Tn Red cell polyagglutination in a healthy blood donor: A case report

Polyagglutinability phenomenon: a case report and review of the literature

BACKGROUND

Polyagglutinability of red blood cells is a rare immunological phenomenon, it is due to a cryptic antigen that is abnormally present on the surface of red blood cells. The aim of our work is to shed light on polyagglutinability, which is still poorly understood cause of discordance between the cell and serum tests and can sometimes have harmful transfusion consequences.

CASE PRESENTATION

We report the case of a 70-year-old African patient admitted for management of hemolytic anemia.

RESULTS

During the erythrocyte grouping, a discordance between the cell and serum tests was observed, with polyagglutinability for the RH phenotype, a positive AB control, and even a positive control. The direct antiglobulin test and the Coombs test were also positive. The same results were obtained even after washing the red blood cells and incubating them at 37 °C for 30 min. For transfusion purposes, erythrocyte genotyping was performed, and the patient was transfused with an A+ red blood cell unit with an RH Kell-compatible phenotype.

CONCLUSION

Polyagglutinability should always be taken into account when grouping anomalies are encountered. Although it may not show any symptoms, hemolysis is frequently observed during transfusions.

Minor Cross-Matching in the Diagnosis of Pneumococcal Hemolytic Uremic Syndrome in an 18-Month-Old Boy

In developing nations, limitations in diagnostic facilities act as a barrier for differentiation of hemolytic uremic syndrome (HUS) based on the etiology. A sick-looking 18-month-old boy presented to our hospital in Bhubaneswar, India, with clinical signs and symptoms of left lobar pneumonia, abnormal hematological and renal parameters, no growth in blood culture, a negative direct antiglobulin test (DAT) result, and low complement levels. A rapid deterioration in his clinical condition necessitated intensive care support, blood transfusion, and renal replacement therapy (peritoneal dialysis and hemodialysis). Because his health care team suspected atypical HUS, therapeutic plasma exchange (TPE) was initiated as soon as possible. In the absence of a lectin panel, minor cross-matching confirmed T-antigen exposure. With a diagnosis of HUS induced by Streptococcus pneumoniae (sp-HUS), TPE was stopped immediately, and washed blood components were administered. Despite the aforementioned measures, the boy died of HUS on day 20 after presentation. This case emphasized the role of minor cross-matching in the detecting of polyagglutination in resolving the diagnostic dilemma of sp-HUS.

A case of Tn polyagglutination discovered by an ABO blood group discrepancy

BACKGROUND

Tn syndrome is an acquired form of polyagglutination arising from somatic mutations of hematopoietic stem cells. Tn red blood cells (RBCs) are agglutinable by naturally occurring anti-Tn antibodies in most adult sera. Current ABO typing reagents are monoclonal and do not detect polyagglutination on forward typing. However, herein we describe a case of Tn activation that was suspected due to cross-reactivity with a monoclonal anti-A reagent.

STUDY DESIGN AND METHODS

A 63-year-old man with myeloproliferative neoplasm, who historically typed as group O, demonstrated unexpected mixed field reactivity with anti-A reagent using a gel-based method. However, manual tube testing was consistent with the patient's historical group O type.

RESULTS

Lectin testing demonstrated reactivity with Salvia sclarea and Glycine soja, but not Arachis hypogea. The patient's RBCs produced positive crossmatches with healthy donor sera, but reactivity was eliminated by ficin pretreatment of the RBCs. Ficin treatment also resolved typing discrepancies on gel-based typing. No reactivity was noted using cord blood sera, and N antigen expression was diminished upon phenotyping. Tn activation was confirmed by detection of a novel 4-nucleotide deletion (c.395-398del) in exon 3 of C1GALT1C1 resulting in a truncated glycosyltransferase.

CONCLUSION

This case of acquired Tn polyagglutination due to a novel mutation was first suspected from an ABO phenotyping discrepancy. It highlights the cross-reactivity of anti-A reagent with Tn antigen when tested on a common gel-based method. Furthermore, the case demonstrates that review of patient history and test information can clarify discrepancies and guide resolution.