In the COVID-19+ cohort, despite adequate CD4 recovery in the majority of participants with a median CD4 count of 609 (Q1–Q3, 466–817), lower nadir CD4 was associated with a significant humoral immune repertoire shift toward more IgM responses and a greater capacity for antibody-specific FcγRIIB binding (Figure 10, B and D). Here, FCGR2B is linked to COVID-19.