Factor XIII deficiency: complete phenotypic characterization of two cases with novel causative mutations

Coagulation factor XIII (FXIII) exists as heterotetramer (FXIII-A(2)B(2)) in the plasma and as dimer (FXIII-A(2)) in cells. Activated FXIII mechanically stabilizes fibrin and protects it from fibrinolysis by cross-linking fibrin chains and (2)-plasmin inhibitor to fibrin. FXIII is essential to maintaining haemostasis, and its deficiency causes severe bleeding diathesis. Due to improper laboratory practices, FXIII deficiency is considered the most under-diagnosed bleeding disorder. The aim of this study was to demonstrate in two cases how FXIII deficiency is properly diagnosed and classified, and to compare results of laboratory analysis and clinical symptoms. FXIII activity from plasma and platelets was measured by a modified ammonia release assay, while FXIII-A(2)B(2), FXIII-A and FXIII-B antigens were determined by ELISA. The exon-intron boundaries and the promoter region of F13A1 gene were amplified by PCR and the amplified products were analysed by direct fluorescent sequencing. FXIII-A mRNA in platelets was determined by RT-qPCR. Two children with severe bleeding symptoms were investigated. In both cases FXIII activity and FXIII-A antigen were undetectable in the plasma and platelet lysate. In the plasma no FXIII-A(2)B(2) antigen was found, while FXIII-B antigen was >30% in both cases. Proband1 was a compound heterozygote possessing a known missense mutation (c.980G>A, p.Arg326Gln) and a novel splice-site mutation (c.1112+2T>C). Proband2 was homozygote for a novel single nucleotide deletion (c.212delA) leading to early stop codon. The discovered mutations explain the severity of clinical symptoms and the laboratory data. Methods precise in the low activity/antigen range are required to draw valid conclusion on phenotype-genotype relationship

Blood eosinophil count and GOLD stage predict response to maintenance azithromycin treatment in COPD patients with frequent exacerbations

INTRODUCTION:Maintenance treatment with macrolides are useful in preventing COPD exacerbations. We investigated which characteristics of COPD patients with frequent exacerbations predicted the best response to maintenance treatment with azithromycin. METHODS:This study was part of the COLUMBUS trial, a prospective randomized, double-blind, placebo-controlled study in 92 COPD patients with frequent exacerbations. During the 1-year treatment period, follow-up data were collected for spirometry, mMRC scores, sputum cultures and blood inflammatory markers. RESULTS:In the azithromycin group a significant lower number of exacerbations per patient was observed in patients with the following characteristics: baseline blood eosinophil count ≥2.0% (x̄ = 1.26), compared to an eosinophil count < 2.0% (x̄ = 2.50; p = 0.02), GOLD stage 1-2 (x̄ = 1.06), versus GOLD stage 4 (x̄ = 2.62; p = 0.02) and GOLD group C (x̄ = 0.45) compared to group D (x̄ = 2.18; p < 0.01). Moreover, the number of hospitalizations was significantly lower in patients, with a blood eosinophil count ≥2.0% (x̄ = 0.26) compared to an eosinophil count < 2.0% (x̄ = 0.90; p = 0.01) and in GOLD stages 1-2 (x̄ = 1.06) compared to stage 4 (x̄ = 2.62; p = 0.04). CONCLUSION:In conclusion, azithromycin maintenance treatment appears to be effective in COPD patients with frequent exacerbations, who are either classified in GOLD stage 1-2 or GOLD C and those with a blood eosinophil count of ≥2.0%

Blood eosinophil count and GOLD stage predict response to maintenance azithromycin treatment in COPD patients with frequent exacerbations

INTRODUCTION:Maintenance treatment with macrolides are useful in preventing COPD exacerbations. We investigated which characteristics of COPD patients with frequent exacerbations predicted the best response to maintenance treatment with azithromycin. METHODS:This study was part of the COLUMBUS trial, a prospective randomized, double-blind, placebo-controlled study in 92 COPD patients with frequent exacerbations. During the 1-year treatment period, follow-up data were collected for spirometry, mMRC scores, sputum cultures and blood inflammatory markers. RESULTS:In the azithromycin group a significant lower number of exacerbations per patient was observed in patients with the following characteristics: baseline blood eosinophil count ≥2.0% (x̄ = 1.26), compared to an eosinophil count < 2.0% (x̄ = 2.50; p = 0.02), GOLD stage 1-2 (x̄ = 1.06), versus GOLD stage 4 (x̄ = 2.62; p = 0.02) and GOLD group C (x̄ = 0.45) compared to group D (x̄ = 2.18; p < 0.01). Moreover, the number of hospitalizations was significantly lower in patients, with a blood eosinophil count ≥2.0% (x̄ = 0.26) compared to an eosinophil count < 2.0% (x̄ = 0.90; p = 0.01) and in GOLD stages 1-2 (x̄ = 1.06) compared to stage 4 (x̄ = 2.62; p = 0.04). CONCLUSION:In conclusion, azithromycin maintenance treatment appears to be effective in COPD patients with frequent exacerbations, who are either classified in GOLD stage 1-2 or GOLD C and those with a blood eosinophil count of ≥2.0%