{"doi":"10.1111/bjh.16696","title":"Peripheral blood mononuclear cells show prominent gene expression by erythroid progenitors in diseases characterized by heightened erythropoiesis","abstract":"Using peripheral blood mononuclear cells (PBMCs) to develop diagnostic or prognostic biomarkers is attractive in diseases where biopsy of the affected tissue is difficult to obtain. The rationale for this approach is that peripheral immune cells are involved in a broad array of diseases. For example, peripheral blood monocytes, a component of PBMCs, mature to macrophages at the location of disease such as the lung perivascular area in pulmonary hypertension.1 Genomic profiles derived from PBMCs have been used in biomarker development for a number of conditions, including cancer,2 chronic obstructive pulmonary disease,3 heart disease,4 idiopathic pulmonary fibrosis,5 pulmonary arterial hypertension,6 metabolic syndrome,7 rheumatoid arthritis8 and sickle cell disease.9 PBMCs are peripheral blood cells with a round nucleus, which form a distinct layer during density gradient centrifugation of peripheral blood samples. PBMCs are comprised of lymphocytes (70–90%), monocytes (10–20%), dendritic cells (1–2%),10 and a trace amount of circulating stem cells including erythroid progenitors.11 As a matter of fact, PBMCs are a source of erythroid progenitors allowing evaluation of their functional characteristics.12 The cell types comprising PBMCs have distinct expression profiles13 and the cell composition of PBMCs can also depend on disease conditions.14 We observed that some of the most differentially expressed genes in PBMCs from patients with accentuated erythropoiesis are erythroid genes, which led us to test the hypothesis that this observation is related to an elevation of peripheral erythroid progenitors in the PBMC fraction in these diseases. Chuvash erythrocytosis (CE) is a congenital disorder with elevated hypoxia-inducible factor (HIF) signalling at normoxia due to the homozygous VHLR200W mutation. It is characterized by heightened erythropoiesis as manifested by elevated erythropoietin levels and red blood cell counts. In a previous microarray gene expression study using PBMCs, we found that many of the 29 genes whose expression levels increased by ≥1·5-fold in CE relative to healthy individuals appeared to have erythrocyte- rather than PBMC-related functions.15 In the present study, we performed RNA sequencing in purified cell fractions of reticulocytes, platelets and granulocytes from CE patients and assessed the expression patterns of the genes that were up-regulated in PBMCs by ≥1·5-fold. As the RNA preparation from reticulocytes includes a haemoglobin RNA depletion step, the HBB and HBD genes, encoding the beta and delta globin chain, respectively, were removed from further analysis, resulting in 27 genes. Based on expression correlation among cell fractions of reticulocytes, platelets and granulocytes, the 27 genes were separated into two distinct hierarchical clusters (Fig 1A). The 16 genes in Cluster I were in general related to erythroid function (Table SI) and were enriched in the Reactome pathway, ‘Erythrocytes take up carbon dioxide and release oxygen’ (Benjamini–Hochberg-adjusted P = 0·068). The 11 genes in Cluster II appeared to have a role in immune responses (Table SI) and were enriched in the Reactome pathway, ‘Interferon alpha/beta signalling’ (adjusted P = 0·025). We then looked at the expression of Cluster I genes in reticulocytes, as a proxy of erythroid progenitors, and in platelets and granulocytes, as proxies of non-erythroid cells. The three cell fractions are excluded from the PBMC fraction during density gradient centrifugation. High expression levels of the Cluster I genes were observed specifically in reticulocytes, but not in platelets or granulocytes (Fig 1B). Reticulocyte expression of the majority of Cluster I genes was not significantly different between CE patients and healthy individuals (adjusted P > 0·05). This suggests that Cluster I gene expression observed in PBMCs of CE patients likely originates from erythroid progenitors. In keeping with this conclusion, the first principal compone","journal":"British Journal of Haematology","year":2020,"id":85530,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":5,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9597,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":301175,"name":"Jihyun Song","orcid":"0000-0002-1269-0892","position":1,"is_corresponding":false},{"id":269842,"name":"Binal N. Shah","orcid":"0000-0001-5169-7301","position":2,"is_corresponding":false},{"id":24998,"name":"Sergeï Nekhai","orcid":"0000-0003-0744-7887","position":3,"is_corresponding":false},{"id":438541,"name":"Galina Miasnikova","orcid":null,"position":4,"is_corresponding":false},{"id":438542,"name":"Adelina Sergueeva","orcid":null,"position":5,"is_corresponding":false},{"id":301181,"name":"Josef T. Prchal","orcid":"0000-0002-8019-2940","position":6,"is_corresponding":false},{"id":269831,"name":"Victor R. Gordeuk","orcid":"0000-0003-4725-7295","position":7,"is_corresponding":false},{"id":351694,"name":"Xu Zhang","orcid":"0000-0002-7732-1385","position":0,"is_corresponding":true}],"reference_count":19,"raw_metadata":null,"created_at":"2026-07-18T21:58:16.217017Z","pmid":"32399971","pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}