Unusual Increased β-Globulins in an Elderly Patient

Abstract

A 90-year-old man who had a history of transurethral prostate resection for benign prostatic hyperplasia was admitted for left hip pain. A hip radiography examination revealed a large osteolytic lesion in the left greater trochanter, and a bone scintigraphy evaluation showed increased activity in the same area. Because of the patient's history, metastasis from prostate carcinoma was suspected, and bone biopsies were performed the same week. Ten days later, the patient was hospitalized in the emergency department after a fall that fractured the femoral neck. At admission, plasma sodium, chloride, and potassium concentrations were all within their respective reference intervals. The plasma concentration of total protein was 5. 4 showed the presence of an unusual spike in the ␤ region (Fig. 1A). We measured an increased urine concentration of free light chain [1.4 mg/dL (14 mg/L); reference interval, 0 -0.2 mg/dL (0 -2 mg/L)], along with a normal concentration of urine ␤ 2 -microglobulin.The patient underwent surgical repair of his left femur. In the meantime, our laboratory asked for serum to complete the investigation of the abnormal UPEP pattern. Investigations of the serum sample revealed a decreased albumin concentration [1.45 g/dL (14.5 g/L); reference interval, 3.0 -4.5 g/dL (30 -45 g/L)]. Immunoglobulin quantification revealed an increased IgG value [2950 mg/dL (29.5 g/L); reference interval, 700 -1000 mg/dL (7-10 g/L)]. IgA and IgM were within their respective reference intervals. Serum protein electrophoresis (SPEP) showed an increased ␣1 region, along with decreased albumin and ␥ regions. Moreover, we found an increased ␤ region (19.1 g/L, quantified from the electrophoresis trace and the total protein concentration), along with a loss of separation between the ␤1 and ␤2 regions because of a narrow spike (Fig. 1B). With a normal concentration of ␤-globulins of approximately 300 mg/dL (3 g/L), we estimated the monoclonal protein concentration at approximately 1600 mg/dL (16 g/L). Serum immunofixation was performed with antibodies specific for heavy chains (G, A, M) and light chains (, ). A band was present in the IgG lane with a ␤ electrophoretic mobility, with no corresponding band for the light chain (Fig. 1C). Serum free light chains included a decreased free chain [0.06 mg/dL (0.6 mg/L); reference interval, 0.33-1.94 mg/dL (3.3-19.4 mg/L)], a decreased free

Gamma heavy chain disease in a patient with rheumatoid arthritis – a laboratory evaluation

“…Immunoassays furthermore show an analytical variability as a result of differing detection antibody specificities (18). The phenomenon of discrepant values for total IgG and sum of IgG subclasses has been previously illustrated by other groups and might be explained by the loss of an antigenic domain normally recognized by the IgG subclass antisera due to truncation of the heavy chain (6,19). We had primarily thought the elevated IgG1 subclass identifies the gamma HC subclass but we failed to subtype the detected IgG in (concentrated) urine supporting our assumption that the heavy chain did not react with our IgG1-4 antisera and the elevated IgG1 concentration in serum did not necessarily stand in connection with the gamma heavy chain.…”

T cell receptor rearrangements in a patient with γ-heavy chain disease: A case report

“…However, the patient's serum levels of IgG subtypes 1-4 were demonstrated to be lower than normal, which had not been previously reported in the literature to the best of our knowledge (11). As the summation of the IgG subtypes (<2.4 g/l) was markedly lower compared with the total IgG level (74.4 g/l), an antigen excess (also known as excess high-dose hook effect) caused by nephelometric assays was considered to be a potential explanation, as this may have resulted in false negative data (12)(13)(14). The discrepancies between the values may additionally have been due to a failure of the IgG subclass antigen to recognize the lost antigenic domain in incomplete heavy chain components.…”