Rouleaux mimicking anti-H in molecularly confirmed para-Bombay siblings: a diagnostic pitfall.

Authors

Bodanapu Vinay, Arun Rajendran, U B Davood, Aswin K Mohan, Vasanth Asirvatham, C H Vinay Kumar, Sanjay C Mohan, S Pradeep, Rati Devendra, Monali Lokhande

Published in

Immunohematology. Volume 42. Issue 3. Pages 77-81. Sep 01, 2026. Epub Oct 11, 2026.

Abstract

The para-Bombay phenotype is a rare H-deficient blood group variant characterized by markedly reduced or absent expression of H on red blood cells (RBCs) because of mutations in FUT1, with variable secretor status influenced by FUT2. The Bombay phenotype is relatively more common in the Indian population, but the para-Bombay phenotype remains exceedingly rare and is frequently underrecognized because of diagnostic challenges during routine serologic testing. We report molecularly confirmed para-Bombay siblings from India in whom rouleaux-induced pseudoagglutination mimicked anti-H reactiv ity. The index case demonstrated absent reactivity with anti-H lectin and weak reactivity with pooled group O RBCs during reverse grouping and thermal amplitude testing, initially raising suspicion of clinically significant anti-H. However, detailed serologic evaluation, including microscopic examination, saline replacement, adsor ption-elution studies, and saliva inhibition testing, favored rouleaux-induced pseudoagglutination over true anti-H-mediated agglutination. Molecular analysis identified homozygous FUT1 c.328G>A and FUT2 c.357C>T mutations in both affected siblings, consistent with para-Bombay secretor phenotype and similar to previously reported variants in the Telangana population. This case highlights rouleaux-induced pseudoagglutination as an impor tant diagnostic pitfall in para-Bombay phenotypes. Integration of conventional serologic methods with molecular characterization was essential for accurate diagnosis, appropriate transfusion planning, and avoidance of unnecessary restrictions on compatible blood components.

PMID:
42859972
Bibliographic data and abstract were imported from PubMed on 12 Oct 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.