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Habitual responses towards addiction-related cues play a relevant role in the development and maintenance of addictions. Such automatic responses may be more likely under stress, as stress has been shown to induce a shift from goal-directed to habitual behavior. The current study investigated these mechanisms in risky gaming behavior. Individuals with risky gaming behavior (n = 68), as established by a structured clinical interview, and a matched control group (n = 67) completed a Pavlovian-to-Instrumental Transfer (PIT) paradigm with gaming-related cues and rewards. After the Pavlovian training, participants underwent a stress (Trier Social Stress Test) or control condition before performing the instrumental training and the transfer phase of the PIT paradigm. To assess habitual behavior, the gaming-related rewards were devalued after half of the transfer phase. In both groups, gaming-related cues enhanced the choice of the gaming-related reward and this gaming PIT effect was reduced, however, not eliminated by the devaluation. Unexpectedly, stress did not significantly increase responding for the gaming-related reward in participants aware of the stimulus-outcome associations, however seemed to enhance habitual responding in unaware participants. Our findings underline the relevance of gaming-related cues in triggering habitual responses, which may undermine attempts to change a problematic gaming behavior., (© 2024. The Author(s).)

While the use of social media and online-communication applications has become an integral part of everyday life, some individuals suffer from an excessive, uncontrolled use of social media despite experiencing negative consequences. In accordance with neuropsychological models of addiction, we assume the tendency of a social-networks-use disorder to be related to an interplay of predisposing personality traits (e.g., impulsivity), and reductions in cognitive functions (e.g., executive functions, inhibitory control). The current study makes first strides towards examining this interplay. In addition to a newly developed social-networks-specific auditory Go-NoGo paradigm, other neuropsychological paradigms were used. Impulsivity and social-networks-use-disorder symptoms were assessed by standardized questionnaires. The results show that the symptom severity of a social-networks-use disorder is mainly associated with attentional impulsivity. General executive functions and specific inhibitory control of social-networks-related cues have no direct effect on symptom severity. However, moderated regression analyses emphasize that increased symptom severity is associated with higher attentional impulsivity, especially if there are additionally reductions in executive functions or specific inhibitory control. The results complement previous findings and inform future research on social-networks-use disorder. The findings support the applicability of theoretical models of addictive behaviors to the social-networks-use disorder and point to social-networks-related specificities regarding attention-related facets.

Genetically modified antigen-presenting cells (APC) represent an attractive strategy for in vitro immunomodulation. In the human system, APC expressing HLA-A1 and a membrane-bound form of CD95L (m-CD95L) were used for selective depletion of HLA-A1-specific T cells. In short-term assays, m-CD95L-expressing APC-induced apoptosis in activated T cells and the constitutive presence of m-CD95L and HLA-A1 expressing APC in long-term T cell cultures prevented the expansion of CD4(+) and CD8(+) HLA-A1-specific T cells and the development of HLA-A1-specific cytotoxicity. However, immunity towards third party, viral and bacterial antigens was maintained and T cells spared from depletion could be induced to develop cytotoxicity towards unrelated antigens. Interestingly, inhibition of HLA-A1-specific T cell response absolutely requires the coexpression of m-CD95L and HLA-A1 antigen on the same APC. Thus, m-CD95L expressing APC might be used in clinical settings to obtain tolerance induction in allogeneic transplantation systems or autoimmune diseases.

Reticular dysgenesis is a very rare congenital immunodeficiency classified within the severe combined immunodeficiencies (SCID) and characterized by impairment of both lymphoid and myeloid cell development. We report our experience in 10 patients with RD, treated between 1979 and 1999 with HLA-haploidentical hematopoietic stem cell transplantation (HSCT). All children but one were symptomatic within the first days of their lives. Five patients required two HSCT. Five patients received conditioning therapy with busulfan (16 mg/kg) and cyclophosphamide. Three of them are alive and well with myeloid and T and B cell lymphoid reconstitution, whereas two patients died (one chronic graft-versus-host disease, one pneumonitis). Transplantation without or with other conditioning regimens in the other five cases led to absent or incomplete engraftment and none of these cases survived. These results demonstrate the mandatory need for intensive conditioning before haploidentical HSCT in RD to achieve full lymphoid and myeloid engraftment.