Immunoglobulin D Multiple Myeloma with a “Hidden” Lambda Light Chain

Introduction/Objective In rare cases, the conventional immunofixation gel electrophoresis technique fails to detect the light chain of an M-protein. We report a case of immunoglobulin (Ig) D multiple myeloma with a hidden lambda (λ) light chain. Methods/Case Report Capillary electrophoresis (CE) (Sebia CAPILLARYS 2) was used to detect and quantify M- proteins in serum specimens. Immunosubtraction (IS) on the CAPILLARYS 2 systems was used to identify the classes of M-proteins. Conventional gel immunofixation electrophoresis (IFE) was performed, using monospecific antisera for IgD, IgE, kappa (κ) or λ in the Sebia HYDRASYS system, and IgG, IgA, IgM, κ or λ in the Helena SPIFE3000 system. Beta-mercaptoethanol (BME) with Fluidil were used as reduction agents. Results (if a Case Study enter NA) Results of serum CE showed two abnormal peaks in beta 2 and gamma regions, suspected to be positive for M-proteins. IS results showed subtraction for λ light chain only in both peaks, suggesting two monoclonal λ light chains. In contrary, no monoclonal λ light chain was detected in gamma region by IFE (Sebia). Epitope masking in the folded monoclonal protein was suspected to cause the “hidden λ light chain” and was further investigated by two laboratory approaches. IFE performed on the Helena SPIFE3000 system found two λ bands in beta 2 and gamma regions, which was consistent with the results from IS. The treatment of BME with Fluidil helped unmasking the hidden epitope and revealed the λ band in gamma region on IFE (Sebia). Conclusion The medical laboratories should be aware of the described scenario. The failure to detect light chains of certain intact M-proteins is most likely due to the structurally inaccessibility of light chains. It is recommended that treatment with reduction agents or use of an alternative methodology or IS might be helpful for investigating suspected heavy chain only cases, due to the limitation of conventional methodology.

Difficult Cases of Autoimmune Hemolytic Anemia: A Challenge for the Internal Medicine Specialist

Autoimmune hemolytic anemia (AIHA) is diagnosed in the presence of anemia, hemolysis, and direct antiglobulin test (DAT) positivity with monospecific antisera. Many confounders of anemia and hemolytic markers should be included in the initial workup (i.e., nutrients deficiencies, chronic liver or kidney diseases, infections, and cancers). Besides classical presentation, there are difficult cases that may challenge the treating physician. These include DAT negative AIHA, diagnosed after the exclusion of other causes of hemolysis, and supported by the response to steroids, and secondary cases (infections, drugs, lymphoproliferative disorders, immunodeficiencies, etc.) that should be suspected and investigated through careful anamnesis physical examination, and specific tests in selected cases. The latter include autoantibody screening in patients with signs/symptoms of systemic autoimmune diseases, immunoglobulins (Ig) levels in case of frequent infections or suspected immunodeficiency, and ultrasound/ computed tomography (CT) studies and bone marrow evaluation to exclude hematologic diseases. AIHA occurring in pregnancy is a specific situation, usually manageable with steroids and intravenous (iv) Ig, although refractory cases have been described. Finally, AIHA may complicate specific clinical settings, including intensive care unit (ICU) admission, reticulocytopenia, treatment with novel anti-cancer drugs, and transplant. These cases are often severe, more frequently DAT negative, and require multiple treatments in a short time.

ABO, Rhesus blood groups and transfusion-transmitted infections among blood donors in Gabon

Background: Few studies focused on the study of blood groups in Gabon. This study aimed to determine the phenotypic frequency of ABO and Rhesus antigens in blood donors of Libreville and to assess the association between ABO blood groups and transfusion-transmitted infections.Materials and Methods: The study of ABO and Rhesus blood groups concerned 4,744 blood donors. ABO and Rhesus phenotyping were obtained using monoclonal monospecific antisera: anti-A, anti-B, anti-AB, anti-D, anti-E, anti-C, anti-c, and anti-e with an automate (QWALYS® 3, DIAGAST, France) or a card gel (ID Card, BIO-RAD) according to manufacturer’s instructions.Results: The phenotypic frequency of blood group antigens A, B, AB and O were respectively 21.0%; 17.6%; 2.6% and 58.9%. Those of rhesus antigens D, d, C, c, E and e were 97.7%; 2.3%; 15.9%; 99.9%; 17.6%; 99.3%, respectively. The prevalence of ABO and Rh antigens in Gabonese donors reported here are significantly different from those of neighboring countries. No association was found between the prevalence of HIV, HCV and syphilis and ABO blood groups. Instead, HBV seroprevalence was twice as high among non-O blood groups donors compared with blood group O donors [OR = 2 (CI 1.26 to 3.2), p = 0.003].Conclusions: This study provides new data on phenotypic frequency of ABO and Rh blood groups in a representative sample of the Gabonese blood donor population. It suggests a significant association between ABO blood group and HBV infection.

Characterization of Nora Virus Structural Proteins via Western Blot Analysis

Nora virus is a single stranded RNA picorna-like virus with four open reading frames (ORFs). The coding potentials of the ORFs are not fully characterized, but ORF3 and ORF4 are believed to encode the capsid proteins (VP3, VP4a, VP4b, and VP4c) comprising the virion. To determine the polypeptide composition of Nora virus virions, polypeptides from purified virus were compared to polypeptides detected in Nora virus infectedDrosophila melanogaster. Nora virus was purified from infected flies and used to challenge mice for the production of antisera.ORF3,ORF4a,ORF4b, andORF4cwere individually cloned and expressed inE. coli; resultant recombinant proteins purified and were used to make monospecific antisera. Antisera were evaluated via Western blot against whole virus particles and Nora virus infected fly lysates. Viral purification yielded two particle types with densities of ~1.31 g/mL (empty particles) and ~1.33 g/mL (complete virions). Comparison of purified virus polypeptide composition to Nora virus infectedD. melanogasterlysate showed the number of proteins in infected cell lysates is less than purified virus. Our results suggest the virion is composed of 6 polypeptides, VP3, VP4a, two forms of VP4b, and two forms of VP4c. This polypeptide composition is similar to other small RNA insect viruses.