Reduction in mRNA expression of the neutrophil chemoattract factor CXCL1 in Pseudomonas aeruginosa treated Barth Syndrome B lymphoblasts

Abstract

Barth Syndrome (BTHS) is a rare X-linked genetic disease caused by a mutation in TAFAZZIN, a cardiolipin transacylase. Approximately 70% of patients with BTHS exhibit severe infections due to neutropenia. However, neutrophils from BTHS patients have been shown to exhibit normal phagocytosis and killing activity. B lymphocytes play a crucial role in the regulation of the immune system and when activated secret cytokines known to attract neutrophils to sites of infection. We examined expression of chemokine (C-X-C motif) ligand 1 (CXCL1), a known chemotactic for neutrophils, in Epstein-Barr virus transformed control and BTHS B lymphoblasts. Age-matched control and BTHS B lymphoblasts were incubated with Pseudomonas aeruginosa for 24 h and then cell viability, CD27+, CD24+, CD38+, CD138+ and PD1+ surface marker expression and CXCL1 mRNA expression determined. Cell viability was maintained in lymphoblasts incubated with a ratio of 50:1 bacteria:B cells. Surface marker expression was unaltered between control and BTHS B lymphoblasts. In contrast, CXCL1 mRNA expression was reduced approximately 90% (p<0.05) in untreated BTHS B lymphoblasts compared to control cells and approximately 70% (p<0.05) in bacterial treated BTHS B lymphoblasts compared to control cells. Thus, naive and bacterial-activated BTHS B lymphoblasts exhibit reduced mRNA expression of the neutrophil chemoattractant factor CXCL1. We suggest that impaired bacterial activation of B cells in some BTHS patients could promote immune dysfunction, and this may contribute to infections.