CCL2 and hypersensitivity pneumonitis: In summary, using conditional knockout mice that have PKD1 deleted in myeloid lineage cells, we found that PKD1 activation in myeloid lineage cells in response to the HP-inciting antigen S. rectivirgula contributes significantly to acute lung injury, including neutrophilic alveolitis and pulmonary inflammation by upregulating the expression of IL-1β, IL-6, TNFα, IFNγ, CCL2, CCL3, CCL4, CXCL1, CXCL2, and CXCL10.