SDC1 and peritonitis: However, an important consideration is that in vitro work indicated that Sdc1-/- monocytes may be the dominant cell type in the increased leukocyte infiltrate [50], and higher numbers of monocytes are usually recruited in vivo after 3 to 4 days following peritonitis [51], which may explain our observations that Sdc1-/- mice do not have elevated leukocyte recruitment in the early response to infection.