March of Mycobacterium: miRNAs intercept host cell CD40 signalling

Tuberculosis dissemination in kidney transplant recipient treated with anti-CD40 monoclonal antibody: a case report

Background

Tuberculosis (TBC) in solid organ transplant recipients represents a severe complication. The incidence among transplant recipients is higher than in the general population, and the diagnosis and treatment remain challenging. We present a case of active disseminated tuberculosis in a kidney transplant recipient treated with an anti-CD40 monoclonal antibody, who had been previously exposed to an active form of the disease, but latent tuberculosis (LTBI) was repeatedly ruled out prior to transplantation. To the best of our knowledge, no other case has been reported in a patient treated with the anti-CD40 monoclonal antibody.

Case presentation

A 49-year-old patient, 1.5 years after primary kidney transplantation, presented with vocal cord problems, a dry irritating cough, and a sore throat. A detailed investigation, including a high-resolution chest CT scan, revealed the diagnosis of disseminated tuberculosis. The antituberculosis treatment consisting of rifampicin, isoniazid, pyrazinamide, and ethambutol was started immediately. The patient's condition became complicated by relapsing diarrhoea. The colonoscopy revealed a circular stenosis above Bauhin’s valve. Microscopical findings showed active colitis and vaguely formed collections of epithelioid macrophages without fully developed caseous granulomas and were consistent with the clinical diagnosis of tuberculosis. The antituberculosis treatment was subsequently enhanced by moxifloxacin and led to a great improvement in the patient’s condition.

Conclusion

In this case, false negativity of interferon-γ release assays and possibly higher risk for intracellular infections in patients on costimulatory signal blockers are discussed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02916-2.

MIR337-3p Enhances Mycobacterial Pathogenicity Involving TLR4/MYD88 and STAT3 Signals, Impairing VDR Antimicrobial Response and Fast-Acting Immunity

Active form of vitamin D (VitD) enhances human innate immunity against Mycobacterium tuberculosis (Mtb) infection. Our previous studies showed that MIR337-3p was highly expressed in lymphocytes of tuberculosis (TB) patients. Here, we identified the mechanism of MIR337-3p in the regulation of fast-acting anti-TB immunity by inhibiting VitD-dependent antimicrobial response pathways. While high-level MIR337-3p expression was induced by mycobacterial infection in cellular models and mice, TB patients exhibited significantly increased MIR337-3p in CD14⁺ monocytes/macrophages, innate-like Vγ2⁺ T cells, and CD8⁺ lymphocytes containing natural killer (NK)/innate lymphoid cells. MIR337-3p promoted the mycobacterial entry/infection and replication/growth in host target cells: macrophages and lung epithelial cells. Such MIR337-3p-enhanced pathogenicity coincided with the MIR337-3p depression of VitD-dependent antimicrobial response of cytochrome P450, family 27, subfamily b, polypeptide 1 (CYP27B1)/Beta-defensin 4 (DEFB4A)/ cathelicidin antimicrobial peptide CAMP pathways. Surprisingly, single MIR337-3p species could specifically target both the Toll-like receptor 4 (TLR4) and signal transducer and activator of transcription 3 (STAT3) 3′-untranslated regions (UTRs) to depress the TLR4/MYD88 and STAT3 signals and impair either of the two signals inhibiting the VitD-dependent antimicrobial pathways in macrophages. Concurrently, human peripheral blood mononuclear cells (PBMCs) expressing high-level MIR337-3p exhibited a reduced ability of innate cell populations to mount fast-acting cellular immunity against intracellular mycobacterial infection. Furthermore, a higher expression of Mir337-3p after mycobacterial infection of mice coincided with much greater colony-forming unit (CFU) counts in lungs and even the death of infected animals, whereas Mir337-3p inhibitor treatment of infected mice reduced Mir337-3p levels and reversed Mir337-3p-mediated increases in CFU counts. Thus, TB-driven single MIR337-3p species could specifically target/impair both TLR4/MYD88 and STAT3 activation signals, inhibiting VitD-dependent antimicrobial response and fast-acting anti-TB immunity, leading to enhanced pathogenicity.