CD4 and pulmonary alveolar proteinosis: The deceased PAP patients had continuously rising levels of MCP-1 and increasing percentages of CCR2+CD4+ T cells in the three follow-up BALs (Figures 6A, B; black circles) while the clinically stable patient showed steady levels of MCP-1 and percentages of CCR2+CD4+ T cells (Figures 6A, B; white circles).