What is happening is that M2 macrophages are being increased. Although usually thought of as anti-inflammatory they can bring on their own problems by keeping bad cells from being killed. They're also known to cause lung problems when they proliferate. Leronlimab is known to decrease M2 macrophages in preference to M1 macrophages. By blocking RANTES it would also keep both types from migrating.

Longhaulers is also producing disregulated B cells that instead of creating antibodies that are attacking virus are creating antibodies that attack the bodies own cells in an autoimmune response. Leronlimab works by dampening down that autoimmune response.