Author Of 2 Presentations
LB1235 - Frequency of SARS-CoV-2 antibodies and COVID-19 severity in a cohort of Italian multiple sclerosis patients on DMTs inhibiting immune cell trafficking (ID 2116)
Coronavirus disease 2019 (COVID-19) pandemic is provoking major concerns among physicians and people living with Multiple Sclerosis (pwMS) undergoing disease modifying treatments (DMT). As per today, we do not know what is the impact of SARS-CoV-2 on pwMS and undergoing treatment with DMTs inhibiting immune cell trafficking that are natalizumab (NTZ) and fingolimod (FTY), and vice versa what may be the effects of these drugs on the infection and related disease.
To investigate the frequency of SARS-CoV-2 antibodies and to report COVID-19 severity in pwMS on NTZ and FTY affiliated to the MS Centre of IRCCS Mondino, Pavia, Lombardy, Italy.
Roche SARS-CoV-2 IgG assay (Elecsys®) was used to test serum samples from 106 pwMS (51 treated with NTZ and 55 with FTY). COVID-19 severity was assessed via a 7-point ordinal scale.
Among our cohort of pwMS on NTZ or FTY, the frequency of antibody anti-SARS-CoV-2 was 15%.
Half of seropositive cases were asymptomatic; and half of symptomatic seropositive cases were pauci symptomatic. About 35% of our cohort of pwMS reported COVID-19 symptoms, none of them required hospitalization or die due COVID-19.
Despite we found a high frequency of SARS-CoV-2 antibodies in our cohort of pwMS, half of seropositive cases were asymptomatic. None of symptomatic cases had a severe COVID-19 course. DMTs inhibiting immune cell trafficking seem to be safe in our cohort of pwMS and may be considered as a therapeutical option for highly active MS during COVID-19 pandemic.
P0094 - Inter-laboratory evaluation of cerebrospinal fluid and serum kappa free light chain measurements (ID 966)
The kappa index, calculated by dividing the cerebrospinal (CSF)/serum kappa free light chain (KFLC) ratio by the CSF/serum albumin ratio, is gaining increasing interest as an indirect marker of intrathecal activation of the humoral immune response. The demonstration of intrathecal synthesis is of particular relevance in the diagnostic work-up of suspected Multiple Sclerosis. However, the lack of consistent data on inter-laboratory agreement in CSF and serum KFLC measurements is one of the factors that hamper the use of kappa index in routine practice.
Aim of this study was to assess agreement in CSF and serum KFLC measurements and kappa index values across different laboratories.
Fifteen paired CSF and serum samples were analyzed in all participating laboratories (nr=8). Four centers used Binding Site instruments and assays, 3 centers used Siemens instruments and assays, and one center used a Siemens instrument and a Binding Site assay.
Absolute individual agreement between laboratories was calculated using a two-way mixed effects intraclass correlation coefficient (ICC). Cohen's kappa coefficient was used to measure inter-laboratory agreement on positive (≥5.8) kappa index values.
Within Binding Site laboratories, ICC for KFLC measurements was 0.96 (95%CI: 0.9-0.98) for CSF, 0.93 (95%CI: 0.63-0.98) for serum and 0.97 (95%CI: 0.94-0.99) for kappa index values. Within Siemens laboratories, ICC for KFLC measurements was 0.99 (95%CI: 0.97-100) for CSF, 0.93 (95%CI: 0.48-0.98) for serum and 0.95 (95%CI: 0.89-0.98) for kappa index values. ICC calculated for all laboratories was 0.93 (95%CI: 0.87-0.97) for CSF KFLC, 0.81 (95%CI: 0.53-0.93) for serum KFLC and 0.65 (95%CI: 0.43-0.84) for kappa index. Cohen's kappa coefficient for a positive kappa index was 0.89 across Binding Site laboratories, 0.70 across Siemens laboratories, and 0.77 across all laboratories.
There was an excellent agreement in CSF KFLC measurements and in kappa index values within laboratories using the same instrument and assay (Binding Site or Siemens), while serum KFLC measurements were less concordant. Agreement across all laboratories was decreased when including the laboratory using a Siemens instrument coupled with a Binding Site assay in the analyses. Concordance for a positive kappa index was substantial across all laboratories and within Siemens laboratories, and very good within Binding Site laboratories.