Background and Aims

Chloroquine derivatives and hydroxychloroquine, which are treatment options in COVID-19, are conventionally used for the treatment and prevention of malaria and for the treatment of autoimmune diseases. Accordingly, this study was initiated by looking for a relation between those.

Methods

Tblastx searches are performed with SARS-CoV-2, by limiting searches to five plasmodium species that infect human.

Presence of aligned sequences in respective organisms' proteomes are searched with blastp.

A 15mer in virus proteome is found to be SARS-CoV-2 query sequence with the highest identity to one plasmodium species. It is searched in the alignments with the other plasmodium species.

Binding of that peptide to MHC class I supertype representatives are predicted. Cytotoxic T lymphocyte epitope predictions is also performed.

Homologous regions with minimum 60% identity to predicted-epitopes in the 15mer are looked for.

Binding strengths of those homologous peptides to previously detected specific MHC class I supertype representative are predicted for homologous sequences.

Results

CFLGYFCTCYFGLFC of SARS-CoV-2 is query sequence with highest identity to P. vivax. It is present in the other plasmodium species' alignments. Its two parts are binding strongly to HLA-A*24:02 . Homologous regions are observed for one, accordingly: Five 10mer peptides in human proteome and twelve 10mer peptides in plasmodium species' proteomes, three of which are predicted to bind strongly to the same allele, in each. Among strong-binder plasmodium peptides, one is homologous to a 10mer in human proteome, which binds strongly to the same allele.

Conclusions

Immune responses to homologous 10mers with strong binding to HLA-A*24:02 may cause autoimmunity.