Residual Anti-pneumococcal Immunity After Pneumococcal Immunization in ANCA-associated Vasculitis

Study Overview
=================
Brief Summary
-----------------
Descriptive study of the residual anti-pneumococcal immunity in patients with Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) who have previously gone through pneumococcal immunization.

Detailed Description
-----------------
The purpose of this study is to determine, through serotype-specific enzyme linked immunosorbent assay (ELISA) and opsonophagocytosis (OPA) titres whether AAV patients who have gone through pneumococcal vaccination are protected against invasive pneumococcal diseases (IPD).

Official Title
-----------------
Residual Anti-pneumococcal Immunity After Pneumococcal Immunization in ANCA-associated Vasculitis. PneumoVas Pilot 1

Conditions
-----------------
Pneumococcal Infection, ANCA-associated Vasculitis

Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age ≥ 18 years Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis: diagnosis for granulomatosis with polyangiitis, microscopic polyangiitis or eosinophilic granulomatosis with polyangiitis according to American College of Rheumatology criteria Anti-pneumococcal immunization in the past 36 months History of anti-pneumococcal vaccination according to French recommendations (simple vaccine schedule with PPV23 or combine vaccine schedule with PCV13 followed by PPV23 8 weeks later) Exclusion Criteria: Known or suspected pregnancy Splenectomy Patient without social security coverage Patient opposal

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------
What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Residual anti-pneumococcal immunity after pneumococcal immunization. | Proportion of patients at baseline (V0) with ≥1 µg/mL ELISA immunoglobulins G (IgG) antibody titers to at least 6 of the 10 shared serotypes (i.e. 3, 4, 6B, 7F, 9V, 14, 18C, 19A, 19F and 23F) included both in the 13-valent conjugate pneumococcal vaccine (PCV13) and in the 23-valent non-conjugate pneumococcal vaccine (PPV23) | visit V0 (day 0) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To assess serotype 3, 4, 6B, 7F, 9V, 14, 18C, 19 A, 19F, 23F, 10A and 12F-specific residual immunity after vaccination | ELISA specific antibody titres to serotype 3, 4, 6B, 7F, 9V, 14, 18C, 19 A, 19F, 23F (included both in PCV13 and PPV23), 10A and 12F (specific to PPV23) | visit V0 (day 0), visit V-1 (pre immunization) | 
| For each of the following serotypes (3, 4, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F), to assess among ELISA-protected patients (i.e. with a ≥1 µg/mL ELISA IgG antibody titer) the proportion who also show in vitro opsonophagocytic antibody activity | Descriptive analysis: a/ For each of the following serotypes (3, 4, 6B, 7F, 9V, 14, 18C, 19A, 19F, 23F), opsonophagocytosis (OPA) titers will be measured in ELISA-protected patients at V0. Opsonophagocytic antibody activity is considered positive if the antibody titer is above a serotype-specific predefined threshold. B/ The proportion of overall OPA-protected patients (meaning ≥ 50% of OPA positive serotypes ) | visit V0 (day 0) | 
| For patients for whom pre-vaccinal serum is available (via the PHENOVASC bank), to assess the impact of immunization on serotype-specific ELISA antibody titer and OPA activity. | For patients already included in the PHENOVASC study (V-1) ≤6 months before receiving pneumococcal immunization, anti-pneumococcal immunity will be assessed for serotype 3 , 4 , 6B, 7F, 9V, 14 , 18C, 19A , 19F , 23F, 10A and 12F (with ELISA only for the two latter). For each serotype: In ELISA, we will describe the proportion of responding patients (i.e. with a two-fold increase from V-1 to VO and a ≥1 μg/ml titre at V0. In VO ELISA-responding patients, OPA titers will be measured. An opsonophagocytic antibody activity is considered positive if the antibody titer shows a four-fold increase from V-1 to V0 and is above a serotype-specific predefined threshold. | visit V-1 (pre immunization) ; visit V0 (day 0) | 
| Composite Outcome Measures - To identify epidemiologic, clinic and biologic predictive factors that may influence vaccine-induced immune response. | Analysis of epidemiological, clinical and biological data collected during follow-up: age, sex, history of immunosuppressive therapy, time since previous PPV23 injection, number of previous PPV23 immunizations, AAV activity and severity according to Birmingham Vasculitis Activity Score and Vasculitis Damage Index, results of biological analyses | visit V-1 (pre immunization) ; visit V0 (day 0) | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Vaccinology, Pneumococcal infection, Invasive pneumococcal disease (IPD), Pneumococcal vaccine, Systemic vasculitis, ANCA-associated vasculitis, Immunocompromised, Auto-immune disease