Red Blood Cell Autoantibodies in Patients Treated with Immune Checkpoint Inhibitors / 대한수혈학회지

Immune-related adverse events, including immune hemolytic anemia, have been reported in patients treated with immune checkpoint inhibitors. In particular, RBC autoantibodies are important because they can cause hemolytic anemia and interfere with pre-transfusion tests. On the other hand, there are few reports on the characteristics of RBC autoantibodies induced by immune checkpoint inhibitors in Korea. The medical history and laboratory results, including pretransfusion tests of ten patients treated with immune checkpoint inhibitors, were reviewed retrospectively. The median interval from the first administration of immune checkpoint inhibitors to the development of autoantibodies was 12 weeks. In eight patients, only cold autoantibodies were developed. Both warm and cold autoantibodies developed in one patient, and warm autoantibodies alone were detected in one patient.Of seven patients tested by a direct antiglobulin test, two were negative, and the remaining five were positive for IgG and negative for C3d. In conclusion, this study presented ten cases of autoantibody developments in patients treated with immune checkpoint inhibitors and the possible relationship between the immune checkpoint inhibitors and RBC autoantibody development. Further comprehensive studies will be needed to elucidate this relationship.

Weak D Type 102 Found in a Family Study: The First Case in Korea / 대한수혈학회지

Weak D type 102 allele (RHD*01W.102) carrying a missense variant (c.73A＞T, p.Ile25Phe) in exon 1 of the RHD has not been reported in Koreans to date. This is the first report of the weak D type 102 allele in the Korean population. The proposita, a 35-year-old woman, showed a serological weak D phenotype in routine RhD typing. Sequencing of all 10 RHD exons and zygosity testing targeting the hybrid Rhesus box revealed this proposita to harbor the weak D type 102 allele, as well as an RHD deletion (RHD*01W.102/RHD*01N.01). Family studies showed that the weak D type 102 allele was also present in her father and older brother (both assumed to be RHD*01W.102/RHD*01) but not in her mother and oldest brother (both assumed to be RHD*01/RHD*01N.01). In silico analysis of the replacement of isoleucine by phenylalanine at position 25 was done with PolyPhen-2, SIFT, and PROVEAN. While PolyPhen-2 predicted the variant as benign, SIFT and PROVEAN predicted it as damaging and deleterious, respectively, suggesting RHD c.73A>T (I25F) as the cause of serologic weak D phenotype. This patient should be treated as D-negative, when transfusion is needed.

Rare ABO Allele Encoding Glycosyltransferase with Dual Specificity Found in a Cambodian Individual with the A 2 B Phenotype / 대한수혈학회지

Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Rare ABO Allele Encoding Glycosyltransferase with Dual Specificity Found in a Cambodian Individual with the A 2 B Phenotype / 대한수혈학회지

Cis-AB and B(A) alleles encode an ABO enzyme with dual A and B glycosyltransferase activity. Although globally rare, the cis-AB phenotype is found relatively often in Korean, Japanese, and Chinese populations. Cases of the B(A) allele have been reported mostly in the Chinese population. Forward typing performed in a Cambodian woman with an ABO discrepancy demonstrated a strong reaction with anti-A and anti-B reagents, while there was no reaction with lectin anti-A 1. The anti-A 1 antibody was detected in reverse typing. Through ABO gene sequence analyses of exons 6 and 7, one of the alleles was identified as ABO*B.01. In contrast, the other allele harboring a c.803G＞C substitution was either ABO*cisAB.05 or ABO*BA.06 allele. The ABO*cisAB.05 and ABO*BA.06 alleles remain indistinguishable despite routine serological testing and ABO genotyping. To the best of the author’s knowledge, this is the first case report of these variants discovered in a Cambodian individual residing in Korea.

Two Cases of Hypersensitivity Reactions Caused by Human Serum Albumin During Therapeutic Plasma Exchange

Iso-oncotic human serum albumin (HSA) is the primary replacement fluid of choice during therapeutic plasma exchange (TPE). Hypersensitivity reactions to HSA are rare, but require proper evaluation and management. In this article, we report two cases of hypersensitivity reactions to 5% HSA during TPE and discuss strategies to address this problem. The first case was a 60-year-old female patient, who was scheduled for TPE for treatment of recurrent focal segmental glomerulosclerosis after ABO-incompatible kidney transplantation. She developed a pruritic rash on her entire body during the first two sessions of TPE using 5% HSA. The third session was conducted using 500 mL normal saline, 1,000 mL 10% pentastarch, and 750 mL 5% HSA, where she eventually developed a pruritic rash when HSA was infused. There were no adverse events during the fourth and fifth session when fresh frozen plasma was used in place of HSA. The second case was a 50-year-old male patient diagnosed with optic neuritis, who was admitted for five sessions of TPE. The patient developed a pruritic rash on his entire body during the first session of TPE using 5% HSA. The patient experienced no adverse events during the following four sessions using fresh frozen plasma. Certain elements contained in HSA, such as albumin aggregates, prekallikrein activator, and caprylate-modified albumin, might be the reason for these hypersensitivity reactions. Careful selection of alternative replacement fluids is important to avoid premature termination of TPE procedures and secure optimal treatment options for patients.

Pitfalls of ABO Genotyping Based on Targeted Single Nucleotide Variant Analysis Due to a Nondeletional O Allele Lacking c.261delG: First Report of ABO*O.09.01 in Korea

No abstract available.

Facklamia hominis Isolated from a Wound: A Case Report and Review of the Literature / 대한임상미생물학회지

Facklamia hominis is a facultative anaerobic Gram-positive coccus generally displaying weak alpha-hemolysis and negativity for catalase and oxidase. Facklamia species are part of the normal flora of the female genitourinary tract and have been reported in invasive diseases such as meningitis and infective endocarditis, albeit rarely. A 67 year-old-man presented to hospital with a tender, erythematous epidermal cyst on the right side of his upper back. Simple excision of the cyst was performed and the pus was taken with a sterile swab for culture, yielding no growth. One week later, discharge was observed in the patient's wound site and a sterile swab for culture was taken. The colonies grown were identified as F. hominis by the Vitek 2 system (bioMérieux, France), and the result was then reported to clinicians, and later confirmed by 16S rRNA gene sequencing and matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry. To the best of our knowledge, this is the first reported case of F. hominis isolation from a clinical specimen in Korea.

Minimum Specimen Volume Analysis of ABO/RhD Typing and Unexpected Antibody Screening Using an Automated Immunohematology System DAYmate S / 대한수혈학회지

BACKGROUND: Phlebotomy performed for laboratory testing has the potential to cause anemia in newborns and infants. This study investigated the minimum specimen volume required for an automated immunohematology analyzer DAYmate S. METHODS: Three combinations of tubes were evaluated: I. 6 mL EDTA tube, II. 0.5 mL microtainer (on top of 3 mL EDTA tube), and III. 1 mL sample cup (on top of 6 mL EDTA tube). ABO/RhD cell typing was done using centrifuged red cells; unexpected antibody screening was carried out using plasma, and Type & Screening was conducted using whole blood samples. The lowest specimen volume capable of performing 10 repetitive tests without errors was investigated. RESULTS: ABO/RhD cell typing could be performed from I. 30 μL, II. 25 μL, and III. 25 μL. Unexpected antibody screening could be performed from I. 170 μL, II. 150 μL, and III. 140 μL. According to the hematocrit levels, Type & Screening could be performed from 30%, I&III 650 μL, II. 800 μL; 40%, I&III 650 μL, II. 900 μL; and 50%, I&III 1,000 μL, II. Testing using specimen volumes below 1,000 μL was difficult. CONCLUSION: By separating red cells and plasma, pre-transfusion testing of ABO/RhD cell typing and unexpected antibody screening could be conducted with very small specimen volumes using DAYmate S compared to Type & Screening using whole blood. The application of small-sized sample tubes was more competitive and this is expected to be very useful for preventing iatrogenic anemia in neonates and infants less than 4 months old.

A Case of Anti-JMH Antibody with High-Titer, Low-Avidity Characteristics: The First Case in Korea / 대한수혈학회지

Anti-John Milton Hagen (JMH) is a high-titer, low-avidity (HTLA) antibody against the high frequency red blood cell (RBC) antigen JMH. It occurs very rarely and has not yet been reported in Korea. Here, we report a case of anti-JMH antibody identified in a 92-year-old man without previous blood transfusion history, who had been hospitalized with pneumonia. The patient's hemoglobin level was reduced to 7.6 g/dL on the 35th day of hospitalization, requiring RBC transfusion. Antibody identification test revealed antibodies that showed pan-reactivity to all panel cells at the antiglobulin phase. A titration test confirmed that it was a HTLA antibody. He was given one least-incompatible unit of RBC without any adverse events, and his hemoglobin level increased to 9.3 g/dL. The patient's sample was referred to a reference laboratory and the antibody was identified as anti-JMH. He was successfully transfused with 6 additional units of least-incompatible RBCs without complication. HTLA antibodies against high frequency antigens, such as anti-JMH, are less likely to cause significant destruction of transfused antigen positive RBCs. However, identifying the specificity of these antibodies is necessary to appropriately understanding the clinical significance of the antibody, detecting other clinically important alloantibodies that may coexist, and determining the appropriate blood for transfusion.

Strategies to Prevent Transfusion-Transmitted Infection in Blood Centers / 대한수혈학회지

There has been continuous effort to prevent transfusion-transmitted infection (TTI). Strategies to prevent TTI can be divided into two components: first, determining donor eligibility, and second, managing bacterial contamination of blood products. To determine donor eligibility, medical history taking and screening tests for infectious diseases should be performed. To prevent bacterial contamination, blood collection process should be aseptic, tests for bacterial detection should be performed, and an application of pathogen reduction technology should also be considered. In this review, screening test items and methods, including nucleic acid amplification tests for determining donor eligibility, and precautions for blood collection, bacterial detection methods, and pathogen reduction technology for the prevention of bacterial contamination of blood products were discussed in detail.