C3 and lymphopenia: Analysis of the individual immunophenotypes further delineated an association with CD3+ (OR 4.6, P = 0.046) and CD4+ (OR 4.5, P = 0.017) T cell lymphopenia in addition to low C3 (<93 mg/dL, OR 6.5, P = 0.015) and low median IgG while receiving replacement immunoglobulin therapy (<800 mg/dL, OR 4.3, P = 0.004) (Table 2, middle panel).