<p>Repeated intravesical injections of autologous platelet-rich plasma (PRP) have shown promise in alleviating symptoms of non-ulcer interstitial cystitis bladder pain syndrome (IC/BPS), but the underlying mechanisms remain unclear. In this single-center prospective study, 80 patients received four monthly PRP injections, with outcomes assessed by symptom scales, urodynamic parameters, and immune indices in urine and serum. PRP significantly reduced 24-h micturition frequency, numeric rating scale (NRS), O’Leary, pelvic pain and urgency/frequency patient symptom scale&#xa0;(PUF), and self-rating anxiety scale (SAS) scores at post-treatment follow-ups (all <i>p</i> &lt; 0.05), while bladder capacity and voided volume remained unchanged. Serum and urinary inflammatory, iron metabolism, and oxidative stress markers were not significantly altered. PRP improved T-lymphocyte mitochondrial metabolic status, reducing CD4⁺ and CD8⁺ T-cell mitochondrial mass and decreasing CD8⁺ effector memory (Tem) T-cell counts, CD8⁺ Tem-MMP^low, and CD8⁺ PD-1⁺ Tem counts after the fourth injection (all <i>p</i> &lt; 0.05). These immunological parameters positively correlated with symptom severity. Baseline NRS &gt; 4 was associated with worse baseline profiles and selective post-treatment improvements, whereas global response assessment (GRA) stratification showed no significant differences. These findings indicate that repeated intravesical PRP alleviates IC/BPS-related pain and urinary symptoms primarily by reversing T-cell exhaustion and enhancing mitochondrial metabolic status, thus highlighting T-cell immunometabolic modulation as a key therapeutic mechanism.</p>