Marseillevirus Adenitis in an 11-Month-Old Child

Abstract

A Marseillevirus (giant virus of amoeba) has been found in the blood and stool samples of individuals who otherwise appear to be healthy. During an attempt to define a serological cutoff for Marseillevirus by enzyme-linked immunosorbent assay (ELISA) in children, we serendipitously detected high antibody responses to Marseillevirus in an 11-month-old boy suffering from adenitis. Marseillevirus DNA was then found in his blood using PCR and with a unique sequence. We identified Marseillevirus in a lymph node using fluorescence in situ hybridization (FISH) and immunohistochemistry, and the lymph node was removed surgically. The child was declared to be cured 1 year later. We conclude that adenitis during early childhood may be caused by Marseillevirus. Giant viruses of amoebas are part of a proposed viral order (1) whose role in human diseases is still being evaluated (2). Mimivirus, the first giant virus isolated from amoeba, has recently been associated with pneumonia (3). Marseillevirus, the other large family of amoeba viruses (4, 5), has been found in water and once in the stool sample of an asymptomatic Senegalese subject (2, 6). Recently, this virus was found in blood samples from asymptomatic blood donors (7). The virus was cultured in one of these cases and identified using immunofluorescence in a blood concentrate, and its genome was partially sequenced (7). It constitutes a new strain compared to the others that were already discovered (7). On this occasion, a serological technique has been implemented that helped highlight that a significant portion of the population had been in contact with Marseillevirus. It therefore became useful to define a positive test cutoff using enzyme-linked immunosorbent assay (ELISA). To determine the serological cutoff for Marseillevirus infections and evaluate its seroprevalence, we selected 10 serum samples that we believed would be negative for Marseillevirus from patients who were supposedly too young to have been exposed to the virus. These serum samples came from individuals who were Ͼ6 months old and Ͻ2 years old and were sent to our laboratory for diagnosis and anonymous testing. Nine tested negative, but the tenth exhibited high antibody titers. This led us, for the well-being of the patient, to lift anonymity and examine the history of the patient. CASE REPORTThe patient, a young boy aged 11 months, presented with nonfebrile lymphadenopathy. He was hospitalized in the pediatric ward of La Timone Hospital for a single right axillary adenopathy. The lymphadenopathy was 1.5 cm in diameter and had evolved over the last month and a half. The child never developed a fever and did not suffer any alteration in his general condition. The history of the child only included systemic Bacillus Calmette Guérin infection ("BCGitis") with an occurrence 2 months after the BCG injection (inoculated at 1 month old). The initial assessment upon admission revealed a decreased neutrophil count and lymphocytosis, with erythrocyte sedimentation rate that accelerated to 33 mm during the ...

The Large Marseillevirus Explores Different Entry Pathways by Forming Giant Infectious Vesicles

“…Given the natural hosts of marseilleviruses, this does not seem to be applicable, as amoebas do not possess an adaptive immune system. However, this could be important if humans were their hosts, since marseilleviruses have already been described as putative human pathogens (17,23). In addition, our results suggest that infection through vesicles evolved as a powerful mechanism to boost the replicative success of this virus within its natural hosts and/or its survival in the environment where they coexist.…”

“…After fixation, the cells were permeabilized with 0.2% Triton X-100 in 3% bovine serum albumin (BSA)-PBS for 5 min, followed by a rinse with 3% BSA-PBS three times. The cells then were stained for 1 h at room temperature with four specific primary antibodies: rabbit polyclonal anti-sorting nexin 2 (SNX2) (Santa Cruz Technology, USA) (16), goat polyclonal anti-GRP 78 (N-20) (Santa Cruz Technology, USA), mouse monoclonal anti-GM130 (BD Biosciences, USA), and mouse polyclonal anti-MsV (17). After incubation with secondary antibodies, fluorescently labeled cells were visualized using a Zeiss (LSM 510 META) microscope.…”

Faustovirus, an Asfarvirus-Related New Lineage of Giant Viruses Infecting Amoebae

“…Because these giant viruses are resistant to killing by phagocytic protists, we hypothesized that they may also reproduce in macrophages and might therefore infect humans. This proposition was validated experimentally by the isolation of mimivirus from atypical pneumonia patients and by the detection of marseilleviruses in blood donors and in human lymph nodes (7)(8)(9). Moreover, we and others identified sequences associated with giant viruses in metagenomes generated from human tissues, suggesting that giant viruses are a component of the human virome (10).…”

Marseillevirus in the Pharynx of a Patient with Neurologic Disorders

“…During assessment of Marseillevirus serology at Institut Hospitalo-Universitaire (IHU) Méditerranée Infection (Marseille, France), we found serum from an 11-month-old boy with lymphadenitis that exhibited a high Marseillevirus IgG titer; the virus was detected by PCR in serum and by fluorescence in situ hybridization and immunohistochemistry in the lymph node ( 6 ). Subsequently, the hospital implemented systematic Marseillevirus PCR in cases of gastroenteritis or pharyngitis, which led to detection of Marseillevirus DNA in pharyngeal and blood samples from a 20-year-old man.…”