Relationship between repertoire diversity of B cell receptor immunoglobulin G heavy chain and infectious complications caused by encapsulated bacteria after allogeneic hematopoietic cell transplantation.

BACKGROUND

We evaluated the relationship between repertoire diversity of IgG-BCR heavy chain and encapsulated bacterial infections after allogeneic hematopoietic cell transplantation.

METHODS

Ten patients with such infections (Infection group) and ten matched controls (Control group) were analyzed. Five patients had repeated infections. High-throughput IgG-BCR heavy chain (IgH) sequencing yielded a median of 147,504 in frame reads (minimum 71,867) and 28,248 unique reads per sample.

RESULTS

IGHV3-11 and IGHV4-59 usage was significantly lower in the Infection group and showed a stepwise decrease from Control to patients with one infection to those with repeated infections. In patients with repeated infections, reduced IGHV3-IGHJ4 usage and increased IGHV3-IGHJ3/5 usage were observed. In addition, CDR3 amino acid (AA) length distribution differed, with fewer 16-AA and more 17- and 21-AA sequences, sharing similar motifs.

CONCLUSIONS

Selective reduction in IGHV3-11 and IGHV4-59 usage and specific CDR3 features may be associated with susceptibility to encapsulated bacterial infections.