In reply

The study showed 2.7- and 1.9-log reductions after heating at 60°C for 10 hours in 20 and 25% albumin (Seki- juji albumin 20 and 25%, Japanese Red Cross Society, Tokyo, Japan), respectively. In addition, our study using KRM238 strain showed 1.5- and 2.2-log reductions after heating at 60°C for 10 hours in 25 and 5% albumin (Albumin 25 and 5%, Benesis Corporation, Osaka, Japan), respectively (Fig. 2). Thus, the KRM238 HAV strain could be a useful strain, because the heat sensitivity of this strain shows similarity with those resistant strains described by Farcet and coworkers,1 although this nature may be affected by the passage history of the virus. These studies may suggest that a certain population of clinical isolates can, during the process of viral adapta- tion to host cells to establish the laboratory strains, acquire amino acid substitution(s) that may affect their physicochemical characteristics including heat sensitivity. Therefore, it is prudent to pay attention to the differences in physicochemical properties among clinical isolates, laboratory-adopted strains, relevant viruses, and model viruses used during the virus safety evaluation studies with worst-case scenario such as virus clearance studies for manufacturing processes of plasma products. CONFLICT OF INTEREST MY and KS are organization staff (employees) of Japan Blood Products Organization, formerly Benesis Corporation. AW is organization staff (employees) of Japan Blood Products Organiza- tion, formerly Japanese Red Cross Plasma Fractionation Center. A part of this study was conducted under joint research between National Institute of Infectious Diseases and The Green Cross Corporation (currently Japan Blood Products Organization). No conflict of interest will arise from publication of this letter. Mikihiro Yunoki, PhD e-mail: [email protected]; [email protected] R&D Division Japan Blood Products Organization Tokyo Department of Virology Research Institute for Microbiological Diseases Osaka University Osaka Pathogenic Risk Evaluation Graduate School of Veterinary Medicine Rakuno Gakuen University Hokkaido Kaoru Sakai, PhD Central Research Laboratory R&D Division Japan Blood Products Organization Kobe Atsuko Totsuka, PhD Department of Virology II National Institute of Infectious Diseases Tokyo Akemi Wakisaka, MD, PhD Chitose Plant Japan Blood Products Organization Hokkaido, Japan REFERENCES 1. Farcet MR, Kindermann J, Modrof J, Kreil TR. Inactivation of hepatitis A variants during heat treatment (pasteurization) of human serum albumin. Transfusion 2012;52:181-7. 2. Shimasaki N, Kiyohara T, Totsuka A, Nojima K, Okada Y, Yamaguchi K, Kajioka J, Wakita T, Yoneyama T. Inactivation of hepatitis A virus by heat and high hydrostatic pressure: variation among laboratory strains. Vox Sang 2009;96:14-9. 3. Robertson BH, Jansen RW, Khanna B, Totsuka A, Nainan OV, Siegl G, Widell A, Margolis HS, Isomura S, Ito K, Ishizu T, Moritsugu Y, Lemon SM. Genetic relatedness of hepatitis A virus strains recovered from different geographic regions. J Gen Virol 1992;73:1365-77. 4. Totsuka A, Kiyohara T. Study of HAV heat stability. Annual report of National Institute of Infectious Diseases Japan 1996. p. 195 [in Japanese]. 5. Murozuka T, Takeda Y, Izumi H, Murai K, Shirakawa S, Emura H, Wakisaka A, Matsumoto S, Fujii N. Viral safety of plasma-derived blood products. Jpn J Transfus Med 1999;45: 362-5 [in Japanese]. In reply: We thank Yunoki and colleagues for sharing their informa- tion on the differential HAV heat inactivation properties of strains KRM238, KRM003, and FR1, which adds more evi- dence to the observation that the overall HAV inactivation that results from wet heating of plasma proteins varies substantially depending on the HAV strain used for small- scale validation studies. The authors further report that a previous study, which unfortunately is only available in Japanese, suggested one specific mutation in the P1 genomic region as causative for the change to a heat sen- sitive phenotype, a mutation that results in a N→S amino acid substitution at Position 17 in the VP1 protein.1 To evaluate whether this might also be the genomic basis for heat sensitivity in the HM175 HAV variants used in our work,2 we aligned the VP1 amino acid sequences of HM175/24a (heat sensitive [hs]) and HM175/18f (heat resistant [hr]) with the sequences of strain KRM003 (hs) and KRM238 (hr), in which the VP1-17 N→S amino acid substitution has been reported.1 In addition, the LETTERS TO THE EDITOR 2104 TRANSFUSION Volume 53, September 2013 mailto:[email protected] mailto:[email protected] sequences of HAV strains KRM031 and TKM005, for which similar inactivation properties as for KRM003 and KRM238 have been reported, respectively,3 were included in the alignment (Table 1). Whereas the VP1-17 N→S amino acid substitution was seen in the KRM003 and KRM238 strains as previously reported, this substitution was not present in any of the other HAV variants investi- gated, irrespective of whether they were shown to be of the hs or hr phenotype (Table 1). We therefore conclude that the VP1-17 N→S amino acid substitution cannot be the sole factor responsible for heat sensitivity in HAV and that the molecular basis for the 100- to 1000-fold difference in HAV sensitivity to heat inactivation remains unknown at present. CONFLICT OF INTEREST MF and TRK are employees of Baxter BioScience; TRK has stock interests. Thomas R. Kreil, PhD e-mail: [email protected] Maria R. Farcet, PhD Global Pathogen Safety Baxter BioScience Vienna, Austria REFERENCES 1. Totsuka A, Kiyohara T. Study of HAV heat stability. Annual Report of National Institute of Infectious Diseases Japan. 1996. p. 195. [in Japanese]. 2. Farcet MR, Kindermann J, Modrof J, Kreil TR. Inactivation of hepatitis A variants during heat treatment (pasteurization) of human serum albumin. Transfusion 2012;52:181-7. 3. Shimasaki N, Kiyohara T, Totsuka A, Nojima K, Okada Y, Yamaguchi K, Kajioka J, Wakita T, Yoneyama T. Inactivation of hepatitis A virus by heat and high hydrostatic pressure: variation among laboratory strains. Vox Sang 2009;96:14-9. Posttransfusion thrombocytopenia: a cautionary tale of female group AB plasma Plasma from parous females poses a well-recognized risk for transfusion-related acute lung injury (TRALI). TRALI mitigation strategies include use of plasma from male- only, never-pregnant female, and/or female blood donors screened for white blood cell antibodies.1 While these strategies have successfully reduced the TRALI incidence of group O, A, and B plasma, demand for group AB plasma has necessitated continued use of female donors, which has resulted in disproportionately high TRALI risks for group AB plasma.2 Accordingly, a recent AABB bulletin urged adherence to TRALI mitigation recommendations for group AB plasma.3 We present a case report of post- transfusion thrombocytopenia (PTT), which underscores the need for caution when transfusing group AB plasma derived from female donors. The patient was a 92-year-old group A man with a history of atrial fibrillation treated with warfarin who pre- sented with a left femoral neck fracture after a fall. In anticipation of surgical repair of his hip fracture, his therapeutic-range INR of 2.4 was to be corrected with oral vitamin K and plasma transfusion. One hour into the transfusion of a group AB, whole blood–derived, thawed plasma unit (initially thawed 3 days before transfusion), the patient became flushed and hypoxic and developed bronchospasm with chills and rigors. The transfusion was immediately stopped and the patient was treated with intravenous (IV) steroids, diphenhydramine, and bron- chodilators. He was transferred to the intensive care unit, where his respiratory symptoms improved over the next several hours. A platelet (PLT) count drawn 12 hours after transfusion showed a dramatic decrease from his admis- sion value of 133 Â¥ 109 to 4 Â¥ 109/L. The patient was treated with IVIG and two washed apheresis PLT transfusions on the day after the adverse event. The first washed apheresis PLT transfusion yielded a 1-hour posttransfusion PLT count of 31 Â¥ 109/L, with a repeat PLT count of 24 Â¥ 109/L 2 hours later. A second washed apheresis PLT unit was transfused later that day, with a 1-hour posttransfusion PLT count of 44 Â¥ 109/L. The PLT count at discharge, 6 days after the adverse event, was 135 Â¥ 109/L. Donor investigation by the blood collection facility identified a 32-year-old female, first-time donor with a history of two failed pregnancies: an ectopic pregnancy and one spontaneous abortion. The donor initially was found to have high levels of anti-HPA-1a with no evidence of anti-HLA Class I or II antibodies; repeated screening was positive for antibodies directed against HLA Class I antigens. Lookback investigation of the implicated plasma component identified a RBC cocomponent issued to a 48-year-old woman who experienced lower back pain, hypertension, and tachycardia with chills and rigors during transfusion. The recipient’s PLT count decreased TABLE 1. Alignment of Amino Acids 12 to 22 of the HAV VP1 protein HAV strain Amino acid sequence Heat sensitive Accession number KRM238 VSTKQ N VPDPQ N*† AB300205 KRM003 VSTKQ S VPDPQ Y*† AB425339 TKM005 VSTEQ N VPDPQ N† AB300207 KRM031 VSTEQ N VPDPQ Y† AB300206 HM175/24a VSTEQ N VPDPQ Y‡ M59810 HM175/18f VSTEQ N VPDPQ N‡ M59808 * HAV strains in which the VP1-17 N→S substitution has been associated with heat sensitivity.1 † Shimasaki et al.3 ‡ Farcet et al.2 LETTERS TO THE EDITOR Volume 53, September 2013 TRANSFUSION 2105 mailto:[email protected]