Hemoglobins With High Oxygen Affinity Leading to Erythrocytosis. New Variants and New Concepts

This review brings some new insights on erythrocytosis of genetic origin related to problems of oxygen delivery by hemoglobin (Hb). A few molecular mechanisms are individualized among the about 100 Hb variants that cause compensatory erythrocytosis. The most frequently observed structural modifications are localized in the α1β2 interface, or at the C-terminal. They impair formation of a stable T state. Others mutations modify directly or indirectly the surrounding of the heme and the site where oxygen binds. A special interest is brought to the dose effect considering the possibility for formation of hybrid tetramers with altered oxygen binding properties. Homozygous cases, and patients who are compound heterozygotes for a high oxygen affinity Hb and a thalassemia (thal), are discussed. Several examples are provided, specially documented for Hb Olympia [β20(B2)Val→Met] and Hb Saint Nazaire [β103(G5)Phe→Ile]. Other mechanisms leading to erythrocytosis are discussed, and finally, an algorithm is proposed for etiological diagnosis.     

Detection of Hb Anti-Lepore Hong Kong (NG_000007.3: g.63154_70565dup) in Chinese Individuals

We have identified four Chinese individuals from three unrelated families with raised Hb A₂ levels. The anti-Lepore hybrid hemoglobin (Hb) variant was amplified using a pair of primers, 5′ to the β-globin gene Cap site and 3′ to the δ-globin gene polyadenylation site (polyA) region, respectively. Direct sequencing of the βδ fusion products confirmed the anti-Lepore Hong Kong (NG_000007.3: g.63154_70565dup) variant. We found that this anti-Lepore variant is positioned in zone 3 on the capillary electrophoresis system. It may help in differential diagnosis of Hb variants and providing better information in clinical counseling.     

A Clinical Update of the Hb Siirt [β27(B9)Ala→Gly; HBB: c.83C>G] Hemoglobin Variant

We report a clinical update of the hemoglobin (Hb) variant [β27(B9)Ala→Gly; HBB: c.83C>G], named Hb Siirt, that was previously described as a silent variant in a 23-year-old Kurdish female. The patient was also a carrier of the codon 5 (–CT) (HBB: c.17_18delCT) frameshift mutation and of the ααα ^{anti 3.7} triplication. Her initial moderate β-thalassemia intermedia (β-TI) phenotype worsened with time, causing the patient to become a transfusion-dependent subject at the age of ～40 years. Subsequent molecular characterization of both parents revealed that the Hb Siirt variant was inherited by the mother, while the other two globin alterations (HBB: c.17_18delCT and ααα^{anti 3.7} triplication) were genetically transmitted by the father. The latter remained a carrier of a mild β-TI phenotype throughout his life, at least until the age of 65 years. We hypothesize that the worsened clinical conditions in the daughter were due to the additional, maternally inherited Hb Siirt variant. However, protein 3D conformational analysis did not seem to reveal substantial overall structural changes. Among the other three described variants [Hb Volga (HBB: c.83C>A), Hb Knossos (HBB: c.82?G>T), Hb Grange-Blanche (HBB: c.83C>T] that are due to nucleotide substitutions at codon 27 of the β-globin gene; only Hb Knossos causes a β⁺-thalassemia (β⁺-thal) phenotype.     

Risk factors for progression to acute respiratory failure after casirivimab and imdevimab administration: A retrospective study

BackgroundCasirivimab and imdevimab are effective in preventing hospitalization in outpatients with coronavirus disease 2019 (COVID-19); however, disease progression after casirivimab and imdevimab administration has been reported. This study aimed to elucidate the risk factors for disease progression after casirivimab and imdevimab administration.MethodsThis retrospective study included patients with COVID-19 who received casirivimab and imdevimab at Hiroshima City Funairi Citizens Hospital between August 6, 2021, and October 10, 2021. All patients had at least one risk factor for severe disease and were treated on admission. The patients’ background characteristics and test results at the first visit were analyzed. The patients were divided into two groups (progressed and improved) based on whether they progressed to acute respiratory failure during hospitalization.ResultsSixty-seven patients were included: 9 patients in the progressed group (median age, 56 years) and 58 patients in the improved group (median age, 51 years). Age, coexistence rate of diabetes, cycle threshold value of polymerase chain reaction test, rate of detectable pneumonia on chest radiographs or chest computed tomography images, lymphocyte count, and the levels of C-reactive protein, interleukin-6, glucose, and glycated hemoglobin were significantly different between the two groups. Multivariate logistic regression analysis revealed that the coexistence of diabetes and the presence of detectable pneumonia on chest radiographs were independent factors predicting the progression to acute respiratory failure.ConclusionAcute respiratory failure after antibody therapy with casirivimab and imdevimab may develop in patients with diabetes or detectable pneumonia on chest radiographs at the first visit.     

Prognostic Implications of Declining Hemoglobin Content in Patients Hospitalized With Acute Coronary Syndromes

BackgroundContemporary definitions of bleeding endpoints are restricted mostly to clinically overt events. Whether hemoglobin drop per se, with or without overt bleeding, adversely affects the prognosis of patients with acute coronary syndrome (ACS) remains unclear.ObjectivesThe aim of this study was to examine in the MATRIX (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox) trial the incidence, predictors, and prognostic implications of in-hospital hemoglobin drop in patients with ACS managed invasively stratified by the presence of in-hospital bleeding.MethodsPatients were categorized by the presence and amount of in-hospital hemoglobin drop on the basis of baseline and nadir hemoglobin values and further stratified by the occurrence of adjudicated in-hospital bleeding. Hemoglobin drop was defined as minimal (<3 g/dl), minor (≥3 and <5 g/dl), or major (≥5 g/dl). Using multivariate Cox regression, we modeled the association between hemoglobin drop and mortality in patients with and without overt bleeding.ResultsAmong 7,781 patients alive 24 h after randomization with available hemoglobin data, 6,504 patients (83.6%) had hemoglobin drop, of whom 5,756 (88.5%) did not have overt bleeding and 748 (11.5%) had overt bleeding. Among patients without overt bleeding, minor (hazard ratio [HR]: 2.37; 95% confidence interval [CI]: 1.32 to 4.24; p = 0.004) and major (HR: 2.58; 95% CI: 0.98 to 6.78; p = 0.054) hemoglobin drop were independently associated with higher 1-year mortality. Among patients with overt bleeding, the association of minor and major hemoglobin drop with 1-year mortality was directionally similar but had wider CIs (minor: HR: 3.53 [95% CI: 1.06 to 11.79]; major: HR: 13.32 [95% CI: 3.01 to 58.98]).ConclusionsAmong patients with ACS managed invasively, in-hospital hemoglobin drop ≥3 g/dl, even in the absence of overt bleeding, is common and is independently associated with increased risk for 1-year mortality. (Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox; NCT01433627)     

Congenital methemoglobinemia caused by Hb-MRatnagiri (beta-63CAT-->TAT, His-->Tyr) in an Indian family

Hb-M is a very rare hemoglobinopathy in the Indian subcontinent. We report a family with Hb-M with lifelong cyanosis from the Ratnagiri district in western India. The propositus was a 11-year-old female child with a history of increasing cyanosis exacerbated by fever and weakness. Similar complaints were also noted in her mother and five maternal family members. There was no history of cardiac illness or exposure to drugs and chemicals. The methemoglobin level was 39.3% in the propositus and 21.1% in her mother with normal NADH-methemoglobin reductase activity. Abnormal absorption peaks by spectroscopic analysis, presence of hemoglobin instability, and a slow-moving band on starch gel electrophoresis supported the presence of Hb-M. Automated DNA sequence analysis of the beta globin gene showed a C-->T substitution at codon 63. This leads to a substitution of histidine (CAT) by tyrosine (TAT) at the beta 63 (E7) position, similar to Hb-M Saskatoon. We have named this variant as Hb-M(Ratnagiri).     

苏叶地黄汤治疗慢性肾衰竭临床观察

目的：观察苏叶地黄汤治疗早中期慢性肾衰竭（ chronic renal fcilure,CRF）的临床疗效。方法：将符合标准的68例CRF患者在基础治疗同时予以自拟苏叶地黄汤口服,观察治疗前后患者尿素氮、肌酐、内生肌酐清除率、血红蛋白、24 h尿蛋白定量变化情况。结果：68例患者中显效43例,稳定14例,无效11例,有效率为83.80%。治疗后尿素氮、肌酐、内生肌酐清除率、24 h尿蛋白定量等指标均有明显改善,与治疗前比较,差异有统计学意义（ P<0.05）。结论：苏叶地黄汤能有效改善早中期CRF患者肾功能水平。