Discussion
In our study, patients who applied to our liver transplant outpatient
clinic were evaluated in terms of serum SARS-COV-2 Ig M + IgG level and
history of COVID-19 disease. The Serum antibody positivity rate was
30.7% in liver transplant patients participating in our study. The
seroprevalence values for the region in which we conducted the current
study are unknown. However, seropositivity was found to be 12.3%
(115/932) in a seroprevalence study conducted on healthcare
professionals in Turkey. The seropositivity among previously undiagnosed
healthcare workers was calculated as 2.7% [4].
Limited data are available for asymptomatic or subclinical infections in
the transmission of the SARS-CoV-2 virus [5]. In our study, the rate
of participants with an asymptomatic history of covid-19 was 7.6%
(7/91). Seventy-five percent of all antibody-positive patients were not
diagnosed with COVID-19, and their inquiries had no specific symptoms of
COVID-19. When all participants were evaluated, 23% (21/91) subclinical
or asymptomatic seropositivity was detected.
In previous studies, acute and past SARS-COV-2 infections were
documented in 3.7% of LT recipients. In the same study, the
asymptomatic seropositivity rate was evaluated as 62.5% (5/8) [6].
The rate of asymptomatic COVID-19 in liver transplant recipients has
been determined by 6% in the Spain series and 14% in a multinational
study (n = 151) [7, 8].
In our study, 66% of patients with seropositive (14/21) were utterly
asymptomatic; at least one symptom was observed in seven participants.
However, there was no significant difference between the symptoms of
both groups.
There was no difference between serum AST and ALT levels in patients
with seropositive and seronegative. But we do not know serum AST and ALT
values in possible disease processes. Studies have been shown to be a
relationship between severe disease and elevated liver enzymes in
patients with COVID-19. In infected individuals with SARS-COV-2,
increased serum liver enzyme levels had seen approximately 15% [9].
In our clinical data, serum AST or ALT levels were found to be two times
or higher in 23% of patients diagnosed with symptomatic covid (n=4/17).
Increased liver enzymes are usually reversible. As expected,
seropositivity is not associated with alone increased liver enzymes.
Asymptomatic or subclinical COVID-19 participants with seropositivity
include the history of risky contact with people diagnosed COVID-19 in
19% and the history of hospitalization in 28%. In contrast to the
expected, the higher rate of seropositivity was not associated with
contact with risky people or hospitalization.
Our limitation of the study is that patients are evaluated in a wide
period of 6 months to determine seroprevalence as serum antibody tests
are observed during routine follow-up.
In conclusion, studies related to the course of the disease in liver
transplant recipients are increasing gradually. However, the frequency
of asymptomatic or subclinical disease is not precise yet. Although the
number of patients in our study was low, the seropositivity rate
(30.7%) and the rate of asymptomatic (75%) among all the participants
were higher than expected. We need large-scale seroprevalence studies to
reach more reliable data.