Case Series Evaluating Lymphocyte Subgroups at Diagnosis and After Treatment in Multisystem Inflammatory Syndrome Associated With COVID-19 in Children

Abstract

Objective: In this case series, we aimed to examine the changes in lym-phocyte subgroups in children diagnosed with the multisystem inflammatory syndrome (MIS-C) during the acute phase and in the first month after treatment. Material and Methods: Ethics committee approval was received for the study from the Ethics Committee of Ondokuz Mayıs University patient data were analyzed from medical records in an electronic database. Ini-tial immunological evaluations of our first five patients diagnosed with MIS-C were made, steroid and IVIG treatments were given to the pa-tients, and lymphocyte subgroups were evaluated for the second time in the first month for control purposes. Results: In MIS-C cases, it was observed that lymphopenia was severe in the acute period, CD3 T cells decreased, the ratio of 2:1 between cytotoxic T cells and helper T cells was impaired, B cells increased proportionally, and NK cells were normal or decreased. When we evaluated MIS-C cases with the control lymphocyte subgroup in the first month, it was observed that lymphopenia improved and CD3 T cells increased proportionally, and active T cells decreased to normal values in the first month after treatment. On the other hand, while naive B cells decreased, non-switching and switching B cells increased and NK cells decreased. Conclusion: While COVID-19 is an acute infection, MIS-C is associated with cytokine storm induced by the acute infection. Immunologic assessment of MIS-C cases is considered important since the condition causes immune dysregulation in the host immune system. Lymphopenia, increased B cell count, reversal of the CD4/CD8 ratio, and increased active T cell count may be beneficial in the early diagnosis of MIS-C. Since it is thought that the cy-tokine storm causes complications in MIS-C, immediate administration of IVIG treatment is considered essential. Although it was demonstrated that the disease manifests with marked cellular changes, there is still a need for further studies. ©Copyright 2022 by Pediatric Infectious Diseases and Immunization Society. Available online at www.cocukenfeksiyon.org.