Free Light Chains of Immunoglobulins in Serum from Patients with Rheumatoid Arthritis, Sarcoidosis, Chronic Infections and Pulmonary Cancer

Abstract

ABSTRACT. Free light chains of immunoglobulins were measured in serum from 181 patients with rheumatoid arthritis (RA), sarcoidosis, pulmonary tuberculosis, pulmonary cancer and chronic bronchitis, i.e. patients with long‐term stimulation of the immune system. Increased concentrations of light chains were found in patients with active sarcoidosis, and the light chain level appeared to be a marker of disease activity in sarcoidosis. The mean (±S.D.) concentration of kappa plus lambda chains in active sarcoidosis of more than two years' duration was 38.3± 13.7 mg/l, that is twice the concentration of 19.4±5.5 mg/l found in normals. Some patients with seropositive RA also had increased serum values. The light chain concentrations in seropositive RA were correlated to the severity of the disease measured by clinical staging and laboratory tests. A modest increase in light chains was observed in one patient with tuberculosis, and in two patients each with chronic bronchitis and pulmonary cancer.

Quantitative Assessment of Serum and Urinary Polyclonal Free Light Chains in Patients with Chronic Kidney Disease

“…A possible explanation for this finding is chronic inflammation, which is well described in patients with diabetes (18,19), because chronic inflammation itself is associated with increased polyclonal FLC (20,21).…”

The association of serum-free light-chain levels with markers of renal function

“…On the other hand, most patients with chronic inflammatory diseases and associated renal impairment have high concentrations of polyclonal FLCs, but with substantially normal k/ ratio. [17][18][19][20] The clinical study of elevated sFLCs in renal impairment are unclear. Reports have suggested that the elevated FLCs lead to reductions in immune function and therefore should be classified as uremic toxins.…”

Serum Free Light Chains and the Risk of ESRD and Death in CKD

“…Such elevations are very common in a wide variety of inflammatory and infectious diseases, which are not frequently associated with renal impairment (12). Conceptually there are two principal reasons why polyclonal sFLCs could have been associated with progressive renal disease.…”

“…In people with CKD, reticuloendothelial clearance and therefore reticuloendothelial health becomes an important component of sFLC clearance. A further consideration is the presence of coincident inflammation, which will further elevate sFLC concentrations (12,13). Although sFLCs do have an immunomodulatory effect (14), there are no studies to date that have assessed their relationship to clinical outcomes in CKD.…”