any structural anomaly of any of the functionally distinct subtypes of cells (alpha or beta) found on the kidney collecting duct epithelium that regulate acid-base homeostasis and play an important role in the kidney's response to acidosis and alkalosis; alpha-intercalated cells secrete acid whereas beta-intercalated cells secrete base; metabolic acidosis results in the conversion of beta- cells to alpha-intercalated cells giving the kidney a greater ability to secrete protons and return pH to the normal range (Mammalian Phenotype Ontology, MP_0011754)