CCR2 and pulmonary alveolar proteinosis: CCL-7 and CCL-8 levels are also high in autoimmune PAP,86 and CCL-2, −7, and −8 are all chemotactic for lymphocytes, suggesting a possible explanation for the lymphocytosis observed in CCR2 deficiency87,88 through a mechanism mediated by lymphocyte receptors other than CCR2, such as CCR1, CCR3, or CCR5.77,89–91 However, the receptors responsible for marked pulmonary lymphocyte recruitment in patients with inherited CCR2 deficiency or other PAP-causing diseases have not been identified.