This clinical trial aims to evaluate the effect of temporary methotrexate (MTX) discontinuation on the humoral immunogenicity of the 20-valent pneumococcal conjugate vaccine (PCV20) in adult patients with autoimmune rheumatic diseases (ARDs).
Key questions:
* Does suspending MTX for 2 weeks after PCV20 enhance humoral immunogenicity? * What is the impact of MTX discontinuation on functional opsonophagocytic activity (OPA) and cellular immunity? * What is the risk of disease flaring with MTX withdrawal?
Adults (>=18 years ) with confirmed ARD diagnosis (e.g., RA, PsA, axial SpA, primary Sjögren's, SLE, IIM, SSc, MCTD).
Stable MTX dose ≥12 weeks.
Prednisone ≤5 mg/day.
Low disease activity/remission according to specific disease activity criteria.
Anaphylaxis to vaccine components.
Acute febrile illness.
Guillain-Barré, decompensated CHF (NYHA III-IV), demyelinating disease.
Live virus vaccine ≤4 weeks or inactivated vaccine ≤2 weeks before.
Parallel
Pneumococcal Vaccine
Biological/VaccineAll participants will receive a single intramuscular dose (0.5 mL) of PCV20 (Prevnar 20®, Pfizer), administered into the deltoid muscle at baseline (Day 0). PCV20 contains purified capsular polysaccharides of 20 pneumococcal serotypes (1, 3, 4, 5, 6A, 6B, 7F, 8, 9V, 10A, 11A, 12F, 14, 15B, 18C, 19A, 19F, 22F, 23F, and 33F), individually conjugated to the nontoxic diphtheria CRM197 carrier protein. The conjugation induces a T-cell dependent immune response, resulting in higher-affinity antibodies and immune memory compared to polysaccharide vaccines.
Seroconversion Rate After Vaccination
Proportion of participants who achieve seroconversion, defined as at least a twofold increase in IgG antibody concentrations for ≥50% of PCV20 vaccine serotypes (1, 3, 4, 5, 6B, 7F, 8, 9V, 12F, 14, 19A e 23F) compared to baseline, measured by multiplex Luminex assay.
Opsonophagocytic Activity (OPA) Response
Functional antibody response will be assessed according to the serotype-specific opsonophagocytic activity (OPA), defined as at least a twofold increase in IgG antibody concentrations for ≥50% of vaccine serotypes (6B, 8, 12F, 14, 19A and 23F) compared to baseline.
Persistence of Humoral Immunity
Persistence of IgG antibody response assessed by Luminex and OPA assays by specific vaccine serotypes.
Frequency of Disease Flares in Rheumatoid Arthritis
To assess the effect of temporary MTX discontinuation on disease activity in participants with rheumatoid arthritis, as measured by the Disease Activity Score 28 (DAS28). The DAS28 includes a count of tender and swollen joints (out of 28), a measure of general health (VAS), and either ESR or CRP. Scores range from approximately 0.9 to 9.4, with higher scores indicating worse disease activity.
Frequency of Disease Flares in Spondyloarthritis
To evaluate the impact of MTX discontinuation on disease activity in participants with spondyloarthritis, as measured by the Ankylosing Spondylitis Disease Activity Score (ASDAS). The ASDAS combines patient-reported outcomes (back pain, duration of morning stiffness, peripheral pain/swelling, and global assessment) and an objective measure of inflammation (CRP or ESR). Scores range from approximately 0.6 to 6, with higher values indicating worse disease activity.
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University of Sao Paulo General Hospital
Lead sponsor
Insituto Adolfo Lutz
Collaborator
