To the Editor.—
I was most interested to read the article and learn of the greatly increased risk of active tuberculosis among patients with renal failure on maintenance dialysis. I do not believe that the authors have evidence that "patients on maintenance dialysis have a greater chance of contracting tuberculous infection." Rather, they have presented evidence that their patients had developed manifest clinical tuberculosis while undergoing dialysis. To my mind, it is far more likely that they were already infected and that the immunosuppressive effect of hemodialysis permitted a flare-up of endogenous tuberculous infection.