Risk and outcomes of COVID-19 in patients with multiple sclerosis

Background and purpose

Limited information is available on incidence and outcomes of COVID‐19 in patients with multiple sclerosis (MS). This study investigated the risks of SARS‐CoV‐2 infection and COVID‐19‐related outcomes in patients with MS, and compared these with the general population.

Methods

A regional registry was created to collect data on incidence, hospitalization rates, intensive care unit admission, and death in patients with MS and COVID‐19. National government outcomes and seroprevalence data were used for comparison. The study was conducted at 14 specialist MS treatment centers in Madrid, Spain, between February and May 2020.

Results

Two‐hundred nineteen patients were included in the registry, 51 of whom were hospitalized with COVID‐19. The mean age ± standard deviation was 45.3 ± 12.4 years, and the mean duration of MS was 11.9 ± 8.9 years. The infection incidence rate was lower in patients with MS than the general population (adjusted incidence rate ratio = 0.78, 95% confidence interval [CI] = 0.70–0.80), but hospitalization rates were higher (relative risk = 5.03, 95% CI = 3.76–6.62). Disease severity was generally low, with only one admission to an intensive care unit and five deaths. Males with MS had higher incidence rates and risk of hospitalization than females. No association was found between the use of any disease‐modifying treatment and hospitalization risk.

Conclusions

Patients with MS do not appear to have greater risks of SARS‐CoV‐2 infection or severe COVID‐19 outcomes compared with the general population. The decision to start or continue disease‐modifying treatment should be based on a careful risk–benefit assessment.

Elongation of the cytoplasmic domain, due to a point deletion at exon 7, results in an HLA-C null allele, Cw*0409 N

The development of molecular techniques for HLA typing has allowed the identification of genes previously assigned as serologic blank alleles. Lack or poor cell surface expression has been found for molecules coded by HLA-A, -B, -DRB4, -DRB5, and -DPB1 genes. In this report we describe the first HLA-C gene encoding for a null cell surface molecule. HLA-Cw*0409 N shows a point deletion at position 1095 within exon 7. This mutation provokes a codon reading shift, generating a new translation stop codon 97 bp downstream to that described in alleles normally expressed. This new stop codon location implies the presence of 32 extra amino acid residues in the cytoplasmic domain. Transfection experiments suggest that elongation of the cytoplasmic domain in Cw*0409 N would be the cause of cell surface expression failure, although Cw*0409 N heavy chain is able to create stable complexes with beta2-microglobulin. HLA-C fragment length analysis in a small selected group of samples with B44-Cblk haplotypic associations allowed us to identify two additional subjects showing both a serologic silent Cw*04 allele and a point base deletion at the 3' end of the HLA-C gene. This finding indicates that the allele frequency of Cw*0409 N within serologic C blank alleles would be appreciable, although basically restricted to the (A23)-Cw*0409 N-B*4403-DR7-DQ2 haplotype.