Of note, WASP-negative patients are more frequently affected by bacterial infections (otitis media, skin abscess, pneumonia, enterocolitis, meningitis, sepsis, urinary tract infection, and others), viral infections (Herpes simplex and Cytomegalovirus) and fungal infections (Candida spp., Aspergillus spp., and Pneumocystis carinii) as compared to WASP-positive patients (Imai et al., 2004). This evidence concerns the gene WAS and susceptibility to pneumonia measurement.