👤 Ingo Helbig

Post-transplant lymphoproliferative disorder (PTLD) is a potentially life-threatening complication, often associated with Epstein-Barr virus (EBV) in the early period after hematopoietic stem cell transplantation (HSCT). Clinical manifestations range from localized to disseminated disease. The cornerstone of therapy is the reduction of immunosuppression and/or immunochemotherapy. We report a 39-year-old female who developed PTLD presenting as lymphoplasmacytic lymphoma (LPL) associated with hemophagocytic lymphohistiocytosis (HLH). Diagnostic evaluation was blurred by features of severe hepatic acute graft-versus-host disease (GVHD). An initial treatment consisted of high-dose steroids, but it failed. As second-line treatment, ruxolitinib and mycophenolate mofetil were administered, but they were ineffective, and the patient's condition worsened. Further detailed evaluation revealed the presence of monoclonal protein immunoglobulin G (IgG) lambda and bone marrow infiltration by clonal plasmacytoid B lymphocytes. The HLH criteria were also met. Immunosuppression was discontinued, and dexamethasone with rituximab was initiated, but no response was observed. The patient eventually died from multiple organ failure. The learning points from this case emphasize that HLH in the context of PTLD remains underreported, with few cases documented in the literature. Studies indicate that EBV plays a central role in pathogenesis, often presenting with systemic inflammation and immune dysregulation. Diagnostic challenges arise due to overlapping clinical features with other post-transplant complications. Treatment strategies vary but often involve balancing immunosuppression reduction and chemotherapy, with rituximab being a cornerstone for EBV-driven cases. This case underscores the necessity of early recognition to mitigate severe outcomes. Show less

Microtubule-actin cross-linking factor 1 (MACF1) is a large protein of the spectraplakin family, which is essential for brain development. MACF1 interacts with microtubules through the growth arrest-specific 2 (Gas2)-related (GAR) domain. Heterozygous MACF1 missense variants affecting the zinc-binding residues in this domain result in a distinctive cortical and brain stem malformation. Evidence for other MACF1-associated disorders is still limited. Here, we present a cohort of 45 individuals with heterozygous or bi-allelic MACF1 variants to explore the phenotypic spectrum and assess possible pathogenic relevance. We observe that de novo heterozygous missense variants in the EF-hand domains also result in distinctive brain malformation and provide experimental evidence that variants in the EF-hand/GAR module increase microtubule binding, suggestive of a toxic gain of function. Notably, no phenotype-genotype correlation was possible for the remaining heterozygous variants in other domains. A clinical review of eight families with bi-allelic variants reveals a possible complex neurodevelopmental syndrome of the central and peripheral nervous systems. In these individuals, bi-allelic variants mostly affect the Plakin domain. Furthermore, RNA sequencing and chromatin immunoprecipitation (ChIP) analyses of human fetal brain tissue reveal five MACF1 isoforms with region-specific expression, differing in their exon 1 transcription start sites but splicing to a common exon 2. This differential expression explains the frontal-predominant lissencephaly in an individual with a homozygous stop-gain in exon 1 (MACF1-204: c.70C>T [p.Arg24∗]), as this isoform is preferentially expressed in the frontal cortex. We conclude that MACF1-related disorders are strictly linked to domain function and the level of transcript expression, explaining the observed wide clinical heterogeneity. Show less

Since the beginning of the coronavirus disease 2019 (COVID-19) pandemic, there has been increasing urgency to identify pathophysiological characteristics leading to severe clinical course in patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Human leukocyte antigen alleles (HLA) have been suggested as potential genetic host factors that affect individual immune response to SARS-CoV-2. We sought to evaluate this hypothesis by conducting a multicenter study using HLA sequencing. We analyzed the association between COVID-19 severity and HLAs in 435 individuals from Germany ( We describe a potential association of HLA-C*04:01 with severe clinical course of COVID-19. Carriers of HLA-C*04:01 had twice the risk of intubation when infected with SARS-CoV-2 (risk ratio 1.5 [95% CI 1.1-2.1], odds ratio 3.5 [95% CI 1.9-6.6], adjusted HLA-C*04:01 carrier state is associated with severe clinical course in SARS-CoV-2. Our findings suggest that HLA class I alleles have a relevant role in immune defense against SARS-CoV-2. Funded by Roche Sequencing Solutions, Inc. Show less