Metapneumovirus infection in children in modern conditions: clinical and immunological parallels

Aim. The study of metapneumovirus infection clinical and immunological features in children of different ages. Patients and methods. An analysis of 22 patients with mono-metapneumovirus infection is presented. There were 7 (31.8%) children under the age of 1 year, 8 (36.4%) — 1—3 years old, 7 (31.8%) — 4—7 years old. Diagnosis of metapneumovirus infection was based on clinical data and on PCR analysis of nasopharyngeal mucus. Immunological studies in 10 patients included immunophenotype of patient's blood lymphocytes and analysis of the interferon system. Results. Among children under the age of 1 year 71.4 ± 17.1% were diagnosed with obstructive bronchitis and 28.6 ± 17.1% had pneumonia. In patients aged 1—3 years pneumonia was observed more often (55.6 ± 17.6%), obstructive bronchitis — less often (33.3 ± 16.7%), and in 11.1 ± 11.1% bronchitis occurred without symptoms of bronchial obstruction. In children aged 4—7 years only the upper respiratory tract was affected in 14.3 ± 13.2% of cases, 57.1 ± 18.7% developed bronchitis and 28.6 ± 17.1% — pneumonia. The immune system state was characterized by a low content of T-helpers (CD3 + CD4 + ) and NK-cells (CD3-CD16 + CD56 + ) detected in 7 (70%) and 5 (50%) patients respectively. IFNγ production was reduced in 70% of children and IFNα in 80%. Conclusion. Metapneumovirus infection in children in modern conditions is characterized by the frequent development of inflammatory changes in the bronchopulmonary system in the early stages of the disease. The disease severity was due to both manifestations of respiratory failure and severe symptoms of intoxication. Immunological studies revealed changes in the cellular link and the interferon system in all age groups.