False-positive hepatitis B serology following IVIG therapy: forgotten but not gone!!

Challenge of hepatitis B testing following intravenous immunoglobulin therapy in patients with autoimmune skin diseases

Intravenous immunoglobulin (IVIg) contains pooled immunoglobulins from the plasma of healthy blood donors. All plasma samples are tested for HIV, hepatitis viruses (A, B, and C), and parvovirus B19. As part of this screening step, nucleic acid amplification technology (NAT) is used and allows the presence of specific antibodies targeting viral structures that are commonly used to test for infection status, such as anti-hepatitis B surface antigen (HBs) or anti-hepatitis B virus core (HBc) antibodies. For this reason, manufacturers point to the possibility of false-positive viral serological test results following IVIg treatment due to the passive transfer of antibodies. IVIg therapy is commonly used to manage patients with severe, treatment-refractory autoimmune skin diseases. The aim of this cohort study was to retrospectively quantify newly-discovered positive serological HBV test results after IVIg treatment in patients with autoimmune skin diseases. Between March 2018 and June 2021, 28 patients with autoimmune skin diseases received IVIg therapy, of whom 17 were longitudinally followed-up. None of the patients had evidence of active HBV infection prior to IVIg therapy. All patients (n = 17) had detectable anti-HBs antibodies and 12 patients had anti-HBc antibodies 4 weeks after commencing IVIg treatment. Passive antibody transfer seems the most likely interpretation. Nevertheless, complete serological hepatitis assessment should be performed to exclude a new infection. We recommend hepatitis screening before IVIg therapy to prevent diagnostic confusion which may arise due to passive antibody transfer.

Misleading Positive Serology for Cat Scratch Disease Following Administration of Intravenous Immunoglobulin

Cat scratch disease (CSD), caused by Bartonella henselae, usually presents as regional lymphadenopathy/lymphadenitis, known as typical CSD or as atypical CSD, which includes, among others, neurological manifestations. Serology for anti-B. henselae IgG antibodies is the most commonly used diagnostic tests for CSD. Intravenous immunoglobulin (IVIG) is given for an increasing number of medical conditions and may cause interference with serological testing. We report six patients with neurological manifestations and two patients with Kawasaki disease mimicking typical CSD, mistakenly diagnosed as CSD due to false-positive serology following IVIG therapy. Bartonella IgG serology was positive one to six days after IVIG administration and reverted to negative in seven of eight patients or significantly decreased (1 patient) ≤30 days later. In patients with CSD, IgG titers remained essentially unchanged 15–78 days after the positive serum sample. An additional eight patients treated with IVIG for various conditions were evaluated prospectively. All were seronegative one day pre-IVIG infusion, five patients demonstrated an increase in the IgG titers one to three days after IVIG administration, one interpreted as positive and four as intermediate, whereas three patients remained seronegative, suggesting that false seropositivity after IVIG therapy may not occur in all patients. Treatment with IVIG can result in false-positive serology for B. henselae. Increased awareness to the misleading impact of IVIG is warranted to avoid misinterpretation. Repeat testing can distinguish between true and false serology. Preserving serum samples prior to IVIG administration is suggested.

Clinical false positives resulting from recent intravenous immunoglobulin therapy: case report

Background

Many clinicians are aware that certain therapies administered to their patients can have downstream consequences in the form of clinical laboratory test interferences. This is particularly true of laboratory tests that depend on, or directly involve the use of, antibody-based methodology. Intravenously-administered immunoglobulin therapy is one such treatment that can in theory directly impact the results of particular tests in the area of viral serology. This study can help serve as a reference for clinicians researching the impact of intravenously-administered immunoglobulin therapy in the context of positive results that do not reflect the clinical background of the patient.

Case presentation

We describe a case whereby an intravenously-administered immunoglobulin therapy led to a series of clinical false positives in viral serology, inconsistent with the known patient history as well as recent laboratory results. The patient presented to hospital with petechiae-type bleeding rashes and was investigated for thrombocytopenia after initial blood investigations indicated very low platelets.

Subsequent testing of the potential causes for low-platelet involved several viral serology investigations, including hepatitis, cytomegalovirus and human immunodeficiency virus. Initial testing indicated patient exhibited negative status for all viral antibodies and antigens (except immunity for hepatitis B surface antigen antibody).

As part of the thrombocytopenia treatment, intravenously-administered immunoglobulin therapy was administered, and subsequent viral serology was ordered. These investigations indicated a positive status for several hepatitis antibodies as well as cytomegalovirus.

Conclusions

This case study illustrates the potential for improper diagnosis of previous or ongoing infection status in patients administered IVIg therapy. Caution should be exercised particularly when interpreting results involving cytomegalovirus and hepatitis.

Transient derangements in Hepatitis B serology in patients post-intravenous immunoglobulin therapy-a case-based review

Intravenous immunoglobulin (IVIg) is a commonly utilized therapy in multiple medical subspecialities, indicated for the management of various primary and secondary immunodeficiency states and autoimmune and inflammatory conditions. A lack of awareness exists among clinicians regarding the serological downstream effects of its use. An observed phenomenon post-IVIg is the passive transfer of antibodies from the product which can lead to transiently positive hepatitis B serology in recipients. When confounding viral serology is encountered, there is a risk to patients of treatment delays and mismanagement. Three patients encountered in the hematology department of a tertiary referral hospital developed spurious hepatitis B serology after administration of IVIg, whose cases are briefly outlined here. These cases highlight the need for routine pre-treatment viral screening and emphasize the importance of clinicians recognizing such potentially confounding results. This is of particular relevance to the sizeable subset of hematology patients who are planned for future immunomodulatory treatment (such as rituximab), where previous hepatitis B infection can often be a barrier to timely treatment.

False interpretation of diagnostic serology tests for patients treated with pooled human immunoglobulin G infusions: a trap for the unwary

Therapeutic immunoglobulin G (IgG) products are produced from numerous plasma donations, and are infused in many medical conditions. The serological testing of patients who have received IgG infusions may well produce falsely positive and misleading results from this infused IgG, rather than endogenously produced IgG. We present two example cases of clinical situations where this could cause concern. We tested multiple IgG products with a range of serological tests performed in infective or autoimmune conditions, including hepatitis B, syphilis, human immunodeficiency virus, human T-lymphotropic virus, anti-neutrophil cytoplasmic antibody (ANCA), anti-nuclear antibody (ANA), anti-cardiolipin antibodies and anti-double stranded DNA (dsDNA) antibody. We found positivity within these products for hepatitis B surface and core antibody, syphilis, ANCA, ANA, anti-cardiolipin IgG and dsDNA antibody, which may result from specific or non-specific reactivity. The serological testing of patients who have received IgG treatment detects the administered IgG in addition to IgG produced by the patient.

False-positive serology following intravenous immunoglobulin and plasma exchange through transfusion of fresh frozen plasma in a patient with pemphigus vulgaris

Intravenous immunoglobulin therapy and plasma exchange through transfusion of fresh frozen plasma are therapeutic options for patients with refractory pemphigus vulgaris. Passive acquisition of various clinically important antibodies through these therapies can occur, leading to false serology and negatively affecting patients' clinical care. It is recommended that dermatologists recognize the possibility of these phenomena and interpret them appropriately. Here, we report false-positive serology following intravenous immunoglobulin therapy and plasma exchange through transfusion of fresh frozen plasma in a patient with refractory pemphigus vulgaris. We also discuss the measure for misinterpretation and unnecessary clinical intervention.

Case report: passive transfer of hepatitis B antibodies from intravenous immunoglobulin

Background

Prior to initiating immunosuppressive therapy in the treatment of autoimmune inflammatory conditions, it is a requirement to screen for certain viral serology, including hepatitis B (HBV). A positive result may indicate the need for antiviral therapy, or contraindicate immunosuppression all together. An accurate interpretation of serological markers is therefore imperative in order to treat patients appropriately. We present a case of passive anti-HBV antibody transfer following intravenous immunoglobulin (IVIg) infusion, in which misinterpretation of serology results almost led to inappropriate treatment with antiviral therapy and the withholding of immunosuppressive agents. This phenomenon has been previously reported, but awareness remains limited.

Case presentation

A 50 year old Caucasian gentleman with a history of allogeneic haematopoietic stem cell transplant for transformed follicular lymphoma was admitted to hospital with recurrent respiratory tract infections. Investigation found him to be hypogammaglobulinaemic, and he was thus given 1 g/kg of intravenous immunoglobulin. The patient also disclosed a 3-week history of painful, swollen joints, leading to a diagnosis of seronegative inflammatory polyarthritis. Prior to initiating long term immunosuppression, viral screening found hepatitis B serology suggestive of past infection, with positive results for both anti-HBc and anti-HBs antibody, but negative HBV DNA. In response, prednisolone was weaned and the local hepatology team recommended commencement of lamivudine. Having been unable to identify a source of infection, the case was reported to the local blood centre, who tested a remaining vial from the same batch of IVIg and found it to be anti-HBc and anti-HBs positive. Fortunately the blood products were identified and tested prior to the patient initiating HBV treatment, and the effect of a delay in starting disease-modifying therapy was inconsequential in light of an excellent response to first-line therapies.

Conclusion

Misinterpretation of serology results following IVIg infusion may lead to significant patient harm, including unnecessary antiviral administration, the withholding of treatments, and psychosocial damage. This is especially pertinent at a time when we have an ever increasing number of patients being treated with IVIg for a wide array of immune-mediated disease. Passive antibody transfer should be considered wherever unexpected serological changes are identified.

Misleading hepatitis B testing in the setting of intravenous immunoglobulin

Intravenous immunoglobulin (IVIG) is commonly used for a wide range of diagnoses, by multiple pediatric subspecialists. We report two cases of hepatitis B screening results post IVIG infusion, where positive anti-Hepatitis B core antigen serology tests indicated possible occult hepatitis infection, leading to a delay in care. However, serial antibody testing showed results consistent with the passive transfer of antibodies.