PMC9773200_01
Clinical photographs. During dermatology consult, the patient reported that the diffuse hyperpigmented macular appearing lesions had erupted in January 2020 (A), and additional, smaller lesions appeared on the torso by June 2020 (B).
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At the time of presentation, the patient reported a six-month history of hyperpigmented, violaceous macules and plaques involving the extremities and torso but sparing the palms, soles, and mucous membranes ( Figure 1 ). Phylogenetic analysis showed that the isolated virus was vaccine-derived ( Figure S1 ) with 97.3% nucleotide identity to the genomic sequence of the RA27/3 strain used in an MMR vaccine.
Low power [2.5x objective, (A)] and high power [10x objective, (B)] histologic examination of diffused skin granulomas (hematoxylin-eosin staining). Immunofluorescence staining of the granulomas with RuV anti-capsid antibody (red) in M2-macrophages (green) (C, D). Blue nuclei were the result of counterstaining with 4',6-diamidino-2-phenylindole (DAPI).
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Double fluorescent immunohistochemical (IHC) staining of formalin-fixed paraffin-embedded (FFPE) tissue sections of the skin biopsy with mouse monoclonal antibody against RuV capsid and rabbit polyclonal antibody against CD206 revealed the presence of RuV in M2 macrophages in the cores of granulomas located in the upper ( Figures 2A, C ) and deep dermis ( Figures 2B, D ).
A timeline of viral shedding and treatments. Changes in VDRV RNA load in sequential patient's samples were determined by RuV RT-qPCR. Samples positive by cell culture were indicated by the red color. Treatments are indicated by the green bars. The anti-VZV treatments included IV acyclovir 750 mg every 8 hours for 10 days followed by oral valacyclovir 1 g every 8 hours for 10 days, then oral acyclovir 800 mg twice daily after this as prophylaxis. Steroid treatments included IV hydrocortisone for 5 days (the first dose 75 mg, and then 50 mg doses), and one dose of IV methylprednisolone 80 mg given with IVIG. Treatments with colony stimulating factor were indicated by the black arrows.
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However, RuV RNA was detected in the NP swab, and replication-competent RuV was isolated in Vero cell culture from the NP swab ( Figure 3 ). VZV as well as for VDRV by RT-qPCR. VDRV viral load was 4.3x102 RNA copies/mL CSF; live VDRV was not recovered from CSF ( Figure 3 ). VDRV RNA was detected in all eight NP swabs; replication-competent viruses were recovered from six of these ( Figure 3 ).
RuV-associated granuloma in bone marrow. Double immunofluorescent IHC staining of sequential tissue sections of bone marrow core biopsy for rubella capsid (RVC, red) and one of the cell type markers (green), CD206 (M2 macrophages), MPO (neutrophils), or CD3 (T cells) shows predominant rubella staining of neutrophils and less frequent rubella staining of M2 macrophages. Numerous RVC-CD3+ T cells were located inside the granuloma outlined with the yellow dashed line. Scale bar: 200 microm.
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To evaluate the possibility of VRDV as a possible etiology of the patient's pancytopenia, the sequential tissue sections of bone marrow core biopsy were double immunostained with RuV capsid antibody and either CD206, MPO, or CD3 antibody ( Figure 4 ).