Simple SummaryBarth Syndrome (BTHS) is a rare X-linked genetic disease in which some patients suffer from severe infections due to neutrophil dysfunction. B cells produce cytokines that attract neutrophils to sites of infection. Here, we examined if B cells from BTHS patients exhibited a reduced ability to express chemokine (C-X-C motif) ligand 1 (CXCL1), a known chemoattractant for neutrophils. We show that B cells from BTHS patients exhibit lowered expression of CXCL1 when stimulated with bacteria compared to control cells. Our findings suggest that an impaired ability of B cells to produce cytokines might contribute to infections in some BTHS patients.AbstractBarth Syndrome (BTHS) is a rare X-linked genetic disease caused by a mutation in theTAFAZZINgene, which codes for the protein tafazzin involved in cardiolipin remodeling. 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, secrete cytokines known to attract neutrophils to sites of infection. We examined the 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 withPseudomonas aeruginosafor 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 in 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 70% (p< 0.05) in untreated BTHS B lymphoblasts compared to control and approximately 90% (p< 0.05) in bacterial treated BTHS B lymphoblasts compared to the control. Thus, naïve 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 influence neutrophil function via impairing neutrophil recruitment to sites of infection and this could potentially contribute to these infections.