case is the first to validate the efficacy and safety of CAR-T cell therapy for isolated secondary CNS lymphoma in clinical practice. Future accumulation of evidence on the efficacy and safety of CAR-T cell therapy is essential.