A non-HIV case with disseminated Mycobacterium kansasii disease associated with strong neutralizing autoantibody to interferon-γ

Anti-interferon-γ Antibody-seropositive Disseminated Nontuberculous Mycobacterial Infection Mimicking POEMS and TAFRO Syndromes

Disseminated nontuberculous mycobacterial infection (DNTM) is typically observed in immunocompromised hosts. Recently, it has been reported that healthy individuals with serum neutralizing autoantibodies for interferon (IFN)-γ can also develop DNTM. We herein report a case of anti-IFN-γ antibody-seropositive DNTM caused by Mycobacterium kansasii with symptoms mimicking TAFRO or POEMS syndrome, including anasarca, organomegaly, skin pigmentation, polyneuropathy, osteosclerotic change, thrombocytopenia, serum M protein, high C-reactive protein level, and reticulin fibrosis. The combination of antimicrobial chemotherapy with glucocorticoid and intravenous immunoglobulin improved his symptoms. Glucocorticoids may be an effective method of suppressing the production of anti-IFN-γ antibodies in DNTM.

Dot enzyme-linked immunosorbent assay strip as a screening tool for detection of autoantibody to interferon gamma in sera of suspected cases of adult-onset immunodeficiency

BACKGROUND

Being able to detect the presence of autoantibodies to interferon (IFN)-γ in serum is essential for evaluating patients with suspected adult-onset immunodeficiency (AOID) with unusual intracellular infections. Most reported patients with AOID have been Asian, although the exact prevalence of this illness is unknown. To date, no standard assay exists to detect autoantibodies to IFN-γ. An easy-to-use, low-cost assay that can be performed in any laboratory would be a valuable tool for clinical management of AOID, as well as better reveal its prevalence.

METHODS

Our experimental study exploited a dot enzyme-linked immunosorbent assay (Dot-ELISA) strip to detect autoantibodies to IFN-γ. Sera from 66 HIV-negative patients having autoantibodies to IFN-γ as determined by indirect ELISA were tested.

RESULTS

Dot enzyme-linked immunosorbent assay was sensitive (100%) and specific (94.5%), with a positive predictive value of 97.6% and a negative predictive value of 100%.

CONCLUSION

This simple method provides prompt qualitative results that can be read visually and used in facilities with limited testing capabilities.

Mediastinal and Disseminated Mycobacterium kansasii Disease in GATA2 Deficiency

RATIONALE

Mycobacterium kansasii usually causes chronic pulmonary infections in immunocompetent patients. In contrast, disseminated M. kansasii disease is commonly associated with advanced human immunodeficiency virus infection, but is reported infrequently in other immunocompromised patients.

OBJECTIVES

To identify common clinical manifestations and potential risk factors for M. kansasii infection in patients with GATA2 deficiency.

METHODS

We reviewed M. kansasii disease associated with GATA2 deficiency at one institution and disease associated with primary and other immunodeficiencies reported in the literature.

MEASUREMENTS AND MAIN RESULTS

Nine patients with GATA2 deficiency developed M. kansasii infections. Six patients developed disseminated disease. All patients presented with significant mediastinal lymphadenopathy or abscesses. Seven patients had pulmonary risk factors, including six smokers. The majority of patients had low numbers of neutrophils, monocytes, B cells, CD4+ T cells, and natural killer cells. Other conditions associated with disseminated M. kansasii disease were thymic disorders and IFN-γ/IL-12 defects.

CONCLUSIONS

Disseminated M. kansasii disease involving mediastinal lymph nodes is surprisingly common in GATA2 deficiency, but also occurs in defects of IFN-γ synthesis and response. Disseminated M. kansasii should be considered a marker indicating a need to evaluate for immunodeficiency syndromes.

Miliary tuberculosis with indeterminate interferon gamma release assay results

Recently, interferon gamma release assays (IGRAs) have become an important clinical tool for detecting latent tuberculosis. However, IGRA results may impede making a diagnosis. We herein present an interesting case of miliary tuberculosis with a nonspecific IGRA reaction due to hemophagocytosis.