A case of haemolytic disease of the fetus and newborn attributed to a novel antigen in the RHAG blood group system.

BACKGROUND AND OBJECTIVES: A newborn presented with jaundice in Thailand. The cord red cells tested positive by direct antiglobulin test (DAT) for an unknown maternal red cell antibody. Initial blood group sequencing suggested that the infant carried a novel variant RHAG c.140T>C, responsible for a low-prevalence antigen in the RHAG blood group system (ISBT 030). We report here on testing of samples from the infant's parents and older sibling to define a new antigen in the RHAG system. MATERIALS AND METHODS: Massive parallel sequencing (MPS) using a custom-designed panel was performed on all four family members. Extended serological testing was also performed to determine whether family members with the same variant as the infant showed reactivity with the antibody in the maternal plasma. RESULTS: We identified a novel single nucleotide variant (SNV) (RHAG c.140T>C, p.[Phe47Ser]) in samples from three of the four family members tested (the infant, the older sibling and the father). The variant was not detected in the mother's sample. Maternal plasma showed positive agglutination with all family members tested; however, when tested with routine panel cells, no reactivity was observed. CONCLUSION: This case study showed that the presence of the novel variant (RHAG c.140T>C), encoding a p.(Phe47Ser) change in the RhAG glycoprotein, was the apparent cause of incompatibility between maternal plasma and that of red cells from the proband, father and older sibling of the proband. We propose this variant to be a new low-prevalence antigen in the RHAG blood group system.

Comparison of Double RBC Collection by Blood Cell Separators.

BACKGROUND: The problem of red blood cell (RBC) shortage occurs because of the expanding demand for blood utilization and the dfficulties in donor recruitment and retention. Resources can be maximized by using current technology to collect two units of RBC from the same donor during a single collection session. OBJECTIVE: To evaluate the performance, collection efficiency (CE), production cost, and donor satisfactions of two commercially available blood cell separators (BCS) for double dose red cell (DDRC) collection. Donor safety, clinical effectiveness, and patient safety were studied. MATERIAL AND METHOD: Thirty-one repeated male donors from the blood bank, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University were recruited for DDRC collection by two BCSs, the Alyx™, Fresenius Kabi, NC, USA, and the MCS®+, Haemonetics Corporation, Scotland. The donation intervals were at least 16 weeks. The target RBC volume was 360 mL (180 mL x 2 units). Pre- and post-donation hematologic parameters were monitored and quality tests for DDRC were performed. Donor reactions (DR) were observed and donor satisfaction questionnaires were collected after donations. Eighty-six units of RBC were transfused to 33 patients. Transfusion reactions (TR) were observed, and hematocrit (Hct) increments were determined pre-transfusion and 24 hours post-transfusion. RESULTS: The Alyx™ was faster for collecting and filtrating RBC (p<0.001) and had better CE (p<0.001). All DDRC from both BCSs met all the quality standards, required by both the American Association of Blood Banks (AABB) and the Food and Drugs Administration (FDA), which were hemoglobin (Hb) >42.5 g, Hct 50 to 70% and the residual white blood cells (WBC) <5x10(6). The Alyx™ processed less whole blood (WB) volume but provided DDRC with higher RBC yield, Hb content, and RBC volume than that of MCS® + (p<0. 001). However; the MCS®+ had one advantage over the Alyx™ whereby the DDRC collected by the MCS®+ were washed to reduce the risk of plasma associated TR. No serious DR from either BCS was observed. All donors had Hb >10 g/dL and Hct >30% after collection, as required by AABB. Serum ferritin reduction and iron depletion found in DDRC donors were not different from WB donors. All donors were satisfied with the DDRC collection process and would like to donate again. There was no evidence of acute or delayed TR in the patients. Hct increased significantly in 69.70% of the patients. CONCLUSION: DDRC collection can be performed safely and efficiently from both BCS. The quality of DDRC from both BCSs met the AABB and FDA standards. Donor safety, transfusion safety, and effectiveness were observed. Even though the production cost of DDRC was slightly higher than that of whole blood derived filtered RBC, DDRC was better in terms of quality, risk reduction for infectious agents, and RBC alloimmunization. Production of DDRC can also be helpful supplying special RBC such as group O, Rh D negative, and phenotyped RBC.