“…Drugs or their metabolites serving as a hapten in the interstitium come from three lines of evidence. There are increased serum IgE titers in some patients with sulfonamide-induced TIN (199), and circulating anti-ampicillin antibodies have been found in two cases (199,373). In a case report of penicillin (PCN)-induced TIN, PCN was detected along the TBM (65); however, PCN can also be detected along TBM in patients receiving PCN who do not have TIN.…”