Discussion
The immunocompromised patient was diagnosed with varicella caused by primary VZV infection based on the results of physical, blood, and histopathological examinations. The patient was also diagnosed with CMV pneumonia based on the results of CMV antigen test in the blood and the findings of chest CT; the previous studies reported that CMV pneumonia on CT is mainly detected as ground-glass opacities 7and varicella pneumonia mainly as nodular lesions 8. The onset of varicella preceded that of CMV pneumonia by a few days.
Three mechanisms have been proposed for the development of adult-onset varicella: i) the reactivation of latent VZV, ii) reinfection by VZV of a different genotype from that of latent VZV, and iii) primary VZV infection. In the case of varicella caused by the reactivation of latent VZV, VZV-specific IgG potentially increases commonly from a certain level, whereas VZV-specific IgM does not. In the case of varicella due to reinfection by VZV of a different genotype, VZV-specific IgM potentially increases, whereas VZV-specific IgG appears to rapidly increase commonly from a certain level at an early time point from the onset 9. In the case of varicella caused by primary VZV infection, VZV-specific IgM definitely increases, whereas VZV-specific IgG gradually becomes elevated over 2-3 weeks from a negative level. Increases in VZV-specific IgM were followed by a gradual elevation in VZV-specific IgG over 2 weeks from a negative level in the present case, which was compatible with primary VZV infection.
VZV-specific IgG levels in SLE patients previously infected by VZV were previously reported to be significantly elevated regardless of total IgG levels through the significant activation of B-cells to specific antigens as the pathogenesis of SLE; however, total IgG and complement factor 3 levels sometimes decrease with an increase in the disease activity of SLE 10. In the present case, the level of VZV-specific IgG in the early stage of varicella was low, which indicated primary VZV infection in our patient.
Cases in which varicella due to the reactivation of or reinfection by VZV preceded CMV reactivation have been reported. In an experiment on monkeys, Ohtaki et al . showed that CMV was reactivated after an inoculation with VZV 11. However, primary VZV infection followed by CMV reactivation has not been reported in humans. This is the first human case of primary VZV infection leading to the reactivation of CMV. Dermatologists need to consider CMV reactivation with the appearance of varicella caused by any type of VZV infection, including reactivation, reinfection, and primary infection.
Acknowledgment: None
Statement of Ethics: This study protocol was approved by The Ethics Committee of The Jikei University School of Medicine and the patient provided written informed consent.
Consent statement: Written informed consent was obtained from the patient to publish this report in accordance with the journal’s patient consent policy.
Data Availability Statement: Additional data sharing is not applicable to this article due to ethical restrictions.