Early infectious risk in patients with anti-neutrophil cytoplasmic antibody-associated vasculitis according to remission-induction therapy.

OBJECTIVE: Few comparative data exist on early infections secondary to remission-induction therapy (RIT) with rituximab (RTX) versus cyclophosphamide (CYC) in newly diagnosed anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) patients. We compared and analysed the rates and predictors of severe infection in such patients within the first 6 months following RIT. METHOD: From the Caen University Hospital databases, we included all consecutive adults newly diagnosed with ANCA-positive granulomatosis with polyangiitis or microscopic polyangiitis between January 2006 and December 2019. We compared rates of survival without severe infection and survival without infections of any severity within 6 months of RIT and used a multivariate Cox analysis to identify predictors of infection. RESULTS: We included 145 patients, 27 in the RTX and 118 in the CYC group. Patients in the RTX group more frequently had pneumococcal vaccination (p < 0.01) and creatinine < 150 µmol/L; other characteristics were comparable between the two groups. Overall, 37 severe infections and 65 infections of any severity were recorded. Rates of survival without severe infection were similar in both groups (p = 0.69), but survival without infections of any severity was lower in the RTX group (p = 0.005). In multivariate analysis, risk factors at diagnosis for severe infections included chronic urinary tract disease, dialysis, and absence of trimethoprim-sulfamethoxazole prophylaxis (p < 0.01 each). CONCLUSIONS: Within 6 months of RIT, rates of survival without severe infection were similar in newly diagnosed ANCA-positive AAV patients treated with RTX or CYC, but survival rates without infections of any severity appeared to be lower with RTX treatment.

The importance of EN ISO 15189 accreditation of allergen-specific IgE determination for reliable in vitro allergy diagnosis.

BACKGROUND: Allergen-specific serum immunoglobulin E detection and quantification have become an important step in allergy diagnosis and follow-up. In line with the current trend of laboratory test accreditation to international standards, we set out to design and assess an accreditation procedure for allergen-specific serum IgE. METHODS: Method validation according to the accreditation procedure under the EN ISO 15189 standard was carried out for allergen-specific immunoglobulin E determination using the fluoroimmunoenzymatic method ImmunoCAP(®) (ThermoFisher). Data were produced by 25 hospital laboratories in France. A total of 29 allergen specificities including mixes, extracts, and molecular allergens were assayed. Allergen-specific serum immunoglobulin E concentrations ranged from 0.1 to 100 kUA /l. RESULTS: Repeatability, reproducibility, and accuracy results fulfilled method validation criteria for automated laboratory tests and proved similar irrespective of the allergen specificity, allergen-specific serum immunoglobulin E concentration, or individual laboratory. CONCLUSION: Allergen-specific serum immunoglobulin E determination with the fluoroimmunoenzymatic method ImmunoCAP(®) is a highly repeatable, reproducible, and accurate method which may be considered as a single analyte assay in view of the EN ISO 15189 accreditation procedure.

Kinetics of spleen and Peyer's patch lymphocyte populations during gut parasite clearing in Cryptosporidium parvum infected suckling mice.

Data from experimental and human cryptosporidiosis have established a major role of specific immunity in the control of Cryptosporidium parvum infection. In this work, alterations in spleen and Peyer's patch (Pp) lymphocytes were investigated in the course of a spontaneously resolutive gut cryptosporidiosis in four-day-old suckling NMRI mice infected with either 4 x 10(5) or 30 viable oocysts. Oocysts from entire small intestines, and spleen and Pp lymphocytes were examined using flow cytometry from day 7 to day 27 post-infection. Compared to uninfected animals, a 3-5 fold increase in the numbers of spleen TCR alphabeta+, CD4+, CD8+, TCR gammadelta+ and CD45R/B220+ lymphocytes was observed on day 17 post-infection in heavily infected animals. In Pp, more than ten-fold increases were observed, except for TCR gammadelta+ lymphocytes. At termination of infection, i.e. on days 21-23 after ingestion of 4 x 105 oocysts, T and B lymphocytes decreased rapidly in both organs, and remained lower than in uninfected animals on days 19-23 post-infection. In mice infected with 30 oocysts, similar alterations were observed in Pp, but not in spleen. Data suggest that in normally developing mice, clearance of gut C. parvum infection is associated with an initial increase in systemic and local lymphocyte numbers, followed by their decrease to below control levels during the recovery phase.