{Reference Type}: Journal Article
{Title}: Differential decline of SARS-CoV-2-specific antibody levels, innate and adaptive immune cells, and shift of Th1/inflammatory to Th2 serum cytokine levels long after first COVID-19.
{Author}: Kratzer B;Gattinger P;Trapin D;Ettel P;Körmöczi U;Rottal A;Stieger RB;Sehgal ANA;Feichter M;Borochova K;Tulaeva I;Grabmeier-Pfistershammer K;Tauber PA;Perkmann T;Fae I;Wenda S;Kundi M;Fischer GF;Valenta R;Pickl WF;
{Journal}: Allergy
{Volume}: 0
{Issue}: 0
{Year}: 2024 Jul 14
{Factor}: 14.71
{DOI}: 10.1111/all.16210
{Abstract}: <B>BACKGROUND: </B>SARS-CoV-2 has triggered a pandemic and contributes to long-lasting morbidity. Several studies have investigated immediate cellular and humoral immune responses during acute infection. However, little is known about long-term effects of COVID-19 on the immune system.<BR><B>METHODS: </B>We performed a longitudinal investigation of cellular and humoral immune parameters in 106 non-vaccinated subjects ten weeks (10 w) and ten months (10 m) after their first SARS-CoV-2 infection. Peripheral blood immune cells were analyzed by multiparametric flow cytometry, serum cytokines were examined by multiplex technology. Antibodies specific for the Spike protein (S), the receptor-binding domain (RBD) and the nucleocapsid protein (NC) were determined. All parameters measured 10 w and 10 m after infection were compared with those of a matched, noninfected control group (n = 98).<BR><B>RESULTS: </B>Whole blood flow cytometric analyses revealed that 10 m after COVID-19, convalescent patients compared to controls had reduced absolute granulocyte, monocyte, and lymphocyte counts, involving T, B, and NK cells, in particular CD3+CD45RA+CD62L+CD31+ recent thymic emigrant T cells and non-class-switched CD19+IgD+CD27+ memory B cells. Cellular changes were associated with a reversal from Th1- to Th2-dominated serum cytokine patterns. Strong declines of NC- and S-specific antibody levels were associated with younger age (by 10.3 years, p < .01) and fewer CD3-CD56+ NK and CD19+CD27+ B memory cells. Changes of T-cell subsets at 10 m such as normalization of effector and Treg numbers, decline of RTE, and increase of central memory T cell numbers were independent of antibody decline pattern.<BR><B>CONCLUSIONS: </B>COVID-19 causes long-term reduction of innate and adaptive immune cells which is associated with a Th2 serum cytokine profile. This may provide an immunological mechanism for long-term sequelae after COVID-19.