Tag: seronegativity

Evidence of previous SARS-CoV-2 infection in seronegative patients with long COVID

Abstract:

Background: There is currently no consensus on the diagnosis, definition, symptoms, or duration of COVID-19 illness. The diagnostic complexity of Long COVID is compounded in many patients who were or might have been infected with SARS-CoV-2 but not tested during the acute illness and/or are SARS-CoV-2 antibody negative.

Methods: Given the diagnostic conundrum of Long COVID, we set out to investigate SARS-CoV-2-specific T cell responses in patients with confirmed SARS-CoV-2 infection and/or Long COVID from a cohort of mostly non-hospitalised patients.

Findings: We discovered that IL-2 release (but not IFN-γ release) from T cells in response to SARS-CoV-2 peptides is both sensitive (75% +/-13%) and specific (88%+/-7%) for previous SARS-CoV-2 infection >6 months after a positive PCR test. We identified that 42-53% of patients with Long COVID, but without detectable SARS-CoV-2 antibodies, nonetheless have detectable SARS-CoV-2 specific T cell responses.

Interpretation: Our study reveals evidence (detectable T cell mediated IL-2 release) of previous SARS-CoV-2 infection in seronegative patients with Long COVID.

Funding: This work was funded by the Addenbrooke’s Charitable Trust (900276 to NS), NIHR award (G112259 to NS) and supported by the NIHR Cambridge Biomedical Research Centre. NJM is supported by the MRC (TSF MR/T032413/1) and NHSBT (WPA15-02). PJL is supported by the Wellcome Trust (PRF 210688/Z/18/Z, 084957/Z/08/Z), a Medical Research Council research grant MR/V011561/1 and the United Kingdom Research and a Innovation COVID Immunology Consortium grant (MR/V028448/1).

Source: Krishna BA, Lim EY, Mactavous L; NIHR BioResource Team, Lyons PA, Doffinger R, Bradley JR, Smith KGC, Sinclair J, Matheson NJ, Lehner PJ, Wills MR, Sithole N. Evidence of previous SARS-CoV-2 infection in seronegative patients with long COVID. EBioMedicine. 2022 Jul;81:104129. doi: 10.1016/j.ebiom.2022.104129. Epub 2022 Jun 27. PMID: 35772216; PMCID: PMC9235296. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9235296/ (Full text)

Japanese patients with chronic fatigue syndrome are negative for known retrovirus infections

Abstract:

Although chronic fatigue syndrome (CFS) is known to be the syndrome that begins with an acute flu-like illness that may be due to the exposure to an infectious agent, there has been no convincing evidence on the causative agents.

Recently, human T-lymphotropic virus type II (HTLV-II)-like virus has been reported to be associated with the CFS by using HTLV Western blot analysis and polymerase chain reaction. However, some investigators could not detect HTLV-II by indirect immunofluorescence analysis.

Lately, CFS patients have been reported in Japan. We detected all 30 tested patients with CFS were seronegative for HTLV-II, HTLV-I and HIV by specific peptide ELISA and Western blot. Further, PCR analysis was negative for HTLV-II and retrovirus was not detected by coculture method with patients’ PBMC. Thus, known human retrovirus infections do not cause a CFS in Japan.

 

Source: Honda M, Kitamura K, Nakasone T, Fukushima Y, Matsuda S, Nishioka K, Matsuda J, Hashimoto N, Yamazaki S. Japanese patients with chronic fatigue syndrome are negative for known retrovirus infections. Microbiol Immunol. 1993;37(10):779-84. http://www.ncbi.nlm.nih.gov/pubmed/7507200