Navigating the diagnostic maze: A case presentation of C1q vasculitis mimicking hypocomplementemic urticarial vasculitis in a patient with systemic lupus erythematosus.

In rare instances, patients with SLE may exhibit atypical clinical manifestations, such as Hypocomplementemic Urticarial Vasculitis, which can pose diagnostic challenges. Here, we present a case report of a 28-year-old female with a history of SLE with lupus nephritis clase IV who developed HUV-like symptoms, ultimately leading to a diagnosis of C1q Vasculitis. This case underscores the importance of considering C1q Vasculitis in SLE patients presenting with HUV-like features and highlights Rituximab as a promising therapeutic option for managing this rare condition.

Features of 847 Childhood-Onset Systemic Lupus Erythematosus Patients in Three Age Groups at Diagnosis: A Brazilian Multicenter Study.

OBJECTIVE: To evaluate demographic data and clinical and laboratory features at disease diagnosis in 3 different age groups of childhood-onset systemic lupus erythematosus (SLE): group A, early-onset (<6 years); group B, school age (≥6 to <12 years); and group C, adolescent (≥12 to <18 years). METHODS: This was a Brazilian multicenter cohort retrospective study in 10 pediatric rheumatology centers, including 847 childhood-onset SLE patients. RESULTS: Patients were divided into 3 groups: group A with 39 patients (4%), group B with 395 patients (47%), and group C with 413 patients (49%). Of 39 childhood-onset SLE patients in group A, 3 (8%) were ages <2 years, 4 (10%) were ≥2 to <3 years, and 32 (82%) were ≥3 and <6 years. A total of 74 childhood-onset SLE patients were analyzed for C1q levels, and complete C1q deficiency was observed in 3 of 74 patients (4%), all in group A. Groups were similar regarding high frequencies of female sex, nephritis, neuropsychiatric involvement, Systemic Lupus Erythematosus Disease Activity Index 2000 score ≥8, autoantibody profile, elevated acute phase proteins, and low complement levels (P > 0.05). However, the frequency of fever (78% versus 61% versus 47%; P < 0.0001), hepatomegaly (42% versus 29% versus 14%; P < 0.0001), splenomegaly (28% versus 12% versus 4%; P < 0.0001), and discoid lupus (13% versus 4% versus 4%; P = 0.020) was significantly higher in group A compared to groups B and C. The frequency of weight loss >2 kg (19% versus 28% versus 36%; P = 0.017), photosensitivity (34% versus 41% versus 51%; P = 0.006), leukopenia <4,000/mm3 (14% versus 25% versus 30%; P = 0.048), and lymphopenia <1,500/mm3 (22% versus 41% versus 47%; P = 0.011) was significantly lower in group A. CONCLUSION: Our large multicenter study identified the finding that the initial appearance of childhood-onset SLE is characterized by comparable high frequency of internal organ involvement and some distinct clinical and laboratory features in early-onset and adolescent groups.

Complement and antibody primary immunodeficiency in juvenile systemic lupus erythematosus patients.

OBJECTIVE: To evaluate the frequency of primary immunodeficiencies (PID) in juvenile systemic lupus erythematosus (JSLE) patients. METHODS: Some 72 JSLE patients were analyzed for levels of immunoglobulin classes and IgG subclasses and early components of the classical complement pathway. Determination of C4 gene copy number (GCN) and detection of type I C2 deficiency (D) were also performed. RESULTS: PID was identified in 16 patients (22%): C2D in three, C4D in three, C1qD in two, IgG2D (<20 mg/dl) in four, IgAD (<7 mg/dl) in three, and IgMD (<35 mg/dl) in three; one of these patients presented IgA, C2 and C4D. Two patients had low C4 GCN and two had type I C2D. Demographic data, family history of autoimmune disease and PID, JSLE clinical findings, occurrence of infections, disease activity and therapies were similar in patients with and without PID (p > 0.05). Remarkably, the median of Systemic Lupus International Collaborating Clinics/ACR-damage index (SLICC/ACR-DI) was significantly higher in JSLE patients with PID compared with patients without these abnormalities (p = 0.0033), likewise the high frequency of SLICC/ACR-DI > 1 (p = 0.023). CONCLUSIONS: A high frequency of PID was observed in JSLE patients, suggesting that these defects may contribute to lupus development. Our findings indicate that these two groups of PID should be investigated in severe pediatric lupus.

The role of apoptosis proteins and complement components in the etiopathogenesis of systemic lupus erythematosus.

Systemic lupus erythematosus is a prototypical autoimmune disease characterized by the deregulation of T and B cells, tissue infiltration by mononuclear cells, tissue damage and the production of autoantibodies. There is a consensus that accelerated apoptosis of circulating lymphocytes and/or impaired clearance of apoptotic bodies may increase the amount of nuclear antigens presented to T lymphocytes. This process is accompanied by autoimmune responses that can lead to the development of lupus. The dysfunction of apoptosis may be a direct consequence of alterations in proteins/genes such as Fas, Bcl-2 and C1q. Increased expression of Fas antigen could intensify the exposure of hidden antigens. The overexpression of Bcl-2 protein might inhibit the removal of auto-reactive cells, and the lack of C1q could impair the clearance of self-antigens. The complete knowledge of the role of apoptosis components in the etiopathogenesis of lupus could lead to the development of new therapies targeting the apoptotic threshold, which could result in a more specific and effective disease response compared to global immunosuppression. This review summarizes the role of each component of the apoptotic process in the pathogenesis of lupus.

The role of apoptosis proteins and complement components in the etiopathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus is a prototypical autoimmune disease characterized by the deregulation of T and B cells, tissue infiltration by mononuclear cells, tissue damage and the production of autoantibodies. There is a consensus that accelerated apoptosis of circulating lymphocytes and/or impaired clearance of apoptotic bodies may increase the amount of nuclear antigens presented to T lymphocytes. This process is accompanied by autoimmune responses that can lead to the development of lupus. The dysfunction of apoptosis may be a direct consequence of alterations in proteins/genes such as Fas, Bcl-2 and C1q. Increased expression of Fas antigen could intensify the exposure of hidden antigens. The overexpression of Bcl-2 protein might inhibit the removal of auto-reactive cells, and the lack of C1q could impair the clearance of self-antigens. The complete knowledge of the role of apoptosis components in the etiopathogenesis of lupus could lead to the development of new therapies targeting the apoptotic threshold, which could result in a more specific and effective disease response compared to global immunosuppression. This review summarizes the role of each component of the apoptotic process in the pathogenesis of lupus.

Alteraciones del sistema complemento en pacientes con nefropatía diabética / Alterations of the complement system in patients with diabetic nephropathy

Se determinó la actividad del sistema complemento en 26 pacientes adultos que se hallaban en la fase terminal de la nefropatía diabética. En estos pacientes se observó una disminución significativa (p<0,001) de la actividad hemolítica de la vía clásica, de los niveles séricos del subcomponente Clq y de los niveles séricos del componente C4. Por el contrario, la actividad hemolítica de la vía alternativa, la actividad hemolítica del factor B y los niveles séricos del componente C3, se mantuvieron dentro del rango normal. Estos resultados sugieren que la disminución prolongada de alguno de los componentes iniciales de la vía clásica del complemento, puede constituir un factor que predispone a estos pacientes para los procesos autoinmunes, o que puede contribuir al mantenimiento del estado de autoinmunidad(AU)

Edema crónico centrofacial con consumo del componente C1q del complemento / Centrofacial chronic edema with consumption of the component C1q of the complement

Se estudia un paciente de sexo masculino de 29 años, que padecía en el momento de la consulta edema de labios y párpados de un año y medio de evolución. Al confeccionar la historia clínica se determinó que los edemas se presentaban con reagudización, acompañados con úlceras de la mucosa yugal y fiebre de 40§C coincidente con las crisis. El edema de los párpados remitía casi en su totalidad con cada tratamiento esteroide, aunque no así el de labios. Los estudios de laboratorio mostraron anormalidades en la fracción C1q del complemento (0.3 mg ciento por ciento). El estudio histopatológico de un corte de labio halló infiltración mononuclear en el estroma, con disposición angiocéntrica. El infiltrado tenía células linfoides atípicas, que fueron positivas a la inmunomarcación con el anticuerpo monoclonal UCHL-1. Se diagnosticó linfoma T de presentación cutánea centrofacial. El caso se presenta por la interesante coexistencia en un individuo de un desorden linfoproliferativo con edema de labios inflamatorio crónico y edema de párpado recurrente por deficiencia adquirida del C1INH

Edema crónico centrofacial con consumo del componente C1q del complemento / Centrofacial chronic edema with consumption of the component C1q of the complement

Se estudia un paciente de sexo masculino de 29 años, que padecía en el momento de la consulta edema de labios y párpados de un año y medio de evolución. Al confeccionar la historia clínica se determinó que los edemas se presentaban con reagudización, acompañados con úlceras de la mucosa yugal y fiebre de 40ºC coincidente con las crisis. El edema de los párpados remitía casi en su totalidad con cada tratamiento esteroide, aunque no así el de labios. Los estudios de laboratorio mostraron anormalidades en la fracción C1q del complemento (0.3 mg ciento por ciento). El estudio histopatológico de un corte de labio halló infiltración mononuclear en el estroma, con disposición angiocéntrica. El infiltrado tenía células linfoides atípicas, que fueron positivas a la inmunomarcación con el anticuerpo monoclonal UCHL-1. Se diagnosticó linfoma T de presentación cutánea centrofacial. El caso se presenta por la interesante coexistencia en un individuo de un desorden linfoproliferativo con edema de labios inflamatorio crónico y edema de párpado recurrente por deficiencia adquirida del C1INH