Interstitial pneumonitis associated with infliximab therapy

Area of Science:

• Rheumatology
• Pulmonology
• Clinical Pharmacology

Background:

• Methotrexate (MTX) is a common disease-modifying antirheumatic drug (DMARD) used for rheumatoid arthritis (RA).
• Interstitial pneumonitis is a known, albeit rare, adverse effect associated with MTX therapy.
• Biologic agents like infliximab are often used in combination with MTX for refractory RA.

Observation:

• A case study of a rheumatoid arthritis patient with over 3 years of MTX treatment is presented.
• The patient developed severe interstitial pneumonitis following their third infliximab infusion.
• This clinical presentation prompted a review of similar reported cases in the literature.

Findings:

• The patient's severe interstitial pneumonitis occurred in the context of combined MTX and infliximab therapy.
• Review of existing literature identified other cases suggesting a potential link between infliximab and MTX-induced lung toxicity.
• Infliximab administration may exacerbate or potentiate the known pulmonary risks of methotrexate.

Implications:

• Clinicians should be vigilant for pulmonary toxicity in RA patients receiving concurrent MTX and infliximab.
• The findings suggest a need for careful monitoring of respiratory symptoms in patients on this combination therapy.
• Further research may be warranted to elucidate the mechanism by which infliximab might potentiate MTX pulmonary toxicity.