NEW MICROBIOLOGICA, 32, 415-417, 2009 Mycobacterium xenopi pulmonary infection resulting in self-limited immune reconstitution inflammatory syndrome in an HIV-1 infected patient Sebastiano Leone 1,2 , Sergio Giglio 1,2 , Patrizia Maio 1 , Piero Capasso 3 , Giuseppina dell’Aquila 1 , Mario Magliocca 1 , Francesco Saverio Nigro 1 , Piera Pacifico 1 , Nicola Acone 1 1 Infectious Diseases Division; 2 AIDS service; 3 Radiology Service, A.O.R.N. San G. Moscati, Avellino, Italy The prognosis for patients infected with human immunodeficiency virus (HIV) type 1 has im- proved dramatically since the advent of Highly Active Antiretroviral Therapy (HAART), which al- lows sustained suppression of HIV replication and recovery of CD4 T cell counts (Lazzarin, 2004). In some patients receiving HAART, im- mune reconstitution is associated with a patho- logical inflammatory response leading to sub- stantial short-term morbidity and even mortality (Shelburne et al., 2006). This report concerns a case of Mycobacterium xenopi pulmonary infection resulting in self-lim- ited immune reconstitution inflammatory syn- drome (IRIS) in an HIV-1 infected patient start- ing HAART. Corresponding author Sebastiano Leone, MD Infectious Diseases Division A.O.R.N. San G. Moscati Contrada Amoretta - 83100 Avellino, Italy E-mail: sebastianoleone@yahoo.it A 39-year-old man with advanced HIV infection (CD4 lymphocyte count of 28 cells/mm 3 , HIV-RNA of 55200 copies/ml) was admitted to our clinic. There was no history of prior infection with my- cobacteria, Mantoux test was negative, and the chest X-ray was normal. Treatment with tenofovir (TDF), emtricitabine (FTC) and efavirenz (EFV) was started. Co-trimoxazole was started for Pneumocystis jiroveci prophylaxis. One month later he present- ed with productive cough and a fever of 37.5°C. Blood investigations revealed C-reactive protein of 58 mg/L, erythrocyte sedimentation rate of 67 mm/h, lactate dehydrogenase of 600 U/L, white blood cell count of 4850 cells/mm 3 with 65.4% neutrophils. The other examinations showed no abnormalities. Multiple blood cultures were ster- ile. At this time the CD4 lymphocyte count had increased to 65 cells/mm 3 and the HIV plasma vi- ral load was undetectable. A High Resolution Computer Tomography (HRCT) scan demon- strated ground-glass opacities (Fig. 1). M. xenopi isolate was obtained from multiple sputum sam- Highly active antiretroviral therapy (HAART) has been shown to induce a major and durable viral load reduction ac- companied by a stable CD4 increase. This process may evolve with adverse clinical phenomena, known as the immune reconstitution inflammatory syndrome (IRIS). In the HIV population, non-tuberculous mycobacteria are a common cause of IRIS. However, only a few cases of Mycobacterium xenopi associated IRIS have been described. This paper concerns a case of M. xenopi pulmonary infection resulting in self-limited immune reconstitution inflammatory syn- drome in an HIV-1 infected patient. KEY WORDS: Mycobacterium xenopi, HIV, HAART, Immune reconstitution inflammatory syndrome SUMMARY Received April 01, 2009 Accepted June 13, 2009