CD4

Overview

CD4 is a co-receptor expressed on helper T cells that facilitates MHC class II antigen recognition. In the context of immune checkpoint therapy monitoring, peripheral blood CD4+ T-cell proliferative dynamics (CD4+PD-1+Ki-67+) serve as a pharmacodynamic biomarker for anti-PD-1 therapy response.

Alterations observed in the corpus

  • Peripheral CD4+ T-cell compartment measured by flow cytometry in 51 recurrent/second-primary HNSCC patients treated with IMRT reirradiation + nivolumab; a ≥1.5-fold increase in PD-1+Ki-67+CD4+ T cells after cycle 1 defined a “proliferative responder” group that trended toward worse PFS and OS — opposite to the expected direction in lung cancer and melanoma PMID:38780927.
  • CD4+ T cells detected as infiltrating immune cells in HGSOC precursor lesions (p53 signatures, STICs, cancer) by GeoMx spatial profiling across 44 fallopian tube specimens; CD4 used as an immune-cell phenotype marker to define infiltrating populations and APC chemoattraction PMID:39386723.

Cancer types (linked)

  • HNSC — CD4+PD-1+Ki-67+ T-cell surge in peripheral blood was a hypothesis-generating biomarker in recurrent/second-primary HNSCC treated with IMRT reirradiation + nivolumab; the paradoxical association with worse outcome warrants prospective validation PMID:38780927.

Co-occurrence and mutual exclusivity

  • The CD4+PD-1+Ki-67+ proliferative surge was evaluated alongside FOXP3+ Treg surge and CD8A+ T-cell dynamics; only the CD4+PD-1+Ki-67+ and FOXP3+ surges trended with worse PFS (neither reached statistical significance: HR 1.42, P = .43 for FOXP3) PMID:38780927.

Therapeutic relevance

  • Paradoxical CD4+PD-1+Ki-67+ surge tracking with worse PFS in the IMRT+nivolumab context suggests context-dependent interpretation of peripheral T-cell pharmacodynamic markers; findings are hypothesis-generating only (n=51, not powered for biomarker analysis) PMID:38780927.

Open questions

  • The mechanism behind the paradoxical CD4+ proliferative surge (regulatory T-cell skew? exhaustion phenotype? lymphatic drainage effects from prior radiation?) is unresolved in the corpus PMID:38780927.

Sources

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