Spurious haemoglobinopathy

A signature of hypoxia-related factors reveals functional dysregulation and robustly predicts clinical outcomes in stage I/II colorectal cancer patients

Background

The hypoxic tumor microenvironment accelerates the invasion and migration of colorectal cancer (CRC) cells. The aim of this study was to develop and validate a hypoxia gene signature for predicting the outcome in stage I/II CRC patients that have limited therapeutic options.

Methods

The hypoxic gene signature (HGS) was constructed using transcriptomic data of 309 CRC patients with complete clinical information from the CIT microarray dataset. A total of 1877 CRC patients with complete prognostic information in six independent datasets were divided into a training cohort and two validation cohorts. Univariate and multivariate analyses were conducted to evaluate the prognostic value of HGS.

Results

The HGS consisted of 14 genes, and demarcated the CRC patients into the high- and low-risk groups. In all three cohorts, patients in the high-risk group had significantly worse disease free survival (DFS) compared with those in the low risk group (training cohort—HR = 4.35, 95% CI 2.30–8.23, P < 0.001; TCGA cohort—HR = 2.14, 95% CI 1.09–4.21, P = 0.024; meta-validation cohort—HR = 1.91, 95% CI 1.08–3.39, P = 0.024). Compared to Oncotype DX, HGS showed superior predictive outcome in the training cohort (C-index, 0.80 vs 0.65) and the validation cohort (C-index, 0.70 vs 0.61). Pathway analysis of the high- and low-HGS groups showed significant differences in the expression of genes involved in mTROC1, G2-M, mitosis, oxidative phosphorylation, MYC and PI3K–AKT–mTOR pathways (P < 0.005).

Conclusion

Hypoxic gene signature is a satisfactory prognostic model for early stage CRC patients, and the exact biological mechanism needs to be validated further.

Acquired hemoglobin variants and exposure to glucose-6-phosphate dehydrogenase deficient red blood cell units during exchange transfusion for sickle cell disease in a patient requiring antigen-matched blood

Red blood cell exchange (RBCEx) is frequently used in the management of patients with sickle cell disease (SCD) and acute chest syndrome or stroke, or to maintain target hemoglobin S (HbS) levels. In these settings, RBCEx is a category I or II recommendation according to guidelines on the use of therapeutic apheresis published by the American Society for Apheresis. Matching donor red blood cells (RBCs) to recipient phenotypes (e.g., C, E, K-antigen negative) can decrease the risk of alloimmunization in patients with multi-transfused SCD. However, this may select for donors with a higher prevalence of RBC disorders for which screening is not performed. This report describes a patient with SCD treated with RBCEx using five units negative for C, E, K, Fya, Fyb (prospectively matched), four of which were from donors with hemoglobin variants and/or glucose-6-phosphate dehydrogenase (G6PD) deficiency. Pre-RBCEx HbS quantification by high performance liquid chromatography (HPLC) demonstrated 49.3% HbS and 2.8% hemoglobin C, presumably from transfusion of a hemoglobin C-containing RBC unit during a previous RBCEx. Post-RBCEx HPLC showed the appearance of hemoglobin G-Philadelphia. Two units were G6PD-deficient. The patient did well, but the consequences of transfusing RBC units that are G6PD-deficient and contain hemoglobin variants are unknown. Additional studies are needed to investigate effects on storage, in-vivo RBC recovery and survival, and physiological effects following transfusion of these units. Post-RBCEx HPLC can monitor RBCEx efficiency and detect the presence of abnormal transfused units.

An "acquired" hemoglobin J variant in a sickle cell disease patient

We report the case of a rare hemoglobin variant, "Hemoglobin J", discovered while performing hemoglobin electrophoresis following exchange transfusion of a sickle cell disease patient. It is usual practice in our institution to confirm the hemoglobin S level in sickle cell disease patients after red cell exchange. The patient had received 5 red cell units and the source of this variant was traced back to two of those units. Due to the uncertain clinical impact of this variant, and the lack of specific guidelines, the two donors were deferred from future donations to our institution.

Blood Transfusions Leading to Apparent Hemoglobin C, S, and O-Arab Hemoglobinopathies

Context.—Apparent hemoglobinopathies caused by blood transfusions rarely have been reported in the scientific literature.

Objective.—To interpret the abnormal hemoglobins appearing as small peaks on hemoglobin chromatograms or electrophoresis membranes.

Design.—In the clinical laboratories of a university hospital and a metropolitan hospital affiliated with a medical school, we interpreted hemoglobin chromatograms and electrophoresis membranes; correlated them with patients' medical, laboratory, and transfusion records; and when possible, identified the abnormal hemoglobin in the donors' transfusion segments.

Results.—We detected 52 incidences of apparent hemoglobinopathies in 32 recipients caused by blood transfusion, of which 46 were hemoglobin C, 4 were hemoglobin S, and 2 were hemoglobin O-Arab. When first detected, the abnormal hemoglobins in recipients ranged from 0.8% to 14% (median, 5.6%). Multiple transfusions with abnormal hemoglobins occurred in 11 patients with 2 patients receiving hemoglobin C blood 5 separate times. One patient received hemoglobin C and later S, and another patient received C and later O-Arab.

Conclusions.—Apparent hemoglobinopathies caused by blood transfusions are far more common than previously reported and represent diagnostic challenges. Misdiagnosis could lead to unnecessary testing, treatment, and counseling. If a hemoglobinopathy from a unit of transfused blood is identified in a recipient, we recommend notifying the donor of that abnormality.

Blood transfusion-acquired hemoglobin C

Unexpected and confusing laboratory test results can occur if a blood sample is inadvertently collected following a blood transfusion. A potential for transfusion-acquired hemoglobinopathy exists because heterozygous individuals show no significant abnormalities during the blood donor screening process. Such spurious results are infrequently reported in the medical literature. We report a case of hemoglobin C passively transferred during a red blood cell transfusion. The proper interpretation in our case was assisted by calculations comparing expected hemoglobin C concentration with the measured value. A review of the literature on transfusion-related preanalytic errors is provided.