First Reported Instance of Hair Color Restoration During Lung Cancer Treatment

Understanding PD-1 and PD-L1 in Cancer Therapy

Programmed cell death protein 1 (PD-1) is an essential protein located on the surface of various immune system cells, including CD4+ and CD8+ T cells, B cells, monocytes, natural killer cells, and dendritic cells. As an immune checkpoint protein, PD-1 plays a crucial role in regulating the immune response and maintaining immune tolerance, preventing the immune system from attacking the body’s own tissues. The function of PD-1 is influenced by PD-1 ligands, which are proteins on the surface of T cells, B cells, and different tumor cells that bind to PD-1, thus dampening the immune response.

PD-L1, in particular, is expressed at elevated levels on many tumor cells, which aids in evading immune attacks. Emerging cancer treatments focus on obstructing the interaction between PD-1 and PD-1 ligands by utilizing antibodies that specifically target PD-1 or PD-L1. Notable examples of PD-1 inhibitors include pembrolizumab and nivolumab, while PD-L1 inhibitors comprise atezolizumab, avelumab, and durvalumab. Among these, nivolumab, pembrolizumab, and atezolizumab have received approval for the treatment of metastatic non-small-cell lung cancer.

Potential Side Effects of Anti-PD1/PD-L1 Therapy

The mechanism of action for these drugs involves blocking PD-1 checkpoint regulation, which may lead to various side effects, including autoimmune reactions. Recently, a team of clinicians at the Hospital Universitari Germans Trias i Pujol in Badalona, Spain, examined a cohort of 52 lung cancer patients undergoing anti-PD1/anti-PD-L1 therapy. Their findings revealed an unprecedented adverse effect: hair repigmentation in 14 of the patients. These observations were documented in JAMA Dermatology.

Details of the Hair Repigmentation Phenomenon

Of the 14 patients who experienced hair repigmentation, 13 showed either a partial response to treatment or stable disease, while one patient had disease progression, leading to the cessation of treatment after four cycles. In most cases, the patients exhibited a diffuse darkening of their hair, whereas one patient developed patches of black hair interspersed with white hairs.

The authors of the study emphasize that this marks the first documented instance of hair repigmentation occurring during lung cancer treatment with PD-1/PD-L1 inhibitors and may suggest a positive therapeutic response. However, the precise molecular mechanisms responsible for this phenomenon remain unclear, warranting further investigation.

Conclusion

The discovery of hair repigmentation in lung cancer patients undergoing anti-PD1/anti-PD-L1 therapy opens new avenues for understanding the effects of immunotherapy. Continued research will be essential to elucidate the underlying mechanisms of this occurrence.

References

1. Jin HT, Ahmed R, Okazaki T. Role of PD-1 in regulating T-cell immunity. Curr Top Microbiol Immunol. 2011;350:17-37. doi: 10.1007/82_2010_116. Review. PubMed PMID: 21061197.
2. Immune checkpoint inhibitors to treat cancer. American Cancer Society. https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/immune-checkpoint-inhibitors.html. Updated May 1, 2017. Accessed August 27, 2017.
3. Rivera N, Boada A, Bielsa MI, Fernández-Figueras MT, Carcereny E, Moran MT, Ferrándiz C. Hair Repigmentation During Immunotherapy Treatment With an Anti-Programmed Cell Death 1 and Anti-Programmed Cell Death Ligand 1 Agent for Lung Cancer. JAMA Dermatol. 2017 Jul 12. doi: 10.1001/jamadermatol.2017.2106. [Epub ahead of print] PubMed PMID: 28700789.