Common causes of PHGG divided by CRP
| High CRP (>30 mg/L) . | Variable CRP . | Low CRP (<30 mg/L) . |
|---|---|---|
| • Infection • Malignancy • Vasculitis • Autoinflammatory • Hematologic (CD, ECD) Note: PHGG in these conditions is typically driven by IL-6 and other inflammatory cytokines. | • Autoimmune (Sjӧgren syndrome, sarcoidosis) • Iatrogenic (IVIG) • Hematologic (lymphoma, RDD) | • Liver disease • IgG4-RD • Immune deficiency (ALPS, dysgammaglobulinemias) • Graves disease Note: PHGG in these conditions is generally from immune dysregulation other than IL-6 signaling. In liver disease, loss of portal filtering and increased exposure to enteric antigens are implicated. |
| High CRP (>30 mg/L) . | Variable CRP . | Low CRP (<30 mg/L) . |
|---|---|---|
| • Infection • Malignancy • Vasculitis • Autoinflammatory • Hematologic (CD, ECD) Note: PHGG in these conditions is typically driven by IL-6 and other inflammatory cytokines. | • Autoimmune (Sjӧgren syndrome, sarcoidosis) • Iatrogenic (IVIG) • Hematologic (lymphoma, RDD) | • Liver disease • IgG4-RD • Immune deficiency (ALPS, dysgammaglobulinemias) • Graves disease Note: PHGG in these conditions is generally from immune dysregulation other than IL-6 signaling. In liver disease, loss of portal filtering and increased exposure to enteric antigens are implicated. |
CRP is a surrogate for systemic inflammation and is the “rule of thumb” with many individual exceptions. For example, a patient with an inflammatory condition may have received corticosteroids suppressing their CRP, or a patient with a condition such as IgG4-RD may have a concomitant infection driving up the CRP.
ALPS, autoimmune lymphoproliferative syndrome.