Monday, March 30, 2015
How safe is that PPD test for tuberculosis?
This article raises concerns about the possibility of a chronic low-grade mycobacterial infection after receiving the PPD (the skin test for tuberculosis screening). Consider using a TB release assay blood test (like QuantiFERON-TB Gold) if your school or employment requires TB testing.
The tuberculin skin test: How safe is safe? - the tuberculins contain unknown forms capable of reverting to cell-wall-deficient mycobacteria
Alexander P. Lysenko, Vladimir V. Vlasenko, Lawrence Broxmeyer, Artem P. Lemish, Tatiana P. Novik, Andrei N. Pritychenko
Clinical and Experimental Medical Sciences, Vol. 2, 2014, no. 2, 55 - 73
"Tuberculin is made from proteins derived from tubercle bacilli that have been “killed” by heating. Yet in both Zwadyk’s 1994 study and Bemer-Melchior’s 1999 investigations ‘heatkilled’ tuberculosis and its related mycobacteria, whether in tuberculin, vaccination or otherwise, have dormant, practically indestructible cell-wall-deficient forms which can revert back to virulent TB bacilli “killed” ― by neither heat nor sterilization. The ability and actual preference of mycobacteria such as Mycobacterium tuberculosis and Mycobacterium bovis to form filterable, multi-shaped cell-wall-deficient (CWD) forms and spores in order to survive unfavorable conditions has in fact been known for some time. But the possibility of PPD tuberculins for human use containing such potentially virulent CWD forms, even after autoclaving, sterilizing and ultrafiltration, has not. Autoclaved ultra-filtrates of the various mycobacteria used to produce tuberculin skin tests, consisting of M. Tuberculosis, M. bovis, and M. avium were investigated. All samples were mixed with growth stimulant, incubated, and placed on a special nutrient medium with a 1% agar base. Within 2-10 days after incubation colonies of a variety of non-acid-fast forms were noted, yet all of these proved, through PCR real time with FAM probe to still have antigens in common with their classic tubercular parent-form, from which they originated. Moreover, in true cell-wall-deficient fashion, the isolates, upon guinea pig inoculation, did not immediately produce visible lesions, but nevertheless persisted. However, tissue homogenates of the infected animals, once placed on a growth-enhancing medium showed cell-wall-deficient mycobacterial forms interspersed with classical acid-fast rods. And a repeated passage of such tissue homogenates back into non-infected guinea pigs, not only induced small mycobacterial granulomas in their livers, but a distinct increase in acid-fast rods. Moreover, similar cell-wall-deficient mycobacterial forms with acid-fast rods occurred when embryonated chicken eggs were inoculated with PPD tuberculins as well.
The autoclaved and supposedly “sterilized” purified protein derivative [PPD] used in tuberculin skin tests contain cell-wall-deficient forms capable of eventually reverting back to virulent acid-fast tuberculosis, both typical and atypical. "