Exploratory Study on Infection and Immunosenescence Based on an Elderly Clinical Cohort

Inclusion Criteria for the Healthy Control Group 1. No clinical symptoms suggestive of infection, including fever, cough, dyspnea, fatigue, or myalgia. 2. No abnormal physical signs, including lymphadenopathy, hepatomegaly, splenomegaly, or skin rash. 3. Normal laboratory test results, including complete blood count (CBC), C-reactive protein (CRP), and liver and renal function tests. 4. Healthy adults without underlying chronic diseases, no history of infectious diseases within the previous 6 months, and generally normal cognitive function. 5. Male or female. 6. Able to understand the study procedures and voluntarily provide written informed consent. Inclusion Criteria for the Infection Group 1.Age: 60 years or older; no gender restrictions. 2. Clinically diagnosed with an infectious disease by the treating physician. 3. The participant provides informed consent and signs the relevant documents. \-------------- Exclusion Criteria for the Healthy Control Group 1. Refusal to participate in the study; 2. Any other condition that, in the opinion of the investigator, makes the participant unsuitable for enrollment. Exclusion Criteria for the Infection Group 1. Final primary diagnosis is a non-infectious disease (e.g., connective tissue disease, tumor, or other conditions). 2. Positive culture results are determined by the clinician to be due to colonization or contamination rather than infection. 3. Refusal to participate in the study. 4. Patients in critical or severe conditions who are unable to cooperate with sample collection. 5. Other conditions deemed unsuitable for inclusion as determined by the researchers.