Polyclonal hypergammaglobulinaemia: towards definition of a threshold

Abstract

BackgroundPolyclonal hypergammaglobulinaemia (PH) represents a classic diagnosis problem in internal medicine. However, there is no consensus threshold for PH. The aim of this study was to define a threshold for PH.MethodsWe conducted a retrospective multicentric study using laboratory biological databases between 1 January 2016 and 31 December 2016 in two university hospitals and one non-university hospital. All patients 18 years old or over and with at least one serum protein electrophoresis (SPE) available in 2016 were included. Exclusion criteria were monoclonal, biclonal, or oligoclonal spikes or, in case of hypogammaglobulinaemia, proven free light chain gammopathy. The main endpoint was to define the threshold values for PH in this population. Another objective was to define the 95th percentile of the distribution.Results20 766 SPEs were included in this cohort. The PH threshold on 95th percentile was 18.9 g/L. The threshold varied according to geographical areas.ConclusionsThis is the first study to scientifically define a PH threshold. The main limitation is that our threshold is only biological. The study was not designed to associate this threshold with a clinically active disease. In conclusion, while the 19 g/L cut-off seems the most relevant threshold, but it will need to be validated by prospective studies.

Positive anti-nuclear antibody in patients with polyclonal hypergammaglobulinemia suggests the presence of multiple distinct comorbidities

“…We identified 209 patients with hypergammaglobulinemia, as defined by gamma-globulin levels ! 20 g/L (6,10). Gamma-globulin levels were calculated as (total protein × percentage of gamma globulin).…”

“…Polyclonal hypergammaglobulinemia (PHGG) results from the excessive production of immunoglobulins in response to diverse immunological challenges. In contrast to monoclonal hypergammaglobulinemia, whereby the monoclonal nature of immunoglobulin-producing cells is the central component of the pathophysiology (1), the etiologies of PHGG are manifold and not limited to hematological diseases, thus requiring clinicians to be well-versed with its diagnostic procedures and diverse differential diagnoses (2)(3)(4)(5)(6). While the diagnostic process of monoclonal hypergammaglobulinemia is relatively straightforward (7)(8)(9) it is often confounded when coincidentally encountered or consulted for PHGG, especially when some disease overlap is suspected.…”