## **Core Concept**
The question presents a case of nephritis with symptoms of haematuria and hemoptysis, along with the presence of antinuclear membrane antibodies. This combination of renal and pulmonary symptoms, along with specific autoantibodies, points towards a systemic autoimmune disease.

## **Why the Correct Answer is Right**
The correct answer, **Goodpasture's syndrome**, is a rare autoimmune disease characterized by the presence of anti-glomerular basement membrane (anti-GBM) antibodies. These antibodies specifically target the basement membrane of the glomeruli in the kidneys and the alveoli in the lungs, leading to nephritis (inflammation of the kidneys) and pulmonary hemorrhage, which manifests as hemoptysis (coughing up blood). The presence of antinuclear membrane antibodies, more accurately termed anti-GBM antibodies in this context, is a hallmark of Goodpasture's syndrome.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, other autoimmune diseases like **Systemic Lupus Erythematosus (SLE)** could be considered. However, SLE is associated with a broader range of autoantibodies, including ANA (antinuclear antibodies), and presents with a wider variety of symptoms beyond nephritis and hemoptysis.
- **Option B:** Similarly, not provided, but another potential differential could be **Wegener's granulomatosis (Granulomatosis with Polyangiitis, GPA)**, which involves anti-neutrophil cytoplasmic antibodies (ANCA) and can present with renal and respiratory symptoms. However, the specific antibody profile and clinical features differ from Goodpasture's syndrome.
- **Option C:** Not specified, but other conditions like **Renal vasculitis** could present similarly. However, the key distinguishing factor would be the specific antibody profile and the extent of organ involvement.
- **Option D:** This option as well is not detailed, but generally, conditions that cause nephritis and hemoptysis need to be distinguished based on their pathophysiology, clinical presentation, and specific diagnostic markers like autoantibodies.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that Goodpasture's syndrome is one of the few autoimmune diseases that presents with a very specific and targeted antibody response (anti-GBM antibodies), which is crucial for its diagnosis. The combination of renal and pulmonary involvement with these antibodies is almost pathognomonic for Goodpasture's syndrome.

## **Correct Answer:** . **Goodpasture's syndrome**