Increased CD8+ T cells in patients with Henoch-Schonlein purpura nephritis exhibit suppressive immune activity

Single-cell transcriptomics reveals the alteration of immune cell profile in peripheral blood of Henoch-Schonlein purpura

Henoch-Schönlein purpura (HSP) is an autoimmune vasculitis affecting multiple organs, and the understanding of circulating immune cell types and their states associated with disease subtypes of HSP remains incomplete. Here, we performed a comprehensive assessment of peripheral blood mononuclear cells of healthy donors and HSP patients, using both single-cell RNA sequencing and multiparameter flow cytometry. We revealed that HSP patients exhibited broad immune activation, evidenced by increased proportions of Effector memory CD8+ T, CD14+ monocytes, Tfh, Th2, Th17, Plasma, and B cells and decreased proportions of Naïve CD4+ T, Treg, Th1, and NK cells. Notably, we identified that cytotoxic effector T cell subsets were enriched in skin and renal type of HSP, whereas Plasma, B, and Tfh cells were expanded in joint and abdominal type of HSP. In conclusion, our findings highlight the dynamic nature of immune responses throughout the progression of HSP with different clinical manifestations.

Involvement of M1-Activated Macrophages and Perforin/Granulysin Expressing Lymphocytes in IgA Vasculitis Nephritis

We investigated the polarisation of CD68+ macrophages and perforin and granulysin distributions in kidney lymphocyte subsets of children with IgA vasculitis nephritis (IgAVN). Pro-inflammatory macrophage (M)1 (CD68/iNOS) or regulatory M2 (CD68/arginase-1) polarisation; spatial arrangement of macrophages and lymphocytes; and perforin and granulysin distribution in CD3+ and CD56+ cells were visulaised using double-labelled immunofluorescence. In contrast to the tubules, iNOS+ cells were more abundant than the arginase-1+ cells in the glomeruli. CD68+ macrophage numbers fluctuated in the glomeruli and were mostly labelled with iNOS. CD68+/arginase-1+ cells are abundant in the tubules. CD56+ cells, enclosed by CD68+ cells, were more abundant in the glomeruli than in the tubuli, and co-expressed NKp44. The glomerular and interstitial/intratubular CD56+ cells express perforin and granulysin, respectively. The CD3+ cells did not express perforin, while a minority expressed granulysin. Innate immunity, represented by M1 macrophages and CD56+ cells rich in perforin and granulysin, plays a pivotal role in the acute phase of IgAVN.

The Immunologic Profiles of Kawasaki Disease Triggered by Mycoplasma pneumoniae Infection

OBJECTIVE

We compared the immunologic characteristics of mycoplasma pneumoniae-triggered Kawasaki disease (MP-KD) with Kawasaki disease (KD) not associated with mycoplasma pneumoniae (MP), with mycoplasma pneumoniae-triggered Henoch-Schönlein purpura (MP-HSP), and with healthy controls.

METHODS

Complement levels, cellular and humoral immunity were assessed in KD, in MP-KD, in MP-HSP, and in healthy children.

RESULTS

Of 622 children with KD, 74 had MP-KD. Complement C3 and CD4/CD8 ratio were significantly increased in MP-KD compared to KD. C3, C4, and the ratio of CD4/CD8 in the MP-KD group were higher than those in the MP-HSP group. IgA and CD56 were lower in the MP-KD group than the MP-HSP group.

CONCLUSIONS

Both C3 and polyclonal CD4+ T lymphocytes may be activated in the patients with MP-KD.