Cryptantigens: time to uncover the real significance of T-activation

Evaluation of Canine Erythrocyte Surface Antigens and Morphological Alterations Induced by Trypsin Treatment

Dogs have multiple blood type antigens, among which DEA 1, DEA 4, and Dal can induce severe acute hemolytic transfusion reactions. Various antigen modulation techniques have been developed to reduce immunogenicity and transfusion reactions. Recently, trypsin has been suggested as a potential tool for modulating the antigenicity of DEA 1 in veterinary medicine. Following this rationale, this study aims to evaluate the effects of trypsin on the antigenicity of these three antigens. A 50% RBC suspension treated with 1 mg/mL trypsin was incubated at 37 °C for 120 min. The antigenicity of DEA 1, DEA 4, and Dal was assessed using blood typing assays before and after trypsin treatment. As a result, trypsin did not reduce the antigenicity of DEA 1 and DEA 4; instead, trypsin significantly increased their antigenicity (p = 0.008) and promoted agglutination, whereas Dal exhibited a significant reduction in antigenicity (p = 0.008). Quantitative morphological parameters obtained from an automated hematology analyzer revealed no significant differences between trypsin-treated and negative control groups. However, morphological scoring under an optical microscope showed significantly fewer echinocytes in the trypsin-treated group (p = 0.008). Consequently, broad-spectrum proteases like trypsin are unsuitable for universal blood production due to their variable effects on erythrocyte surface antigens.

Do hematological biomarkers predict surgical necrotizing enterocolitis?

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal emergency in preterm infants and the clinical presentation of NEC may vary with gestational age. We lack reliable biomarkers for early diagnosis of NEC limiting timely intervention. Hematological changes in NEC are actively researched for their potential role as biomarkers. The pattern and severity of hematological abnormalities have been correlated with rapid progression, the need for surgery, increased risk of mortality, and morbidity. In this issue of Pediatric Research, Chong et al. report GA-specific hematological biomarkers in preterm infants with NEC that could predict the need for surgery. Thrombocytopenia at NEC onset was an independent predictor of surgical intervention in extremely preterm infants. Persistent thrombocytopenia and lymphopenia at 72 h and elevated C-reactive protein at 48 h after NEC onset, predicted surgery in infants of 28 to <32 weeks GA. Persistent thrombocytopenia at 24 h after the onset of NEC was predictive of mortality in infants who underwent surgery. Well-designed, prospective, multi-center studies are needed to confirm the role of hematological biomarkers in early diagnosis and prognostication in NEC.

Erythrocyte T-antigen activation in children: Patient characteristics and the hemolytic risk of transfusion

BACKGROUND

T-antigen activation usually occurs upon red blood cell (RBC) membrane cryptantigen exposure due to bacterial enzymes. Although uncommon, the condition is probably underrecognized. There is concern about hemolysis after plasma and plasma-containing platelet transfusions due to naturally occurring anti-T antibody in healthy blood donors. However, experts have debated the extent and severity of clinical hemolysis due to anti-T.

PROCEDURE

We retrospectively identified patients who tested positive for polyagglutination with Arachis hypogea and Glycine max lectins from 2008 to 2019. The records of the patients were reviewed to determine clinical symptoms, laboratory evidence of hemolysis, need for transfusion, and clinical outcomes.

RESULTS

Ten patients were identified. At diagnosis, all were anemic and four had thrombocytopenia. Severe Streptococcus pneumoniae infection affected seven patients; one died. Seven of 10 patients (70%) had laboratory evidence of hemolysis. Peripheral blood smear findings in six patients included RBC agglutination and changes suggesting hemolysis (spherocytes and schistocytes), but three had unremarkable RBC morphology. Four patients required plasma or platelet transfusions; all survived to discharge.

CONCLUSIONS

T-antigen activation is a rare entity. Most patients diagnosed at our hospital had hemolytic anemia and severe pneumococcal infection. Hemoglobin decreased after plasma and platelet transfusions in all patients assessed, but these transfusions were necessary to support treatment. RBCs were given to maintain appropriate hemoglobin levels.