The prevalence and meaning of eosinophilia in renal diseases on a nephrology consultation service.

Background. In recent years, we have come to understand that the eosinophil is more than the end point in clearance of parasitic infection or a maladaptive response to asthma and allergic reactions. Since eosinophilia has been reported to be common in renal diseases, we thought that an evaluation of the associations of eosinophilia on a renal consultation service would add some value to the understanding of their role in renal disease. Methods. This was a prospective cross-sectional study of 1339 consecutive patients referred to the nephrology service after hospitalization who were evaluated for the relationship of the amount of serum eosinophils to their diagnosis, gender, age and the presence of autoimmune disease, cancer, infection, liver disease, pleural effusions, allergies and use of prednisone, beta-blockers or beta agonists, in addition to the total white blood count, urine protein, serum concentration creatinine and phosphorus levels and estimated glomerular filtration rate. Results. The presence of vascular disease correlated the most strongly with increased eosinophil count (partial correlation coefficient, r = 0.18, P = 0.006), followed by pleural effusions (r = 0.17, P = 0.001), while total white cell count (r = -0.18, P = 0.008) and administration of beta-blockers (r = -0.13, P = 0.047) demonstrated significant inverse correlations and the presence of autoimmune disease, cancer, allergies, proteinuria and serum phosphorus concentration demonstrated no significant correlation. Conclusion. There are multiple associations with increased eosinophil counts in patients seen on a nephrology consultant service; however, their presence appears less often in association with allergies or uremia and more often with vascular disease.