Assessment of Immune Memory - Humoral and Cellular - in mPOX-infected Patients : an Ancillary Study of the ANRS0258s MOSAIC Cohort

N/ANot Yet RecruitingNCT07592429

ANRS, Emerging Infectious Diseases60 enrolled

Overview

Primary objective The overall objective is to assess the long-term amplitude and durability of the immune responses after mpox virus (MPXV) infection. Primary endpoint The main outcomes are: the presence of neutralizing antibodies in the serum and the presence of detectable mpox virus-specific memory B cells. Neutralizing antibodies titers will be measured with a semi-automated cell-based assay using live mpox virus. Memory B cells will be measured by flow cytometry and other techniques. Secondary objectives 1. Assess the amplitude and the stability of the MPXV antigen-specific B-cell memory response after infection, against the immunodominant antigens A27, A33, B5, L1, D8, and H3. 2. Assess the breadth of the B-cell repertoire and its neutralizing capacity in a subset of patients 3. Assess the humoral immunity using different serological techniques, for the detection and quantification of anti-MPXV antibodies, and assess the seroneutralization capacities of each antibody. Secondary endpoints 1. The presence of MPXV antigen-specific B-cell memory. Memory B cells will be measured by flow cytometry and other techniques. 2. The breadth and neutralizing capacity of the B-cell repertoire in a subset of patients. 3. The humoral immunity using serological techniques.

Single inclusion visit with data collection and blood sample. No further follow-up of participants. A total of 60 participants previously enrolled in the main cohort ANRS 0758s MOSAIC are planned to be included, distributed among France (n = 35), Italy (n = 20), and Switzerland (n = 5).

Study Type

INTERVENTIONAL

Allocation

Purpose

HEALTH_SERVICES_RESEARCH

Masking

NONE

Enrollment

Conditions

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Written informed consent, signed by the participant and the investigator prior to any study-related procedure * Person previously enrolled in the ANR0258s-MOSAIC cohort (see Appendix 19.2 for MOSAIC inclusion criteria) between July 2022 and July 2023 * Person with a blood sample taken within 8 months following mpox infection * ≥ 18 years old Exclusion Criteria: * Individuals who, in the investigator's opinion, are unlikely to comply with study procedures or whose medical condition is incompatible with study participation * For France only: person not affiliated to or not benefiting from a social security scheme in accordance with article L1121-11 of the French Public Health Code (Aide Médicale d'Etat \[AME\] does not constitute a social security scheme) * Pregnant or breastfeeding women * Individuals under guardianship or curatorship, or deprived of liberty by judicial or administrative decision

Outcomes

Primary Outcomes

The main outcomes are: the presence of neutralizing antibodies in the serum and the presence of detectable mpox virus-specific memory B cells.

Neutralizing antibodies titers will be measured with a semi-automated cell-based assay using live mpox virus. Memory B cells will be measured by flow cytometry and other techniques.

Time frame: Baseline (Day 1)