CD40LG and pneumocystosis: We observed a significant increase in the geometric mean concentration of anti‐PCP IgG, IgG2, IgM, and IgA post‐pneumococcal vaccination in 20 MM patients, 80% of them obtained a protective antibody titer for at least one subtype including 60% for IgG, showing the ability of MM patients to respond after a pneumococcal vaccination.