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Archived Comments for: Emerging trends in Lassa fever: redefining the role of immunoglobulin M and inflammation in diagnosing acute infection

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  1. Standing on the shoulders of giants...

    Luis Branco, Tulane University

    27 October 2011

    After this manuscript was published in preliminary form we recalled a report by Niklasson, Jahrling and Peters published in 1984 by the Journal of Clinical Microbiology entitled "Detection of Lassa virus antigens and Lassa virus-specific immunoglubulins IgG and M by enzyme-linked immunosorbent assay" that reported persistence of LASV-specific IgM in a relevant nonhuman primate model of LF. Niklasson, Jahrling and Peters observed that rhesus macaques surviving LF continued to generate significant serum titers of LASV-specific IgM until at least day 532 post-infection. The authors considered that, "this unexpected persistence of virus-specific IgM in the nonhuman primate model deserves further investigation and should also be evaluated in patients. The finding raises concerns about possible virus persistence and also suggests that the mere finding of virus-specific IgM in a single serum sample tested by ELISA may not imply recent infection." The current study demonstrates that LASV-specific IgM persists in human LF patients and provides evidence that LASV-specific IgM is not a reliable serological marker for acute LASV Infection. Moreover, in Niklasson et al isolation of nonhuman primates in controlled laboratory environments suggests that re-exposure to LASV is not responsible for the prolonged virus-specific IgM titers in the serum of convalescent animals. The findings in NHP suggest that prolonged IgM responses observed in humans is a common immunological response to LASV infection and opens discussions to its implications in the pathogenesis of LF.

    Competing interests

    None declared