Unfortunately, studies of ALI patients are often incomplete and subject to ambiguities resulting from the broad and complex character of symptoms and contributing etiologies [2, 37] . Compounding these issues are the limited sample materials that are available for analysis (e.g., lung tissue or BAL fluid), including the timing of when the samples were recovered during the course of a given patient's care. In this respect, the study presented here is subject to these very same limitations. That is, our study is of a small heterogeneous cohort of patients (n = 20) whose disease origins and severity vary Figure 2 Assessment of individual patient biopsies revealed that unlike traditional H&E histopathology, EPX-mAb immunohistochemistry demonstrated that ALI patients have increased levels of eosinophils relative to control subjects and that within the ALI cohort this increase correlated with patient survival. Serial sections from either control subjects or acute lung injury patients were stained with H&E and subjected to EPX-mAb immunohistochemistry prior to evaluation for infiltrating eosinophil numbers per high powered field. Eosinophil counts per hpf were determined by individual investigators (n = 2) as the average count resulting from the examination of 10 randomly selected fields; investigators were blinded to both the clinical outcome and the scores of the fellow evaluator. The scatter plots presented represent values for each individual patient derived as the mean of the average eosinophil counts from these evaluators (ICC = 0.785 (95% confidence interval: 0.540 to 0.908). The scatter plots within the shaded area represent acute lung injury patients following EPX-mAb immunohistochemistry that were then stratified (following decoding of the data) on the basis of their hospital survival. The mean for each cohort is presented as a horizontal bar. *p < 0.01