BACKGROUND:

We have shown that the "immuno-modulators" methotrexate and 6-MP and the "anti-inflammatory" 5-ASA inhibit MAP growth (www.PLoSONE.org) and concluded that their most plausible mechanism of action in several idiopathic diseases is as antiMAP antibiotics. Thalidomide is an "immunomodulator" used in multiple "auto-immune" and "inflammatory" diseases and the mycobacterial diseases leprosy and tuberculosis. We now test the hypothesis that thalidomide inhibits MAP growth.

METHODS

Thalidomide (±) and (+) and (-) and its two components, phthalimide and 1-hydroxy 2,6 piperidine dione (HPD) were evaluated in culture of two strains each of MAP (ATCC 19698 [bovine] & Dominic [human]) and M. avium subspecies avium (ATCC 25291 & 101.) We used a radiometric (¹⁴CO₂ Bactec®) detection system. Inhibition is indicated by "percent decrease in cumulative Growth Index" (%-DcGI) from control.

RESULTS:

Phthalimide has no dose dependent inhibition on any strain. There was no dose dependent inhibition on either M. avium strain with thalidomide or its components. With the two MAP strains, there is dose dependent inhibition with thalidomide (±); Dominic (31%-DcGI) and ATCC 19698 (26%-DcGI) at 64µg/ml. Thalidomide (+) is more inhibitory than (-). HPD is, on a weight for weight basis, the most inhibitory agent evaluated; Dominic (46%-DcGI) and ATCC 19698 (44%-DcGI at 64µg/ml)

CONCLUSIONS:

We show in vitro heretofore-undescribed inhibition of MAP growth by racaemic thalidomide. Thalidomide (+) is more potent than (-). Of thalidomide's two moieties, phthalimide has no antiMAP activity and HPD is the active component in inhibiting MAP growth. We suggest that since 1942, initially with 5-ASA, the medical profession has unknowingly been treating MAP infections. These data are compatible with our concern that MAP is zoonotic. We conclude that all idiopathic "autoimmune" and "inflammatory" diseases, empirically treated with medications that we show are active against MAP, should now be evaluated for MAP as the etiological agent.