Background Mutations in DOCK8 cause a combined immunodeficiency (CID) also classified as autosomal-recessive hyper-IgE syndrome (HIES). Recognizing patients with CID / HIES is of clinical importance due to a difference in prognosis and management. Objectives Define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs; study the mutational spectrum of DOCK8 deficiency; and report on the frequency of specific clinical findings. Methods Eighty-two patients from 60 families with CID and the phenotype of autosomal-recessive HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with 10 AR-HIES patients without a DOCK8 mutation and 64 patients with STAT3 mutations. Results DOCK8-deficient patients had a median IgE of 5,201 IU, high eosinophil levels of usually at least 800/µl (92% of patients), and low levels of IgM (62%). About 20% of patients were lymphopenic, mainly due to low CD4+ and CD8+ T cells. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of five clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations. Conclusions DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels, who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures.

Five patients from 4 unrelated Tunisian families who presented with disseminated neonatal infection by Mycobacterium bovis bacille Calmette-Guérin strain were investigated. Two unrelated patients had different homozygous interleukin-12 receptor beta1 subunit gene splice-site mutations (64+5G-->A and 550-2A-->G). Two siblings and 1 unrelated patient, all of whom were from the same town, carried the same mutation (297del8) within the interleukin-12p40 gene. This is the first description of familial cytokine deficiency reported so far. All patients had complete lack of expression of the affected polypeptide and a profound deficiency of in vitro interferon-gamma production. The clinical severity of the mycobacterial infection was heterogeneous, even among affected members of the same family, which suggests the intervention of modifying genes.

Disclosure of potential conflict of interest K. Niespodziana receives grant support (grant no. P29398) from the Austrian Science Foundation (FWF). K. F. Chung has received honoraria for participating in advisory board meetings of GlaxoSmithKline (GSK), AstraZeneca, Novartis, Merck, Boehringer Ingelheim, and Teva regarding treatments for asthma and chronic obstructive pulmonary disease and has also been renumerated for speaking engagements. A. Custovic reports personal fees from Novartis,

Early secreted antigenic target 6 kDa (ESAT‐6) and culture filtrate protein 10 kDa (CFP‐10) are complex proteins secreted by Mycobacterium tuberculosis that play a major role in the pathogenesis of tuberculosis. However, studies focusing on the biological functions of ESAT‐6 led to discordant results and the role of ESAT‐6 remains controversial. In the present study, we aim to address a potential explanation for this discrepancy and to highlight the physiological impact of two conformational states of ESAT‐6. Analysis of a recombinant form of ESAT‐6 by native gel electrophoresis, size exclusion chromatography and CD spectroscopy revealed that ESAT‐6 forms dimers/multimers with higher molecular weight, which disappeared under the action of the detergent amidosulfobetaine‐14 (ASB), giving rise to another conformational state of the protein. NMR has further indicated that ASB‐treated versus nontreated ESAT‐6 adopted distinct structural forms but with no well defined tertiary structure. However, protein–protein docking analysis favored a dimeric state of ESAT‐6. Interestingly, the two preparations presented opposing effects on mycobacterial infectivity, as well as macrophage survival, interferon‐γ secretion and membrane pore formation. Thereafter, we generated a recombinant form of the physiological heterodimer ESAT‐6/CFP‐10 that ASB was also able to dissociate and which showed functions similar to those of ESAT‐6 dimers/multimers. Our data suggest that, in the absence of CFP‐10, the hydrophobic regions of the ESAT‐6 can form dimers/multimers, mimicking the ESAT‐6/CFP‐10 heterodimer, whereas their dissociation generates a protein presenting entirely different activities. Overall, the present study clarifies the intriguing divergences between reports that could be attributed to the ESAT‐6 oligomeric state and sheds light on its importance for a better comprehension of the physiopathology of tuberculosis.