Immune reconstitution is the trigger of herpes zoster with lymphopenia and high neutrophil-to-lymphocyte ratio (NLR) in a retrospective cohort study.

BACKGROUND: Herpes zoster (HZ) rarely results in later death, but predictive biomarkers for mortality necessitates further elucidation.

OBJECTIVE: To investigate immune dynamics prior to HZ event, risk factors for HZ onset, and immune status at initial HZ.

METHODS: This retrospective study extracted the absolute neutrophil and lymphocyte counts (ANC and ALC, respectively) at the initial HZ date and up to 30 days before HZ. A follow-up survey was completed within 180 days of the onset of illness.

RESULTS: Patients with HZ showed higher neutrophil-to-lymphocyte ratio (NLR) and lower ALC than the control at the initial date and had poorer prognosis. In the pre-onset examination, the maximum and minimum ALC values were significantly lower in patients with HZ than in the control, and the maximum ALC value in patients with HZ was lower than the minimum value in the control. The lowest ALC value was observed 7 days before the onset of HZ. An NLR value of 4.53 or more and ALC value of 0.64 × 109 cells/L or less were predictive markers of HZ development within 30 days. Patients who died after HZ had lower minimum ALC than those who survived longer.

LIMITATIONS: The study had small population size, varying age distribution, and retrospective nature. The pre-onset data might have been exaggerated.

CONCLUSION: HZ develops in a state of immune reconstitution with immunocompromised conditions, as part of the unmasking immune reconstitution inflammatory syndrome (IRIS). Lymphopenia prior to HZ onset is one of the most crucial factors in its pathogenesis and vital prognosis.