Antiphospholipid antibodies investigation in Pneumocystis jirovecii carriers.

It is well documented that antiphospholipid antibodies are increased in patients with HIV-1 infection and these are most commonly seen in those with Pneumocystis jirovecii pneumonia. Therefore it has been proposed that this could be the cause of its presence. Recently, P. jirovecii subclinical infection has been described in non-immunodeficient patients. We report here our experience concerning the possible relationship between P. jirovecii infection in non-immunocompromized adults and the production of antiphospholipid antibodies. Circulating lupus anticoagulant and IgM anticardiolipin antibodies were negative in all patients. IgG anticardiolipin antibodies were positive in 2 out of 5 (40%) P. jirovecii carriers and 2 out of 10 (20%) subjects with no evidence of pulmonary infection by this microorganism (p=0.4).