J Clin Immunol. 2024 May 22. 44(6): 131
Jingyu Zhou,
Mengqing Qian,
Ning Jiang,
Jing Wu,
Xiaoqian Feng,
Meiping Yu,
Qing Min,
Haoxin Xu,
Yixuan Yang,
Qingluan Yang,
Feiran Zhou,
Lingyun Shao,
Haoxiang Zhu,
Yun Yang,
Ji-Yang Wang,
Qiaoling Ruan,
Wenhong Zhang.
RHOH, an atypical small GTPase predominantly expressed in hematopoietic cells, plays a vital role in immune function. A deficiency in RHOH has been linked to epidermodysplasia verruciformis, lung disease, Burkitt lymphoma and T cell defects. Here, we report a novel germline homozygous RHOH c.245G > A (p.Cys82Tyr) variant in a 21-year-old male suffering from recurrent, invasive, opportunistic infections affecting the lungs, eyes, and brain. His sister also succumbed to a lung infection during early adulthood. The patient exhibited a persistent decrease in CD4+ T, B, and NK cell counts, and hypoimmunoglobulinemia. The patient's T cell showed impaired activation upon in vitro TCR stimulation. In Jurkat T cells transduced with RHOHC82Y, a similar reduction in activation marker CD69 up-regulation was observed. Furthermore, the C82Y variant showed reduced RHOH protein expression and impaired interaction with the TCR signaling molecule ZAP70. Together, these data suggest that the newly identified autosomal-recessive RHOH variant is associated with T cell dysfunction and recurrent opportunistic infections, functioning as a hypomorph by disrupting ZAP70-mediated TCR signaling.
Keywords: Opportunistic infection; Primary immunodeficiency; RHOH; T cell; TCR signaling