ABSTRACT
Background: Cystic echinococcosis is non-endemic in Denmark and primarily diagnosed in migrants from endemic areas. Here, we report a case of pulmonary cystic echinococcosis in a Danish woman with no history of longer-term stays abroad, only holiday travelling to tourist destinations. This is the first case reported in international literature from Denmark where the causative parasite was identified to species and genotype level. Case: A 27-year-old pregnant Danish woman was admitted for examination because of haemoptysis for three months.Chest X-ray and computed tomography revealed a cystic structure in the left lung and a left-sided thoracotomy was performed to remove the cyst. Postoperative histopathological examination revealed a hyaline membrane and protoscoleces. Subsequently, infection with Echinococcus granulosus was confirmed by molecular methods. The causative agent was further characterised as E. granulosus sensu stricto G1, which is not known to have an established life cycle in Denmark. It was concluded that the infection was most likely acquired during a tourist travel to an endemic country. The patient was treated with albendazole for four weeks. Conclusion: This case of pulmonary cystic echinococcosis in a person who had lived in Denmark and had history of only short-term tourist travelling abroad highlights that the disease may be acquired during tourist travelling. Thus, a diagnosis of cystic echinococcosis should be considered not only in migrants from endemic countries but also in travellers upon incidental findings of a lung or liver cysts. The case also exemplifies the importance of reaching a diagnosis at species and genotype level.
ABSTRACT
Antibody-based immunotherapy targeting the interaction between programmed cell death 1 (PD-1) and its ligand PD-L1 has shown impressive clinical outcomes in various cancer types, including nonsmall cell lung cancer (NSCLC). However, regulatory mechanisms in this immune checkpoint pathway still needs clarification. PD-L2 is structurally homologous to PD-L1 and is a second PD-1 ligand. Alternative mRNA splicing from the CD274 and PDCD1LG2 genes holds the potential to generate PD-L1 and PD-L2 isoforms, respectively, with novel functionality in regulation of the PD-1 immune checkpoint pathway. Here, we describe alternative splicing in NSCLC cells potentially generating eight different PD-L2 isoforms from the PDCD1LG2 gene. Extension of exon 6 by four nucleotides is the most prominent alternative splicing event and results in PD-L2 isoform V with a cytoplasmic domain containing a 10 amino acid extension. On average 13% of the PDCD1LG2 transcripts in NSCLC cell lines and 22% of the transcripts in NSCLC tumor biopsies encode PD-L2 isoform V. PD-L2 isoform V localizes to the cell surface membrane but less efficiently than the canonical PD-L2 isoform I. The cytoplasmic domains of PD-1 ligands can affect immune checkpoint pathways by conferring membrane localization and protein stability and thereby represent alternative targets for immunotherapy. In addition, cytoplasmic domains are involved in intracellular signalling cascades in cancer cells. The presented observations of different cytoplasmic domains of PD-L2 will be important in the future delineation of the PD-1 immune checkpoint pathway.
