Lymphocyte subsets in 32 patients with multisystem inflammatory syndrome
in children (MIS-C)
Abstract
BACKGROUND: Lymphopenia is a hallmark of multisystem inflammatory
syndrome in children (MIS-C). We aimed to characterize lymphocyte
subsets’ shifts and their correlations with other severity markers of
MIS-C. METHODS: In this prospective cross-sectional study, we performed
peripheral lymphocyte phenotyping in 32 patients with MIS-C. We analyzed
lymphocyte subsets at three time-points of the disease: the acute (A),
convalescent (B), and recovery (C) phases. Based on age-normalized
lymphocyte counts, we distinguished two groups of patients: “the mild”
and “the severe”. In addition, we examined differences between these
groups regarding other severity markers. RESULTS: In phase A, 84% of
children had lymphopenia. Decreased absolute counts of CD3, CD4, and CD8
cells were observed in, respectively, 88%, 72%, and 84% of patients.
The natural killer cells were decreased in 63% and CD19 in 59% of
children. “The severe” group had significantly higher procalcitonin
and troponin I levels and lower platelets and albumin. Moreover, “the
severe” group had hypotension more frequently (73% vs. 20%, p=0.008).
In phase B, all lymphocyte counts increased, and 32% of children had
lymphocytosis. The increase of CD3, CD4, and CD8 counts correlated with
some laboratory severity markers (hemoglobin, procalcitonin, D-dimer,
lactate dehydrogenase, N-terminal prohormone of brain natriuretic
peptide, albumin), but not with steroid use. In phase C, most children
had normal lymphocyte counts. CONCLUSIONS: Substantial shifts in
lymphocyte counts during MIS-C apply most to T lymphocytes and correlate
with the disease severity markers, particularly hypotension prevalence.
A proportion of children with MIS-C develops transient lymphocytosis
during convalescence.