Privacy Implications of Retrieval-Based Language Models

Retrieval-based language models (LMs) have demonstrated improved interpretability, factuality, and adaptability compared to their parametric counterparts, by incorporating retrieved text from external datastores. While it is well known that parametric models are prone to leaking private data, it remains unclear how the addition of a retrieval datastore impacts model privacy. In this work, we present the first study of privacy risks in retrieval-based LMs, particularly $k$NN-LMs. Our goal is to explore the optimal design and training procedure in domains where privacy is of concern, aiming to strike a balance between utility and privacy. Crucially, we find that $k$NN-LMs are more susceptible to leaking private information from their private datastore than parametric models. We further explore mitigations of privacy risks. When privacy information is targeted and readily detected in the text, we find that a simple sanitization step would completely eliminate the risks, while decoupling query and key encoders achieves an even better utility-privacy trade-off. Otherwise, we consider strategies of mixing public and private data in both datastore and encoder training. While these methods offer modest improvements, they leave considerable room for future work. Together, our findings provide insights for practitioners to better understand and mitigate privacy risks in retrieval-based LMs. Our code is available at: https://github.com/Princeton-SysML/kNNLM_privacy

Four cases of recalcitrant pemphigus vulgaris salvaged with rituximab

Although the long-term use of immunosuppressives – supplemented with more aggressive treatments such as immunoadsorption, intravenous immunoglobulins, or plasmapheresis in recalcitrant cases has dramatically improved the prognosis of pemphigus vulgaris, opportunistic infections secondary to immunosuppression continue to cause significant mortality. We report four cases– three old ones, who had accumulated significant morbidities over their disease duration ranging from 5 to 10 years, and the fourth, a teenage female intolerant to corticosteroids and idiosyncratic to methotrexate– who achieved complete remission on administration of rituximab by the lymphoma protocol. One of the old cases who had recalcitrant mucositis experienced its complete subsidence without any adjuvant whatsoever. All continue to remain asymptomatic for 11–20 months. None had infusion reactions or any delayed side effects