A rare aberrant alpha-2 band in an elderly anemic patient

INTRODUCTION

Serum protein electrophoresis (SPE) is ordered for detecting and quantifying a monoclonal protein when a patient is suspected of having a monoclonal gammopathy. Monoclonal gammopathy occurs when there is a selective propagation of a single clone of plasma cells producing a single clone of immunoglobulins which appears as a “M spike” on protein electrophoresis. It ranges from benign monoclonal gammopathy of undetermined significance to malignant multiple myelomas. It affects mainly older people and males are more commonly affected than females.^[1]

Our case elaborated below showed an aberrant (extra) peak in the alpha-2 region. As monoclonal peaks are more common in the gamma region followed by the beta region,^[2] this case merited follow-up with extensive history and correlation with other investigations to determine its cause.

Our study was approved by the institute’s ethics committee. Approval number: post BH&R 67/02.2025-07.

CASE REPORT

A 72-year-old female patient presented to our outpatient department with a history of recurrent anemia for which she received repeated transfusion over the past 5 years. She also had pain abdomen with recurrent aphthous ulcers of the mouth and a history of frequent use of nonsteroidal anti-inflammatory drugs (diclofenac/aceclofenac) for 20 years which she discontinued 5 years ago. Due to a sharp drop in hemoglobin (Hb) and considering her age, the hematooncologist referred her for SPE to rule out multiple myelomas. Routine tests revealed a slightly elevated creatinine and microcytic hypochromic anemia with a Hb of 7.6 g/dL [Table 1]. Upper gastrointestinal endoscopy revealed hyperemia with small superficial ulcers in the duodenum. Triphasic contrast-enhanced computed tomography (CECT) of the liver suggested the possibility of cryptogenic multifocal ulcerous stenosing enteritis.

SPE was run by capillary zone electrophoresis (Minicap Flex-Piercing analyser, Sebia, Lisses, France). It showed two distinct peaks in the alpha-2 region and acute inflammation [Figure 1]. Kappa lambda ratio (Nephelometry, the Atellica Neph630, Siemens, Forchheim, Germany) was within normal limits. Immunofixation electrophoresis (IFE) was done in serum (3351– QuickGel IFE Kit, Helena, UK). It showed normal polyclonal distribution of immunoglobulins – no monoclonal bands.

Close

Figure 1:

The initial serum protein electrophoresis result for the 72-year-old female patient showing the distribution of various protein fractions. An aberrant peak (a second peak), indicated by the red arrow, is visible in the alpha-2 globulin region.

Export to PPT

Due to the presence of the aberrant peak in a patient with normal kappa-lambda ratio and no monoclonal bands detected on IFE, we took a thorough look into the patient’s history, reports, and investigations.

We determined that a CECT was ordered for this patient for which the patient was administered 70 mL non-ionic iodinated contrast (iohexol) intravenously. The blood sample for SPE was collected following CECT.

Thus, a repeat serum sample was collected from the patient 3 days later and SPE rerun on the fresh sample. The repeat SPE showed attenuation of the aberrant peak in the alpha-2 region, protein loss, and acute inflammation [Figure 2]. The presence of an extra peak in the first SPE and its elimination in the second SPE is consistent with the administration and excretion of an exogenous substance (radio-opaque dye) which is consistent with the history of the patient.

Close

Figure 2:

The serum protein electrophoresis results for the same 72-year-old female patient performed after 3 days. The red arrow indicates the attenuation of the aberrant peak.

Export to PPT

DISCUSSION

The diagnostic features of multiple myelomas include a monoclonal band on protein electrophoresis, clonal plasma cells of >10% on bone marrow biopsy, and one or more features of end-organ damage, the so called CRAB symptoms, which are hyperCalcemia of >11g/dL, Renal failure indicated by serum creatinine of more than 2g/dL or glomerular filtration rate (GFR) of less than 40 mL/min, Anemia of < 10 g/dL or a recent drop in hemoglobin of >2g/dL, and lytic Bone lesions on x-ray, CT or MRI.^[1]

This patient is a 72-year-old female with an Hb of 7.6 g/dL with an aberrant band (M band) in the alpha-2 region. When such a sharp M band is visible on protein electrophoresis in an elderly symptomatic patient, the diagnosis of multiple myelomas has to be considered. Monoclonal bands are most common in the gamma region followed by the beta-2 and beta-1 regions.^[2] Monoclonal bands in the alpha-2 region are rare and other causes of the appearance of such bands – variant phenotypes of haptoglobin, improper haptoglobin-Hb complex that forms due to hemolysis, or radiopaque dyes^[3-5] – have to be considered. In SPE, as with most investigations, several pre-analytical errors might occur due to the collection of improper sample or contamination during sample collection. There was no hemolysis in the sample. Serum kappa lambda ratio and serum IFE were within normal limits suggesting that a monoclonal protein is not causing the band. Since this patient’s blood was collected following the administration of non-ionic iodinated contrast (iohexol) and not before as per protocol, the iodinated contrast was considered the most probable cause.

A repeat sample was collected after 3 days which showed attenuation of the peak – the disappearance of this band suggests the presence of an exogenous administered substance which was then eliminated (excreted) by the patient which based on the history of the patient indicate that it was caused by the non-ionic iodinated contrast (iohexol) used for CECT. Organic iodine molecules (e.g., iohexol, iodixanol, and ioversol) have been shown to interfere in several biochemical assays including cardiac troponin I and SPE.^[6] Thus, drawing of a blood sample should be done before administration of the contrast dye.

Similar bands in the alpha region due to contrast dye have also been observed by other researchers.^[5,7,8] Duggal et al. found five cases of monoclonal bands in the alpha region due to lambda isotype on immunofixation.^[9] This suggests that IFE of immunotyping electrophoresis should be done in all cases of monoclonal bands in the alpha-2 region.

Being alert and aware that not all bands on protein electrophoresis indicate a monoclonal protein, especially when not accompanied by a band on IFE enabled us to avoid unnecessary further investigations and interventions.

CONCLUSION

The knowledge of different contaminants that can cause aberrant bands in protein electrophoresis helps us identify the actual cause and not misdiagnose the patient as one of multiple myelomas, avoiding unnecessary investigations and interventions.