In addition to their role as effector cells in virus control, natural killer (NK) cells have an immunoregulatory function in shaping the antiviral T-cell response. This function is further pronounced in perforin-deficient mice that show the enhanced NK-cell proliferation and cytokine secretion upon mouse cytomegalovirus (MCMV) infection. Here, we confirmed that stronger activation and maturation of NK cells in perforin-deficient mice correlates with higher MCMV load. To further characterize the immunoregulatory potential of perforin, we compared the response of NK cells that express or do not express perforin using bone-marrow chimeras. Our results demonstrated that the enhanced proliferation and maturation of NK cells in MCMV-infected bone-marrow chimeras is an intrinsic property of perforin-deficient NK cells. Thus, in addition to confirming that NK-cell proliferation is virus load dependent, our data extend this notion demonstrating that perforin plays an intrinsic role as a feedback mechanism in the regulation of NK-cell proliferation during viral infections.

Introduction: Adverse drug reactions (ADRs) are threat to the patient’s safety and the quality of life, and they increase the cost of health care. Spontaneous ADR reporting system mainly relies on physicians, but also pharmacists, nurses, and even patients. The aim of this study was to explore attitudes, barriers, and possible improvements to ADR reporting practices in Bosnia and Herzegovina.Methods: A self-reported questionnaire was developed to collect data on the perception of pharmacovigilance practice and ADR reporting. The survey was conducted in the period between September, 2014 and October, 2014.Results: The response rate was 73% (44 of 60) and 93% (148 of 160) among the pharmacist and family medicine physician groups, respectively. Regarding the attitudes to pharmacovigilance practice and reporting, both the pharmacists and physicians found the practices important. The majority of pharmacists and physicians in year 2014 did not report any ADR, while 18% of the pharmacists and 12% of the physicians, who participated in this study, reported one ADR. Reporting procedure, uncertainty, and their exposure were the main barriers to reporting ADRs for the pharmacists. The physicians claimed lack of knowledge to whom to report an ADR as the main barrier. A significant number of the respondents thought that additional education in ADR reporting would have a positive impact, and would increase the ADR reporting rate.Conclusions: Despite the overall positive attitude towards ADR reporting, the reporting rate in Bosnia and Herzegovina is still low. Different barriers to the ADR reporting have been identified, and there is also the need for improvements in the traditional education in this field.