Search Results (42)

Background and Objectives: This study explores the immunogenetic associations of human leukocyte antigens (HLAs) and cytokine levels in people living with HIV/AIDS (PLWH) who exhibit HIV-related skin disorders. HIV-related skin disorders, including inflammatory eruptions, atopic and seborrheic dermatitis, psoriasis, and pruritic papular eruption, are common among PLWH. These conditions may be influenced by genetic and immunological factors. This study aims to investigate the associations between HLA class II alleles, cytokine levels, and the presence of HIV-related dermatoses, providing insights into genetic susceptibility and immune mechanisms. Materials and Methods: This study included 115 PLWH with HIV-related skin disorders and a control group of 80 healthy individuals. HLA allele frequencies were analyzed, and cytokine levels (IL-1β, IL-10, IFN-y) were measured in blood samples. Statistical analyses were performed to identify significant differences in allele frequencies and cytokine responses between the groups. Results: Risk alleles (DQB1*0201:0301, OR = 19.4 and DQA1*0101:0501, OR = 4.2) and protective alleles (DRB1*07:13, OR = 0.19, DRB1*01:13, OR = 0.09, DRB1*04:11, OR = 0.07, and DQA1*0501:0501, OR = 0.24) showed statistically significant differences in frequency (p < 0.05) between PLWH and healthy controls. The protective DQA1*0501:0501 allele was associated with elevated levels of IL-1β (p < 0.001, r = 0.79) and IL-10 (p = 0.010, r = 0.63). Increased IL-1β levels may enhance immune responses, while higher IL-10 levels may exert anti-inflammatory effects, potentially reducing susceptibility to HIV-related dermatoses. Regression analysis revealed that IL-1β (Exp(B) = 0.76, p < 0.001) and IFN-γ (Exp(B) = 1.06, p = 0.043) are significant predictors for the likelihood of developing HIV-related dermatoses. An increase in IL-1β levels reduced this likelihood by 24%, while an increase in IFN-γ levels increased it by 6%. Conclusions: The findings emphasize the interaction between HLA class II alleles and cytokine profiles in determining genetic risk and clinical outcomes in PLWH with HIV-related skin disorders. Protective alleles, such as DQA1*0501:0501, may contribute to immune regulation, offering potential targets for therapeutic interventions in PLWH with dermatoses. Our results highlight the importance of IL-1β and IFN-γ as key modulators in the progression of HIV infection and the development of HIV-related dermatoses. Further research is needed to explore the mechanisms underlying these associations, particularly in the Latvian population, to inform targeted therapeutic strategies. Full article

Background/Objectives: Inflammatory bowel diseases (IBDs) comprise a group of chronic idiopathic disorders, including ulcerative colitis (UC), Crohn’s disease (CD), and indeterminate colitis (IC). Complex genetic factors, in addition to environmental triggers, have been shown to play a fundamental role in the pathogenesis of IBD, contributing to disease susceptibility. The transition of adolescents with inflammatory bowel disease (IBD) to adult care represents a significant challenge for patients, their families, and healthcare providers. Approximately 25% of individuals with IBD receive a diagnosis before the age of 16, and this population is at increased risk for adverse clinical outcomes. As a result, the transition of care has garnered substantial attention in the scientific and clinical communities over the past decade. This study aims to analyze a cohort of pediatric Sardinian patients with IBD to assess clinical characteristics at diagnosis and at the time of transition and determine potential correlations between NOD2/CARD15 gene variants and HLA class II with the disease phenotype. Methods: From January 2014 to August 2024, we performed an observational, cross-sectional study that included pediatric patients with IBD enrolled in the only pediatric IBD reference center in Sardinia. Data were obtained from the patients’ medical records and from a questionnaire administered at the inclusion visit. In addition, we genotyped a portion of our cohort for the Leu1007fsinsC (SNP13), Gly908Arg (SNP12), and Arg702Trp (SNP8) variants of the NOD2/CARD15 gene, as well as for HLA-DRB1, -DQA1, and -DQB1 class II genes. The obtained results were compared with pediatric data from the national epidemiological IBD registry and existing literature. Results: Seventy-one IBD patients were enrolled (UC 43, CD 28, M 34, F 37). Median age at diagnosis was 12.2 years (IQR 2–17). After a median disease duration of 5 years (IQR: 1–16), only three UC patients experienced proximal extension of proctitis or left-sided colitis, and no CD patients experienced new localizations of disease. Fifteen patients developed extraintestinal manifestations. No significant difference was found in median diagnostic delay (DD) between UC [4 months (IQR: 1–84)] and CD patients [4.5 months (IQR: 1–48)]. At the transition visit, overall, twenty-nine patients (42%) were exposed to one biologic agent (vs. 3% at baseline; p < 0.02); 3 patients (4%) were exposed to two or more biologic agents. 7% of patients (5/71) underwent surgery. By comparing the distribution of NOD2/CARD15 SNPs between pediatric patients and an adult CD population, we found a significant association between gene allelic variants and pediatric onset (p = 0.00048). Our study also revealed a statistically significant association between Sardinian pediatric patients carrying NOD2/CARD15 mutations and early-onset CD (p < 0.009492), along with a stenosing phenotype (p < 0.024) and increased surgical risk (p < 0.026). No significant associations were observed between HLA class II alleles and IBD in our population. Conclusions: Our results provide important insights into the clinical and epidemiological features of the pediatric IBD population. In addition, our study highlights the significant role of NOD2/CARD15 gene polymorphisms in pediatric onset CD. These variants influence the age of onset and disease phenotype, characterized by greater severity and a higher risk of surgical intervention in pediatric patients. Full article

Several indirect findings suggest that host-related factors influence susceptibility to Coxiella burnetii infection. We decided to explore the influence of genetic factors related to both innate and adaptive immunity in acute Q fever susceptibility. TLR2 (Arg753Gln) and TLR4 (Asp299Gly, Thr399Ile) polymorphisms, along with HLA-DRB1 alleles, were analyzed for 38 patients with acute Q fever, 38 matched controls, and 121 blood donors. No significant associations were found for TLR polymorphisms. However, HLA-DRB1*04 was more frequent in patients. HLA-DRB1 variants may play a role in Q fever susceptibility, supporting the need for further investigation into their potential implications for vaccination and risk assessment. Full article

Background: HLA homozygosity of specific alleles at a single locus is associated with increased risk for autoimmunity and/or more severe clinical phenotypes. However, the contribution of the overall limitation of HLA diversity across multiple loci to autoimmunity risk remains to be determined. Methods: We conducted a proof-of-concept case–control study of 413 individuals (279 cases with pediatric-onset autoimmune rheumatic diseases, 134 matched controls) examining the “Limitation of HLA Diversity” (LoHLAD) across multiple loci as an allele-independent risk factor for autoimmunity. We examined the association of LoHLAD with pediatric-onset autoimmune rheumatic diseases at five HLA loci (A, B, DQB1, DRB1, DRB3/4/5). LoHLAD was defined as (1) homozygosity at any of the examined loci, and/or (2) the presence of a single allele or the complete lack of an allele at the HLA-DRB3/4/5 locus. Results: The frequency of LoHLAD at any locus was significantly higher in cases compared to controls (65.95% vs. 30.60%, OR 4.39 [2.82–6.84], p < 0.0001). Higher frequencies of LoHLAD in cases compared to controls were observed at both class I (19.35% vs. 10.45%, OR 2.06 [1.10–3.86], p = 0.031) and class II (54.48% vs. 20.15%, OR 4.74 [2.92–7.69], p < 0.0001) loci. Specifically, significant differences between cases and controls were observed at the B (OR 8.63 [1.14–65.55], p = 0.016), DQB1 (OR 3.34 [1.27–8.78], p = 0.016), and DRB3/4/5 (OR 4.64 [2.77–7.75], p < 0.0001) loci. Multiple logistic regression models confirmed the ability of LoHLAD to positively predict autoimmunity. Conclusions: LoHLAD is a significant allele-independent risk factor for pediatric-onset autoimmune rheumatic disease. Full article

Background/Objectives: Unrelated bone marrow transplantation (BMT) is a curative treatment for hematological malignancies. While HLA mismatch is a recognized risk factor in unrelated BMT, the significance of non-HLA single nucleotide polymorphisms (SNPs) remains uncertain. Cytokines play key roles in several aspects of unrelated BMT. Although the relationship between cytokine gene SNPs and BMT outcomes has been examined, the findings obtained have been inconsistent; therefore, further investigations in additional cohorts are warranted. Methods: Four SNPs in the IL2, IL6, IFN-gamma, and TGF-beta1 genes were retrospectively genotyped in 822 malignant patients and their corresponding donors who received unrelated BMT through the Japan Marrow Donor Program with compatibility at minimum HLA-A, -B, and -DRB1. The relationships between these SNP genotypes and BMT outcomes were statistically analyzed. Results: The donor interleukin-6 (IL6) SNP, rs1800796, also known as -572G>C and -634C/G, was associated with the relapse of the original disease in both univariable and multivariable regression analyses (minimum p-value = 0.0013), and the cumulative incidence curve analysis identified CC as a risk genotype (p-value = 0.0012). None of these SNPs correlated with overall survival. Conclusions: The donor IL6 SNP, rs1800796, may serve as a useful predictor of tumor relapses if validated. Full article

Background: Parkinson’s disease (PD) is a neurodegenerative disorder characterised by a high prevalence of sporadic cases. Various molecular mechanisms are involved in its pathogenesis. This pilot study aimed to identify potential risk and protective human leukocyte antigen (HLA) alleles in PD, discover candidate alleles for further research, and evaluate potential blood biomarkers. Methods: A total of 43 PD patients and 79 unrelated sex-matched controls were enrolled in this study. We analysed the polymorphism of HLA-DRB1, HLA-DQA1, and HLA-DQB1 alleles and the blood levels of biomarkers such as S100 calcium-binding protein A9 (S1000A9), kynurenic acid (KYNA), neurofilament light chain (NfL), and glutamate decarboxylase (GAD1). Results: We found that the frequencies of the HLA-DRB1*04, -DQA1*02:01, and -DQA1*03:01 alleles were significantly higher in the PD patients than in the controls, suggesting that these alleles are potential risk factors. Furthermore, the HLA-DQA1*02:01 allele was detected more frequently in the PD group when the disease onset was at 60 years or older. On the contrary, the HLA-DRB1*01 and HLA-DQA1*05:01 alleles were less common in the PD patients, indicating a possible protective effect. Regarding biomarkers, the blood levels of S100 calcium-binding protein A9 were significantly higher, and the kynurenic acid levels were significantly lower in the PD group. The NfL levels were also higher in the PD group but did not reach statistical significance, possibly due to the sensitivity limitations of the ELISA method used. The GAD1 levels showed no significant differences between the two groups. Conclusions: Our findings indicate that the HLA-DRB1*01 and -DRB1*04 alleles and the HLA-DQA1*02:01, -DQA1*03:01, and -DQA1*05:01 alleles are associated with PD. Moreover, S100 calcium-binding protein A9 and kynurenic acid can be considered potential blood biomarkers for PD. These findings contribute to the growing body of knowledge on PD and offer new directions for further research in Latvian cohorts. Full article

The origins of multiple sclerosis (MS) have been a subject intriguing researchers and scholars for generations. The multifactorial etiological nature of the disease continues to be studied as a complex combination of genetic aspects and environmental or external risk elements contributing to the development of the disease. Descriptions of symptoms or clinical disorders suggestive of MS affecting historical figures or prominent individuals (i.e., Lidwina of Schiedam, Heinrich Heine, Augustus d’Este) did not provide clues on the origin of the disease, except for the observation that all these early possible cases were white European individuals. MS was initially framed as a neurological entity and named in the 19th century by the historical participation of the French masters Cruveilhier, Vulpian, and Charcot, among others, but the question of how the disease originated was not addressed until Charles Poser raised his conjecture on the origins of MS in two historical essays (1994 and 1995), raising the question if the Viking voyages and invasions from the 8th to the 11th century carried the Scandinavian MS genetic risk factor to Europe and the rest of the known world at that time. Poser did not have the benefit of access to ancient molecular DNA data and based his theoretical postulation on interesting historical and archeological observations. A series of studies and opinions published in 2024, utilizing sophisticated genetic analyses and genome identification, archeological DNA analysis, and other advanced techniques and biological computation, distinctly demonstrate the installation of HLA-DRB1*15:01 (class II allele) in Europe (with a higher prevalence in Scandinavia) following the massive Yamnaya pastoralists migration from the Pontic Steppe in Eurasia to western Europe (~5000 to 2500 BCE). The data suggest HLA-DRB1*15:01, the strongest genetic association with MS, underwent an evolutive switch (“thrifty drift”) from immune protector against novel zoonotic diseases appearing among the early pastoralists of the Yamnaya civilization to an autoimmune deleterious reactor to molecular mimicry and self-antigens, enabled by lifestyle changes and reduction of pastoralism once communities settled in Europe after the migration from the Pontic Steppe. This writer offers a new perspective on the origins of MS through a phase 1, the ancient east to west migration in the late Bronze Age, consolidating the HLA-DRB1*15:01 haplotype in Europe, and phase 2, the additional dissemination of the genetic MS risk through the Viking invasions, reinforcing inheritability by enabling a homozygous dominant inheritance. Full article

Autoimmune diseases are among the most prevalent diseases across the world with genetic and environmental factors that contribute to their etiology. Because the exact causes of autoimmune diseases are largely unknown, a Mendelian randomization (MR) approach is used here to examine the potential causal association between gene expression levels and disease risk across various tissues. Specifically, this study focuses on six autoimmune diseases including Crohn’s disease, ulcerative colitis, rheumatoid arthritis, multiple sclerosis, type 1 diabetes mellitus, and systemic lupus erythematosus. Several of these diseases are currently treatable with immunosuppressants that target specific genes, such as TNF-alpha, IL-23, CD20, and more. In this study, a two-sample MR analysis is performed with multitissue expression quantitative trait loci (eQTLs) and large-scale genome-wide association studies to investigate how gene expression can influence the risk of developing these diseases. Our results show that genes HLA-DQA1/2, HLA-DRB1/6, HLA-DQB2, C4A, CYP21A2, and HLA-DQB1-AS1 have a high causal effect across several diseases and tissues, and almost all of these findings originate from the major histocompatibility complex (MHC) region on Chromosome 6. Our findings support the current knowledge of genes associated with these diseases while also revealing novel genes that can be used for drug therapies in the future. Although several drug therapies currently exist to treat this selection of autoimmune diseases, we provide further insights into the main, common pathways responsible for autoimmune disease pathogenesis and discuss novel genes that lack research focus. Full article

Autism Spectrum disorders (ASD) are diagnosed more often in males than in females, by a ratio of about 3:1; this is likely to be due to a difference in risk burden between the sexes and/or to “compensatory skills” in females, that may delay the diagnosis of ASD. Identifying specific risk factors for ASD in females may be important in facilitating early diagnosis. We investigated whether HLA- class I: -A, -B, -C and class II -DRB1 alleles, which have been suggested to play a role in the development of ASD, can be considered as sex-related risk/protective markers towards the ASD. We performed HLA allele genotyping in 178 Italian children with ASD, 94 healthy siblings, and their parents. HLA allele distribution was compared between children with ASD, sex-matched healthy siblings, and a cohort of healthy controls (HC) enrolled in the Italian bone marrow donor registry. Allele transmission from parents to children with ASD and their siblings was also assessed. Our findings suggest that HLA-A*02, B*38, and C*12 alleles are more frequently carried by females with ASD compared to both HC and healthy female siblings, indicating these alleles as potential risk factors for ASD in females. Conversely, the HLA-A*03 allele was more commonly transmitted to healthy female siblings, suggesting it might have a protective effect. Additionally, the HLA-B*44 allele was found to be more prevalent in boys with ASD, indicating it is a potential risk factor for male patients. This is the first Italian study of sex-related HLA association with ASD. If confirmed, these results could facilitate early ASD diagnosis in female patients, allowing earlier interventions, which are crucial in the management of neurodevelopmental disorders. Full article

Background: Rheumatoid arthritis (RA) is a complex autoimmune disease that negatively affects synovial joints, leading to the deterioration of movement and mobility of patients. This chronic disease is considered to have a strong genetic inheritance, with genome-wide association studies (GWAS) highlighting many genetic loci associated with the disease. Moreover, numerous confounding and non-genetic factors also contribute to the risk of the disease. Aims: This study investigates the association of selected genetic polymorphisms with rheumatoid arthritis risk and develops a polygenic risk score (PRS) based on selected genes. Methods: A case-control study recruited fully consenting participants from the East Midlands region of the UK. DNA samples were genotyped for a range of polymorphisms and genetic associations were calculated under several inheritance models. PRS was calculated at crude (unweighted) and weighted levels, and its associations with clinical parameters were determined. Results: There were significant associations with the risk of RA at six genetic markers and their associated risk alleles (TNRF2*G, TRAF1*A, PTPN22*T, HLA-DRB1*G, TNFα*A, and IL4-590*T). The TTG haplotype at the VDR locus increased the risk of RA with an OR of 3.05 (CI 1.33–6.98, p = 0.009). The GA haplotype of HLADRB1-TNFα-308 was a significant contributor to the risk of RA in this population (OR = 2.77, CI 1.23–6.28, p = 0.01), although linkage disequilibrium was low. The polygenic risk score was significantly higher in cases over controls in both unweighted (mean difference = 1.48, t₂₈₅ = 5.387, p < 0.001) and weighted (mean difference = 2.75, t₂₈₅ = 6.437, p < 0.001) results. Conclusion: Several genetic loci contribute to the increased risk of RA in the British White sample. The PRS is significantly higher in those with RA and can be used for clinical applications and personalised prevention of disease. Full article

Antigen presentation is a crucial mechanism that drives the T cell-mediated immune response and the development of Multiple Sclerosis (MS). Genetic alterations within the highly variable Major Histocompatibility Complex Class II (MHC II) have been proven to result in significant changes in the molecular basis of antigen presentation and the clinical course of patients with both Adult-Onset MS (AOMS) and Pediatric-Onset MS (POMS). Among the numerous polymorphisms of the Human Leucocyte Antigens (HLA), within MHC II complex, HLA-DRB1*15:01 has been labeled, in Caucasian ethnic groups, as a high-risk allele for MS due to the ability of its structure to increase affinity to Myelin Basic Protein (MBP) epitopes. This characteristic, among others, in the context of the trimolecular complex or immunological synapsis, provides the foundation for autoimmunity triggered by environmental or endogenous factors. As with all professional antigen presenting cells, macrophages are characterized by the expression of MHC II and are often implicated in the formation of MS lesions. Increased presence of M1 macrophages in MS patients has been associated both with progression and onset of the disease, each involving separate but similar mechanisms. In this critical narrative review, we focus on macrophages, discussing how HLA genetic alterations can promote dysregulation of this population’s homeostasis in the periphery and the Central Nervous System (CNS). We also explore the potential interconnection in observed pathological macrophage mechanisms and the function of the diverse structure of HLA alleles in neurodegenerative CNS, seen in MS, by comparing available clinical with molecular data through the prism of HLA-immunogenetics. Finally, we discuss available and experimental pharmacological approaches for MS targeting the trimolecular complex that are based on cell phenotype modulation and HLA genotype involvement and try to reveal fertile ground for the potential development of novel drugs. Full article

A few cases of multiple sclerosis (MS) onset after COVID-19 vaccination have been reported, although the evidence is insufficient to establish causality. The aim of this study is to compare cases of newly diagnosed relapsing–remitting MS before and after the outbreak of the COVID-19 pandemic and the impact of COVID-19 vaccination. Potential environmental and genetic predisposing factors were also investigated, as well as clinical patterns. This is a single-centre retrospective cohort study including all patients who presented with relapsing–remitting MS onset between January 2018 and July 2022. Data on COVID-19 vaccination administration, dose, and type were collected. HLA-DRB1 genotyping was performed in three subgroups. A total of 266 patients received a new diagnosis of relapsing–remitting MS in our centre, 143 before the COVID-19 pandemic (until and including March 2020), and 123 during the COVID-19 era (from April 2020). The mean number of new MS onset cases per year was not different before and during the COVID-19 era and neither were baseline patients’ characteristics, type of onset, clinical recovery, or radiological patterns. Fourteen (11.4%) patients who subsequently received a new diagnosis of MS had a history of COVID-19 vaccination within one month before symptoms onset. Patients’ characteristics, type of onset, clinical recovery, and radiological patterns did not differ from those of patients with non-vaccine-related new diagnoses of MS. The allele frequencies of HLA-DRB1*15 were 17.6% and 22.2% in patients with non-vaccine-related disease onset before and during the COVID-19 era, respectively, while no case of HLA-DRB1*15 was identified among patients with a new diagnosis of MS post-COVID-19 vaccine. In contrast, HLA-DRB1*08+ or HLA-DRB1*10+ MS patients were present only in this subgroup. Although a causal link between COVID-19 vaccination and relapsing–remitting MS cannot be detected, it is interesting to note and speculate about the peculiarities and heterogeneities underlying disease mechanisms of MS, where the interactions of genetics and the environment could be crucial also for the follow-up and the evaluation of therapeutic options. Full article

Pustular skin diseases, with pustular psoriasis (PP) being the prototype, are immune-mediated diseases characterized by the presence of multiple pustules, resulting from neutrophil accumulation in the layer of epidermis. Sterile skin pustular eruption, like PP, is also observed in 20–30% of patients with adult-onset immunodeficiency syndrome (AOID) and anti-interferon γ autoantibodies (IFN-γ), leading to challenges in classification and diagnosis. While the mechanism underlying this similar phenotype remains unknown, genetic factors in relation to the immune system are suspected of playing an important role. Here, the association between human leukocyte antigen (HLA) genes, which play essential roles in antigen presentation, contributing to immune response, and the presence of skin pustules in AOID and PP was revealed. HLA genotyping of 41 patients from multiple centers in Thailand who presented with multiple sterile skin pustules (17 AOID patients and 24 PP patients) was conducted using a next-generation-sequencing-based approach. In comparison to healthy controls, HLA-B*13:01 (OR = 3.825, 95%CI: 2.08–7.035), C*03:04 (OR = 3.665, 95%CI: 2.102–6.39), and DQB1*05:02 (OR = 2.134, 95%CI: 1.326–3.434) were significantly associated with the group of aforementioned conditions having sterile cutaneous pustules, suggesting a common genetic-related mechanism. We found that DPB1*05:01 (OR = 3.851, p = 0.008) and DRB1*15:02 (OR = 3.195, p = 0.033) have a significant association with pustular reaction in AOID patients, with PP patients used as a control. A variant in the DRB1 gene, rs17885482 (OR = 9.073, p = 0.005), was observed to be a risk factor for PP when using AOID patients who had pustular reactions as a control group. DPB1*05:01 and DRB1*15:02 alleles, as well as the rs17885482 variant in the DRB1 gene, were proposed as novel biomarkers to differentiate PP and AOID patients who first present with multiple sterile skin pustules without known documented underlying conditions. Full article

HLA class II molecules are key factors determining susceptibility to autoimmune disorders, and their role in immune-mediated skin conditions such as psoriasis has been extensively investigated. However, there is currently little understanding of their role in antibody-mediated skin diseases such as autoimmune blistering disorders. We researched the available literature using PubMed to narratively review the current knowledge on HLA associations in antibody-mediated blistering skin pathologies. Our results summarized the risk alleles that are identified in the literature, together with certain known protective alleles: in the pemphigus group, alleles HLA-DQB1*0503 and HLA-DRB1*0402 are most commonly associated with disease; in the pemphigoid group, the most studied allele is HLA-DQB1*0301; in epidermolysis bullosa acquisita, few genetic studies are available; in dermatitis herpetiformis, the association with haplotypes HLA-DQ2 and HLA-DQ8 is strongly established; finally, in linear IgA bullous disease, specific HLA alleles may be responsible for pediatric presentations. Our current pathogenic understanding of this group of disorders assigns a key role to predisposing HLA class II alleles that are able to bind disease autoantigens and therefore stimulate antigen-specific autoreactive T cells. The latter engage B lymphocytes that will produce pathogenic autoantibodies. The distribution of HLA alleles and their disease associations are variable across demographics, and an in-depth pathogenetic understanding is needed to support associations between HLA alleles and disease phenotypes. Additionally, in a personalized medicine approach, the identification of HLA alleles associated with the risk of disease may become clinically relevant in identifying susceptible subjects that should avoid exposure to known triggers, such as medication, when possible. Full article

Background: Pulmonary alveolar proteinosis (PAP) is a rare pulmonary disease characterized by abnormal accumulation of pulmonary surfactant lipids in alveoli or terminal bronchioles, leading to increased infection risk and progressive respiratory failure. Approximately more than 90% of all cases are autoimmune PAP (aPAP). Since one of the predisposing factors has been identified as genes located within the major-histocompatibility-complex region, an investigation of human leukocyte antigen (HLA) alleles associated with the risk of aPAP is warranted. Methods: We retrospectively studied 60 patients pathologically diagnosed with PAP from 2019 to 2022. Patients were divided into the aPAP group or secondary PAP (sPAP) group according to their clinical information. Qualified DNA was extracted from the paraffin-embedded tissue of 28 patients, and the PCR-sequence-based typing method was used for HLA-DRB1 genotyping. Results: A similar HLA-DRB1 allele profile (including the HLA-DRB1*08:03) between the aPAP group and sPAP group was revealed, except that HLA-DRB1*14:54, which has never been reported in aPAP patients, was only detected in the aPAP group rather than the sPAP group (19.4% vs. 0.0%, p = 0.030). Under inhaled granulocyte-macrophage colony-stimulating factor therapy, more clinical remission was observed in HLA-DRB1*14:54 carriers rather than in HLA-DRB1*08:03 carriers (80.0% vs. 57.1%). Conclusions: Our real-world study revealed for the first time that a population with HLA-DRB1*14:54 was subject to aPAP, and HLA-DRB1*14:54 might imply a response in aPAP patients to inhaled granulocyte-macrophage colony-stimulating factor in aPAP patients. Full article