Disruption of CCR5 signaling to treat COVID-19-associated cytokine storm: Case series of four critically ill patients treated with leronlimab

Coronavirus disease 2019 (COVID-19) is associated with considerable morbidity and mortality. The number of confirmed cases of infection with SARS-CoV-2, the virus causing COVID-19 continues to escalate with over 70 million confirmed cases and over 1.6 million confirmed deaths. Severe-to-critical COVID-19 is associated with a dysregulated host immune response to the virus, which is thought to lead to pathogenic immune dysregulation and end-organ damage. Presently few effective treatment options are available to treat COVID-19. Leronlimab is a humanized IgG4, kappa monoclonal antibody that blocks C–C chemokine receptor type 5 (CCR5). It has been shown that in patients with severe COVID-19 treatment with leronlimab reduces elevated plasma IL-6 and chemokine ligand 5 (CCL5), and normalized CD4/CD8 ratios. We administered leronlimab to 4 critically ill COVID-19 patients in intensive care. All 4 of these patients improved clinically as measured by vasopressor support, and discontinuation of hemodialysis and mechanical ventilation. Following administration of leronlimab there was a statistically significant decrease in IL-6 observed in patient A (p=0.034) from day 0–7 and patient D (p=0.027) from day 0–14. This corresponds to restoration of the immune function as measured by CD4+/CD8+ T cell ratio. Although two of the patients went on to survive the other two subsequently died of surgical complications after an initial recovery from SARS-CoV-2 infection.

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Leronlimab is a monoclonal antibody in clinical trials to treat the cytokine storm.

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Critically ill patients received leronlimab through compassionate use and had remarkable recoveries measured objectively.

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The CCR5 receptor is important in recruiting inflammatory cells mainly T cells and macrophages.

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Leronlimab disrupted this signal and may have been responsible for restoration of the immune system, improved survival and decrease in IL-6.

Failure of the circulatory system limits exercise performance in patients with systemic sclerosis

OBJECTIVE

To determine the mechanisms for exercise impairment in symptomatic patients with systemic sclerosis (SSc) using breath-by-breath expired-gas analysis with incremental exercise testing.

DESIGN

Prospective, open trial.

PATIENTS AND METHODS

Fifteen consecutive patients with SSc seen at the Medical University Hospital (a tertiary referral center) with complaints of exercise intolerance underwent pulmonary function testing (spirometry, helium dilution lung volumes, and diffusing capacity of carbon monoxide) and incremental exercise testing on a cycle ergometer measuring oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (R), oxygen saturation, blood pressure, and heart rate (HR). Values for oxygen uptake at anaerobic threshold (VO2AT) were derived graphically by blinded clinicians experienced in exercise testing, and the results were averaged. Ventilatory reserve and oxygen pulse were calculated from measured values, and all data were subjected to analysis by standard clinical algorithms.

MEASUREMENTS AND MAIN RESULTS

Of 15 patients studied, 14 had either restrictive lung disease or normal results of spirometry on pulmonary function testing. One patient with a history of tobacco use had evidence of airways obstruction. Three patients were unable to exercise maximally (as determined by maximum respiratory exchange ratio [Rmax] greater than 1.09 or maximum heart rate [HRmax] greater than 85% predicted), and exercise testing was terminated in one with Mobitz type II atrioventricular block. The following data (mean +/- SEM) were obtained from 11 maximally exercising patients: VO2max 795 +/- 75 mL oxygen (O2)/min, R 1.34 +/- 0.05, VO2AT/VO2max predicted 0.21 +/- 0.02, O2 pulse 5.1 +/- 0.4 mL O2/beat, ventilatory reserve 0.52 +/- 0.06, and tidal volume/forced vital capacity ratio 0.46 +/- 0.02. Of the 11 patients completing breath-by-breath expired-gas analysis, all had circulatory impairment to exercise, as determined by low O2 pulse and low VO2 at anaerobic threshold, and circulatory impairment was limiting in 9 of 11 patients. Of those nine patients, four had evidence of impaired gas exchange compatible with pulmonary vascular disease. Arterial oxygen desaturation occurred in 2 of 11 patients.

CONCLUSION

Circulatory impairment to exercise is common in SSc patients with exercise intolerance. Restrictive lung disease, although also common, does not limit exercise tolerance in patients capable of maximal effort.