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Updated: Aug 5, 2026
Simultaneous Detection of Different Antibody Classes in a Multiplexed Serological Test
Published on: July 14, 2023
Use of Principal Component Analysis to Discover Distinct Patterns of Serologic Class II Subtypes With WHO Specificity
Nabil Mohsin1, Isabelle Wood, Indira Guleria
1From the Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Tissue Typing Laboratory, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA and Sultan Qaboos College of Medicine and Health Sciences, Muscat, Oman.
Objectives:
Patient serum for anti-HLA antibodies are tested with purified antigens covalently affixed to beads as targets. Serologic nomenclature from the World Health Organization (WHO) is currently used to specify the reactivity of antibodies, although target antigens are defined at a finer allelic level. We investigated whether different reactivity patterns could be present at the allele level of a single WHO serologic antigen.
Materials And Methods:
We analyzed 2389 serum samples from 1215 patients waiting for solid-organ transplant by using class II single antigen beads for detection of HLA antibodies. We used principal component analysis to identify unique antibody reactivity patterns against the beads. We particularly focused on patterns within a WHO antigen that suggested the presence of new serologic class II HLA specificities. We used the HLA DQ7 data to illustrate the principle of the discovery methodology. Four assay target beads representing different DQA1 alleles were classified as DQ7.
Results:
Two principal components accounted for about 98.6%of the DQ7 data variance. The dominant principal component, which accounted for 83.9% of the variance, represented a reaction pattern in which sera reacted equally with all 4 beads. The second principal component (14.7% of the variance) represented sera that reacted selectively with DQA1*03:01, DQB1*03:01. Four of 10 DR and 6 of 7 DQ WHO serologic specificities that were studied showed more than 5% nonconcordant patterns revealed by principal component analysis.
Conclusions:
Principal component analysis revealed differential reactivity patterns of the alleles of single WHO serological specificity. This method could be a powerful tool for identifying patterns of reactivity, which may represent new serological specificities.
