Failure of isoniazid chemoprophylaxis during infliximab therapy

Mycobacterium kansasii infection in a psoriasis patient treated with adalimumab and switch to apremilast: First report and literature review

Patient under anti-TNF-alpha treatment have an increased risk of mycobacterial infections, particularly tuberculosis. Only four case reports of Mycobacterium kansasii infection under anti-TNF-α treatment (two with etanercept, two with infliximab) have been reported, but none under adalimumab. A 72-year-old man treated with adalimumab for psoriasis vulgaris and arthropathic psoriasis, complained on nocturnal cough, occasional hemoptysis and the new onset of ill-defined, reddish, asymptomatic persistent plaques-nodules covered by serum crusts on his back, on the dorsum of the right hand and right middle finger. Routine laboratory investigations, HIV and TB screening (QuantiFERON-TB-Gold test) were all within normal limits. A skin biopsy was inconclusive and special staining resulted negative for microorganisms. Only PCR identified M. kansasii. The patient stopped adalimumab and started anti-TB treatment with gradual improvement of the skin lesions. At 26 months follow-up visit no signs or symptoms of relapse of M. kansasii disease occurred.

Relevance of latent TB infection in areas of high TB prevalence

About one-third of the world population has latent TB infection (LTBI), the majority of which is distributed in 22 high-burden countries. Early diagnosis and treatment of active TB remains the top priority in resource-poor countries with high TB prevalence. Notwithstanding, because LTBI contributes significantly to the pool of active TB cases later on, its diagnosis and treatment is essential, especially in high-risk groups. The lack of a gold standard and several limitations of currently available tools, namely the tuberculin skin test and interferon-γ release assays, are major constraints for LTBI diagnosis. In areas with high TB prevalence, interferon-γ release assays have not shown superiority over the conventional tuberculin skin test and are yet to be systematically studied. Decisions regarding LTBI treatment with isoniazid preventive therapy should be made, keeping in mind the high prevalence of isoniazid resistance in these settings. Although efforts to shorten the LTBI treatment duration are encouraging, most trials have focused on adherence and toxicity. Future trials on short-duration regimens in high-burden settings should address drug efficacy issues as well. LTBI management, therefore, should comprise a targeted screening approach and individualization of LTBI treatment protocols. In addition, efforts should focus on airborne infection control measures in high-burden countries. A high prevalence of drug-resistant TB, the HIV epidemic, and delays in the diagnosis of active TB cases are other major concerns in areas of high TB prevalence. There is ample space for further research in these countries, whose outcomes may strengthen future national guidelines.

Anti-TNF-α agents in the treatment of immune-mediated inflammatory diseases: mechanisms of action and pitfalls

TNF-α is a potent inducer of the inflammatory response, a key regulator of innate immunity and plays an important role in the regulation of Th1 immune responses against intracellular bacteria and certain viral infections. However, dysregulated TNF can also contribute to numerous pathological situations. These include immune-mediated inflammatory diseases (IMIDs) including rheumatoid arthritis, Crohn’s disease, psoriatic arthritis, ankylosing spondylitis, ulcerative colitis and severe chronic plaque psoriasis. Animal and human studies concerning the role of TNF-α in IMIDs have led to the development of a therapy based on TNF blockage. This article focuses first on the potential mechanisms by which the three currently licensed agents, adalimumab, etarnecept and infliximab, decrease the inflammatory activity of patients with different IMIDs. Second, it focuses on the risks, precautions and complications of the use of TNF-α inhibitors in these patients.